[MEncoder-users] Audio sync / shift issue with Real Media rm files

[Nate Solas]

My problem is I'm writing a script to automatically (hands off) convert Real
Media rm videos to flv videos.  The command line I've worked out seems solid
for almost all of our source files, but a few have somehow been originally
encoded with the video starting about 5 seconds after the audio.

My biggest confusion is that mplayer is able to correct for this after about
8 seconds if I use the -mc flag:
mplayer -mc .1 rtsp://ice.walkerart.org:8080/translocations/media/Jamie.rm
(that's an example I'm working with, please give it a try)

But mencoder never regains sync:
mencoder rtsp://ice.walkerart.org:8080/translocations/media/Jamie.rm -ni -o
output.flv -oac mp3lame -lameopts abr:br=56 -srate 22050 -ovc lavc -lavcopts
vcodec=flv:vbitrate=300:mbd=2:mv0:trell:v4mv:cbp:last_pred=3 -fps 15 -ofps
15 -mc 1 -of lavf -lavfopts
i_certify_that_my_video_stream_does_not_use_b_frames -ss 00:00:00 -endpos
00:04:12

The mplayer -identify info is below:
MPlayer 2:1.0~rc1-0ubuntu13 (C) 2000-2006 MPlayer Team
CPU: Dual-Core AMD Opteron(tm) Processor 2218 (Family: 15, Model: 65,
Stepping: 2)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.
. . .
VIDEO:  [RV30]  320x240  24bpp  15.000 fps    0.0 kbps ( 0.0 kbyte/s)
Clip info:
 name: Jamie
ID_CLIP_INFO_NAME0=name
ID_CLIP_INFO_VALUE0=Jamie
 author: Walker Art Center
ID_CLIP_INFO_NAME1=author
ID_CLIP_INFO_VALUE1=Walker Art Center
 copyright: �2003
ID_CLIP_INFO_NAME2=copyright
ID_CLIP_INFO_VALUE2=�2003
ID_CLIP_INFO_N=3
ID_FILENAME=Jamie.rm
ID_DEMUXER=real
ID_VIDEO_FORMAT=RV30
ID_VIDEO_BITRATE=0
ID_VIDEO_WIDTH=320
ID_VIDEO_HEIGHT=240
ID_VIDEO_FPS=15.000
ID_VIDEO_ASPECT=0.0000
ID_AUDIO_FORMAT=sipr
ID_AUDIO_BITRATE=0
ID_AUDIO_RATE=8000
ID_AUDIO_NCH=1
ID_LENGTH=252.00


Is there any way I can detect the video delay from a script and correct it
that way?  (although using -delay 5 -mc 0 causes me to lose the first 5
seconds of audio)  Why can mplayer regain sync but mencoder can't?

Thanks for any tips!  I've been working on this for two days and just can't
find a way...

Nate