[MEncoder-users] splitting mpegs

[Giacomo Comes]

On Wed, Sep 26, 2007 at 08:38:18AM -0700, RC wrote:
> On Wed, 26 Sep 2007 07:59:09 -0400
> Giacomo Comes <comes at naic.edu> wrote:
> 
> > 1) the hand-calculation is the most difficult part of the process.
> > There is no magic formula that will give you the agruments of -ss and
> > -frames. Other tools (like mpeg2enc/mplex) allows you to specify
> > directly the size of the chunk, mencoder doesn't.
> 
> Mencoder allows chunk size for the -endpos argument.  And once you've
> cut off that first chunk, you can determine its length, and use that for
> the -ss argument.  

I use -frames insted of -endpos because with -endpos some frames can
be lost. When -endpos decides to stop mencoder, it does not end the
copy of frames at the last P/B frame before the next I frame.
And when I start the copy of the next chunk, it will start always
with the I frame. The are therefore some (~<7) frames that get lost.
With -frames you can give mencoder the "exact" point where to stop and
you can avoid to loose frames.

Giacomo