[mythtv-users] Stuttering in DVD menus
Richard
peper03 at yahoo.com
Sat Nov 10 19:56:21 UTC 2012
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 a lot of conditions, and I don't know what they all relate to but
the last one looks suspiciously like one that could cause the stuttering
as it would prevent the assignment if we're in a menu.
Can anyone shed any light onto the purpose of that condition (maybe it
should only apply to non-animated menus?).
Richard.
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