[mythtv] Funky 720p playback

Matt S. skd5aner at gmail.com
Thu Feb 28 23:27:45 UTC 2008


On Wed, Feb 20, 2008 at 1:45 AM, Bill Cizek <cizek at rcn.com> wrote:
>
> A few weeks ago I noticed playback problems on some of ABC's 720p programs.
>
> The symptoms are jerky playback, out of sync audio, and incorrect
> program length
> (an hour long program will be displayed as 45 minutes in the OSD).
>
> The frontend log shows a bunch of lines like
>     'video_output' mean = '22090.37', std. dev. = '7938.94', fps = '45.27'
>     'video_output' mean = '22820.35', std. dev. = '8543.71', fps = '43.82'
>
> Interspersed with dozens of messages:
>      "NVP: Video is xxx frames ahead of audio."
>
> If I watch the recorded video in mplayer I get the same audio problem and
> constant warnings like this:
>
>     Warning! FPS changed 47.952 -> 59.940  (-11.988010) [7]   2%  5.7% 9 0
>     A:75362.5 V:75362.4 A-V:  0.021 ct:  0.189 1399/1353 45%  2%  5.6% 9 0
>     demux_mpg: 24000/1001fps progressive NTSC content detected,
> switching framerate.
>     A:75362.5 V:75362.4 A-V:  0.045 ct:  0.191 1401/1354 44%  2%  5.6% 9 0
>     demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
>     Warning! FPS changed 47.952 -> 59.940  (-11.988010) [7]   2%  5.6% 9 0
>     A:75362.8 V:75362.8 A-V: -0.004 ct:  0.195 1418/1366 44%  2%  5.4% 9 0
>     demux_mpg: 24000/1001fps progressive NTSC content detected,
> switching framerate.
>
> This started at the end of January using recent SVN. It's on ABC in Chicago.
> The only thing I found on the web is
> http://forum.videohelp.com/topic344584.html ,
> which implies ABC did something to new program episodes.  Unfortunately
> my depth of
> knowledge on this topic is quite shallow.
>
> My questions:
>
> Has anyone else noticed this?
> Is this something that is wrong with the broadcast or should the player
> be able to handle it?
>
> Just curious.  It's been a long time since I've had any non-trivial
> problems in MythTV --
> It's been rock solid.
>
> -Bill
>
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>

Not sure if this is the same thing, but I saw something with similiar
behaviors recording the ABC show "Eli Stone" in HD via QAM.  I was
able to watch 3/4 of the show, then all of a sudden the video would
slow down, audio would keep playing, and then the video would catch
up.  Happened about every 3 seconds, then finally it would just
freeze.  Exiting the recording and then restarting it at that point
would only net me about 4 seconds of working before it started again.
It was definitely the recording as all my other HD and SD recordings
were fine.

Thanks!
Matt


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