[MEncoder-users] audio sync problens when encoding realtime TV

[Roberto Hradec]

Hi There...

I use mencoder compiled with X264 and FAAC to do realtime capture and 
encode of live TV (in ASF).  After doing the capture/encode, I use 
mplayer to separate the A/V tracks, and mp4creator to combine those 
tracks back into a ITunes/Quicktime compatible mp4.

It works fine most of the times... but, sometimes, for some reason that 
I didn't find out yet, theres a problem in the capture that leads to the 
ASF endup dropping some frames.

*If I play the ASF, it plays fine, even after the point whith the 
dropped frames. no problem so far.*

The problem is when I split the tracks and combine again... I got a A/V 
sync error after the dropped frames point.

After research a lot, I finally found out about  the harddup video 
filter. After adding the harddup, i got much less sync problens with 
minor frame droppings, but still sometimes I got files with pretty bad 
frame dropping, that gives me sync problens in the mp4. (the ASF files 
still works fine tough)

On those files, even if I try to remux it using mencoder to AVI (not 
re-encoding... just copying the tracks) I got a mencoder error saying 
that I should use the -ni option to be able to do the convertion... I 
tried again with the -ni, but still got the error saying to me to use -ni.

I'm using the latest SVN mencoder, with latest SVN X264 and FAAC 1.24.

these are options for x264 and faac in mencoder:

$h264_extra = "me=umh:subme=6:ref=4:merange=16:subq=5:threads=1 ";
$audio="-oac faac -faacopts br=$abr:quality=40:mpeg=4";

I'm writing to the list because I really cant find a solution for this 
now... I'm researching a lot on forums and mailing lists on the net, but 
no luck so far!


any ideas?? any help would be really apreciated guys...


all the best...

-H


PS: I'm a experienced programer. Even tough I dont have any experience 
with mplayer code, I'm willing to dig into it to build a solution for 
this problem... Maybe do a HARDESTDUP filter... LOL... I just need some 
help to figure out WHY this is happening and come up with a idea for a 
solution... also, some tips on where to look in the code would be really 
nice!!