[mythtv] Problem with severe video jitter in current MythTv CVS

Tue Dec 7 06:42:45 UTC 2004

Robert Clark wrote:
> On Sun, 2004-12-05 at 15:51, Terry Barnaby wrote:
> 
> 
>>I have just updated my system to use the MythTv from CVS on
>>3/12/04 and am now experiencing severe display jitter. about once
>>per second the video display jumps. Previously I was using MythTv
>>from CVS 21/11/04 and everything was fine. Going back to this version 
>>cures the problem.
> 
> 
>   Just another data point: I made the jump from 2004-09-24 to 2004-12-04
> yesterday on my EPIA box which I think is set up similarly to yours. I'm
> not seeing any jitter.
> 
> 
>>2004-12-05 15:40:37.072 Image size. dispxoff -120, dispyoff: 18, dispwoff: 960, disphoff: 540
>>2004-12-05 15:40:37.074 Image size. imgx 0, imgy: 0, imgw: 720, imgh: 576
> 
> 
>   Well, those look a little strange, but I can't think how that would cause jitter.
> 
>   My log says:
> 
> mythtv interlace_test1.mpeg
> 2004-12-06 20:41:44.889 Joystick disabled.
> 2004-12-06 20:41:45.557 AVFD
> 2004-12-06 20:41:45.558 AVFD: Opening Stream #0: codec id 2
> 2004-12-06 20:41:45.559 detectInterlace(Detect Scan, Detect Scan, 25, 576) ->Interlaced Scan
> 2004-12-06 20:41:45.561 Interlaced: Interlaced Scan  video_height: 576  fps: 25
> 2004-12-06 20:41:45.569 AVFD: Looking for decoder for 4
> 2004-12-06 20:41:45.571 AVFD
> 2004-12-06 20:41:45.573 AVFD: Opening Stream #1: codec id 86020
> 2004-12-06 20:41:45.574 AVFD: Looking for decoder for 86020
> 2004-12-06 20:41:45.588 Initializing audio parms from stream #0.
> 2004-12-06 20:41:45.592 Estimated bitrate = 128000
> 2004-12-06 20:41:45.614 SyncPositionMap prerecorded, from DB: 0 entries
> 2004-12-06 20:41:45.631 Opening audio device '/dev/dsp'.
> 2004-12-06 20:41:45.633 Opening OSS audio device '/dev/dsp'.
> 2004-12-06 20:41:47.486 Over/underscan. V: 0, H: 0, XOff: 0, YOff: 0
> Using XvMC version: 1.0
> 2004-12-06 20:41:47.504 XvMCSurfaceTypes::find(w 720, h 1, c 0, i 2, m 0,sw 0, sh 56, disp, p<= 56, 5760 <=p, port, surfNum)
> 2004-12-06 20:41:47.506 Trying XvMC port 56
> 2004-12-06 20:41:47.507 Found a suitable XvMC surface 0
> XvMC found and using VLD surface
> 2004-12-06 20:41:47.509 Using XV port 56
> 2004-12-06 20:41:47.601 Image size. dispxoff 107, dispyoff: 0, dispwoff: 506, disphoff: 576
> 2004-12-06 20:41:47.603 Image size. imgx 0, imgy: 0, imgw: 720, imgh: 576
> Unknown element: surface
> 2004-12-06 20:41:49.626 Changing from None to WatchingPreRecorded
> 2004-12-06 20:41:49.642 XvMC will use bob deinterlacing
> 2004-12-06 20:41:49.644 Using deinterlace method bobdeint
> 2004-12-06 20:41:49.647 Using realtime priority.
> 2004-12-06 20:41:49.671 nVidiaVideoSync: Could not open device /dev/nvidia0, No such file or directory
> 2004-12-06 20:41:49.689 positionMap[ 0 ] == 2062.
> 2004-12-06 20:41:49.705 Using video as timebase
> 2004-12-06 20:41:49.706 Video timing method: DRM
> 2004-12-06 20:41:49.706 Refresh rate: 19997, frame interval: 40000
> 2004-12-06 20:41:49.720 waiting for prebuffer...
> 2004-12-06 20:41:49.902 A/V diverged by -3.30975 frames, dropping frame to keep audio in sync
> 2004-12-06 20:41:49.903 A/V diverged by -3.66355 frames, dropping frame to keep audio in sync
> 2004-12-06 20:41:49.903 A/V diverged by -3.68515 frames, dropping frame to keep audio in sync
> 2004-12-06 20:41:49.904 A/V diverged by -3.4576 frames, dropping frame to keep audio in sync
> 2004-12-06 20:41:49.904 A/V diverged by -3.03695 frames, dropping frame to keep audio in sync
> 2004-12-06 20:41:49.905 prebuffering pause
> 2004-12-06 20:41:49.905 waiting for prebuffer...
> 2004-12-06 20:41:49.957 positionMap[ 1 ] == 55310.
> 2004-12-06 20:41:50.561 HandleGopStart: gopset not set, syncing positionMap
> 2004-12-06 20:41:50.565 SyncPositionMap prerecorded, from DB: 2 entries
> 2004-12-06 20:41:50.567 Stream initial keyframedist: 15.
> 2004-12-06 20:41:50.568 detectInterlace(Ignore Scan, Interlaced Scan, 25, 576) ->Interlaced Scan
> 2004-12-06 20:41:50.570 Interlaced: Interlaced Scan  video_height: 576  fps: -1
> 2004-12-06 20:41:50.582 XvMC will use bob deinterlacing
> 2004-12-06 20:41:50.584 Using deinterlace method bobdeint
> 2004-12-06 20:41:50.585 positionMap[ 2 ] == 114702.
> 2004-12-06 20:41:51.141 positionMap[ 3 ] == 174094.
> 2004-12-06 20:41:51.741 positionMap[ 4 ] == 233486.
> 2004-12-06 20:41:52.341 positionMap[ 5 ] == 294926.
> 2004-12-06 20:41:52.941 positionMap[ 6 ] == 356366.
> 2004-12-06 20:41:53.541 positionMap[ 7 ] == 415758.
> 'video_output' mean = '38334.30', std. dev. = '10521.26', fps = '26.09'
> 
> [...]
> 
>   The obvious difference is that you're using the audio as timebase, I'm
> using the video. I'm also using slightly old unichrome drivers
> (r26/0.12.0) & DRI (1.5.0).
> 
> 	Robert
> 
> 
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Thanks for the info. I just tried turning on the "Use Video for
timebase" option and this fixed the juddering issue ...

I will play a bit with CVS versions ...

Terry

-- 
   Dr Terry Barnaby                     BEAM Ltd
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Software Dev
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