[mythtv] Funky 720p playback

Kevin Kuphal kkuphal at gmail.com
Wed Feb 20 19:23:23 UTC 2008


On Feb 20, 2008 12:45 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.


I've seen the same thing on ABC HD programming in Chicago for about the past
two months.  It only occurs on HD programs, not SD programs in HD (like
Supernanny) with letterboxing.  I've tried finding a place to notify them
about it but haven't and also haven't put much effort into it.

Kevin
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