AltEPG

Hi there
I have recorded a lot of programs in mode 0 but have converted back to mode 4 since because of the flashes and blocks of color I was getting in mode 0. What I wanted to know is it ok to watch those higher resolution programs on now a lower resolution outputting tivo now its in mode 4? It want do any harm to the tivo will it, as I have a lot of programs in mode 0 I haven't watched? Does it convert the high res to a low one automatically?
Thanks for any help

The Mode is set at the time of recording, so only recordings after you changed the setting will be in Mode 4.

Your existing Mode 0 recordings will remain at Mode 0.

It is not thought to damage the Tivo, just display the glitches/flashes as you have seen.

Thanks for the reply

Jonmon - see my long waffley post here http://www.tivoland.com/forum/viewtopic.php?f=8&t=474&p=9844#p9843

In summary, I am convinced that the mode 0 flickers/flashes are highly dependent on the quality of the input signal. If you feed it a signal of the highest possible quality (which certainly must be via SCART) then I think you will see far fewer flashes/flickers (and possibly hardly any at all - that's been my experience). If you are already using what you believe to be a high quality SCART source then it may be worth trying to feeding TiVo with an alternative set top box.

In particular, as confirmed by drgeoff in the thread mentioned, I think the analogue noise (which may not be particularly visible to the eye) in a picture signal arriving via the RF aerial feed pushes the MPEG decoder to the edge of its abilities and leads to significantly more flickers/flashes (and a generally lower quality picture from the MPEG decoder).

tivofantastic wrote:In summary, I am convinced that the mode 0 flickers/flashes are highly dependent on the quality of the input signal. If you feed it a signal of the highest possible quality (which certainly must be via SCART) then I think you will see far fewer flashes/flickers (and possibly hardly any at all - that's been my experience). If you are already using what you believe to be a high quality SCART source then it may be worth trying to feeding TiVo with an alternative set top box.

In particular, as confirmed by drgeoff in the thread mentioned, I think the analogue noise (which may not be particularly visible to the eye) in a picture signal arriving via the RF aerial feed pushes the MPEG decoder to the edge of its abilities and leads to significantly more flickers/flashes (and a generally lower quality picture from the MPEG decoder).

The mode0 flickers only appear when the recording is played by Tivo to the TV screen. They are NOT in the recording itself.

You can prove this by copying the recording from (networked) Tivo to a PC and then burning to DVD (for example). You don't get any flashes when you watch the recording. Feeding Tivo with different set top boxes etc. will make no difference to the flashes.

The mode0 flickers only appear when the recording is played by Tivo to the TV screen. They are NOT in the recording itself.

You can prove this by copying the recording from (networked) Tivo to a PC and then burning to DVD (for example).

You don't get any flashes when you watch the recording.

Agreed - I had also noticed the lack of flickering when playing a TiVo recording on a PC, even when I used to record from the RF input (i.e. via the aerial input on the TiVo).

Feeding Tivo with different set top boxes etc. will make no difference to the flashes.

This is definitely NOT the case, but is still consistent with what you say above. I can assure you that changing to a clean SCART fed source has all but eliminated flickering on my TiVo.

As mentioned, it is the MPEG decoder that introduces the flickering during playback. I guess this is down the bit rate of an MPEG stream originally derived from a noisy RF source being somewhat higher than for a recording of a cleaner SCART source. I am not an expert on MPEG decoding, but I guess the bit rate is variable and perhaps the flickers (when played back on the TiVo) appear when the bit rate peeks due to a spike in the noisiness/complexity of the source.

I can confirm that my TiVo used to flicker a lot more when I used to record via the RF input, as opposed to the SCART feed I now use. I used to use a terrestrial freeview box via the RF input, but now use an old Sky box (with Freesat card) via the SCART - I can't remember the last time I noticed a flicker.

YMMV, but from my experience I would definitely recommend trying to feed TiVo with a nice clean signal via SCART even if you do think your current RF source appears fairly clean to the eye.

I am running Sky Digital via scart and scart to the tv and have been using Mode 0 for about 3 months (since I found the kickstart codes on this forum) on a Tivo heaven upgraded drive and have never seen any problems at all: no flashes, green bands or break-ups - just a stunning picture on the ol lcd.

Why arn't I experiencing the problems you guys are talking about?

The problem occurs because this mode pushes the tivo hardware hard, past a limit where they can guarantee it will work on every tivo without problems. Hence it not being offered from day 1 in late 2000, even though your particular tivo works fine with it. The results varies from tivo to tivo. You may be just lucky.

There were also issues with VBR (variable bit rate) which resulted in lipsync errors on some machines, which is why that option was disabled too. (the menu options remained, but regardless of whether or not you selected "save disc space" it still uses the same fixed bitrates for both "on" and "off". Earlier in the beta testing of 2.5.5, this option enabled/disabled VBR)

These days of course we can use both Mode0 and VBR by editing the resources in tivoweb etc.

tivofantastic wrote:As mentioned, it is the MPEG decoder that introduces the flickering during playback. I guess this is down the bit rate of an MPEG stream originally derived from a noisy RF source being somewhat higher than for a recording of a cleaner SCART source. I am not an expert on MPEG decoding, but I guess the bit rate is variable and perhaps the flickers (when played back on the TiVo) appear when the bit rate peeks due to a spike in the noisiness/complexity of the source.

Interesting.
My tivo is fed by a Pioneer freeview STB via the scart (RGB) and I have had the mode0 flashes from day 1.
Last weekend, I retired my old Hitachi CRT and hooked up a new Panasonic LED.
An interesting side effect of this swap is the mode0 flashes from Tivo have gone.
No change to Tivo or the STB, just a new TV.

johalareewi wrote:Last weekend, I retired my old Hitachi CRT and hooked up a new Panasonic LED.
An interesting side effect of this swap is the mode0 flashes from Tivo have gone.
No change to Tivo or the STB, just a new TV.

Could it be down to a difference on how much overscan the TV has? In my case mode 0 flashes happened right at the bottom of the screen and I could hide them by increasing the overscan.

The other possibility I can think of is some TVs have digital processing (e.g. to double frame rate) and this is somehow removing the flashes.

DX30 wrote:The other possibility I can think of is some TVs have digital processing (e.g. to double frame rate) and this is somehow removing the flashes.

This can be tested by connecting the old TV at the same time (via TiVo's RF output). See if the flashes happen on one display and not the other.

DX30 wrote:Could it be down to a difference on how much overscan the TV has? In my case mode 0 flashes happened right at the bottom of the screen and I could hide them by increasing the overscan.

Possibly. My mode0 flashes were at the bottom of the screen too.

I ended up using mode0 for recordings that would be moved to the PC for viewing / processing and used mode1 for run of the mill stuff.

The other possibility I can think of is some TVs have digital processing (e.g. to double frame rate) and this is somehow removing the flashes.

The new TV does do some processing of the the Tivo output. Upscaling and double frame rate seem to be automatic for SD sources. I am not complaining, now I can use mode0 for everything.