[mythtv] frame dropping with ticket #5900 (AC3-enc) + #6279 (soft-volume)

[Markus Schulz]

Am Sonntag 19 Juli 2009 schrieb Mark Kendall:
> 2009/7/20 Markus Schulz <msc at antzsystem.de>:
> > hello,
> >
> > i've much trouble with heavy judder cause of frame dropping.
>
> Can you clarify what you mean here? Are you seeing frame drops
> generally or is this just 'judder' following a skip/seek/etc as the
> player settles down again.

frame drops all the time during playback.


> > I'm using trunk with vdpau (2xadvanced) with a 9400GT (latest
> > stable nvidia-cs) with mostly SD.
>
> Which driver are you using?

NVRM version: NVIDIA UNIX x86 Kernel Module  185.18.14

> > At first i think the videoout_vdpau should return true on
> > hasHWAcceleration() to prevent additional juddering (see void
> > NuppelVideoPlayer::AVSync(void) function):
>
> <snip>
>
> > This changes the Frame drops to skipping A/V wait (less of judder).
> >
> > But i don't understand why i still got a lot of:
> > 2009-07-19 18:31:03.311 NVP(1): Video is 3.22685 frames behind
> > audio (too slow), skipping A/V wait.
> > 2009-07-19 18:31:05.891 NVP(1): Video is 3.20082 frames behind
> > audio (too slow), skipping A/V wait.
> > 2009-07-19 18:31:05.911 NVP(1): Video is 3.1756 frames behind audio
> > (too slow), skipping A/V wait.
> > 'video_output' mean = '40207,36', std. dev. = '25365,55', fps =
> > '24,87' 2009-07-19 18:31:07.060 NVP(1): Video is 3.02257 frames
> > behind audio (too slow), skipping A/V wait.
> > 2009-07-19 18:31:07.064 NVP(1): Video is 3.17943 frames behind
> > audio (too slow), skipping A/V wait.
> > 2009-07-19 18:31:07.070 NVP(1): Video is 3.0658 frames behind audio
> > (too slow), skipping A/V wait.
> > 2009-07-19 18:31:09.553 NVP(1): Video is 3.2014 frames behind audio
> > (too slow), skipping A/V wait.
> > 2009-07-19 18:31:09.556 NVP(1): Video is 3.26355 frames behind
> > audio (too slow), skipping A/V wait.
> > 2009-07-19 18:31:09.570 NVP(1): Video is 3.07265 frames behind
> > audio (too slow), skipping A/V wait.
> > 'video_output' mean = '39984,38', std. dev. = '22128,54', fps =
> > '25,01'
>
> As noted in NuppelVideoPlayer::AVSync, hasHWAcceleration doesn't
> return true for vdpau because VDPAU doesn't actually skip the av
> wait. VDPAU always waits for the next vertical retrace when showing a
> frame - hence I'm not surprised that after your patch the video is
> always behind the audio, as it never gets a chance to catchup.

ok sorry, i've read over this.

> > i can reproduce the problem with the following setup:
> > - softvolume enabled (mixer = software)
> > - internal volume completely disabled
> > - internal volume enabled with alsa:default as mixer (useless cause
> > of ac3-enc and passthru)
> >
> > and all interlaced stuff or HD-1080p stuff. Progressive avi with
> > 25FPS shows no frame drops.
> >
> >
> > the problem arrived with ffmpeg sync (approx. cause i've build no
> > version after ~20650 and before ffmpeg sync).
> >
> > Can someone help me to analyze this problem? Which change can
> > introduce such a behavior?
>
> r20773 might be relevant, depening on which revision you're using and
> your settings.

thanks, i will have a look at this.

msc