[mythtv-users] A/V diverged by -3 frames

Christian Hack christianh at edmi.com.au
Mon Dec 27 22:40:10 UTC 2004


> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org 
> [mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Doug Larrick
> Sent: Tuesday, 28 December 2004 12:57 AM
> To: Discussion about mythtv
> Subject: Re: [mythtv-users] A/V diverged by -3 frames
> 
> 
> Christian Hack wrote:
> > Using the libav option on mythfrontend (very recent CVS), 
> I'm getting jerky
> > playback on one channel (SBS for the Australians) which 
> seems related to
> > these error messages. It also seems that the pitch of the 
> sound is off by
> > small fraction - slightly deeper. Using video as timebase 
> results in exactly
> > the same result.
> > 
> 
> [snip]
> 
> > Input #0, mpeg, from
> > '/mnt/store/recorded/1028_20041227203000_20041227210000.nuv':
> >   Stream #0.0: Video: mpeg2video, 720x576, 25.00 fps
> >   Stream #0.1: Audio: mp2, 48000 Hz, stereo, 192 kb/s
> [snip]
> > 2004-12-27 21:50:04.916 Refresh rate: 16665, frame interval: 40000
> 
> This is at least part of your problem... your video is at 
> 25Hz but your 
> screen is at 60 Hz.  50 or 75 Hz would work much better.
> 
> I would guess that maybe your soundcard is using 44100 Hz 
> output as well?
> 

Same deal although 50Hz +  realtime has made my tickers and panning etc go
much smoother. Don't know why I didn't try that before. Thanks for the
suggestion.

It's just the one channel, and it appears that once transcoded to MPEG4 they
play fine. So it's something to do with the MPEG2 from the DVB card. I can
host a stream of it if someone wants to look. It's obviously very big though
and I only have 128kb/s upstream.

I'm not sure about the soundcard. It's an nVidia nForce 1. How can I check
the audio rate? All the other channels broadcast 48kHz and are fine. Using
video as the timebase makes gives the +3 frames error and is noticeably
jerky on otherwise good channels. Audio as timebase is by far the best
solution so far.

Input #0, mpeg, from
'/mnt/store/recorded/1028_20041227210000_20041227213000.nuv':
  Stream #0.0: Video: mpeg2video, 720x576, 25.00 fps
  Stream #0.1: Audio: mp2, 48000 Hz, stereo, 192 kb/s
2004-12-28 08:39:42.636 Position map found
2004-12-28 08:39:42.639 Opening audio device '/dev/dsp'.
2004-12-28 08:39:42.639 Opening OSS audio device '/dev/dsp'.
2004-12-28 08:39:42.647 Over/underscan. V: 0, H: 0, XOff: 0, YOff: 2
2004-12-28 08:39:42.651 Using XV port 103
2004-12-28 08:39:42.655 Image size. dispxoff 0, dispyoff: 85, dispwoff: 720,
disphoff: 405
2004-12-28 08:39:42.655 Image size. imgx 0, imgy: 0, imgw: 720, imgh: 576
2004-12-28 08:39:43.396 Using realtime priority.
2004-12-28 08:39:43.397 Changing from None to WatchingPreRecorded
2004-12-28 08:39:43.500 nVidiaVideoSync: VBlank ioctl did not work,
unimplemented in this driver?
2004-12-28 08:39:43.531 DRMVideoSync: Could not open device /dev/dri/card0,
No such device
2004-12-28 08:39:43.531 Using audio as timebase
2004-12-28 08:39:43.531 Video timing method: RTC
2004-12-28 08:39:43.532 Refresh rate: 19999, frame interval: 40000
2004-12-28 08:39:43.532 waiting for prebuffer...
2004-12-28 08:39:43.684 A/V diverged by 4.675 frames, extending frame to
keep audio in sync
2004-12-28 08:39:43.764 A/V diverged by 6.125 frames, extending frame to
keep audio in sync
2004-12-28 08:39:43.844 A/V diverged by 6.9625 frames, extending frame to
keep audio in sync
2004-12-28 08:39:43.924 A/V diverged by 7.34062 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.004 A/V diverged by 7.3742 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.084 A/V diverged by 7.14315 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.164 A/V diverged by 6.7261 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.245 A/V diverged by 6.16332 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.324 A/V diverged by 5.49122 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.405 A/V diverged by 4.73715 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.485 A/V diverged by 3.9216 frames, extending frame to
keep audio in sync
2004-12-28 08:39:44.565 A/V diverged by 3.0537 frames, extending frame to
keep audio in sync
2004-12-28 08:39:45.426 A/V diverged by -3.0978 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:45.514 A/V diverged by -3.43782 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:45.517 A/V diverged by -3.1471 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:45.519 A/V diverged by -3.19782 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:45.907 A/V diverged by -3.30865 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:45.910 A/V diverged by -3.00647 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:45.912 A/V diverged by -3.0486 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.300 A/V diverged by -3.14002 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.388 A/V diverged by -3.40062 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.391 A/V diverged by -3.08795 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.393 A/V diverged by -3.11595 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.781 A/V diverged by -3.16027 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.869 A/V diverged by -3.40578 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.871 A/V diverged by -3.08558 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:46.874 A/V diverged by -3.11418 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.261 A/V diverged by -3.16735 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.349 A/V diverged by -3.416 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.352 A/V diverged by -3.0995 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.354 A/V diverged by -3.12462 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.742 A/V diverged by -3.18167 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.830 A/V diverged by -3.435 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:47.832 A/V diverged by -3.12 frames, dropping frame to keep
audio in sync
2004-12-28 08:39:47.835 A/V diverged by -3.14625 frames, dropping frame to
keep audio in sync
'video_output' mean = '45941.36', std. dev. = '33887.32', fps = '21.77'
2004-12-28 08:39:48.223 A/V diverged by -3.20487 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:48.311 A/V diverged by -3.45898 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:48.314 A/V diverged by -3.14422 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:48.316 A/V diverged by -3.1769 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:48.704 A/V diverged by -3.23105 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:48.791 A/V diverged by -3.47837 frames, dropping frame to
keep audio in sync
2004-12-28 08:39:48.794 A/V diverged by -3.15878 frames, dropping frame to
keep audio in sync



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