[mythtv] Funky 720p playback

Keith Cremer mythtv at keithandjill.com
Fri Feb 29 16:33:53 UTC 2008


On Feb 28, 2008, at 5:27 PM, Matt S. wrote:

> 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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>> mythtv-dev at mythtv.org
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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

I record from both QAM and OTA with the HDHomeRun.  ABC never works  
now for full HD shows from either source.  Jimmy Kimmel records, as  
its just SD in an HD letterbox.  As far as history goes : the first  
program I had problems with was Desperate Housewives starting last  
January, but my other HD shows on ABC continued working (Lost, Ugly  
Betty).  When the fall season started, Ugly Betty stopped recording  
correctly.  Now that Lost has restarted, it is also broken.  In fact,  
this week's Lost caused my mythbackend to die a minute or two in.

Very frustrating.  I'm in Houston, TX, with QAM from Comcast.

Keith C





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