[mythtv-users] Upgraded to 0.21, video "stutters"

[Michael T. Dean]

On 03/19/2008 07:23 PM, Sam Varshavchik wrote:
> Michael T. Dean writes:
>> On 03/18/2008 07:51 AM, Johnny Russ wrote:
>>> Sam Varshavchik wrote:
>>>> I'm running X on a PVR-350's framebuffer (using the ivtv X driver). 
>>>> Should I try switching to a VGA monitor? But, video from 0.20.2 was 
>>>> ok.
>>> I had problems with video playback when I upgraded to 0.21.
>> Just choose the Slim playback profile group if you want 0.20-like 
>> rendering.
>
> That was it. I didn't think to look in there, because it just never 
> occured to me that there's more than one way to decode an MPEG stream. 
> This piques my curiosity -- what exactly might be to do here, besides 
> scaling the MPEG stream to the desired resolution.

Getting it on screen.  Deinterlacing the video.  Drawing an OSD on top 
of the video.  Fading the OSD (or not).  Applying filters for 
post-decode-processing to improve playback quality.

> It also appeared to me that the video I was getting looked kind of 
> grainy, compared to 0.20;

Why would depend on exactly what playback profile you were using (and 
which parts of it were supported by your hardware).

> now with the slim playback profile it's clear again.

BTW, Sam, using the Slim profile is the 0.20 equivalent of "software 
rendered" output.  If you're using the PVR-350 for output, that means 
you're using the PVR-350's Xv output and are not using the PVR-350's 
decoder.  If you want to use the decoder, you may have to create your 
own profile group.  Using CPU-- might work "out of the box," but it has 
a bunch of stuff that's not really useful to you, so I'd recommend 
creating your own.

However, I'd say you're probably better off using Xv (and, so, you can 
stick with Slim) since PVR-350 output support is bitrotting since no one 
has stepped up to maintain it.

Mike