[mythtv-users] PVR250 + TVWonder = jerky

Bruce Markey bjm at lvcm.com
Wed Jun 4 01:20:44 EDT 2003


Isaac Richards wrote:
> On Wednesday 04 June 2003 12:18 am, Bruce Markey wrote:
> 
>>Vincent AE Scott wrote:
>>...
>>
>>
>>>so then i tried switching over to mpeg4, and the jittery playback
>>>suddenly ceased.  that was with the new option both enabled and
>>>disabled.  so it looks more likey that the problem is with the rtjpg
>>>codec.
>>
>>Confirmed. One potential problem that I'd seen, and Mark
>>Chou pointed, is that prebuffering and rebuffering may be
>>contributing to choppiness for Live TV. RTjpeg writes
>>larger files so more data to move through the buffers.
>>If I use RTjpeg at low res for local live TV, I see 90%+
>>idle CPU but it's constantly pausing to prebuffer. I
>>hadn't been testing with RTjpeg so thanks for pointing
>>this out.

Of course, I meant 10%+ idle.

> Hm.  Does changing line 363 of nuppeldecoder.cpp to:
> 
>     ringBuffer->CalcReadAheadThresh(12000);
> 
> help any?  Not that that's an actual fix, but I'd like to see..

Inconclusive. This wrote more "rebuffering (125268 128000)"
messages but the "prebuffering..." messages are triggered
by high motion. It's hard to tell if they are more common
one way or the other.

I neglected to ask you if you could uncomment the prebuffer
message for when you see the 10ms std dev.

--  bjm



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