Modes and Bitrates

[PhilG]

I have tried and tried to make sense of all the discussions on "mode 0" and "bitrate settings" and I am getting nowhere

Is there a thread (or somewhere) that explains SIMPLY what mode 0 is/does and what the different bitrate settings do?

Many of the threads seem to be fiddling with settings without coming to any concrete conclusions

Santa is bringing us a nice new Panasonic plasma and I want to make sure that Tivo is up to the job.

Our citrus friend is enabling mode 0 for me whilst he is doing a warrantly replacement on my 200Gb drive, but I wondered what else I need to consider (and I don't like to exceed his goodwill by asking too many stupid questions!)

Basically, I guess what I'd like to know is how to get the BEST picture quality at each of the recording settings of Tivo. In the past I have tended to go for quantity of recordings over quality (and, to be honest, on a CRT TV, the picture doesn't look THAT bad), but with the plasma I think I need to be more choosy

Thanks for any pointers (especially ones with concise explanations!)

Cheers

Phil G :o

[blindlemon]

Mode 0 is a special "hidden" recording mode on your TiVo that gives you near-DVD quality recordings (720x576px) and increased bitrates to reduce artifacts. Hopefully you have already read the threads on the TiVo forum discussing Mode 0 and enhanced bitrates:-

http://www.tivocommunity.com/tivo-vb/showthread.php?threadid=128288
http://www.tivocommunity.com/tivo-vb/showthread.php?s=&threadid=157650

If not, I should mention that there are a couple of issues with using Mode 0. The main one is that the picture is shifted to the left. This can be completely corrected using "LJ's fix", which I load as part of the setup, so is not really a problem at all. The other thing that people notice is the presence of occasional "white flashes". As yet there is no known fix for this - but I can honestly say that, for me and many others who use Mode 0, 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, and worse with BBC channels for some reason.

I normally supply Mode 0 drives setup with my preferred bitrates:-

Best : Mode 0, 7500000/9000000, VBR
High: Mode 0, 3660000/6000000, VBR
Med: Mode 0, 2500000/5960000, VBR
Basic: Mode 1, 1700000/2000000, VBR

This is great if you are not bothered by white flashes as you get 3 qualities in Mode 0, and all except one of my customers so far has been happy with this. However, one guy was very bothered by the white flashes as he recorded a lot of stuff from BBC channels (which seem most prone to them), so I changed his drive to the following:-

Best - Mode 0, 7500000/9000000, VBR
High - Mode 4, 5960000/5960000, CBR (effectively the same as normal "best")
Med - Mode 0, 3660000/6000000, VBR (not as sharp as the equivalent "high" setting above)
Basic - Mode 1, 1700000/2000000, VBR

One other thing you should be aware of before deciding to use Mode 0 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. The reason for the discrepancy is because these screens use 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, or even less than the VBR-bitrate unless recording continously fast-action material.

This means that for a 200gb drive, which normally reports 67 hours Best and 235 hours Basic (based on the default CBR bitrates of 5960000 and 1700000), with Mode 0 enabled the TiVo information screens will report around 45 hours Best and 200 hours Basic because they are now making the calculations using bitrates of 9000000 and 2000000 respectively. However, assuming you use VBR, your actual capacities for a 200gb drive are more likely to be at least 53 hours Best, and 235 hours Basic based on the lower of each of the VBR bitrate pairs. In fact, if you use VBR, they will probably be better than this as the encoding chip will always use the lowest sensible bitrate it can get away with.

Approximate capacities calculated assuming the first set of bitrates, mode 0 and VBR are:-

1 x 120gb - 31 hours best, 135 hours basic
1 x 160gb - 42 hours best, 185 hours basic
1 x 200gb - 53 hours best, 235 hours basic
1 x 250gb - 66 hours best, 293 hours basic
1 x 300gb - 80 hours best, 353 hours basic
1 x 400gb - 110 hours best, 487 hours basic
1 x 500gb - 137 hours best, 608 hours basic

2 x 250gb - 137 hours best, 608 hours basic
2 x 400gb - 220 hours best, 973 hours basic

Of course, if you have TiVoWeb then you will be able to tinker with all the above bitrates to your heart's content, and may find that lower or higher bitrates, or a larger spread between the VBRBitrate and MaxBitrate for a particular recording quality gives you more of what you want (ie. either quality or quantity). If you find a setup that seems to be spectacularly better than the above in any respect, or manage to eliminate white flashes completely by some means then please let us know :)

[Heuer]

And if you have a fixed pixel device (Plasma or LCD) you will be able to move the picture down slightly which will all but eliminate the white flashes.

[chrisd]

aaaahhh, so its 'blind lemon', not 'blindle mon' like i've been reading all these years!! :o

[Pete77]

aaaahhh, so its 'blind lemon', not 'blindle mon' like i've been reading all these years!! :o

Just some people's interpretation of it I believe.

I don't believe the master of heavenly Tivo upgrading has ever fully explained his choice of forum member name.

[chrisd]

So what settings do I change within resource editor on tivoweb?
there's 3 sets that I can see- DBS, CATV, and Rooftop.. do I need to change all 3 of them for basic, medium, best ??

[Mike B]

IIRC, you need to change CATV if you are using Freeview or Digital Cable as your programme source or DBS if you are using Sky. Changing Rooftop bitrates will only affect recordings made using the internal tuner.

I'm sure someone will correct me if I'm wrong...

[Pete77]

IIRC, you need to change CATV if you are using Freeview or Digital Cable as your programme source or DBS if you are using Sky. Changing Rooftop bitrates will only affect recordings made using the internal tuner.

I'm sure someone will correct me if I'm wrong...

You are correct and also Best for CATV needs changing to at least Mode 4 instead of the Mode 2 set by Tivo as its widely regarded to have been a mistake that they used a lower quality resolution for Best on Cable and Freeview compared to Sky Digital. Perhaps they thought it was all analogue cable which does have a less good picture quality. Mode 2 for Best on Aerial would probably be a sensible setting.

[chrisd]

I'll give it a go as soon as the other half finishes with her program.

I'm guessing that if I only ever record stuff in 'best' then I only really need to change the one bitrate? Or do I still need to do high, basic etc anyway?

One other thing. These settings are for the recordings correct? So if I watch some live tv ever (you never know, it might happen!) will the quality be the same as it is currently, or do the new bitrates affect that ?

[blindlemon]

I'm guessing that if I only ever record stuff in 'best' then I only really need to change the one bitrate?Indeed.
if I watch some live tv ever (you never know, it might happen!) will the quality be the same as it is currently, or do the new bitrates affect that ?Live TV is normally recorded at Best quality, so if you change the "Best" bitrates you will affect LiveTV.

There is also another variable "DefaultLiveRecordQuality" that selects which quality Live TV is recorded at, so if you want to have Live TV recorded at Medium quality for instance, change it be the same as the "RecordQualityMedium" value.

[Pete77]

Indeed.
Live TV is normally recorded at Best quality, so if you change the "Best" bitrates you will affect LiveTV.

But if you watch Live Tv when Tivo is also recording it at a lower quality setting like Medium or Basic then during that time the Live Buffer displays in that lower quality setting. It changes back to the Best setting at the end of the recording.

[chrisd]

I keep trying to change the CATVBestVBRBitrate to 7500000 and CATVBestMAXBitrate to 9000000, but I then have to click on resource editor again in order to save the settings, then it just reverts back to the normal 5960000 in both fields... what am I doing wrong?

Also, for CATVBestResolution, should I change this to 0?

[Raisltin Majere]

Are you hitting enter after changing each value?

[Pete77]

I keep trying to change the CATVBestVBRBitrate to 7500000 and CATVBestMAXBitrate to 9000000, but I then have to click on resource editor again in order to save the settings, then it just reverts back to the normal 5960000 in both fields... what am I doing wrong?

Also, for CATVBestResolution, should I change this to 0?

You need to press the Return key after each value you enter and then Update Resources at the end when you have backed out one screen. If you don't press Enter after each value you change they won't be saved when you Update Resources.

You should change Best on CATV to 0 if you want to have the best possible quality when watching Live tv and when recording in Best (which will now be Mode 0)

There is a whole thread about this if you go back a Page or 2 on the index or use Advanced Search. Also there is a whole article about the best settings to use on the www.tivoheaven.co.uk website.

[chrisd]

Are you hitting enter after changing each value?

ah, that's the puppy!

Cheers, got it working finally.

I think those flashes at the bottom are gonna get too annoying though !
Will have to go back to the normal res before long.

[Pete77]

I think those flashes at the bottom are gonna get too annoying though !

Will have to go back to the normal res.

Try using 9000000 and 6000000 instead of 9000000 and 7500000. I found BBC Three was one of the main problem channels for white flashes.

[chrisd]

yeah that seems a bit better, i'll stick with it for a while and see..

[Pete77]

yeah that seems a bit better, i'll stick with it for a while and see..

9000000 and 4500000 were I think even mentioned by ikb as being a viable Mode 0 option that he ran. You should still get the 9000000 when there is fast motion in the picture. Or perhaps 7500000 and 4500000. There is nothing saying you have to use 9000000 and 7500000 and of course your total recording capacity will be a lot better with any of those reduced settings.

I notice that Hard Core Mode 0'ers never seem to make any mention of running out of space to record programs as being an issue. ;)