90.19 Video Trim and Cut
20201113
This section deals with the extraction of time extents of the video, that is, to trim or to cut the video. If you are wanting to crop the video image itself throughout a video see Section 90.9. To cut a section out of a video, cut the video into two sections, pre and post the part to be cut, then concat the two parts together as explained in Section 90.2.
Using ffmpeg we can extract a segment from a video file
input.mp4
(identified as the input using -i
) starting at the
location 7 minutes and 41 seconds from the beginning using -ss
and
ending at the 53 minute mark from the beginning of the video using
-to
.
$ ffmpeg -i input.mp4 -ss 00:07:41 -to 00:53:00 cut.mp4
The audio stream can also be synchronised at the beginning of the
output stream to match the timestamp using -async 1
.
$ ffmpeg -i input.mp4 -ss 00:07:41 -to 00:53:00 -async 1 cut.mp4
The process will undertake a re-encoding of the video and can take
some time. To avoid the re-encoding use the -c copy
command to
ensure that the video is simply copied rather than re-encoding the
video.
$ ffmpeg -i input.mp4 -ss 00:07:41 -to 00:53:00 -async 1 -c copy cut.mp4
By replacing -to
with -t
the output will be truncated after the
specified duration.
$ ffmpeg -i input.mp4 -ss 00:07:41 -t 00:45:19 -async 1 -c copy cut.mp4
If -t
is specified prior to -i
(the input) then the duration
refers to the input video rather than the output video. That is, it
specifies the duration from the beginning of the input video.
Using avisplit we can also extract a particular section
of an avi file (specified as the -i
nput file) and using -t
to
specifiy the starting point and the end point (starting at 7 minutes
and 20 seconds into the video and stopping at 8 minutes and 20 seconds
in, respectively):
$ avisplit -i a.avi -t 0:7:20.0-0:8:20.0
Other Options
A graphical interface to trim a video is Video Trimmer which is installable as a FlatPack.
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