[mythtv-users] Stuttering in DVD menus

Mike Perkins mikep at randomtraveller.org.uk
Sat Nov 10 20:55:09 UTC 2012


On 10/11/12 19:56, Richard wrote:
> On 10/11/12 14:52, Richard wrote:
>>
>> I still don't understand why this should only affect playback of DVD
>> menus.  What's different about a menu?  The traces seem to indicate that
>> video decoding is ahead of audio but is there a some way to determine
>> whether it's a video or an audio problem?
>
> Ok, I tried comparing the log messages between ffmpeg and VDPAU decoding.  The
> only difference that appears significant is this when VDPAU is selected:
>
> Player(0): Forcing decode extra audio option on (Video method requires it).
>
> I searched through the source code and found this log entry eventually causes
> the 'lowbuffers' variable in avformatdecoder.cpp to be set to true.  Looking at
> where 'lowbuffers' is used, I found this:
>
> -------------------------------
> else if (lowbuffers && ((decodetype & kDecodeAV) == kDecodeAV) &&
>           storedPackets.count() < max_video_queue_size &&
>           lastapts < lastvpts + 100 &&
>           !ringBuffer->IsInDiscMenuOrStillFrame())
> {
>        storevideoframes = true;
> }
> -------------------------------
>
That's the sort of compound conditional which I would automatically group with 
parenthesis. Doing it like that is asking for trouble.

-- 

Mike Perkins



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