[MEncoder-users] cutting mpeg-2

[Giacomo Comes]

On Tue, Dec 04, 2007 at 01:10:23AM -0800, Pawel K wrote:
> > > > > I have the mpeg-2 file and want to cut it
> > without
> > > > > decompressing it. The I-frame cut resolution
> > suits
> > > > me.
> > > > > I use the following command:
> > > > > 
> > > > > mencoder -ss 0 endpos 10 -ovc copy -oac copy
> > > > > source.mpg -o result.mpg
> > > > > 
> > > > > The result.mpg contains exactly 10 seconds
> > from
> > > > the
> > > > > beginning of the source.mpg.
> > > > > 
> > > > > I found that a few frames around frame nr 50
> > have
> > > > > strange rectangles, they are a bit distored.
> > > > > 
> > > > > I tried to cut the movie in other arbitrary
> > > > locations
> > > > > and had always the same distored frames at
> > around
> > > > > 50th.
> > > > > 
> > > > > How can I cut the movie with mencoder without
> > need
> > > > to
> > > > > decompress it.
> > > > > 
> > > > > thank You for help.
> > > > 
> > > > Adding -mc 0 should fix your problem.
> > > 
> > > Thanks a lot. Indeed it solved the problem :)
> > > but I found that 3 first frames are blank, 4th and
> > 5th
> > > is a bit distorted and the remaining ones are OK.
> > > 
> > > Doesn't matter whether I cut it at the beginning
> > or in
> > > the middle of the movie.
> > > 
> > > I think that's because I use the "-ss <sec>"
> > mencoder
> > > option to select the cut point.
> > 
> > Looks like a bug. rc1 does not have this problem.
> > 
> > > I should cut it at exactly the I-frame.
> > > Right ?
> > 
> > This is exactly what normally happens.
> > You don't need to specify "cut at the closest
> > I-frame"
> > 
> > I will try to figure out when the bug was
> > introduced.
> 
> Thanks a lot.
> I'm using version:
> mplayer-1.0_rc1_p20070824

The change was introduced last february
with r22112

Giacomo