[MEncoder-users] expert help wanted for realvideo transcoding!

[Karlis]

I'm looking for an mencoder and/or ffmpeg expert to help us with a 
realvideo transcoding project.  We've got 2500+ videos encoded in 
realplayer and we want out!! So we're transcoding to flv format.  Each 
video is quite long, up to 1hr, encoded over 8 years or so so each one 
has slightly different encoding specs. I've got a nice setup with amazon 
e2/s3 so I can start processing the batch as soon as I have a solution 
to the mencoder problem, the commands I've tried so far leave me with 
large video rate and audio sync problems.

I could really use some help with the options.   Here are some of my issues:

Can mencoder autodetect audio/video bitrates and framerates? Or do I 
have to inspect each file with ffmpeg, determine the audio/video 
bitrates and framerates, and specify that in the mencoder options?  I'm 
currently already doing something like this for the video codec: 
mencoder doesn't seem to recognize the difference between rv20 and rv30, 
so I check the file for rv20 with ffmpeg, and add the "-vc rv20" if I 
detect rv20.  Do I have to do this for every parameter?

I'm also getting a lot of skipped frame/duplicate frame errors, although 
ignoring these doesn't seem to hurt much, or rather, with or without, I 
get audio sync problems.

This is my last best transcode command, which was mostly taken from some 
forum post online:

mencoder %s -ni -vc rv20 -o %s -oac mp3lame -lameopts abr:br=56 -s rate 
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

any help or guidance at this point much appreciated.

cheers
karlis