Changing bitrate & resolution (Mode 0)

[sanderton]

I know you can change the bitrate and resolution used by the MPEG chip on US stanadalone Series 1s.

Has anyone tried this with a UK machine?

The resolution settings for US machines are well understood, but do we know what the numbers are for ours?

[Sneals2000]

Originally posted by sanderton
I know you can change the bitrate and resolution used by the MPEG chip on US stanadalone Series 1s.

Has anyone tried this with a UK machine?

The resolution settings for US machines are well understood, but do we know what the numbers are for ours?

I was interested in this as well - as I find the horizontal subsampling the most annoying thing about Tivo (especially the chroma) However ISTR that whilst people have had a good level of success modifying US Tivos to run at 720 samples horizontally, when this was tried on UK models there were problems with positioning and green bands appearing to one side of the picture?

I think that people HAVE managed to improve the picture quality at the standard resolutions by increasing the bit rate though.

[mrtickle]

I did a lot of experimenting with this last week as it happens! Knowing that I was going to replace the drive I had nothing to lose!

Assuming you have tivoweb of course and know how to use the resource editor (press return to submit each and every change you make; select the "update resources" link after doing them all). I measured these resolutions (*):

0 = 720x576
4 = 544x576 "best"
2 = 480x576 "high"
1 = 352x576 "basic"/"medium"

Selecting resolution "0" (I modified my "high" setting as I don't use it much) did have the problems you mentioned. Basically the picture is offset to the left quite a bit and up a little bit. But the increase in resolution was certainly noticeable.

The other main thing I noticed was that we don't have VBR. Even with "save disc space" turned on, tivo still doesn't use VBR mode. I'm suspicious that this is because both the "DBSBestVBRBitrate" and "DBSBestMAXBitrate" are set to the exact same value (for example Best quality with Sky digital lineup). When you start a recording the tvlog says "using CBR, bitRate=5960000, maxBitrate=5960000" nomatter whether you have Save Disc Space on or off. If you then set the VBRBitrate to a different (lower) value, tivo reports that it is using VBR mode in the logs.

I also changed the live buffer to Medium :)

There is also this thread:
http://www.tivocommunity.com/tivo-vb/showthread.php?s=&threadid=108462&highlight=bitrate

I set my "Basic" to 800000 and 850000 values (NB: this made it use VBR mode, even in Basic!). It looked fantasically awful - like old AVI files where the colour disappears and you get blotches of grey. It also made the tivo say I had 314 hours of Basic quality on my 138GB drive.

HTH

[sanderton]

Interesting; I will have a play.

If VBR is not set up right (It's the AltBitrate settings for VBR mode isn't it?) then are those who report lower quality suffering from a placebo affect?

(Personally I've never been able to tell the difference so I feel vindicated!)

I only use Basic for Radio, so will se how low you can go!

[mrtickle]

Originally posted by sanderton
Interesting; I will have a play.

If VBR is not set up right (It's the AltBitrate settings for VBR mode isn't it?) then are those who report lower quality suffering from a placebo affect?


To answer the question - dunno :)

But I don't think that the AltBitrate page controls VBR. You'll see two values for each quality setting - I think the one with "VBR" in it controls VBR.

My suspicion is that the Alt page is for the 2nd tuner on DirecTivos. Annoyingly, all guides seem to say "change them all just in case" without any more discussion :(

On my machine I didn't touch the Alt page - and I only edited the DBS values on the main Bitrates page. This was after trial and error of setting all 6 possibilites (DBS, CAT, Roof in Bit and Alt) to slightly different values and seeing which values made it into the logfile!)


(Personally I've never been able to tell the difference so I feel vindicated!)


Indeed. I set Best from 5960000, 5960000 to 5660000, 5960000. This made it start to use VBR. An hour of Best went from 2580MB down to 1800MB (reported sizes from tivoweb) and I couldn't really tell unless I looked very hard that it was different.


I only use Basic for Radio, so will se how low you can go!

Yes that was the idea of the chap on the other thread :). I noticed that even on the Sky digibox radio screens, where the only thing that changes is the time - once a minute - it takes a very long time to settle down to a clear image!

[sanderton]

OK, I've done a bit of fiddling!

Here are some stills of the results (http://www.beaconhill.demon.co.uk/restest.htm) .

They are quite large, I'm afraid; the page is ~2Mb.

Here are the Sky red dots in the two resolutions:

http://www.beaconhill.demon.co.uk/reddotbest.bmp http://www.beaconhill.demon.co.uk/reddotmedium.bmp

To do this I reset Medium resolution to be resolution = 0 and upped its bitrarte to 7000000.

Although the screengrabs show a green area on the right, it does not appear on my TV. I see a perfectly normal looking picture. It seems from comparing the captions that there is a slight left shift - but it's not noticeable unless you are looking for it.

You can also see from the artifacting on the caption that the bitrate increase has had a noticeable effect.

The "real" resolutions of the two (ie, the picture area, not black or green bars) are 533 x 568 in Best and 677 x 568 in my edited Medium, so the resolution increase is real!

I may have to lash out on another 120Gb drive to allow me to up the bitrate and res!

[mrtickle]

Cool, glad you got it working! I can only just see the green bar on my TV too - although I do have the overscan reduced to minimum.

[Brownedger]

Are you saying that VBR doesn't actually work on the normal Tivo's or just the upgraded Turbonet Tivo's?

[sanderton]

All TiVos.

[Brownedger]

Ok is it working in the latest American release ver.3.0?

[sanderton]

I assume so. To be honest it looks like a mistake by the people rolling out the UK version - the configuartion file variables just look like they are set wrong, with the max and min bitrate set to be the same!

I'm going to try boosting Best by leaving the minimum at the current CBR level but giving it the option of adding maybe 1Mbps at peaks to see if that helps it with fast moving sports.

[NickDvl]

For us lesser mortals, how many hours of recording time can you get out of those higher bitrate/resolution settings on a 120GB drive? Are there any other side-effects besides the green strip on the right? Do the settings survive a reboot?

I've always found the horizontal resolution somewhat lacking on widescreen broadcasts, would be great if it could be improved... :)

[LJ]

Is there a list of the resolution modes somewhere? Is there a mode 3? ;) I tried a search of the forums and read the Philips datasheet but couldn't find anything.

Mode 0 does look much better, but on my TV the 'wide screen' mode chops a bit too much off the left hand side for it to be useable. :(

NickDvl: Yes, the settings survive reboots - you have to reboot after you've changed the settings to make them take effect.

What's the lowest bitrate anyone's managed to get working? Down at around 600000 I get a "kb per second too small" message in tverr (and other errors in the kernel log) and the rate appears to default to some higher value.

[mrtickle]

Note that changing the resolution doesn't alter the recording capacity, only changing the bitrate does. When I changed my high from res 2 to 0 the reported capacity was the same, because the bitrate was the same. The result is that the same amount of movement will produce more artefacts than before unless you increase the bitrate as well.

According to the other thread I found tivo defaults to Best quality if the bitrate is too small. When it happened to me it basically lied in the tvlog (said it was using the bitrate I had set, but didn't). I didn't think of checking the other logs!
650000 was too low when I tried. 675000 worked.

[Dapper Dan]

Originally posted by sanderton
I assume so. To be honest it looks like a mistake by the people rolling out the UK version - the configuartion file variables just look like they are set wrong, with the max and min bitrate set to be the same!

I'm going to try boosting Best by leaving the minimum at the current CBR level but giving it the option of adding maybe 1Mbps at peaks to see if that helps it with fast moving sports.

Have you tried this yet ? I'd be interested to know how you got on.

As an aside, I was reluctant to up my bitrate in case I caused the mpeg chip to overheat, though for all I know it may be operating well within it's design limits. Can anyone comment ?

[rharnwel]

Originally posted by Dapper Dan
Have you tried this yet ? I'd be interested to know how you got on.

As an aside, I was reluctant to up my bitrate in case I caused the mpeg chip to overheat, though for all I know it may be operating well within it's design limits. Can anyone comment ?

Surely the higher the bitrate, the less demand on the MPEG chip....?

[sanderton]

I'd be surprised if you could damage the chip from a software setting.

[Dapper Dan]

I was thinking of it as a form of overclocking. I'm sure that someone will correct me if I'm wrong, but if you make a chip work harder it runs hotter, this in turn increases the rate of electron migration which eventually causes the chip to fail.

[iankb]

But, as rharnwel says, the higher the bitrate, the lower the amount of work required to compress it.

Ian.

[sanderton]

The chip is good for up to 15Mbs so, I doubt I'll stress it at 7. The HD is another matter!

http://products.sel.sony.com/semi/PDF/CXD1922Q.pdf

[Dapper Dan]

Originally posted by iankb
But, as rharnwel says, the higher the bitrate, the lower the amount of work required to compress it.

Ian.

I'm sure that you're both right, it justs seems so counter-intuitive that you should be getting higher quality for less effort, surely you have to pay somewhere along the line ?

[Dibblah]

Originally posted by Dapper Dan
I'm sure that you're both right, it justs seems so counter-intuitive that you should be getting higher quality for less effort, surely you have to pay somewhere along the line ?

Disk space.

Cheers,

Allan.

[sp99]

Originally posted by mrtickle
I did a lot of experimenting with this last week as it happens! Knowing that I was going to replace the drive I had nothing to lose!

Assuming you have tivoweb of course and know how to use the resource editor (press return to submit each and every change you make; select the "update resources" link after doing them all). I measured these resolutions (*):

0 = 720x576
4 = 544x576 "best"
2 = 480x576 "high"
1 = 352x576 "basic"/"medium"

Selecting resolution "0" (I modified my "high" setting as I don't use it much) did have the problems you mentioned. Basically the picture is offset to the left quite a bit and up a little bit. But the increase in resolution was certainly noticeable.
HTH

Broadcast spec for a composite signal at 720 x 576 only has 702 visible (active ? ) lines with the rest being used for VBI, windscreen switching etc..
- I can't remember for component signals but maybe Tivo have used this as their guide.

It could be worth a try .

p.s. have lurked for a year, so thanks to everyone for your informative posts.

[sanderton]

The resolutions are all either DVD or DVB standard resolutions or bastardised versions of them (horizontal form one and vertical from another), so presumably are influences by the encoder/decoder chips options.

In the USA TiVos tend to be 480 x 480 I think.

[mrtickle]

The USA series 1 tivos have exactly the same horizontal res as the figures above, but with "480" everywhere I put "576".

As far as DVD goes, I believe both 720x576 and 702x576 are valid. I hear what you say about VBI but in the case of the UK tivo the shift up/left is way off. Presumably all the other settings to define the screen were left at the US default timing values, which is fair enough as this resolution isn't available to the user normally so would never be used.

HTH

[LJ]

Originally posted by mrtickle
Presumably all the other settings to define the screen were left at the US default timing values, which is fair enough as this resolution isn't available to the user normally so would never be used.

Wonder if we can change them... Resolution 0 looks better than res 4 (unsurprisingly!).

[xxxx]

An interesting topic.
Could those who have experimented give a full list of settings that they think look best for RGB widescreen on a UK Tivo? Disk space no object. With and without VBR would be nice.

On the odd occasions when I have experimented with this (in order to get recordings that are directly compatible with DVD resolution) I have become bogged down with settings that only work on US Tivos. In the end I gave up.

Banned uses aside, I would really like to improve on the UK Tivo "best" setting for day to day recodings as I can clearly see the quality drop from live and have plenty of disk space. I suspect that I am not alone.

[Dibblah]

Unfortunately, one thing that MPEG doesn't handle too well are sudden transitions. With the green bar running down the side of the screen, you have a constant "drain" on available bitrate.

Unless we can tune the parameters of the SA7118E, the 0 resolution is mostly useless.

Oh. And yes, it's easy to tune it - However, on every channel change it gets reset. I was looking a while back for a 'portable' way to effectively copy PALMod (Tridge's), but got lost too quickly.

Cheers,

Allan.

[sanderton]

I don't think the green bar has any effect on anything. It seems to just appears on screen grabs and in PC video editing software which is aware what the pixel size of the image is! Certainly it does not appear on my TV. The sharpness of the transition from black to green in the still suggests to me that it's not a part of the MPEG encoded signal, just an artifact of the display software.

The main problem with Resolution 0 is that a part of the far left of the screen is not encoded at all. This appears to be a pretty small part, if you look at the pics I posted above, but you will always have that trade off.

The MPEG chip is capable of far higher bitrates than TiVo uses, but with a recording stream and a playback stream happening simultaneously you get very close to the limits of the IDE/HD infrastructure.

[LJ]

Originally posted by Dibblah
And yes, it's easy to tune it

Yeay!

However, on every channel change it gets reset.

Ah :p

I was looking a while back for a 'portable' way to effectively copy PALMod (Tridge's), but got lost too quickly.

Have you got a link to Tridge's site handy? How do you mean portable?

[Dapper Dan]

Originally posted by LJ
Originally posted by Dibblah
And yes, it's easy to tune it

Yeay!

However, on every channel change it gets reset.

Ah :p

I was looking a while back for a 'portable' way to effectively copy PALMod (Tridge's), but got lost too quickly.

Have you got a link to Tridge's site handy? How do you mean portable?


I think that this is what you want:

http://pserver.samba.org/cgi-bin/cvsweb/tivo/palkit/?hideattic=0&only_with_tag=MAIN#dirlist

[LJ]

Thanks. Will have a look later...

[xxxx]

Originally posted by xxxx
I suspect that I am not alone.

Looks like I was wrong. :(

[LJ]

Nono... I'd like to do the same. Mode 0 recordings, but without bits chopped off! 'Later' hasn't arrived yet for me :D

[Dibblah]

Originally posted by xxxx
Originally posted by xxxx
I suspect that I am not alone.

Looks like I was wrong. :(

You aren't alone... However, I've only just got my spare Tivo working again.

You remember I said a while ago that I'd bust it by telling it it had 4Mb of RAM? Well, I fixed it.

Thanks to Mr Stanley (For the really sharp blades), I now have 2 UK SAs with socketed PROMs.

Final solution was to flash the PROM on the now completely doorstopped Tivo on the working one. And it was... Very hair-raising at some points.

I started with 2 working Tivos. I managed to break one. Half way through socketing the previously OK one up, I seemed to have busted it. Imagine the scene: Unwatched Corrie, Sex and the City, etc. I almost started looking for plane tickets.

Anyway. I intend doing some hacking about with this issue when I have a large enough HD available (the spare Tivo's HD went into the server).

Cheers,

Allan.

[mrtickle]

Excellent news! Let us know if you need testers when the time comes :)

LJ's red dot script already checks for recordings starting and ending, perhaps some of this code could be useful for something which resets the paramters every time tivo changes channel?

My wishlist would be the paramters for mode 0, the vertical shift in all modes, and the black crushing/white clipping.


Originally posted by sanderton
I don't think the green bar has any effect on anything. It seems to just appears on screen grabs and in PC video editing software which is aware what the pixel size of the image is! Certainly it does not appear on my TV. The sharpness of the transition from black to green in the still suggests to me that it's not a part of the MPEG encoded signal, just an artifact of the display software.


I'd cautiously disagree there. I think that what is happening is that the tivo is "looking" at the wrong portion of the input signal at the time it creates the recording. It is encoding a space of picture which is offset. The parts where there was physically no signal end up as "green" in the mpeg data. So this is why it is clearly visible on a PC capture card - it's in the recording.

[sanderton]

Originally posted by mrtickle


My wishlist would be the paramters for mode 0, the vertical shift in all modes, and the black crushing/white clipping.



I'd second that. esp. the crushing/clipping thing which for me renders the RGB unusable.

Originally posted by mrtickle


I'd cautiously disagree there. I think that what is happening is that the tivo is "looking" at the wrong portion of the input signal at the time it creates the recording. It is encoding a space of picture which is offset. The parts where there was physically no signal end up as "green" in the mpeg data. So this is why it is clearly visible on a PC capture card - it's in the recording.

Ok, but I think we can agree that it has not recorded an actual green colour, just a "no signal" byte which is being represented on PC as green (but is ignored by my TV).

[LJ]

Found a useful page showing chip details here (http://www.9thtee.com/insidedirectv-tivo.htm). Not all the chips match what's in my TiVo, but there're some links that might come in useful...

Originally posted by Dibblah
Unless we can tune the parameters of the SA7118E, the 0 resolution is mostly useless.

I'm confused :p Why do we need to change the parameters of the SAA7118E? The 7118's a decoder (http://www.semiconductors.philips.com/pip/SAA7118E_V1.html). Or am I missing something? Do we need to change encoder and decoder parameters?

The MPEG encoder looks like chip 23 (Sony CXD1922Q). (Some datasheets here (http://products.sel.sony.com/semi/search.html))

Oh. And yes, it's easy to tune it - However, on every channel change it gets reset. I was looking a while back for a 'portable' way to effectively copy PALMod (Tridge's), but got lost too quickly.

I'm confused again ;) What does setting the "Resolution" in the Resource Editor actually do?

Time to search for more Sony datasheets...

[Dibblah]

Originally posted by LJ
Found a useful page showing chip details here (http://www.9thtee.com/insidedirectv-tivo.htm). Not all the chips match what's in my TiVo, but there're some links that might come in useful...

Originally posted by Dibblah
Unless we can tune the parameters of the SA7118E, the 0 resolution is mostly useless.

I'm confused :p Why do we need to change the parameters of the SAA7118E? The 7118's a decoder (http://www.semiconductors.philips.com/pip/SAA7118E_V1.html). Or am I missing something? Do we need to change encoder and decoder parameters?

The MPEG encoder looks like chip 23 (Sony CXD1922Q). (Some datasheets here (http://products.sel.sony.com/semi/search.html))

Oh. And yes, it's easy to tune it - However, on every channel change it gets reset. I was looking a while back for a 'portable' way to effectively copy PALMod (Tridge's), but got lost too quickly.

I'm confused again ;) What does setting the "Resolution" in the Resource Editor actually do?

Time to search for more Sony datasheets...

Quote from the link for the datasheet in your post:

The SAA7118E is a video capture device for applications at the image port of VGA controllers.

It's the frontend to the CXD1922Q. It handles the messy bits of A/D, etc.

Cheers,

Allan.

[Dibblah]

After having had a bit of a look around the Tivo, the resolution / settings tables appear to be hardcoded in fpga7114.o. So all we need is a binary patch.

Looking at it now, however, this WILL be different for everyone's setup.

Cheers,

Allan.

[sanderton]

"Everyone" as in UK/US, or er, everyone!

[Dibblah]

Everyone as in everyone with different preferences, TVs, eyes, etc.

Cheers,

Allan.

[Modan]

Well keep us posted on how you are getting on. I take it you mean that everyon will want different settings rather than everyone will start with a different source file?

Well I look forward to your findings. I might even be persuaded to right an editor for this once you have it figured out. Too much time on my hands right now

[Dapper Dan]

Originally posted by Dibblah
After having had a bit of a look around the Tivo, the resolution / settings tables appear to be hardcoded in fpga7114.o. So all we need is a binary patch.

Cheers,

Allan.

... or you could do what tridge did and install a bypass function on calls inside binary kernel modules. Here's a link:

http://tivo.samba.org/download/tridge/

which also points at a very detailed pdf document describing the SAA7114 chip. It appears (page 131-132) that you need to poke about in I2C bus addresses 80 to BF.

[Dibblah]

Originally posted by Dibblah
Unfortunately, one thing that MPEG doesn't handle too well are sudden transitions. With the green bar running down the side of the screen, you have a constant "drain" on available bitrate.

Unless we can tune the parameters of the SA7118E, the 0 resolution is mostly useless.

Oh. And yes, it's easy to tune it - However, on every channel change it gets reset. I was looking a while back for a 'portable' way to effectively copy PALMod (Tridge's), but got lost too quickly.

Cheers,

Allan.

Really? Like I said here? ;)

[Dibblah]

Originally posted by Dapper Dan
... or you could do what tridge did and install a bypass function on calls inside binary kernel modules. Here's a link:

http://tivo.samba.org/download/tridge/

which also points at a very detailed pdf document describing the SAA7114 chip. It appears (page 131-132) that you need to poke about in I2C bus addresses 80 to BF.

Yes, I could do. There are differences on the UK Tivo -
It's a 7118.
It's a different i2c address.

And this means you go through an extra indirection for _every_ i2c call on the Tivo. Which is quite a few. I'd rather just patch the table referenced by SAA7112CaptureSize directly.

Cheers,

Allan.

[Dapper Dan]

Originally posted by Dibblah


...... I'd rather just patch the table referenced by SAA7112CaptureSize directly.

Cheers,

Allan.

Ok, I look forward to seeing whatever you come up with :D

[kwangomango]

Originally posted by sanderton
I'd second that. esp. the crushing/clipping thing which for me renders the RGB unusable.


Have you tried setting Tivo to output RGB but accept PAL as input. Obviously your digibox needs to be set to output PAL also. I have only tried this on my portable at the mo, but whites seem less intense and blacks more detailed.

[mrtickle]

Originally posted by sanderton

Ok, but I think we can agree that it has not recorded an actual green colour, just a "no signal" byte which is being represented on PC as green (but is ignored by my TV).

On my TV (with a lot less overscan I suspect) I could actually see the green. I no longer have a res-0 recording to recheck it though. Also I vaguely remember reading that people with the early (pre-1.5.2) software reported "flashing green at the top of the picture" - and I've alway been suspicious that the fix to that was more of a "bodge" (move the whole screen up and hide the problem).

Originally posted by LJ

I'm confused again ;) What does setting the "Resolution" in the Resource Editor actually do?

Time to search for more Sony datasheets... [/B]

You are awfully confused aren't you :) It sets one of four resolutions:

0 = 720x576
4 = 544x576 "best"
2 = 480x576 "high"
1 = 352x576 "basic"/"medium"

...in the same way that setting the bitrate value affect the bitrates used in a recording.

Originally posted by kwangomango
Have you tried setting Tivo to output RGB but accept PAL as input. Obviously your digibox needs to be set to output PAL also. I have only tried this on my portable at the mo, but whites seem less intense and blacks more detailed.

Hmm, that could be worth a try...

[bobnick]

Is resolution 0 the same as the 'extreme' quality setting that's available in version 5 of the tivo software?

- Oh, I've just seen your other post in another thread where you say it is!

I'm feeling all left behind in this Tivo Revolution, what with being stuck with version 2.5.5 - the americans only need another 0.1's worth of improvements, and the can go and laud over us that their Tivo's are twice as advanced as ours :D

[sanderton]

Originally posted by mrtickle
On my TV (with a lot less overscan I suspect) I could actually see the green.

I guess it's down the the TV then - I don't think its' overscan related, as if you look at the screengrab of the res-0 video, you'll see there is a vast area of green to the right. There's no way I have that much overscan (in fact I've minimised it through the service menus).

I have seen similar - in fact larger - green zones on Medium res TiVo video too.

[ccwf]

Originally posted by sanderton
If VBR is not set up right (It's the AltBitrate settings for VBR mode isn't it?) then are those who report lower quality suffering from a placebo affect?

(Personally I've never been able to tell the difference so I feel vindicated!) It should be easy to tell whether or not untweaked UK TiVos have functioning VBR. For example, look in the log files to see how many minutes each full-length allocated block lasts on average. Then toggle the VBR/CBR setting, record or watch the live buffer for an hour, and see how long the blocks last now. With high-quality slow-moving video input, the difference should be quite noticeable if VBR is working. An audio channel might be a good test.

Also, the “min bitrate” isn't a minimum, I'm almost certain.

[LJ]

Had some time to have a look around... Dibblah how do these sound:

Offset a7f4 for the generic 7118 settings, which are in byte pairs - first byte is the sub address, second the value to load.

Offset a934 for the mode zero specific settings (I'm guessing there are three).

Now to try patching a version... ;)

[LJ]

Err, mebbe it's not a934... lots of green vertical bars everywhere :eek:

a880 seems to work though ;)

...and it helps if you remember to flag rc.sysinit as executable :o :D

[LJ]

Mods have been running fine on my TiVo for a couple of days now - any one else want to try them? Knocked up a page here (http://www.ljay.org.uk/tivoweb/tivo_fpga.html).

[Dapper Dan]

Originally posted by LJ
Mods have been running fine on my TiVo for a couple of days now - any one else want to try them? Knocked up a page here (http://www.ljay.org.uk/tivoweb/tivo_fpga.html).

I'll try this tonight. What have you changed ?

[Dibblah]

Getting a 403 - Forbidden on the actual module download.

Cheers,

Allan.

[sanderton]

Great stuff.

This looks like a typo in the instructions:

cp fpga7114.0 fpga7114.o.original

[xxxx]

I'd like to try this but as a complete Linux novice can I be sure that the command prompt instructions given will work with my twin drive Tivo with Turbonet, anti-teletext-bug OS (which I understand is on a different partition to normal), etc. etc.?
Having got it all working perfectly I don't want to muck it up!

[technograndad]

Originally posted by LJ
Mods have been running fine on my TiVo for a couple of days now - any one else want to try them? Knocked up a page here (http://www.ljay.org.uk/tivoweb/tivo_fpga.html).

I'm getting a 'forbidden' from that link too.

What exactly does this do? Remove the green verical bar when in mode 0? - or is that just wishful thinking on my part :)

(fingers crossed!)

[LJ]

Fixed the typo, fixed the Error 403.

What this does is modify what I believe are the default settings for the SAA7118E for all modes:

Device Sub Default New Purpose
0x42 0x2A 0xB1 0x90 Luminance brightness - Set lower
0x42 0x2B 0x60 0x4A Luminance contrast - Set lower
0x42 0x2C 0x5D 0x49 Chrominance saturation - Set lower

And what I think are the settings for mode 0:

Device Sub Default New Purpose
0x42 0x06 0xCB 0xC3 Horizontal sync start - move left

I guess the values need a bit more tweaking - the colour is still a bit rich (to my eyes anyway ;) )

[Dibblah]

Hmmm... Only just noticed this. It seems to break RF input.

Looking to see why now.

<edit>
Dunno what was happening, but I can't reproduce it. Now. Everyone install this. :)
</edit>

Cheers,

Allan.

[technograndad]

Yay! It certainly fixed the mode 0 vertical green bar. There's still an upwards shift but I think that might be in all resolutions., and it's not too severe.

I used BBC3's closedown screen, covering some text with a sheet of paper and swithing between live and aux you'll see the text shift upwards by what I guess would be about 20 pixels.

I dont use the RF input so I'm ok with this fix so far. Love it!!

[xxxx]

In spite of not being sure about compatibility with my set up I couldn't resist this so I tried it.
It seems to work fine though I've dropped from 53hrs to 39hrs (I'll have to buy a second 120Gb drive to replace the orgininal Maxtor).
Noticeable increase in picture quality (why isn't this option on as standard on the Tivo? - lack of disk space?) and, above all, my blue shift problem has completely disappeared, and that's just plain brilliant! Woo-hoo!

[sanderton]

Lack of disk space - remember back in 2000 when this was being set up a 40Gb disk was BIG!

[xxxx]

Yes. The standard 40Gb drive was considered large but only gave 12hrs at "best". Use resolution 0 and that drops to about 9. Interesting that the possibility was built in though.

I just looked online and I can get a 120Gb WD with 3 year warranty delivered to me tomorrow for £80 ........ I'm tempted.

[cyril]

Since a 600gb TiVo is now possible, that would give 135 hours resolution zero, maybe 100 hours if we maxed out the bitrate too.

[Dapper Dan]

Originally posted by xxxx
... It seems to work fine though I've dropped from 53hrs to 39hrs

I have a feeling that this might be misleading. I think it's a worse case scenario, i.e assume that everything gets recorded at the VBR (which I presume you've increased).

[xxxx]

I increased the DBSBEST max br setting to 8000000 but didn't yet adjust the DBSBEST var br setting. I have disk saving set to "on" but IIRC there was talk the other day that this didn't have any effect on UK Tivos that weren't using "0" resolution. Though of course I'm now using "0" resolution. I have yet to do a test to see if this "0" resolution and 8000000 bitrate setting corresponds to a valid DVD format or not. I hope that it will. Otherwise I shall set the bitrate to something that is DVD compliant.

In the meantime should I change the DBSBEST var br setting to 8000000 also and is VBR really active on resolution 0, or should I just switch disk saving off?

I'm not unduly bothered by the reduction in available recording time as I can always change my drive 2 to 120Gb, thus getting a total of 80hrs.

[sanderton]

The VBR is inactive in UK TiVos because the Max and Min bitrate values are the same. If you've increased the Max and left the Min unchanged, then VBR is now active for you.

[xxxx]

The min setting seems only to be in the AltBitrate table which I haven't touched as I don't know what it's for.

All my changes were made in the Bitrate table and I now have :

Resolution = 0
DBSBESTMAXBR = 8 000 000 (from 5 960 000)
DBSBESTVARBR = 8 000 000 (from 5 960 000)

The AltBitrate table settings are still at the default.

[sanderton]

Then you are on CBR at 8 Mbps.

[technograndad]

I've read on another forum that the bitrate includes a fixed 160000bps, allegedly for audio.

So where previously best was 5960000 it was really 5.8Mbps video.

It's a small point but if someone was aiming *specifically* for 8000000 bitrate it would need to be specified as 8160000.

Has anyone calculated a 'good' figure for mode 0? Are there any mathematically 'sweet' numbers?

John

[sanderton]

To get the same bits per pixel per second as Best, Res0 would have to be 7,676,467, so 8,000,000 looks fair enough.

[Dapper Dan]

I've just tried the fpga mod and it works.

Unfortunately, in my setup the picture quality is worse using mode 0 (extreme ?) compared with mode 4 (best), given the same bitrates (5960000 VBR and 7000000 MAX), it looks fuzzier. I thought this might be due to the bitrates, so I upped them to 7888235 VBR and 9264706 MAX (factor of 720/544). This gave me a very bad picture, lots of pixellation and green 'splodges'. Perhaps if the chip is good for 1.5Mbs (is that input and output?) then we shouldn't be going for more than half of this, so 7500000 would be a practical MAX.

[Dapper Dan]

Set res 0 to 7500000 7500000 and found that Tivo would no longer reboot properly, just sat there after the usual messages with a black screen, no visible response from the remote. Pulling the power lead didn't help either. Don't really know why this happened because I changed the settings for medium and this is never used unless I explicitly tell it to. Fortunately I was still able to telnet in so I put the old fpga7114.o back and all is well again, phew!

[mrtickle]

Excellent stuff :D. Just to clarify, as I'm getting a big bogged down in all the different chips:

Philips SAA7118E video decoder/scaler
- is this the one we altered at the weekend, to alter the colour output? (device 8C - all this stuff:
iicset 0x8Ch 0x39h 20 (colour)
iicset 0x8Ch 0x38h 21 (luminance))

Sony CXD1922Q video encoder

IBM MPEGCS22 video decoder/OSD generator:

Philips SAA7128H video encoder
- this is the one LJ's patch affects? device 0x42

a block diagram of the tivo would be nice if anyone's got time :)

My understanding is that LJ's change fixes the mode 0 and expands the range of signals at recording time. So the tweaks to the output are still worth doing?

[xxxx]

I'm not clear about this.

sanderton wrote:
>If you've increased the Max and left the Min unchanged, then VBR is now active for you.

I wrote:
>The min setting seems only to be in the AltBitrate table which I haven't touched as I don't know what it's for.
Resolution = 0
DBSBESTMAXBR = 8 000 000 (from 5 960 000)
DBSBESTVARBR = 8 000 000 (from 5 960 000)

sanderton wrote:
>Then you are on CBR at 8 Mbps.

Now it seems to me that my min setting (in AltBitrate) is unchanged and the max setting (in Bitrate) is increased therefore I should be on VBR. Or am I still missing something?

[xxxx]

Originally posted by Dapper Dan
Unfortunately, in my setup the picture quality is worse using mode 0 (extreme ?) compared with mode 4 (best), given the same bitrates (5960000 VBR and 7000000 MAX), it looks fuzzier. I thought this might be due to the bitrates, so I upped them to 7888235 VBR and 9264706 MAX (factor of 720/544). This gave me a very bad picture, lots of pixellation and green 'splodges'. Perhaps if the chip is good for 1.5Mbs (is that input and output?) then we shouldn't be going for more than half of this, so 7500000 would be a practical MAX.

I also notice a slight problem with the 8 000 000 br setting. I seem to get occasional white flashes near the bottom right of the screen, as though the Tivo can't keep up with the picture. It's not the end of the world and I can't say I notice anything else wrong with the picture at that setting but the general improvement in picture quality without my blue shift problem is so great that it's hard to notice anything else.

I was about to try some other settings (7 500 000 or 7 000 000) for the max br until I read the other post about the Tivo not booting and that put me off! I may just put it back to 5 960 000 and see what happens for a while.

[sanderton]

Originally posted by xxxx
I'm not clear about this.

sanderton wrote:
>If you've increased the Max and left the Min unchanged, then VBR is now active for you.

I wrote:
>The min setting seems only to be in the AltBitrate table which I haven't touched as I don't know what it's for.
Resolution = 0
DBSBESTMAXBR = 8 000 000 (from 5 960 000)
DBSBESTVARBR = 8 000 000 (from 5 960 000)

sanderton wrote:
>Then you are on CBR at 8 Mbps.

Now it seems to me that my min setting (in AltBitrate) is unchanged and the max setting (in Bitrate) is increased therefore I should be on VBR. Or am I still missing something?

The consensus is that AltBitrate does nothing on UK TiVos.

If the two settings on the Bitrate page determine the range that VBR works over, and if the two are the same, then you have effectively fixed the bitrate whether "Save Disk Space" is on or not.

[ccwf]

Originally posted by sanderton
If the two settings on the Bitrate page determine the range that VBR works over Again, this is definitely not the case for U.S. TiVos. For us, the VBR bitrate is either the max VBR bitrate or a predicted average bitrate and not the minimum bitrate used by VBR.

[sanderton]

Originally posted by ccwf
Again, this is definitely not the case for U.S. TiVos. For us, the VBR bitrate is either the max VBR bitrate or a predicted average bitrate and not the minimum bitrate used by VBR.

Whatever the two numbers actually represent, they are different on US TiVos, yes? On UK ones the two numbers have the same value.

[ccwf]

They are different for series 1 U.S. TiVos. I believe that VBR is a feature of the new TiVo+DVD combos, so I would assume the numbers are different for them, too.

However, series 2 standalone TiVos have VBR disabled; the menu item to “Save Disk Space” is not even present. I do not know if the values are the same or different for those TiVos.

Also, I'll add that TiVolutionary long ago indicated that VBR used an “average” bitrate with the ability to “burst” above that. However, he was an official TiVo advocate and not a technical expert, so there is some chance that information is not correct.

[xxxx]

Originally posted by xxxx
I also notice a slight problem with the 8 000 000 br setting. I seem to get occasional white flashes near the bottom right of the screen, as though the Tivo can't keep up with the picture.

In the end I also found that there were lots of dropped mpeg frames that correspond with the white flashes at the bottom right of the screen as output by the Tivo. So I assume that 8 000 000 is much too high.

In the absence of anything better I reset both bitrate settings to 5 960 000 (BTW IFOEdit confirms that only 5 800 000 is video with 160 000 taken up by the audio) and IFOEdit is absolutely delighted with the resulting 720x576 DVD format. Perfect results with no green band.

Many thanks to LJ for the file and instructions.

[sanderton]

Hmm, but with a lower bitrate per pixel the artifacts etc should be quiet a bit worse, convenient as it is for the E-word.

Time to try a few tests with vales between 6000000 and 8000000 I think!

[xxxx]

Yes. I was about to test some other numbers in the range you mention when I saw the message about the non-booting Tivo on 7 500 000. This put me off making any more modifications though I don't understand why such a simple change should stop the Tivo from booting.
8 000 000 - 160 000 = 7 840 000 which isn't any sort of magic MPEG number that I recognise. Or does the Tivo br have to be some sort of multiple of the resolution, as suggested?

I can't see any extra artifacts to speak of though the general picture improvement without my blue shift problem is great enough to mask any such decrease in picture quality anyway.

All in all I am satified with the picture quality, the vanished green band and the DVD compliant resolution.
Though if anyone comes up with some working br numbers between 5 960 000 and 8 000 000 then I would like to try those.

[Lysander]

When I tried this, I started with a bitrate of 8M and got exactly the same symptoms - white flashes at the bottom of the screen. So I changed it to 7M which had worked successfully for me with Resolution 4.

Still got the white flashes! so this got me thinking. It is probably that the number isn't a great one for the number of pixels.

So, to get the same bitrate as Best I calculated that 5.8M needs to rise to 7.6M, just as has been previously described by sanderton. Then I added the 160,000 for the sound and bingo - no more white flashes.

I am using 7,836,000. Resolution 0. No ill effects yet...

BTW, I have kept the decoder changes intact as well to get the AUX and Live TV colours the same.

James

[sanderton]

That bitrate works fine for me.

Here are some revised still showing the effect of LJ's patch.

(Warning, large files!)

Screen images of Res 0 (http://www.beaconhill.demon.co.uk/Res0.htm)

Excellent stuff chaps!

[Dapper Dan]

Originally posted by Lysander


I am using 7,836,000. Resolution 0. No ill effects yet...

James

Are using this value for both VBR and MAX settings ?

(same question to sanderton)

[Modan]

Any chance of a res 0 to res 4 comparison (or does it not show up any difference on your screen-grabber?)

[Dapper Dan]

Not strictly part of this thread, but do the quality settings on the resource page have any effect (0, 40, 75 and 100) ? I don't see how they can if you're fixing the bitrate, and if you get can get a better quality compression for the same bitrate then why aren't they all at 100 ? Maybe they only affect VBR. I seem to remember changing them so that they no longer matched the resolution numbers (i.e set basic to 100), and when I recorded basic I got best quality instead (this was back before we knew that VBR wasn't working so everything was CBR).

[xxxx]

Originally posted by Lysander
I am using 7,836,000. Resolution 0. No ill effects yet...

BTW, I have kept the decoder changes intact as well to get the AUX and Live TV colours the same.


I'll give that br a try and report back. Thanks.

Your comment about the AUX and "Live" picture makes me think that there was (is) indeed something wrong with my Tivo as it left the factory. Even with the altered fpga file the live picture is still significantly brighter and more contrasty than the AUX one though it is all a great deal better than it was before.
Given that I had that strange blue shift that no one else seems to have (and which was clearly to do with excessively high image settings as with the new fpga file it has now gone) I can only suppose that my colour/brightness/contrast settings need to be lowered even more to bring them into line with everyone else.

Something for the future.

[xxxx]

Originally posted by xxxx
I'll give that br a try and report back.

7 836 000 looks lovely on the TV screen but the MPEG in IFOEdit is full of glitches and dropped frames. Shame.

So far only 5 960 000 works well in MPEG for me.

[technograndad]

Eh.. How can that be? I thought the picture on screen was *exactly* what's been written to the disk. Hence if you press pause, you resume by reading that same data off the drive. Surely you'd see the same glitches?

Perhaps the ext****** process is mangling the data.

John

[Lysander]

<Q>
Your comment about the AUX and "Live" picture makes me think that there was (is) indeed something wrong with my Tivo as it left the factory. Even with the altered fpga file the live picture is still significantly brighter and more contrasty than the AUX one though it is all a great deal better than it was before.
</Q>


Max and VBR figures have been set the same on my Tivo.

I have also applied the output fix to lower the colours to the same as that on Aux, LJ's patch doesn't do this for me either. Click on the link in my signature, although I just applied the changes at the bash prompt, because putting them in the .author file caused lock up problems for me.

Cheers,

James

[technograndad]

Originally posted by Lysander
... although I just applied the changes at the bash prompt, because putting them in the .author file caused lock up problems for me.


Try puting this at the end of of /etc/rc.d/rc.sysinit.author...

/var/hack/setrgb.sh &


Where setrgb.sh is a command script containing...

-start---------------------------------------
#!/bin/bash

echo "this is setrgb.sh ... wait for 40 seconds..."
sleep 40

echo "adjust RGB inputs (39=colour,38=luminance)"
/var/hack/bin/iicset 0x8Ch 0x39h 20
/var/hack/bin/iicset 0x8Ch 0x38h 21
-end------------------------------------------------

(Ignore the start/end lines of course).

The delay (sleep 40) allows the system to initialise properly before you adjust the settings.

John

[Lysander]

Thats sort of what I did, but instead of creating a separate file, I put those lines including the sleep 40 in the .author file.

My problem was weird. Daily calls worked fine over NTL until Sunday. If I had this script in place the NTL proxies fix caused a system hang on reboot.

By removing this script, getting the daily call to work and then typing this at the bash prompt everything is working. Not sure the wife will appreciate my final test of putting the script back in and rebooting... Corrie is on tonight!

[technograndad]

Originally posted by Lysander
Thats sort of what I did, but instead of creating a separate file, I put those lines including the sleep 40 in the .author file.


That would just hold up the initialisation. By making a call to an external script (containing the delay) it allows rc.sysinit (and author) to complete, meanwhile the setrgb bides its time until its safe to run the adjustments.

You can tell it's worked properly by examining /var/log/kernel - the diags from setrgb.sh should then be the last entries.

John

[Lysander]

aahhh....

Understand.

I sense a Corrie interruption coming! *lol* Thanks

[TiVoMango]

This thread is great :D

[sanderton]

Originally posted by xxxx
Originally posted by xxxx
I'll give that br a try and report back.

7 836 000 looks lovely on the TV screen but the MPEG in IFOEdit is full of glitches and dropped frames. Shame.

So far only 5 960 000 works well in MPEG for me.

I think you should try a different way of getting the MPEGs, as I'm fine. Maybe we should contine this part in Another Place!

[sanderton]

Originally posted by Modan
Any chance of a res 0 to res 4 comparison (or does it not show up any difference on your screen-grabber?)

I posted a Best image further up the thread. The pictures are stills from the actual MPEG, not videograbbed.

[TiVoMango]

Originally posted by sanderton
I posted a Best image further up the thread. The pictures are stills from the actual MPEG, not videograbbed.

And it took him bl**dy ages to sort them out and post them I can tell you.

:D ;) ;)

[Modan]

Originally posted by sanderton
I posted a Best image further up the thread. The pictures are stills from the actual MPEG, not videograbbed.

OK, I'll let you off this time. I can't wait to get back to my TiVo (have been in the states for the last 7 months), and apply these settings.

Of course I'll have around 180 hours of TV to catch up with first :D

[xxxx]

Originally posted by Lysander
I have also applied the output fix to lower the colours to the same as that on Aux, LJ's patch doesn't do this for me either. Click on the link in my signature, although I just applied the changes at the bash prompt, because putting them in the .author file caused lock up problems for me.

Interesting thread. Thanks. Is it possible to edit the fpga file directly in any way?
It does what it does just fine for me, but what it does isn't quite enough for my Tivo! I don't trust myself to poke registers from the command prompt.

[xxxx]

Originally posted by sanderton
I think you should try a different way ......

I tried to PM you about this but your mailbox is full.

[xxxx]

Glitch problem solved with latest version of jdiner's software.

All working well on 7 836 000.

All I need now is a way of changing the settings in the fpga file.

[sanderton]

Originally posted by xxxx
Originally posted by sanderton
I think you should try a different way ......

I tried to PM you about this but your mailbox is full.

Didn't knoiw there was a limit on mailboxes!

Freed up some space now.

[Dibblah]

Originally posted by xxxx
Originally posted by Lysander
I have also applied the output fix to lower the colours to the same as that on Aux, LJ's patch doesn't do this for me either. Click on the link in my signature, although I just applied the changes at the bash prompt, because putting them in the .author file caused lock up problems for me.

Interesting thread. Thanks. Is it possible to edit the fpga file directly in any way?
It does what it does just fine for me, but what it does isn't quite enough for my Tivo! I don't trust myself to poke registers from the command prompt.

Poke away. The values are not stored anywhere and the worst you'll do is blow up your TV if you feed it out of spec syncs ;)

... But of course, that hardly ever happens.

What you are editing is nothing to do with the FPGA - It's actually the configuration registers in the 7118 (input) and 7129 (output). Which are initially set in the kernel modules. LJ's patch changes the values in one of these modules, however, it needs a little bit of experimentation at the moment to find which values are active, then make an editor. I'll probably be posting something (not an editor, just information to make an editor) soon.

Cheers,

Allan.

[LJ]

8000000 was just a number I pulled out of the air - roughly 5960000 * 720 / 544 :) I've not seen the glitches other people have reported. Maybe it's something to do with VBR - I left DBSBestVBRBitrate as 5960000...

The disadvantage of changing the module is that you need to reboot to make the changes take effect.

[Milhouse]

I'm getting the white flashes on every MAX bit rate suggested so far, both with and without VBR. I'm even getting the white flashes with Min/Max rates of 5960000 (the original defaults).

I have analogue cable (and am changing the CATV settings) with an RF feed to the TiVo - perhaps resolution zero with an RF feed is the reason for the flashes, as bitrate seems to make no difference.

Going to try resolution 4 at min/max 5960000 as the default for CATV is resolution 2 so I may still be able to get some benefit from this thread! :D

[Milhouse]

It's only been a few minutes but res 4 @ min/max 5960000 looks good for CATV with RF feed - by now I'd have had maybe half a dozen flashes with res 0.

Picture quality is improved - woohoo! :) Am I likely to get any further improvements to picture quality by increasing bit rate?

Maybe one day Telewaste will have the money to upgrade the analogue cable in my street. And while I'm dreaming, maybe someone will release a Series II TiVo in the UK :D

[LJ]

It's worth a try - not sure what resolution analog cable is broadcast in. In theory all you've got to lose is recording capacity :D

[Milhouse]

I've upped the max bit rate for CATV to 7836000 (min at 5960000) and still no flashes with resolution 4 - with different min/max VBR has kick in so the extra bitrate should only used when necessary, and with 240Gb of storage I can spare the megabytes! :) Not sure there's any significant improvement, but I haven't noticed any picture break up when watching the Premiership (fast camera pans etc.)

Resolution 4 is definately an improvement over res 2 - previously vertical lines in the corners of the picture tended to bend inwards slightly. Now, they're perfectly straight! :)

[Modan]

Quick question. Are the people who are seeing flashes the same people as have used LJs patch?

Just wondering, as when playing around with this before, I had no bad effects at all. Basically I set it to mode 0 (looks much better IMHO, and the green doesn't show on my telly for whatever reason).

I then set all the Bitrates to something huge (working up in small steps of course), I think maybe 16M ie double what you are all using, without seeing any ill effects. I think I had to put it down a bit in the end due to an increase in artefacts during quick moving scenes (football mainly), and settled on something like 12M I think.

I'm wondering why I seem to have got so lucky compared to others here.

[Dapper Dan]

Originally posted by Dapper Dan
Set res 0 to 7500000 7500000 and found that Tivo would no longer reboot properly, just sat there after the usual messages with a black screen, no visible response from the remote. Pulling the power lead didn't help either. Don't really know why this happened because I changed the settings for medium and this is never used unless I explicitly tell it to. Fortunately I was still able to telnet in so I put the old fpga7114.o back and all is well again, phew!

I think that the reboot failure was due to calling technograndads's setrgb.sh from my rc.sysinit.author file and having typed reboot when it was NOT in standby mode. I've since used higher bitrates than 7.5M with LJ's patch with no problem if Tivo is in standby mode. Depending on what the tivo is doing, calling the iicset commands can upset it.

[Dapper Dan]

Originally posted by Modan
Quick question. Are the people who are seeing flashes the same people as have used LJs patch?

Just wondering, as when playing around with this before, I had no bad effects at all. Basically I set it to mode 0 (looks much better IMHO, and the green doesn't show on my telly for whatever reason).

I then set all the Bitrates to something huge (working up in small steps of course), I think maybe 16M ie double what you are all using, without seeing any ill effects. I think I had to put it down a bit in the end due to an increase in artefacts during quick moving scenes (football mainly), and settled on something like 12M I think.

I'm wondering why I seem to have got so lucky compared to others here.

Are you sure that you were using 16M ? (the chip is only supposed to be good for 15).

What settings have you got (VBR, MAX, resolution, save disk space ?).

If you're on res 0 without LJ's patch then you're losing some picture (try switching between aux and live to see how much).

I did all of my tinkering with LJ's patch and resetting the medium settings rather than best (my default). No matter what settings I used, the picture on medium was always worse than on best, even at higher bitrates (before picture break up), even at the same resolution. I've since changed the settings on Best quality instead and I believe I'm getting the best picture yet (at the standard 5.96M, 5.96M bitrate) and don't appear to have any noticeable artefacts.
It seems that there maybe something hard coded that lowers the quality of medium compared to Best (perhaps the quality settings are ignored, even though I changed them).

I think that a more comprehensive test is required...

[Milhouse]

Originally posted by Modan
Quick question. Are the people who are seeing flashes the same people as have used LJs patch?


Yes, I'm using LJ's patch, and to test your theory I repleaced the original file and applied res 0/min=5.96M/max=7.83M and still had flashes.

I'm applying my changes to CATVBest, and I'm using an RF feed - is anybody getting flashes with DBS and/or SCART? Perhaps it's only flashing on RF due to the reduced quality feed?

[Modan]

Originally posted by Dapper Dan
Are you sure that you were using 16M ? (the chip is only supposed to be good for 15).

What settings have you got (VBR, MAX, resolution, save disk space ?).

If you're on res 0 without LJ's patch then you're losing some picture (try switching between aux and live to see how much).



OK, so it was probably 15 then, as at the time I did look into what the max rating for the chip was. I had everything set to 15M and save disk space to off.

Yeah, I figured I was losing some picture, but I felt the advantages were worth it.

I will definitely be using LJs patch as soon as I get back to my TiVo.

[Modan]

Originally posted by Milhouse
Yes, I'm using LJ's patch, and to test your theory I repleaced the original file and applied res 0/min=5.96M/max=7.83M and still had flashes.

I'm applying my changes to CATVBest, and I'm using an RF feed - is anybody getting flashes with DBS and/or SCART? Perhaps it's only flashing on RF due to the reduced quality feed?

I for one have only tried this over SCART.

[Lysander]

Could it be that the flashes are not to do with the chipset, but are due to the write capabilities of the hard disks?

I don't get a higher frequency of white flashes at 12M than I do at 8, which makes me think that this is a write issue.

BTW, when watching Live TV at 7.8M I got white flashes... now back at 5.8M :(

James

[Milhouse]

I'm confused - if this were a HD write issue wouldn't you expect flashes to become more common as the bit rate is increased?

I did wonder if the HDs could be the bottleneck with increased bitrate but the fact that flashes occur for me even at the default 5.96M min/max bitrate with resolution 0 indicates this probably isn't a HD issue, as resolution 4 at 5.96M/7.8M is perfect (ie. no flashes).

For reference, I'm using two 120Gb Seagate Baracuda V 7200.7 disks.

Lysander - I see you're on NTL Digital. Does this mean you're using the DBS settings with SCART input? I'm on CATV/RF and suspect this to be the reason (though not sure why, reduced quality input perhaps).

:)

[xxxx]

I thought that changing from 7 836 000 back to 5 960 000 on res 0 had cured my white flash problem but having looked at some new recordings I can see that it is still there, though reduced I think. It seems to happen mostly on bright or high contrast images like outdoor video and rarely on film.

When I have time I shall experiment a bit. After all, there are only three variables : the bitrate, the resolution and the patched fpga file.

[Dapper Dan]

Originally posted by xxxx
I thought that changing from 7 836 000 back to 5 960 000 on res 0 had cured my white flash problem but having looked at some new recordings I can see that it is still there, though reduced I think. It seems to happen mostly on bright or high contrast images like outdoor video and rarely on film.

When I have time I shall experiment a bit. After all, there are only three variables : the bitrate, the resolution and the patched fpga file.

I thought the same until last night:

scrapheap challenge (1 flash)
rolf harris art program (lots of flashes)

Re: experiment, I make it at least 7 variables:

resolution (0, 1, 2, 4)
quality value (0-100)
quality setting (basic-best)
save disk space option
max bitrate
vbr bitrate
fpga file

[sanderton]

Pretty sure that Quality Value is just a numeric shorthand for the Quality setting and chnages nothing of itself. Certainly, the numeric value is used to store the setting in the database.

[Dapper Dan]

Originally posted by sanderton
Pretty sure that Quality Value is just a numeric shorthand for the Quality setting and chnages nothing of itself. Certainly, the numeric value is used to store the setting in the database.

I suspected that when I changed the basic quality to 100 and it recorded as best instead.

OK, only 6 variables then.

[Lysander]

I am using Scart and have changed the DBS settings.

I am not using save disk space, and have VBR and Max at the same values.

In fact, the only change I now have in place is the fpga file. Still get some "glitching".

Looks like we aren't quite there yet.

Back to Res 4 for a while...

James

[Dibblah]

Righty ho. Here we go... This is just a list of the registers in the 7118 in easy-to-parse text format.

It's the basis of what the editor will work from.

[Dibblah]

... And the list of addresses of the tables in the fpga7114.o file.

The first item in the table is the number of bytes of data in the table +1 (!?)

Cheers,

Allan.

[Modan]

Originally posted by Dapper Dan
I thought the same until last night:

scrapheap challenge (1 flash)
rolf harris art program (lots of flashes)

Re: experiment, I make it at least 7 variables:

resolution (0, 1, 2, 4)
quality value (0-100)
quality setting (basic-best)
save disk space option
max bitrate
vbr bitrate
fpga file

To be honest, I think you can cut it down to the following without too much fear of missing anything

fpga file
max bitrate + resolution
is vbr on
program source

seems like Millhouse has eliminated the fpga
Millhouse also sees it with and without VBR
program source has been eliminated by Lysander

So sounds like it is a combination of higher bitrates and higher res. So sounds like maxing out some part of the graphics subsystem. Perhaps this is why we see different people getting different effects, since there may be different chip revisions? and certainly my TiVo runs significantly cooler than the norm (by maybe as much as 5 degrees), so chip overheating may be a problem.

[xxxx]

I put my Tivo back onto res 4 to see whether the white glitches would go away and discovered that it is the res setting that is responsible for my blue shift problem, not the fpga file. Res 0 or res 1 = no blue shift. Res 4 = blue shift. Bitrate has no effect on this.

Has anyone noticed any particular programme that always displays the white glitches? It would be nice to find something like an intro to a regular programme that does it, for testing.

[Dibblah]

For me, I've seen it in res 4 on Andromeda. Title sequences (White text scrolling on a black background) are worst. Note: This is BEFORE any hacking about. It's not consistent - It won't do it all the time. I'm also wondering if drive speed has anything to do with it - I still have the original Quantum (Slow as a slow thing on the go-slow pills) drive in, with a 120Gb slave.

Cheers,

Allan.

[Dibblah]

Originally posted by Dibblah
... And the list of addresses of the tables in the fpga7114.o file.

The first item in the table is the number of bytes of data in the table +1 (!?)

Cheers,

Allan.

Downloaded 18 times?!?!? My, we have some (in) : (a)quisitive beavers here!

Cheers,

Allan.

[ruperte]

Originally posted by xxxx
Has anyone noticed any particular programme that always displays the white glitches? It would be nice to find something like an intro to a regular programme that does it, for testing.

Just as a reference point, I have NTL and if I record any of the radio channels, the NTL decoder displays a spinning "Audio" logo. This seems to upset the encoder in the same way.

Normally I record radio at Basic quality and that will give a white flash once per revolution. Note this has been true ever since 2.5.5 came along.

Rupert

[occitan]

How is this going now after a week or so's experiments ? Are you guys happy with the new high resolution, or have you all gone back to the TiVo defaults ?

Cheers

[LJ]

Working fine here. Haven't had time to play with the colour/brightness/etc settings yet.

[xxxx]

It's OK for me apart from the white glitches and they seem to be entirely to do with the res 0 setting. Nothing I change in the bitrates seems to make the glitches go away. For me they seem to only appear on hand-held video source material (ie flaky sources), never on film. I use the res on 0 and left the bitrate on the original default setting as I can't really see the difference. I only really want the res 0 setting for the 720x576 resolution and the fact that only the res 0 setting gets rid of my blue shift problem which presumably is a fault on my Tivo.

I would like to reduce the contrast and brightness more though as my Tivo is clearly set at much higher levels than other people's Tivos are. Or perhaps it's all part of the same fault?

[Dapper Dan]

Mine was working fine. Still got occasional white flashes but nothing too distracting. Disks appear to have failed now, only been in there a month. :mad:

[technograndad]

Originally posted by Dapper Dan
Mine was working fine. Still got occasional white flashes but nothing too distracting. Disks appear to have failed now, only been in there a month. :mad:

Are those Samsungs? Both failed? That's a worry...

John

[xxxx]

Originally posted by Dapper Dan
Disks appear to have failed now, only been in there a month. :mad:

What brand/model are they?

[Dapper Dan]

They're the Samsung spinpoint SV1204H.

I only said they've appeared to fail, in that Tivo refuses to boot (don't even get any messages, just a grey screen). I've pulled them out and they seem ok in the quick test in HUTIL so I figured I'd have a look at the logs and maybe copy some files off the old 40gb disk if anything looked wrong (fpga7114.o, etc). However, I don't seem to be able to mount them when using the mfstools2 cd or the nic_install cd. Mind you, this happened when I first ran mfstools on them, that ran fine but I couldn't mount them. Same cds and pc worked fine with my old 120GB maxtor so I'm a bit confused (might try downgrading the bios to see if that helps). I also have redhat 9 on one partition so tried booting into that, but that wouldn't mount them either (think that you might need mac partition support, might have to rebuild kernel).

Any ideas ?

PS - When I ran HUTIL, the smart diagnostics said that one disc had been running for 650 hours (about right), but the other had been running for 1476 hours.

[iankb]

Originally posted by Dapper Dan
... one disc had been running for 650 hours (about right), but the other had been running for 1476 hours. Check the manufacturing dates printed on the drives to see if they (roughly) match. I assume that the Samsung website has the ability to check the warranty date for each serial number. Check those to make sure that you were definitely sold new drives.

As to the drive problems, you could try a new IDE cable. Also check that there are no bents pins on the drives.

Ian.

[Dapper Dan]

Originally posted by iankb
Check the manufacturing dates printed on the drives to see if they (roughly) match. I assume that the Samsung website has the ability to check the warranty date for each serial number. Check those to make sure that you were definitely sold new drives.

As to the drive problems, you could try a new IDE cable. Also check that there are no bents pins on the drives.

Ian.

Pins are fine, dates are the same (03.2003), boxes looked original and new. Haven't tried a new cable, but the old one is running fine with the original disk. Have also wondered if it just fell over because it got so full (>80%). I'd also used the -r 4 option when I created it, and whatever the option was to make enough swap.

[iankb]

My drives are almost permanently 100% full, but then I rarely use KUID. If you mean that you uses KUID on up to 80% of the drives, then maybe that might cause a problem.

I used the '-r 4' option, and my drives failed completely when I created an advanced wishlist. Since then, I have avoided both the '-r 4' option and advanced wishlists. Probably just a coincidence in both cases, but I've been running reliably since.

Ian.

[Dapper Dan]

The % of KUIDs is pretty small I think, and I have no advanced wishlists. Don't have time to investigate any further until next week.

[Dapper Dan]

Originally posted by Dapper Dan
Mine was working fine. Still got occasional white flashes but nothing too distracting. Disks appear to have failed now, only been in there a month. :mad:

After a bit of a saga I have finally got it working again :)

It seems that calling iicset in setrgb.sh from rc.sysinit.author might not be such a good idea. The kernel log had an I2C transaction timeout which stops it from booting properly and you end up with a blank screen (but can still get a bash prompt). When this happens, I normally copy my backup of rc.sysinit.author (that does nothing) over the top of the version that calls setrgb.sh. Unfortunately, in this case I copied it over the top of rc.sysinit instead, which means that it doesn't boot and you don't get a bash prompt. That meant I had to hoik out the disks with the hope of mounting them via the mfstools2 cd and seeing if I could see what had gone wrong. Unfortunately, there seems to be a problem with this CD related to byte swapping which means that it won't mount the disk. I managed to get it working, however, by typing:

vmlnodma hda=bswap initrd=initrd.img load_ramdisk=1 prompt_ramdisk=0

Then I could mount the required partition with a:

mkdir /mnt/var4
mount -t ext2 /dev/hda4 /mnt/var4

and finally work out what I'd done wrong.

[LJ]

in this case I copied it over the top of rc.sysinit instead

Don't you just hate it when that happens ;)

Forgetting chmod +x is my favourite...

[Roj]

Originally posted by mrtickle
I also changed the live buffer to Medium

How do you do this? I thought it might be the defaultrecordquality / defaultliverecordquality settings (e.g. change them to 40 for medium), but that doesn't seem to do it for me?

Thanks,
Roj

[technograndad]

You just need to change the menu option under Settings, Video Quality (or something like that). Whatever you're preferred default recording quality will also be the live buffer quality setting.

[ktbken]

As far as I know the live buffer always records in best regardless of the settings for recording quality.
As an example my system is set to high as the default setting. But if I choose to record a program which has started I get a popup saying do I wish to record from the beginning of the buffer at best or start from now and record at high.

[mas]

yes, live buffer is always Best unless recording something - which will be at specified or default quality setting

[tivo_boj]

I tried reading through this but have lost the plot a bit

I note on LJs page on what I need to set to a 0 setting, but what are the actual bitrate etc I need to set via tivoweb.


I want to increase the live buffer to best possible (better than it is now) and also the "best setting" to better.

an idiots guide may help others as well as me!

Also was ther conclusiont have you could not harm tivo buy increasing any of the settings?

[xxxx]

The "0" setting changes the Tivo resolution. If you do this you'll need to change the file as mentioned earlier in this thread as otherwise you'll have some nasty side-effects. There was quite a bit of discussion about the bitrate settings and the white glitch that goes with the change to res "0". You'll need to suck it and see what works for you.

I have gone to res "0", with the file change, main bitrate settings of max 7836000 and VBR 5960000, and I have put the quality down to 75% which seems to reduce the white glitches and gives me surprisingly small file sizes of about 2Gb per hour. I haven't touched the AltBitrate settings and still don't know what they do, if anything.

All in all I am quite happy though I would like to get rid of the remaining few white glitches and would also like to make further reductions to the contrast, brightness and colour, all of which are still way over the top on my Tivo.

[Dapper Dan]

Originally posted by xxxx
...would also like to make further reductions to the contrast, brightness and colour, all of which are still way over the top on my Tivo.

Have you tried running iicset; this changes the luminance and colour on playback, I think, or are you trying to change it on input ?

[Lysander]

xxxx,

check out the link in my sig.

This gives you a very good colour and brightness match.

James

[xxxx]

Originally posted by Dapper Dan
Have you tried running iicset;

No, I hadn't heard of that one.

this changes the luminance and colour on playback, I think, or are you trying to change it on input ?

I'm hoping to change the input settings as it seems neater. The existing fpga7114.o mod does a fair enough job but I would like to tweak it a bit more: my Tivo's settings seem to be further off than most.

[xxxx]

Originally posted by Lysander
check out the link in my sig.
This gives you a very good colour and brightness match.

Thanks for that link. It seems to be what Dapper Dan was referring to also.

I'm hoping for a solution along the lines of the existing fpga7114.o mod as it seems to be very effective and nicely permanent without putting any load on the Tivo processor. I suspect that a Windows editor for that file would allow for quite a few interesting adjustments.

[Lysander]

The mod changes the output settings, is a one off change and doesn't add any load to the Tivo, apart from the extra line in rc.sysinit.author of course...

James

[xxxx]

Hmm. I'll give it a try. The input modifcation would be nice though.

Can the fpga7114.o file be safely edited with a Windows XP hex editor or are there any special Linux issues to watch out for?

[stevelup]

Hi

I'm having a bit of trouble with the resource editor.

I change the resolutions and bitrates, click update resources, then reboot as requested.

Every time TiVo comes back up, the settings are back how they were!

Help!

Thanks,

Steve

[Dibblah]

Change one of the values. Press 'Enter'. Then change another. Press 'Enter'. Then update resources and reboot.

Cheers,

Allan.

[stevelup]

Thanks!

Wasn't pressing enter! What a wally.

Much appreciated.


Steve

[technograndad]

You have to press Enter each time you type in a new value. Then at the end you click on Update Resources and reboot.

John

Edit: Oops.. shouldn't have gone to make a coffee before replying :)

[stevelup]

Hi

Just a word of thanks to all the people who have contributed on this thread.

I have my TiVo connected to a Sanyo PLV-Z1 projector and the images from TiVo were always a bit disagreeable.

If there was something on TV that we really wanted to watch on the PJ, we would watch it live using Aux Bypass.

With the new high resolution mode and increased bitrate, the picture from the projector is an order of magnitude better than it was.

You *can* see the difference it makes on the TV, but the projector really shows up the difference.

I would strongly recommend that anyone who uses their TiVo with a projector should do the hacks on this thread.

I am using 7680000 for the bitrate BTW, and have seen no white flashes as reported by others.


Cheers!

Steve

[Craig B]

I have read the posts over a series of weeks and would like to give it a go. Could anyone give an idiots guide on how to do it and best settings?

I have Tivoweb, a 120Gb drive and will be outputting to a 42 inch plasma. I have already broken one Tivo upgrading and wouldn't like to face the girlfriends wrath if I did it again. Thanks

[Lysander]

Follow LJ's instructions here:

http://www.ljay.org.uk/tivoweb/tivo_fpga.html

Then follow TechnoGrandad's instructions here:

http://www.tivocommunity.com/tivo-vb/showthread.php?postid=1401427#post1401427


Reboot and away you go.

James

[Craig B]

I'm trying to download LJ's fpga patch but his website is down. I have found a cached copy of his instructions but not the file. Could somebody please point me in the right direction. Thanks

[Craig B]

Don't worry about the previous request, it's back up now.

[tivo_boj]

Sttll having problems getting the tivo to record in VBR - see thread

http://www.tivocommunity.com/tivo-vb/showthread.php?s=&threadid=138483

[sanderton]

I just did this:

In TiVoWeb's resource editor, the Bitrate page, changed CATVHighMAXBitrate to 5960000 (I use FreeView on that TiVo, so the CATV variables are the relevant ones). Hit return. Updated Resources. Turned Save Disk Space on. Rebooted. Recorded something on High and this was the tvlog entry:

Oct 25 11:38:52 (none) TmkMediaswitch::Trace[149]: using VBR, bitRate=3660000, maxBitRate=5960000

[tivo_boj]

I use sky on scart, freeview on RF. Which should i changes for each? is the CATV the scart input? and rooftop RF?,

what do the DBS ones mean, as I have been altering these?

[sanderton]

If you look in Channels I Receive you'll see the input source in brackets by each channel number.

My guess is that:

sat = DBS
cab = CATV
aer = Rooftop

[tivo_boj]

All comes clear now why I only got the odd VBR recording.

Thanks for the info

(endpad rules OK)

[tivo_boj]

found that Tivo seems to report the wrong quality on recording now I have changed the bitrates to force VBR

For instance see below from tivoweb - this is a suggestion which should have recorded at basic (altered for VBR) but shows as best. However looking at the size it unlikely it was recorded at best .....any ideas

Duration 0:27
Original Air Date Sat 1st Nov 2003
Actors Keri Russell, Scott Speedman, Amy Jo Johnson, Tangi Miller, Greg Grunberg, Amanda Foreman, Scott Foley
Guest Stars Tyra Banks
Directors Keith Samples
Exec Producers Brian Grazer, Ron Howard, Tony Krantz, J.J. Abrams, Matt Reeves
Writers John Eisendrath
Genres Drama
Bits Stereo, Sub
Type Series
Channel 6 ITV2
Showing Date Sat 1st Nov 03:40
Expiration Date Wed 5th Nov 18:00
Deletion Date
Cancel Date
Cancel Reason
Quality Best
Score Predicted 1 80
Selection Type Suggestion
State Now Playing
Size 344 MB

[sanderton]

When you turn on Save Disk Space (VBR) it says on that screen that VBR doesn't work with Basic.

[tivo_boj]

Originally posted by sanderton
When you turn on Save Disk Space (VBR) it says on that screen that VBR doesn't work with Basic.

but it shows "best" - should it not just say basic even if it recorded at CBR (although the log says VBR)

[sanderton]

Check the TiVoWeb code, perhaps it assumes Best when Quality is not specified? (Default recordings have no Quality entry in the db)

[tivo_boj]

This could be it cause as other vbr recording done at high or medium also show as best (although they show OK on Tivo itself)

[kitschcamp]

Originally posted by sanderton
I just did this:

In TiVoWeb's resource editor, the Bitrate page, changed CATVHighMAXBitrate to 5960000 (I use FreeView on that TiVo, so the CATV variables are the relevant ones). Hit return. Updated Resources. Turned Save Disk Space on. Rebooted. Recorded something on High and this was the tvlog entry:

Oct 25 11:38:52 (none) TmkMediaswitch::Trace[149]: using VBR, bitRate=3660000, maxBitRate=5960000

I've just been experimenting altering the Basic settings for DBS.

DBSBasicVBRBitrate 2760000 (standard medium)
DBSBasicMAXBitrate 3660000 (standard high)
DBSBasicResolution 2 (standard high)

And recorded two 35 mins programs on the same channel us

Programme 1: Gardening, lots of grass & trees. 729088Kb
Programme 2: Houses. 708608Kb.

Normal High: 955392Kb
Normal medium: 724764Kb

I expected the values to be somewhere between the two. Seems in some cases it can be somewhat lower.

[SteveWilkins]

Excellent work guys. This thread was one of the deciding factors for me finally opening up my TiVo and starting hacking, that and the warranty has now expired.

I have just completed hacking my TiVo (New Drives and TurboNet) and have been following the instructions on this thread to improve the record quality of my TiVo.

However, I am unable to find a binary of Tridge's iicset utility. His web site only has the source file. So I thought, all I need is the Cross compiler and I'll compile it. No such luck. I am unable to run gcc. I just get an error "1: Syntax error: "(" unexpected". This is even if I just run it with no parameters, not even and input file. I am slightly cheating by attempting to run gcc under Cygwin on WinXP, as I don't have linux on my PC.

Does anyone have the binary of iicset or can someone advise me on what I am doing wrong with the cross compiler. The latter would also be useful as I would like to be able to build my own binaries, being a programmer myself.

[LJ]

There's one hiding in the zip that's not a zip here (http://www.tivocommunity.com/tivo-vb/showthread.php?postid=890995#post890995) ;)

[mrtickle]

Originally posted by Roj

Originally posted by mrtickle
I also changed the live buffer to Medium

How do you do this? I thought it might be the defaultrecordquality / defaultliverecordquality settings (e.g. change them to 40 for medium), but that doesn't seem to do it for me?

Thanks,
Roj

In the Resources editor in TiVoweb, it was the 4th down from the top - "DefaultLiveRecordQuality". change it to 75/40/0 for a High/Medium/Basic Live buffer.

I wanted to experiment with different numbers, after reading the posts from the US forums. But tivoweb has so many instances of 100/75/40/0 hard-coded into it it was too much hassle.

The white flashes and how to predict where they will appear: I have seen them on my (standard bit rates) tivo without fail every week on the end titles of (a) The Office, (b) 24. These programmes both had action immediately followed by a mostly-black screen. HTH!

[SteveWilkins]

I found that the glitches at the bottom of the screen seem to vary depending upon what is being recorded. The worst I have seen was on Parkinson on BBC1 on Saturday. The glitches were happening constantly every few seconds. I have the bit-rate increased to 7.8Mbps. I also tried switching VBR on and off, and found it didn't make any difference. I switched over to ITV1, and there were no glitches to be seen. :confused:

MrTickle, is your standard bit-rate Tivo running in Mode 0 when you get the white flashes?

Anyone got any theory about what is causing the glitches and how to stop them. Going back to Mode 4 is not an option as I love my Tivo even more now the picture quality is so good I cannot tell the difference between Aux and "Live TV". But then I'm a fussy git with a 36" TV. :D

And being in a native DVD resolution has other advantages ;)

I'd just like to fix the slight vertical offset and my Tivo would be sheer perfection.

[mrtickle]

Originally posted by SteveWilkins

MrTickle, is your standard bit-rate Tivo running in Mode 0 when you get the white flashes?


Nope, this was bog-standard "Best" quality.

[xxxx]

I am starting to think that the white glitches are to do with the ambient video noise level and/or mpeg artefacts present in the source. On my sat-only system it seems to affect BBC channels the most (almost exclusively in fact) and these are often said to have relatively low bit rates compared to the other FTV channels. They also tend to use domestic hand-held cameras that they say are "broadcast quality" but which often give a very grainy result.
I must do some testing with the nastier low bit rate shopping channels.

[Fozzie]

Finally got round to having a dabble with this. Although I have NTL digital cable I was expecting the DBS resources to apply but they don't - it's the CATV ones. I was surprised to find the Best Resolution mode set to 2 - I was expecting it to be 4!

I installed LJs mod'd fpga file and set Best mode to 0 and changed the max bitrate to 8000000. Rebooted and wow, what a difference :)

None of the reported problems reported so far. Best capacity has dropped from 68hrs to 50hrs which is fine as I only use it for LiveTV and sports recordings.

[iankb]

If you're using VBR, the capacity reported by the TiVo will be incorrectly calculated using the Max Bitrate. In fact, the true capacity should be based on the Average BitRate, which should give you significantly more. Using bobone's settings increased my resolution, but decreased my filesizes by 40-50%.

[Fozzie]

I've got VBR off but since I've increased the max resolution by ~30% the drop in recording time seemed about right.

I don't suppose you (or anyone) know how to derive the values used in the Tivoweb info.itcl module to calculate the recording capacity? Best still shows 68hrs as it doesn't 'know' that I've increased the bit rate!

[mark.stringer]

After much research over the last week (here and on the other place) I have changed the medium quality settings on my Tivo to use resolution 0 with a bitrate of 7660000 and quality set to 70%. I installed LJs mod but not the iicset changes.
I tried a short recording and all seems fine and this has solved a separate problem I had with viewing on other equipment.
A few questions:
1. Do these settings seem reasonable? The output seems fine viewing by either method.
2. The amount of disk used seems about the same as best. Should I be using a quality setting of 100% rather than 70? Presumably this will cost me more disk space.
3. Should I be using VBR and if so what settings would you recommend?
4. Do I need to make the iicset changes given all looks fine and, if so, where do I get iicset as I could only find iicset.c sourcecode and no compiled version?
After some more reading, to answer my own question about the binary see here:
http://www.tivocommunity.com/tivo-vb/showthread.php?postid=1512699#post1512699

I have searched quite extensively for answers to the above here and other there but there is a glut of information on this topic with no good summaries that I can find, or at least no good UK summaries. Don't get me wrong, the info in this thread is great but I wanted to clarify the above as well.

Thanks,
Mark.

[blindlemon]

The Recording Quality setting does, IMHO, make a difference.

There is a noticeable difference (although hard to pin down exactly) between a RQ setting of 75 (high) and 100 (best). If you go below about 75, then regardless of the resolution, the picture becomes less sharp and the difference between a RQ of 5 and 95 with all other factors the same is very obvious (http://www.tivocommunity.com/tivo-vb/showthread.php?s=&postid=2149613&highlight=RQ+95#post2149613).

If you use 100 for both best and medium the TiVo UI will get confused and report your medium recordings as "best", but I would suggest you try, say 95, and see if that looks better than your recordings made at 70.

FWIW, These are the settings I am currently using:-

Best 7500000/9000000, mode 0, RQ 100
High 3660000/6000000, mode 0, RQ 75
Medium 2500000/5960000, mode 0, RQ 55
Basic 1700000/2000000, mode 1, RQ 0

[mark.stringer]

Thanks blindlemon,

I take it from your settings that you are allowing VBR to operate. Does this work well and help reduce overall recording size? If I transfer files to other places I would be concerned about them getting too big.

You didn't mention if you were using the iicset changes or not. Are you just using LJ's changes or those and the iicset?

Cheers,
Mark.

[sanderton]

VBR massively reduces filesize, but if you've implemented Res0 to improve picture quality, you may not want to take it back down again by switching on VBR.

[mark.stringer]

I've implemented Res0 more because of compatibility issues elsewhere, so I am looking for advice on a happy medium on the bitrate and quality settings. I am happy with the quality I was getting with Best, just not the format. From what I read I got the impression that using Res0 with the existing Best settings did not give good results.

[blindlemon]

The default "best" bitrate of 5960000 is good, but too low to be described as "best". You really do need the higher bitrates to avoid pixellation when running in mode 0.

I have only tried one CBR recording in mode 0 (at 6000000, by accident!) and although it was very nice on fairly static scenes, pixellation was noticeable on scenes with significant motion or "difficult" subject matter such as water or flames.

That's why I've set my "best" bitrates to 7500000/9000000. With these values I hardly see any pixellation at all in even the most demanding scenes, so I use this when absolute quality is required at the expense of disk space - eg. when I know I will be archiving (ahem;)) to DVD.

However, my "high" settings of 3660000/6000000 are more than adequate for everyday viewing of movies etc. and I make most of my recordings on "high", with medium and basic reserved for US sitcoms and kids' stuff.

I don't use iicset as I watch 99% of my TV through my TiVo and have adjusted the TV instead :D:D

[aerialplug]

Having only recently experimented with increased bitrate, I've found that using MAX 9000000 and average 4800000 on mode 0 causes the unwanted artifacts at the bottom of the screen on far too many programmes. Mostly these are programmes originally sourced on film, so there's a lot of ambient grain, but I did see it happen last night several times on Stargate (which is also sourced on film, but not at all grainy).

The artifacts seem to be replications of bits of the picture from other parts of the screen that flash at the bottom of the screen for a single frame (often repeating for a few subsequent frames in different patterns). I guess the coder can't handle the bitrate. After all, it is technology that's over 5 years old - when domestic MPEG coders were largely unheard of...

Mind you, I've seen these artifacts in all other modes, but usually only on still images such as credits or when TiVo's recording the caption that's on screen while recording radio programmes.

I'll try dropping the MAX bitrate to 8000000 to see if that alleviates the problem whilst maintaining the excellent increase in picture quality observed in Mode 0.

Incidentally, with the above settings (including the VBR), a mode 0 recording looks superb compared to best quality, so it would be good to get some sort of compromise to work where the quality is almost as good without the flashes at the bottom of the screen.

Conversely, I've changed basic quality to be 750000Kb/s. The picture quality is AWFUL to the extent that on some busy images, the coder completely fails and you get large gray areas on screen for some frames, but it's excellent for radio, with roughly 100Mb per 15 minutes.

[Dunkwho]

I dropped my mode 0 bit rate back to 7890000 last night from 9000000 in the hope that some of my white flashes will disappear ... and that some of my stuttering will stop (why do you stutter so Mr Tivo?). New 160gb hd so wasn't expecting to see any problems but seems to have conicided with the upgrade, I uped the res and bitrate in the same process too so am trying to wind back bitrate to see if theres any improvement. I decided to use 789k because its 1.353x596k based on mode 0 being 1.353xmode4's pixels (mode 4 IS the freeview default isn't it ... and 596k the matching default bitrate as delivered from tivo?).

Incidentally ... can anyone with a 160gb lba48 upgraded system running with 900k CBR bitrate tell me what their total best recording time is from the system page? I was surprised to see it reported as 35hrs (and something minutes) - decided it was because tivo was taking my uped bitrate into account (which i didn't think it did), the basic was shown as 185 which lined up with my expectations (I was concerned that my upgrade might have gone wrong somewhere, maybe the lba wasn't loaded correctly or the -x restore option gone wrong somewhere ...?)

Duncan

[iankb]

When using VBR and mode 0, the TiVo system screen appears to show calculations based upon the max bitrate rather than the average/target bitrate. This appears to reduce the number of hours from the standard settings while, in fact, it substantially increased them.

[blindlemon]

Originally posted by Dunkwho
I dropped my mode 0 bit rate back to 7890000 last night from 9000000 in the hope that some of my white flashes will disappear I Use 7500000/9000000 mode 0 (best) and 3660000/6000000 mode 0 (high) on both my lounge TiVos and very rarely see the white flashes in either mode.

Some people have suggested it may be down to the individual TiVo - but in that case I would expect one to be worse affected than the other and I can't say I've noticed any pattern. If I see 2 white flashes in a 2 hour film I'm surprised.
Originally posted by Dunkwho
can anyone with a 160gb lba48 upgraded system running with 900k CBR bitrate tell me what their total best recording time is from the system page? 35 hours sounds about right. A 120gb drive with a max bitrate of 9000000 for best shows 25 hours 45 minutes. The capacity multiplier for a 160gb LBA48 drive compared to 120gb is about 1.36 and 1.36 * 25.75 is, funnily enough, 35 :)

However, your actual capacity at best for a 160gb LBA48 drive is more likely to be around 42 hours if you use a lower bitrate of 7500000 as I have suggested.

[gyre]

Do any of you with VBR get lip sync problems? If so, how badly?

Thanks.

-- gyre --

[sanderton]

No more than I used to.

[blindlemon]

I have yet to prove that a lip-sync problem is the fault of VBR. You can't tell on a recording unless you have the source to compare it with.

Whenever I've noticed lip-sync problems in a programme being recorded, or while watching Live TV I have always found the same discrepancy in the original signal. Some Sky channels are regularly abysmal.

[Fozzie]

Not noticed it at all on mine.

[aerialplug]

Well, I recorded Brirish Isles: A Natural History tonight in 7500000/9000000 mode 0. It was FAR worse than my previous recording in 4800000/9000000.

After doing a lot more experimentation, I've come to the definite conclusion that the errors that cause the flashing at the bottom of the screen are appearing in the decoding phase rather than the encoding.

One reason I've come to this conclusion is that the artefacts appear differently (but roughly in the same place) each time I play a sequence.

Another reason - you can never freeze frame on an artefact - they're like a rainbow - whenever you know where to stop - they're not there!

There are other far more conclusive proofs that illustrate this that can't be discussed here.

Suffice to say that for some reasons, 4800000/9000000 is what I'll be using in future - but only for "special" recordings. I'll continue to experiment to see what optimum settings work for my TiVo in mode 0 for every day use.

[Fozzie]

I'm using 5960000/7836000 with Mode 0 for Best, on NTL cable. Rarely get white flashes at the bottom of the screen; when I do, IIRC, they are mainly on BBC1. YMMV.

[gyre]

I've seen the flashes appear when the source material is poor quality.

Also, it is deffo in the playback and not the recording :)

-- gyre --

[kitschcamp]

Originally posted by Fozzie
I'm using 5960000/7836000 with Mode 0 for Best, on NTL cable. Rarely get white flashes at the bottom of the screen; when I do, IIRC, they are mainly on BBC1. YMMV.

I have to agree - it does predominantly affect BBC1. I've yet to see flashes when I've recorded GPs at Mode 0 on ITV, yet most things on BBC1 do.

[blindlemon]

Originally posted by aerialplug
Well, I recorded Brirish Isles: A Natural History tonight in 7500000/9000000 mode 0. It was FAR worse than my previous recording in 4800000/9000000. If you have another recording of exactly the same programme then that's interesting. If it's a different episode then I'm afraid it means very little.

The flashes are clearly related to the source material - I can kind of anticipate now where they'll occur. It's usually, IME, in scenes with very brigh areas to the top of the screen and very dark ones at the bottom - eg. contrasty, against the sun, landscapes etc. I saw a couple in an episode of Grand Designs Abroad ("Ireland") I was watching yesterday. Of course they weren't repeatable and not present when the recording was viewed (ahem;)) on a different playback device.

FWIW the recording that exhibited this on my TiVo was made at 3660000/6000000 in Mode 0 (high), and I have also seen white flashes in recordings made in Mode 0 at 2500000/5960000 (medium) - so it's not only restricted to the very high bitrates.

[aerialplug]

Yes, I agree that a conclusive test would be using the same source with different settings. I think I may set up a test bed using my DVD player for this - but not yet.

However, it was consistetly happening on all recordings made in that resolution combination. My guess is that I'm pushing TiVo's decoder to its limits - and the limits may be different on various TiVos. Mine is a very early TiVo from the first production run so maybe later TiVos can cope better with high bit rates? I'll try dropping the max bitrate to see if that makes any difference.

[Chris T]

Originally posted by aerialplug


My guess is that I'm pushing TiVo's decoder to its limits - and the limits may be different on various TiVos. Mine is a very early TiVo from the first production run so maybe later TiVos can cope better with high bit rates? I'll try dropping the max bitrate to see if that makes any difference.

That’s interesting, I have original very early ex-shop demo Tivo that can’t stand having its video tweaked in any way. If increase the bit rate to anything that may a useful increase then the amount of white flashes becomes intolerable.

[Dunkwho]

I wonder ... what 60XX models do we all have, could this be linked to how well white flashes are handled? Mine flashes more than a pervert with a new coat in mode 0 (doesn't with mode 4 even with the high bit rates I've tried) - its an older model from memory with 2 hd brackets ... a 601F

Duncan

[iankb]

Originally posted by Dunkwho
I wonder ... what 60XX models do we all have, could this be linked to how well white flashes are handled?Think that is irrelevant. I have a 601E model, and probably notice white flashes less than once a month. However, I have a different artifact that often appears on the TiVo, though not on 'archived' recordings. That is what appears to be a single flickering 'pixel' in a fixed position on the screen; a bit like a distant star.

I think that it is just the random limits of the components, and we are using 'out-of-band' values that TiVo decided were not reliable enough for the standard configuration. If you've ever tried to overclock a PC processor, you will know that every chip has significantly-different limits. And the configured clock speed of a CPU is often determined by sampling, rather than being specifically manufactured as such.

[themonk]

There seems some discrepancy as to what the best bit rate values are to use to eliminate the white flashing problems. I've just done this mod as per LJ's instructions and have set both xxxBestMAXBitrate and xxxBestVBRBitrate to 8000000 and have moved what were the Best values down to the High settings. The entries for both DBS (SkyDigital) and Rooftop have been changed.
I'm intending to run these values for a couple of weeks or so to see if anything spurious appears. If everything looks okay then I might have a play with VBR.

Has anyone any conclusions as to what might be causing the white flashing? Running with VBR perhaps?

[B33K34]

I get some white flashes on standard 'best' settings - credits are particularly prone where theres a lot of black with fine white text. It must just be where the capabilities of the MPEG encoder are exceeded.

[gyre]

Might it be the decoder, rather than the encoder?

-- gyre --

[iankb]

It is the decoder. The files on disk do not include the white flashes; or so I'm told. ;)

[Dunkwho]

My experience ... flashing is brought on by moving to mode 0. I don't recall ever seeing it before I started with my res\bitrate changes - not to say it wasn't there just that it'd have been so infrequent as for me to ignore it\put it down to the broadcast. I'm heading back to mode 4 with uped bit rate from my current mode 0 uped bit rate config ... last time I did this I didn't see any flashing (boo hoo, would like mode 0 for the projector :( ).

Duncan

[B33K34]

OT slightly but indulge me. IIRC Tivo either drops or raises the picture. i corrected this by adjusting the scan on the TV (I rarely use any other source so would rather have Tivo 'right'). I think the flashes tend to be at the extreme bottom of the screen - maybe Tivo's picture was dropped on purpose to hide these and my fiddling revealed them?

They reappear when the coding chip is pushed harder. i still havent got around to fiddling with the bit rates themselves

[aerialplug]

Originally posted by Dunkwho
My experience ... flashing is brought on by moving to mode 0. I don't recall ever seeing it before I started with my res\bitrate changes - not to say it wasn't there just that it'd have been so infrequent as for me to ignore it\put it down to the broadcast. I'm heading back to mode 4 with uped bit rate from my current mode 0 uped bit rate config ... last time I did this I didn't see any flashing (boo hoo, would like mode 0 for the projector :( ).


I'm afraid I've had to come to the same conclusion. My TiVo just doesn't "do" mode 0. I've tried a variety of bit rates - all cause the flashing at the bottom of the screen. I suppose some chips can cope with mode 0 and others can't swhich kind of explains why some here have no problems and others like myself can't get rid of the white flashes (on all recordings).

I guess TiVo knew what they were doing when they elected not to use the mode.

Hmm... as I was typing this, I've just realised that my mode 0 recording has a quality setting of 75, not 100. I wonder if this'll make any difference? More experimenting tonight I think...

[Nevets]

After a long hesitation (life's not worth living if I screw up our only beloved Tivo) I finally changed my "medium" quality settings to 6000000/8000000, mode 0. After rebooting, my test recording showed as CBR 8000000 in the TVLog (as expected, since I hadn't enabled the "save disk space" option).

Then I decided to go the extra step to enable VBR, and upped the quality to 80 (RecordQualityMedium in the resource editor - I assume that's the correct setting). After rebooting, any recordings I schedule for medium quality now record as basic (i.e. CBR, bitRate=1700000), but show up in Tivoweb's Now Showing as "Medium". I don't know what they look like on Tivo, as I'm at work.

The settings I have changed so far (I only have analogue rooftop aerial) are:
RecordQualityMedium = 80
RooftopMediumVBRBitrate = 6000000
RooftopMediumMAXBitrate = 8000000
RooftopMediumResolution = 0
Everything else has been left at default.

Has anyone got any idea what I've done wrong?

[blindlemon]

You need to hack ui.itcl to change all the places where it refers to "40", meaning "medium", to "80" instead. There are about 4 occurences you have to change.

TivoWeb uses hardcoded lookups on the default RQ numbers assigned to each quality to infer which quality is which. I suspect that what's happening is that when you try to schedule a "medium" recording it's looking for a quality that matches your RQ of 80. When it doesn't find it, the code drops through to the default quality, which is "basic" and uses that instead.

If you schedule the recordings from the TiVo UI when you get home you will find that they come out as medium with your expected resolution and bitrates. You will, however, have to reset any SPs or autorecord wishlists that were set to record in "medium" to "medium" again - as the same thing will have happened to them and they will now be showing as "basic".

An alternative to all the above would be to change "best" or "high" to use mode 0 and higher bitrates instead - as both these have a RQ setting >= 75 (which is where the quality changes from fuzzy to clear in mode 0). You would not then need to change the RQ for that mode, and would not confuse TiVoWeb or the TiVo UI.

[Nevets]

Thanks Blindlemon... you were spot-on.

I've changed the RQ back to 40 and it's behaving itself now. I will change "best" when I'm happy that everything works ok, but for now I've got another problem...

I have a green vertical bar on the right-hand side of the picture from ALL types of output (nudge nudge). I haven't applied LJ's fpga mod yet, but am I right in assuming that it only affects output to scart and RF (and not to things that should be discussed in the other place)?

[blindlemon]

I haven't seen the green bar on any output since applying LJ's patch :)

[Nevets]

Yep - that's fixed it. No green bar on any output since aplying LJ's patch!

About those pesky white flashes... I've noticed that on scenes which are primarily one strong colour, the 'white' flashes actually change to that colour (e.g. a shot of a very green lawn changes the flashes to green, and a shot of a very blue sea produces blue flashes). Has anybody else noticed this? Do you think this gives us any clues as to what's happening?

[aerialplug]

Personally, it looks to me as if the mpeg decoder can't cope with the bitrate/resolution. I see similar artefacts on normal resolutions occasionally when credits are being shown - or on the Sky digital channel change banner, when bits of the text appears elsewhere on the screen (usually down the bottom where the white flashed appear in mode 0).

The artefacts become much more pronounced if you REALLY turn down the bitrate (to something like 0.75Mb/s) where the mpeg really falls appart. Here, the white flashes can be seen occupying most of the screen - there really isn't enough bitrate to encode the picture here so the decoder throws its hands up in horror and displays the white flashes.

I'm surprised it's not green flashes - that's the colour "MPEG going wrong" usually seems to resort to!

It's definately been proven to be a decoding problem though, not an issue with the encoder.

What you have to remember is that the decoder chipset is about 5 year old technology now. I saw my first US DVD player only 3 years prior to this chipset being developed so it's pretty much a first generation domestic decoder/encoder combination.

[B33K34]

Is there a conclusion on this? I've yet to try changing anything but i've got sufficient disc space to cope. Like aerialplug i get artefacts appearing, usually on credits, which seems normal.

Mode 0 seems unreliable - is it worth upping the bitrate at all or are the benefits negligable?

[aerialplug]

I've given up using mode 0 for programmes that I'm going to watch through TIVo, but it still has its uses...

[blindlemon]

Originally posted by B33K34
Mode 0 seems unreliable - is it worth upping the bitrate at all or are the benefits negligable? Mode 0 is not unreliable, and the benefits in terms of picture quality are very significant - especially with larger TVs and Plasmas. I've been running Mode 0 on both my lounge TiVos since May with no problems :)

The main issue with using Mode 0 is that the picture is shifted to the left. This can be corrected using "LJ's fix" (see my sig). As for the "white flashes" I can honestly say that, for me, they're not really a problem. They are more like flickers than flashes - a bit like seeing a 1 frame scratch on an old movie - and they always occur right at the bottom of the screen. They also seem to happen more with poor quality, grainy or contrasty, source material. I watched the whole of "The Hours" last night, recorded in Mode 0 at 7500000/9000000, and only saw one white flicker.

One thing you should be aware of is that increasing the bitrates to make best use of the Mode 0 quality causes the TiVo to incorrectly report the number of hours available in the System Information and Video Recording Quality screens as it uses the max-bitrates set for each mode to calculate the capacities - whereas, in actual fact, the bitrate used 90% of the time for a recording (if you enable the "Save Disc Space" option, ie. VBR) is likely to be fairly close to the min-bitrate unless recording continously fast-action material.

This means that for a 120gb drive, which normally reports 39 hours Best, 63 hours High, 83 hours Medium and 135 hours Basic (based on the default CBR bitrates of 5960000, 3660000, 2760000 and 1700000 respectively) the TiVo information screens will report 25hrs Best, 38hrs High, 38hrs Medium and 114hrs Basic. However, assuming you use VBR, your actual capacities are more likely to be around 31 hours Best, 63 hours High, 92 hours Medium and 135 hours Basic based on the lower of each of the VBR bitrate pairs I have used:-

Best : 7500000/9000000, Mode 0, RQ 100
High: 3660000/6000000, Mode 0, RQ 75
Med: 2500000/5960000, Mode 0, RQ 55
Basic: 1700000/2000000, Mode 1, RQ 0

Why not give it a go? As you have TiVoWeb you can always change back to the default modes if you don't like the results...

[iankb]

I think that the lower of the two values is not the minimum bitrate, but the target (or average) bitrate for VBR. I use 4800000/9000000 for Best and rarely see the white flash. Maybe I'm just lucky with the tolerance of my decoding chip. I aim for DVD resolution and 50% saving on diskspace, since I'm not using a plasma. The benefit of DVD resolution comes in when you create archive copies, since there is less conversion involved.

[blindlemon]

Originally posted by iankb
I think that the lower of the two values is not the minimum bitrate, but the target (or average) bitrate for VBR. Quite right.

I must stop referring to it as "min" bitrate! I guess I just think of it that way as it's the lower of the two :)

[ccwf]

Originally posted by blindlemon
in actual fact, the bitrate used 90% of the time for a recording (if you enable the "Save Disc Space" option, ie. VBR) is likely to be fairly close to the min-bitrate unless recording continously fast-action material Relatively fast for the bitrate and resolution&mdash;when using VBR for Basic quality, I often find the resultant bitrate to be towards the maximum.

[swarrans]

...that is the question!
I don't care about number of hours available - 10 to 15 is fine with me. If I'm using a 120GB disc and mode 0 will turning VBR on or off have any impact on the white flashes or anything else?

Simon

[Dunkwho]

Originally posted by swarrans
...that is the question!
I don't care about number of hours available - 10 to 15 is fine with me. If I'm using a 120GB disc and mode 0 will turning VBR on or off have any impact on the white flashes or anything else?

You're gonna have to suck-it-and-see. Personally the white flashes are bad enough for me to stop using mode 0, other people report differently. We've not seen each other's units in action but the general theory is that different tivo units will handle mode 0 with differing ease - some flash a lot, others just a few times. There's no way to know what yours will do until you try it.

Duncan

[JeFurry]

So are the mode, the two bitrates and the recording quality percentage the only values which affect recording quality?

I've been using BoBones settings for a while now. I get white flashes occasionally, under the same circumstances other people have described, but they're not a major problem for me. However, I have been more aware of solarisation and colour banding (due to VBR, perhaps), and as as I'm about to invest in a large plasma screen (Pioneer 435XDE), I want to re-tweak.

I'm planning on downgrading "Basic" to a bare-minimum bitrate, as near as possible to audio-only recordings, restoring "Medium" to more or less its default out-of-the-box settings (but probably with VBR), changing "High" to mode 0 and highish-quality VBR, and pushing "Best" to the absolute best possible quality I can possibly get from the box regardless of space, for important stuff.

I imagine I can fiddle with this myself (and report back), but if anyone's already experimented along these lines, would you post the settings you've used, or any high/low limits I should be aware of? Ta...

[Edited to include the mode, which I forgot in the first line]

[iankb]

Before abandoning Mode-0 altogether, make sure that you've tried with Bobones' settings. These work for a lot of people (myself included), and maybe more extreme settings either way could have less success. You might not get a perfect picture, but it could be better than the default settings.

[mrtickle]

Originally posted by JeFurry
I imagine I can fiddle with this myself (and report back), but if anyone's already experimented along these lines, would you post the settings you've used, or any high/low limits I should be aware of? Ta...


Agree with the post above. If Bobones' settings don't work well for you you could try a slightly lower maximum. I use
DBSBestVBRBitrate=4800000
DBSBestMAXBitrate=6635500

For Basic quality, note there is a lower limit. 650000 is too low and the TiVo uses Best quality instead! (the tvlog also incorrectly says it is using 650000 for the recording).
675000 worked for me but I didn't try any values inbetween the two to find the absolute lowest.

Note you can also change "DefaultLiveRecordQuality" to other values - mine is at 40 so that the live buffer would be Medium quality. I thought that a mode 0 live buffer might strain the TiVo a bit much so wanted to give it a rest. The UI gets confused when you press Record to save the buffer into a recording though.

Finally, very strange things can happen when you change the Quality levels. I still don't know what is going on so I've gone back to the standard 100, 75, 40, 0 values.

[JeFurry]

Oh, I'll stick with mode 0 - the resolution gained can't be argued with, even aside from its ... "extra uses"! BoBones' settings are an improvement in resolution, definitely, but the VBR seems to introduce more colour banding, hence the wish to create a new "best" mode with the resolution but no banding. I'll probably tweak the bitrates again to see what is the max I can get that produces an improvement. Has anyone come across an upper limit for "Best"?

And mrtickle, what sort of strange things do you mean? Do they occur when you swap around those 4 default values you've listed, or only when you set the Quality level to something other than one of those 4? If you can let me know what to look out for, I'd appreciate it...

thanks for the replies...

[mrtickle]

Originally posted by JeFurry
And mrtickle, what sort of strange things do you mean? Do they occur when you swap around those 4 default values you've listed, or only when you set the Quality level to something other than one of those 4? If you can let me know what to look out for, I'd appreciate it...

thanks for the replies...

Apologies for the delay :). I found I got very "sharp" visible pixels sometimes. Medium is 352x576, and 352 pixels in a line isn't very much, particularly when it's stretched to fill a 16:9 screen. But normally it looks fine. But on some recordings with tweaked values it looked extremely blocky with very hard edges as if the resolution was more like 176x576!

[JeFurry]

Thanks for that. I ended up not changing the record quality settings, since without fairly extensive patching you can only use the 4 supplied settings, and if you set both High and Best to 100 then everything gets recorded in Best anyway.

However, I did alter the bitrates. Below are what I'm currently using... though I'm still experimenting if I feel like it, I've more-or-less stabilised on these for now. They're not much different from other people's, really. I hoped to find something markedly better, but didn't. All that's changed really is my usage - I no longer need to use Best all the time:

Best: Used only for the high-bandwidth Sky channels with programmes I'll be archiving to DVD or really REALLY want at the absolute best. I've a 43" high-def plasma screen, so if guests are coming round to see something chez moi, this is the setting to use. I do get the odd white flash at the bottom, but they're rare and small - covering less than the bottom two rows of MPEG macro-blocks.

High: Used for almost all manually specified recordings, stuff I watch and wipe - still better quality than the original "Best" mode, and frankly quite good. No flashes at this or lower settings.

Medium: Used for suggestions (I use Sanderton's famous endpad to force suggestions to Medium even though my default is High) and stuff like <i>Have I Got News For You</i> where movement is low and quality isn't paramount. LOTS of space at this setting!

Basic: Used for audio only. Lowest video bandwidth I could get without problems.

DBSBestVBRBitrate 7 000 000
DBSBestMAXBitrate 9 000 000
DBSBestResolution 0

DBSHighVBRBitrate 5 500 000
DBSHighMAXBitrate 7 000 000
DBSHighResolution 4

DBSMediumVBRBitrate 2 760 000
DBSMediumMAXBitrate 4 000 000
DBSMediumResolution 1

DBSBasicVBRBitrate 675 000
DBSBasicMAXBitrate 675 000
DBSBasicResolution 1

I experimented with much higher bitrates for Best, and only found more flashes with no visible improvement in quality. With High, I whacked the settings up massively, then lowered them until just before the quality became less than satisfactory. Medium's fairly soft and fuzzy, but not heavily pixellated. I wanted to get an efficient use of space without making it look like crap, and although the recording resolution is low, it manages to look soft-focus rather than pixellated most of the time. VBR means that it's got some headroom if needed. Basic speaks for itself.

Hope that's of use to someone - sorry I couldn't find anything more revolutionary, but I guess those who did this before me had done a fine job and there simply wasn't much room for improvement, only tweaking to taste.

-Jef.

[swarrans]

JeFury - how is your banding issue now? I've got a plasma too and I think the banding is worse with mode 0 and 9m/7.5m settings - plus the colours look even more lurid than normal. I'm seriously considering going back to original settings as I'm not convinced I see an overall improvement in quality.

Simon

[scgf]

After some experimentation I decided on a BestVBRBitrate of 5960000 and a BestMAXBitrate of 8560000, mode 0.

I recently tried the 7000000/9000000 settings but found the quality on my plasma screen to be inferior to my old settings. It wasn't so much the objective quality but more of a subjective thing. I went with 7000000/9000000 for a few days then switched back. The difference is very noticeable - the picture is now somehow more watchable. There are fewer digital artifacts too.

Maybe a particular combination of VBR & MAX bitrates does more than the individual settings would suggest?

[swarrans]

Thanks scgf, I'll certainly try it.
As I don't have Tivo web or anything (bought the drive with mode 0) I'll try and get one of those serial cables...

Simon

[JeFurry]

Originally posted by swarrans
JeFury - how is your banding issue now? I've got a plasma too and I think the banding is worse with mode 0 and 9m/7.5m settings - plus the colours look even more lurid than normal. I'm seriously considering going back to original settings as I'm not convinced I see an overall improvement in quality.

Simon
It's actually harder to tell than you'd think - I have a high-def plasma with all sorts of smart gradient smoothing capabilities, and it makes quite a difference when I turn selected ones on or off.

With as many of the filters turned off as I can get, it's still way better than my old 100Hz CRT (which was an early one, and had the negative effect of solarizing images badly, so I'm kinda spoiled by the plasma which smooths things out).

I think this depends so much on your own equipment that any comparison I might offer wouldn't help lots.

However, scgf's suggestion is something I haven't tried... it simply didn't occur to me to lower the maximum rate. I shall experiment further, probably over Christmas, and report back.

[Fatbloke]

I tried this yesterday and finally got it working in mode 0.
Since live TV is set to BEST, I've noticed it's chopping off the left side of the picture. Things like the 'Sky News' logo now read 'ky News' !

My question is, will the LJ fpga7114 file shift the picture to the right or more to the left? I can't see any green bar on my TV at the moment.

Either that, or is it possible to change Live buffer to 'High quality' ?

Happy Christmas!

[Lysander]

Fatbloke,

The patch should solve that. The reason you can't see the green bar is the overscan on your TV, you still need LJs patch when using Mode 0.

Lysander. (Stuffed...)

[Fatbloke]

Ah, some confusion here.
I CAN see the green par at the bottom of the screen that shows you how far through the buffer you are. That's fine.
However, I was just commenting that luckily I cant see and of the vertical green edge on right side of the screen that I've noticed when I've done undiscussable things :)

So I was wondering whether the patch would just shift the picture to the right a small way?

[Lysander]

Nope, no confusion. The vertical green bar on the right is there on all pictures in Mode 0, but if the overscan on your TV is quite large then it will not be shown.

LJ's patch will indeed move the picture to the right.

[blindlemon]

LJ's patch moves the picture to the right on the input to the encoder too, so the green bar disappears from the recording too :)

If you have that much overscan on your TV though you are missing quite a bit of your screen! Most TVs allow you to fix this from the Service menu - but you may need to hunt around to find how to access it.

[gyre]

OK, after a goodly period of time folks will have worked out what settings are best for them.

Is there a general concensus on what is the best setting for mode 0 for best quality?

Thanks!

-- gyre --

[kitschcamp]

Not really. What works for one seems not to for others. I haven't found a range yet that do not lead to lip sync problems eventually.

[Fatbloke]

Originally posted by Lysander
LJ's patch will indeed move the picture to the right.


Worked a treat ! :)