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

[Sam Varshavchik]

Michael T. Dean writes:

> <fixed top posting>
> 
> On 03/18/2008 07:51 AM, Johnny Russ wrote:
>> Sam Varshavchik wrote:
>>   
>>> I upgraded from 0.20.2, that was working just fine, to 0.21. Now, 
>>> randomly, the video appears to "stutter". The best description I can 
>>> come up with is that randomly, the next frame is rendered out of 
>>> position horizontally, by 16 or 32 pixels. The following frame is 
>>> rendered in the right place. This happens frequently, but randomly and 
>>> without any apparent pattern. Also, more randomly, a frame appears to 
>>> be drawn offseted vertically by one scan line.
>>>
>>> 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. My problem 
>> sounded a little different, mine would just skip or hang in places. I 
>> found out that in 0.21 they changed the way the video is rendered. More 
>> CPU intensive methods are used by default. I had to go into TV settings 
>> -> Playback. There is a section that allows you to choose which playback 
>> method is used based on resolution, etc. I only have a P III at 1 GHz in 
>> my box so I had to switch mine from the new settings back to using XvMC 
>> and that got things working for me. I am not sure what settings would be 
>> appropriate for your box. I believe you can also try ivtv as the primary 
>> playback in the same dialog. Good luck.
> 
> 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.

It also appeared to me that the video I was getting looked kind of grainy, 
compared to 0.20; now with the slim playback profile it's clear again.


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