Re: Truncating MPGs or MP4s
I usually use avidemux for that, telling it to copy the audio
and video
rather then reencode them. Then I do the transcoding
with handbrake.
+1 for Avidemux as a GUI tool. To my knowledge it is the only gui
tool
in linux which allows simple truncation of files
without reencoding.
Last time I checked, Openshot, Pitivi and Kino couldn’t just
truncate
(copy) the streams, they always reencoded them. Apart from loss of
quality, this also means loss of time.
I also use the ffmpeg solution mentioned earlier. It’s simple and
effective if you don’t need frame accurate precision in
your timings.
Technically truncation can’t actually start or stop on just any
frame in
the video. Start and stop must be on a keyframe (one of the frames
encoded in full and not deduced from others, more on this here:
http://www.avidemux.org/admWiki/doku.php?id=using:cutting).
I'm not sure how ffmpeg deals with the situation where the
timecodes you
specify don’t match actual keyframes. I suppose they shift the
start/stop time a bit earlier or later. It’s usually not a big
deal but
sometimes it matters. If you want full control over this,
avidemux’s gui
can help you set the trim markers to keyframes.
In case you don’t want to enable an extra repo just for avidemux,
it’s
fairly easy to compile it yourself. I followed the instructions
here:
http://www.avidemux.org/admWiki/doku.php?id=build:install_2.6 The
gtk
gui crashes on my debian testing with xfce, but the qt one (which
is the
default) works just fine.
Regards,
Victor
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