[FFmpeg-user] Issue trimming an AVI

[Francois Visagie]

> -----Original Message-----
> From: ffmpeg-user-bounces at ffmpeg.org [mailto:ffmpeg-user-
> bounces at ffmpeg.org] On Behalf Of CJ Myers
> Sent: 19 February 2013 15:33
> To: FFmpeg user questions
> Subject: Re: [FFmpeg-user] Issue trimming an AVI
> 
> I'm attaching a link to a small sample, Carl.  It has the same problem.
Is there
> anyway to overcome that, without re-encoding?
> 
> Francois, how would I go about assigning or finding a new keyframe?  Do I
> just need to re-encode it?  I'm trying to preserve as much quality as
possible
> because it will get reencoded again when it's uploaded.

There probably is a way in ffmpeg, but I use tools like Avidemux or
VirtualDub to find the keyframe closest to the cut I want to make.

Then use its position as the starting offset in your ffmpeg command line. If
you don't do this, ffmpeg will either re-encode up to the first keyframe
(not too bad), or faithfully copy the first keyframe-less frames frames
(quite bad). The latter will either cause your output to play with garbage
at the start, or a more intelligent player might ignore all content until it
reaches the first keyframe.

> Thanks all!!
> 
> https://dl.dropbox.com/u/27674054/TestUpload.avi
> 
> 
> On Tue, Feb 19, 2013 at 7:44 AM, CJ Myers <cjandash at gmail.com> wrote:
> 
> > I'm uploading a small sample, Carl.  It has the same problem.  Is
> > there anyway to overcome that?
> >
> > Francois, how would I go about assigning or finding a new keyframe?
> > Do I just need to re-encode it?  I'm trying to preserve as much
> > quality as possible because it will get reencoded again when it's
uploaded.
> >
> > Thanks!!
> >
> > ~CJ
> >
> >
> > On Tue, Feb 19, 2013 at 3:42 AM, Carl Eugen Hoyos
> <cehoyos at ag.or.at>wrote:
> >
> >> CJ Myers <cjandash <at> gmail.com> writes:
> >>
> >> > [avi @ 000000000030c140] non-interleaved AVI
> >>
> >> Difficult to say without a sample but this may be the culprit.
> >>
> >> Carl Eugen
> >>
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> >>
> >
> >
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