[MEncoder-users] audio sync problems encoding from vob

[Christopher M. Jones]

Background: I want to back up a dvd. I copied the data to disk using
cpdvd, I have a bunch of vobs, etc. dvdauthor (via qdvdauthor) refuses
to make the dvd filesystem, and asks me to remultiplex the audio. This
is where the problem comes in. Neither transcode nor mencoder will do t
his correctly. Always, I end up with audio sync problems. After playing
around with this for several days, I finally have the following:

 mencoder -o 01_firstcontact.mpg -ovc lavc -lavcopts
vcodec=mpeg2video:vbitrate=5000:vhq:acodec=ac3  -oac lavc  -srate 48000
-ofps 24000/1001 VTS_01_1.VOB

This creates an -almost- correct mpg. However, I get a few duplicate
frame warnings and one skipped frame, resulting in a very slight lag in
the audio, when played with mplayer. However, if I play this file with
vlc or xine, there is no lag at all! 

Any suggestions? 

MEncoder 2:0.99+1.0pre7try2+cvs20060117-0ubuntu8 (C) 2000-2006 MPlayer
Team
CPU: Intel Pentium 4/Celeron 4 Northwood; Pentium 4 EE/Xeon
Prestonia,Gallatin (Family: 15, Stepping: 4)
CPUflags: Type: 15 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
91 audio & 204 video codecs
success: format: 0  data: 0x0 - 0x40000000
MPEG-PS file format detected.
VIDEO:  MPEG2  720x480  (aspect 3)  29.970 fps  9800.0 kbps (1225.0
kbyte/s)
[V] filefmt:2  fourcc:0x10000002  size:720x480  fps:29.97  ftime:=0.0334
==========================================================================
Opening audio decoder: [liba52] AC3 decoding with liba52
Using SSE optimized IMDCT transform
AC3: 5.1 (3f+2r+lfe)  48000 Hz  448.0 kbit/s
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 448.0 kbit/29.17% (ratio: 56000->192000)
Selected audio codec: [a52] afm: liba52 (AC3-liba52)
==========================================================================
Opening video filter: [expand osd=1]
Expand: -1 x -1, -1 ; -1, osd: 1, aspect: 0.000000, round: 1
==========================================================================
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 720 x 480 (preferred colorspace: Mpeg PES)
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
The selected video_out device is incompatible with this codec.
Try adding the scale filter, e.g. -vf spp,scale instead of -vf spp.
VDecoder init failed :(
Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder
libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2))
==========================================================================
Building audio filter chain for 48000Hz/2ch/s16le -> 48000Hz/0ch/??...
Building audio filter chain for 48000Hz/2ch/s16le ->
48000Hz/2ch/s16le...
VDec: vo config request - 720 x 480 (preferred colorspace: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
videocodec: libavcodec (720x480 fourcc=3267706d [mpg2])
High quality encoding selected (non real time)!
Writing header...2f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.003 [0:0]
ODML: Aspect information not (yet?) available or unspecified, not
writing vprp header.
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not
writing vprp header.

1 duplicate frame(s)!
Pos:   0.1s      4f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.010 [0:0]
1 duplicate frame(s)!
Pos:   0.5s     11f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.033 [0:0]
demux_mpg: 24000/1001fps progressive NTSC content detected, switching
framerate.Pos:   1.0s     24f ( 0%)  0.00fps Trem:   0min   0mb
A-V:0.087 [90:224]
Skipping frame!
a52: CRC check failed!  ) 30.73fps Trem:   0min 630mb  A-V:0.051
[3222:223]]
Pos:1533.6s  36771f (100%) 30.73fps Trem:   0min 630mb  A-V:-0.028
[3222:224]
Flushing video frames
Writing index...
Writing header...
ODML: Aspect information not (yet?) available or unspecified, not
writing vprp header.

Video stream: 3222.659 kbit/s  (402832 B/s)  size: 617773223 bytes
1533.574 secs  36771 frames

Audio stream:  224.000 kbit/s  (28000 B/s)  size: 42954240 bytes
1534.080 secs