[linux-dvb] problems with a/v sync from a vdr recording [NTSC]

[Jeremy Hall <jhall@maoz.com>]

Hello,

NOTE: not crossposted to vdr because I don't think this is a vdr problem.  
Those who do, feel free to cc them in your response.

I have a program I recorded with vdr that seems to toggle frame rate.  
Consequently vdr seems to think this program is shorter than it actually 
is.

The original program aired beginning at 12:45 and ended at 14:30, making 
the length 105 minutes, or 1:45:00 or there-abouts.

Vdr, on the other hand, thinks the program is indeed 01:42:39.

Other recordings that are an hour in length, but not a movie, vdr seems to 
think are longer than they are by a variable rate depending on the 
channel.  I randomly picked a recording that is one of the hour-long shows 
and it says it is 1:07:43, when in fact it is an hour in length.

Obviously vdr is finding the length by something that is variable.  
Running mplayer on the files shows the frame rate changing, like this:

NOTE: a portion of the path removed

/2004-02-20.12:45.50.99.rec # mplayer -vo mpegpes -ao mpegpes 001.vdr
MPlayer dev-CVS-040227-02:04-2.95.3 (C) 2000-2004 MPlayer Team

CPU: Advanced Micro Devices Athlon 4 /Athlon MP/XP Palomino 1667 MHz 
(Family: 6, Stepping: 2)
Detected cache-line size is 64 bytes
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE

Reading config file /usr/local/etc/mplayer/mplayer.conf: No such file or 
directory
Reading config file /root/.mplayer/config
Reading /root/.mplayer/codecs.conf: Can't open 
'/root/.mplayer/codecs.conf': No such file or directory
Reading /usr/local/etc/mplayer/codecs.conf: Can't open 
'/usr/local/etc/mplayer/codecs.conf': No such file or directory
Using built-in default codecs.conf.
font: can't open file: /root/.mplayer/font/font.desc
font: can't open file: /usr/local/share/mplayer/font/font.desc
Using Linux hardware RTC timing (1024Hz).
Can't open input config file /root/.mplayer/input.conf: No such file or 
directory
Input config file /usr/local/etc/mplayer/input.conf parsed: 50 binds

Playing 001.vdr.
MPEG-PES file format detected.
VIDEO:  MPEG2  640x480  (aspect 2)  29.970 fps  15000.0 kbps (1875.0 
kbyte/s)
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
MP3lib: init layer2&3 finished, tables done
AUDIO: 48000 Hz, 2 ch, 16 bit (0x10), ratio: 24000->192000 (192.0 kbit)
Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
Opening /dev/dvb/adapter0/video0+audio0
==========================================================================
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 640 x 480 (preferred csp: Mpeg PES)
VDec: using Mpeg PES as output csp (no 0)
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
VO: [mpegpes] 640x480 => 640x480 Mpeg PES
Selected video codec: [mpegpes] vfm:mpegpes (Mpeg PES output (.mpg or 
Dxr3/DVB card))
==========================================================================
Checking audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/16bit...
AF_pre: af format: 2 bps, 2 ch, 48000 hz, little endian signed int
AF_pre: 48000Hz 2ch Signed 16-bit (Little-Endian)
AO: [mpegpes] 48000Hz 2ch Signed 16-bit (Little-Endian) (2 bps)
Building audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/16bit...
Starting playback...
A:27974.4 V:27974.4 A-V: -0.021 ct: -0.152  166/163   0% 16%  0.7% 0 0 0%%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:27974.8 V:27974.7 A-V:  0.034 ct: -0.132  174/171   0% 15%  0.7% 0 0 0%
demux_mpg: 30fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970  (-5.994000) [4]   15%  0.7% 0 0 0%
A:27975.1 V:27975.1 A-V:  0.028 ct: -0.102  185/180   0% 15%  0.7% 0 0 0%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:27977.9 V:27977.9 A-V:  0.041 ct:  0.052  257/251   0% 14%  0.7% 0 0 0%
demux_mpg: 30fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970  (-5.994000) [4]   14%  0.7% 0 0 0%
A:27978.3 V:27978.3 A-V:  0.033 ct:  0.087  269/261   0% 14%  0.7% 0 0 0%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:27981.8 V:27981.7 A-V:  0.037 ct:  0.272  356/348   0% 13%  0.7% 0 0 0%
demux_mpg: 30fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970  (-5.994000) [4]   13%  0.7% 0 0 0%
A:28016.0 V:28015.5 A-V:  0.494 ct:  1.916  1368/1357   0% 14%  0.7% 0 0 
0%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:28031.8 V:28031.8 A-V:  0.040 ct:  2.497  1760/1749   0% 14%  0.7% 0 0 
0%
demux_mpg: 30fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970  (-5.994000) [4]  0% 14%  0.7% 0 0 
0%
A:28035.3 V:28035.3 A-V: -0.020 ct:  2.560  1868/1852   0% 14%  0.7% 0 0 
0%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:28035.8 V:28035.8 A-V:  0.041 ct:  2.586  1879/1863   0% 14%  0.7% 0 0 
0%
demux_mpg: 30fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970  (-5.994000) [4]  0% 14%  0.7% 0 0 
0%
A:28042.1 V:28042.1 A-V: -0.012 ct:  2.647  2070/2050   0% 14%  0.6% 0 0 
0%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:28051.5 V:28051.4 A-V:  0.043 ct:  2.706  2296/2275   0% 14%  0.6% 0 0 
0%
demux_mpg: 30fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970  (-5.994000) [4]  0% 14%  0.6% 0 0 
0%
A:28054.2 V:28054.2 A-V: -0.025 ct:  2.770  2380/2353   0% 14%  0.6% 0 0 
0%
demux_mpg: 24fps progressive NTSC content detected, switching framerate.
A:28057.2 V:28057.2 A-V:  0.011 ct:  2.793  2452/2425   0% 14%  0.6% 0 0 
0%

MPlayer interrupted by signal 2 in module: play_audio

When the movie starts, it holds at 24fps, but occasionally it seems to run 
faster, getting up to 30fps and sometimes showing 23.976 and so on.  When 
mplayer plays this, it rushes the audio when the video goes faster, and 
when vdr plays this, it shows the time passing at a nonconstant rate, but 
the sound doesn't skitter like it does in mplayer.

When vdr plays for a while, the sound seems to hang occasionally, then the 
audio and video are out of sync, you have to press a left/right arrow to 
make them happy again.

VDR handles live tv just fine.  Has anybody seen this before? It's quite 
frustrating to have to go press an arrow every 10 minutes or so because 
vdr desynced the audio and video.

Kindest regards

Jeremy


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