If I switch to Mode 0 will I need to ditch any recordings?

[itm]

I've just invested in a 42" LCD (1366x768), so presumably would benefit from Mode 0. My question is: will I lose access to my existing recordings when I switch??

[aerialplug]

No - new recordings will be made in the new mode and old recordings will continue to play in their original resolution.

I've recently bought a 42 inch plasma Panasonic Viera) and find default best quality to be prefectly acceptable from the correct viewing distance (at least three times as far away as the screen height). I have mode 0 set up on selected recordings but occasionally grey flashes at the bottom of the screen when the image is busy.

On the plus side, I've held off buying a plasma/LCD for a very long time having seen how they show up MPEG artefacts but I've been more than pleased with the Viera.

[itm]

Hmmm...if "normal" Best Quality looks OK on plasma I wonder if the same will be true for LCD?

[aerialplug]

Try it and find out.

Mode 0 is undoutedly sharper than mode 1 as it has more horizontal pixels to represent the picture, so you will notice the difference.

If I sit any closer to my screen than I do when sitting on the sofa, I start to see MPEG artefacts all the time - but not at the distance/size I wanted when I bought it so it's fine for me.

[itm]

I've now got Mode 0 set up and Match of the Day did seem a little sharper than usual last night. I did see alot of white flashes at the bottom of the screen though. Is there a fix for this?

[Pete77]

I've now got Mode 0 set up and Match of the Day did seem a little sharper than usual last night. I did see alot of white flashes at the bottom of the screen though. Is there a fix for this?

Try lower values for Best VBR BitRate in the Bitrates section of Tivoweb's Resources Editor while leaving the Max Birate at 9000000.

iankb says he uses 4700000 (I think) as the VBR BitRate and gets almost no white flashes. This also has the advantage of giving you a much higher number of recording hours than a VBR BitRate of 7500000. Approximately 50% more I believe, although System Information won't report this as it makes all its calculations based on the Recording Mode and the Max Bitrate used for each recording quality. For the UK Tivo software Tivo assumed that people would only be using Constant Bit Rate, which is why setting a lower VBR BitRate does not increase the quoted recording hours in System Information, even though it does substantially up the actual recording hours.

Alternatively you might want to try a VBR bit rate of 6000000 first and then change to 4700000 if you still get white flashes.

[itm]

Dumb question - how do you save changes to the bitrates in the Tivoweb Resource Editor page? There's no "save" button!

Also, do I need to change all of the following values?
DBSBestVBRBitrate
CATVBestVBRBitrate
RooftopBestVBRBitrate

[Pete77]

Dumb question - how do you save changes to the bitrates in the Tivoweb Resource Editor page? There's no "save" button!

Also, do I need to change all of the following values?
DBSBestVBRBitrate
CATVBestVBRBitrate
RooftopBestVBRBitrate

You need to hit the Enter key after entering each value in each white box you want to change and then also hit the back button to get back to the main resources editor page and click the "Update Resources" link.

If you only use Sky then you only need to change the DBS values but if you also use use Freeview or Cable you need to change the CATV settings too or the Rooftop settings if you use the internal tuner to record anything.

[blindlemon]

You need to hit the Enter key after entering each value in each white box you want to change and then also hit the back button to get back to the main resources editor page and click the "Update Resources" link.Then reboot.

[blindlemon]

4700000 [...] has the advantage of giving you a much higher number of recording hours than a VBR BitRate of 7500000. Approximately 50% more I believeNot really, as the VBRBitrate is just a 'target' bitrate for the encoder to aim for, so if a scene requires significantly less - eg. 2000000 - for a few seconds then it will probably be encoded at roughly the same bitrate regardless of the target.

You will get slightly smaller recordings with a lower VBRBitrate, but not in direct relation to the bitrates, and you run the risk of seeing more pixellation too.

[Pete77]

You will get slightly smaller recordings with a lower VBRBitrate, but not in direct relation to the bitrates, and you run the risk of seeing more pixellation too.

But less white flashes though. ;)

[itm]

I've just switched to dual-source, with a Freeview box, and I've got the white flashes back on the Freeview channels. I already have CATVBestVBRBitrate and RooftopBestVBRBitrate set to 47000000. Should I try lower values?

[blindlemon]

IME lowering the bitrates doesn't make that much difference to the white flashes - it's the quality (or lack of) of the source signal that is critical.

If you're running the freeview box in via RF then you will suffer more from white flashes on Freeview as the extra noise in the RF-modulated signal will upset the decoder. Not sure which set of values the TiVo will use for Freeview in a dual-source setup though...

[Pete77]

I've just switched to dual-source, with a Freeview box, and I've got the white flashes back on the Freeview channels. I already have CATVBestVBRBitrate and RooftopBestVBRBitrate set to 47000000. Should I try lower values?

In view of Blindemon's comments and the fact that one has to use the highly unsatisfactory RF source as the Freeview box secondary source input feed I suspect that it makes more sense to set CATV Best to Mode 4 (i.e normal Best recording quality) in these circumstances while leaving VBR Birate enabled (ie different values for Max and Variable BitRate). You might even find that Mode 2 works better as I believe this is the original default Best value on Rooftop for the Tivo.

Realistically the only channels you are going to record from Freeview with a dual source setup are E4, More4, UK History, FTN and UK Bright Ideas and conceivably (although rather unlikely) The Hits and TMF. As the only channels you would probably record any quantity from are E4, More4 and UK History its probably best to pick the lower Mode quality and avoid the white flashes.

[itm]

Thanks for the tip - I'll try setting CATVBestResolution to 4 initially and see if that improves things.
Actually I plan to record all of my terrestrial channel stuff from Freeview to stop it tying up the Sky box (that way I can watch the footie even if my wife is recording Corrie).

[Pete77]

Actually I plan to record all of my terrestrial channel stuff from Freeview to stop it tying up the Sky box (that way I can watch the footie even if my wife is recording Corrie).

I hadn't realised that in which case you might want to stick with Mode 0 for CATV but try setting 4700000 for the Variable Bit Rate, which forum regular iankb reported as resolving most of his white flashes issues. If this doesn't do the trick you could try downgrading to Mode 4 for CATV.

The prevalence of white flashes seems to vary on a box by box and channel by channel basis so its hard to forecast in advance what may work for you.

[iankb]

... try setting 4700000 for the Variable Bit Rate, which forum regular iankb reported as resolving most of his white flashes issues.I use 4800000 for VBR, but haven't really tried experimenting with different rates - because I don't need to. I'm lucky enough to have one of those models that only rarely has an issue with white flashes. :)

Since the white flash appears to be a by-product of running components out of specification, it will vary between motherboards, and might even vary with the accuracy of the PSU voltage levels.

[Pete77]

I use 4800000 for VBR, but haven't really tried experimenting with different rates - because I don't need to. I'm lucky enough to have one of those models that only rarely has an issue with white flashes. :)

Since the white flash appears to be a by-product of running components out of specification, it will vary between motherboards, and might even vary with the accuracy of the PSU voltage levels.

Almost correct on the rate you are using then ian.

How many hours recording capacity do you seem to actually get with 4800000 VBR Mode 0 rate compared to what System Information wrongly suggests is your total Best recording capacity?

[iankb]

Haven't bothered to check it since I first switched to Mode 0, but it was almost twice as much, as you would expect with a 4800000 to 9000000 ratio between VBR and Max.

It won't be a perfect fraction, since the blocksize of the MFS filesystem is very large, and you will always lose half a block on average, whatever the bitrate. I tend to make longer recordings (e.g. films), and so my savings will be larger than those who record soaps and cartoons.

[Pete77]

Haven't bothered to check it since I first switched to Mode 0, but it was almost twice as much, as you would expect with a 4800000 to 9000000 ratio between VBR and Max.

It won't be a perfect fraction, since the blocksize of the MFS filesystem is very large, and you will always lose half a block on average, whatever the bitrate. I tend to make longer recordings (e.g. films), and so my savings will be larger than those who record soaps and cartoons.

Interesting as ever.

What kind of job do you work in exactly as your technical knowledge is always amongst the most impressive in the forum.

[iankb]

What kind of job do you work in exactly ...Just a Software Consultant/Contractor.

But I do tend to do a lot of R&D, and specialise in developing real-time graphics, network programming, cryptographic systems, anti-fraud, search engines, and the like. Currently finishing off a project on integrating the graphical layout of magazine advert placement within an order processing system. Drag an advert to a new location within the layout and it will instantly move on every other user's screens. I just love it when a plan comes together. :p

[Pete77]

Just a Software Consultant/Contractor.

But I do tend to do a lot of R&D, and specialise in developing real-time graphics, network programming, cryptographic systems, anti-fraud, search engines, and the like. Currently finishing off a project on integrating the graphical layout of magazine advert placement within an order processing system. Drag an advert to a new location within the layout and it will instantly move on every other user's screens. I just love it when a plan comes together. :p

All extremely complex and clever stuff although annoyingly usually the marketing types who dream up the outline of these systems (but have little clue as to their actual ability to be implemented) tend to do better financially than those who do all the hard work of creating them....................

I hope that's not true in your case though.

[itm]

I hadn't realised that in which case you might want to stick with Mode 0 for CATV but try setting 4700000 for the Variable Bit Rate, which forum regular iankb reported as resolving most of his white flashes issues. If this doesn't do the trick you could try downgrading to Mode 4 for CATV.


Thanks for the tip. I was already running at 4700000 for VBR, but switching CATV to Mode 4 seems to have doen the trick.

[Pete77]

Thanks for the tip. I was already running at 4700000 for VBR, but switching CATV to Mode 4 seems to have doen the trick.

Not getting white flashes on your Sky box with Mode 0 though? If you did BBC Three and Two Pints would be one of the favourite candidates for a problem.

If you get the white flashes issue on the Sky feed then just cutting VBR to 4800000 should hopefully do the trick, and as iankb points out it also increases total recording time available.

[TCM2007]

In view of Blindemon's comments and the fact that one has to use the highly unsatisfactory RF source as the Freeview box secondary source input feed I suspect that it makes more sense to set CATV Best to Mode 4 (i.e normal Best recording quality) in these circumstances while leaving VBR Birate enabled (ie different values for Max and Variable BitRate). You might even find that Mode 2 works better as I believe this is the original default Best value on Rooftop for the Tivo.

Realistically the only channels you are going to record from Freeview with a dual source setup are E4, More4, UK History, FTN and UK Bright Ideas and conceivably (although rather unlikely) The Hits and TMF. As the only channels you would probably record any quantity from are E4, More4 and UK History its probably best to pick the lower Mode quality and avoid the white flashes.

I don't know this for sure, but I would expect that it's the Rooftop settings which control the Freeview box in a dual setup arrangement. You'll be able to tell in Channels I Receive; if labeled AER it's rooftop or CAB its CATV.

E4 and More4 are actually broadcast in 544 x 576, which is I believe Mode 1, so even Mode 4 is unlikley to bring any improvement.

[itm]

The Freeview channels are shown as CAB in Channels You Receive.

BBC3 is also devoid of white flashes, and so I believe is Sky (from watching Live TV, anyway). It looks as if Pete77's suggestions did the trick.

[Pete77]

The Freeview channels are shown as CAB in Channels You Receive.

Yes that's correct. Rooftop only covers the internal UHF tuner Ch21-69 channels inside the Tivo. However a Freeview box by RF as a secondary source is about the same quality of picture i.e. watchable but not very good quality. Freeview by Scart and Mode 0 is a different story and more or less as good as digital satellite by Scart, at least on the BBC Freeview channels, if not on ITV or CH4 channels.