[mythtv] Problem with Via VLD XVMC display and DVB recordings in current CVS: Gaps in video and audio

[Terry Barnaby]

Terry Barnaby wrote:
> Terry Barnaby wrote:
> 
>> Hi,
>>
>> The current MythTv CVS version of MythTV has a stange problem with 
>> display on my Via M10K box which uses Via VLD XVMC hardware MPEG decode.
>> The Via M10K box is a simple client with a separate server containg 
>> DVB cards.
>>
>> Myth CVS after 2005.03.30 has this problem.
>> MythTV CVS before 2005.02.20 is Ok.
>>
>> If I watch an old recording, all is fine.
>> If I watch live TV or a new recording the video and audio seems to
>> have continuous gaps (about 4 per second) resulting in unwatchable/
>> unlistenable output. This results in a start/stop display.
>> There are no special messages from mythfrontend.
>> Watching using another system using software MPEG decode and Xv output
>> all is fine.
>>
>> Could some change to the DVB code have resulted in an MPEG stream that 
>> the Via MPEG hardware cannot decode correctly ?
>>
>> Any ideas ?
>>
>> Terry
>>
>>
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> 
> 
> I have been playing around with this and this is where I am:
> 
> 1. The new DVB code's Autopid feature means that on channels where
>     there are multiple Audio streams these are saved in the
>     recording.
> 
> 2. On a Via M10K box using VLD XVMC HW MPEG, this results in very
>     jumpy display/audio with error messages:
> "A/V diverged by 3.0873 frames, extending frame to keep audio in sync"
> 
> 3. Using Xv output with software decoding is fine.
> 
> 4. Not sending any IDCT data to the HW mpeg decoder has no effect on
>     the problem.
> 
> In an example case the recording has a 2 channel audio stream and
> a mono audio stream (possibly one for the hard of hearing). The
> overall frame rate when playing this is about 14frames/s. It is almost
> as if MythTv was trying to sync to the agregate of the two audio
> streams .....
> 
> I would not have thought that using XvMC VLD video decoding would
> have affected the audio decoding .....
> 
> Terry
> 
> 
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Hi,

Another little snippet on this.
If I disable Audio in NuppelVideoPlayer.cpp by setting disableaudio, the
resulting Video output is fine ...

Terry