[FFmpeg-user] Accurate Trimming Without Transcoding

C E Macfarlane c.e.macfarlane at macfh.co.uk
Mon Mar 7 11:55:56 CET 2016

Please see below ...


>     Is it possible to achieve frame accurate trimming of clips without
>     transcoding?
>     e.g. if I have a 50 fps file with a fixed gop of 50 frames 
>     and I'd like to
>     trim the first 24 frames without transcoding. Shouldn't ffmpeg simply
>     generate a remuxed file with a startTime of 0.48s and a 
>     duration adjusted
>     accordingly?
>     Is this possible to achieve?

I too have this problem.  Say you want to save one particular clip from a programme such as Singer-Songwriters On The BBC, inevitably what happens is that either you have some of the previous clip at the beginning, or you cut short the introduction to the song that is wanted.

As Carl has pointed out, it is not possible just to throw away the leading frames, but what could be done, and would be very useful, is, where codec copying has been seleceted, to re-encode only the leading frame, and to copy the rest without re-encoding, and this would allow frame accurate editing of clips.

If, as I suppose, it is not already possible to do this, I suggest it as a possible enhancement to the programme.

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