85.13 Video Trim and Cut

20201113 This section deals with the extraction of time extents of the video, that is, trim or cut the video. If you are wanting to crop the video image itself throughout a video see Section 85.6.

Using ffmpeg we can extract a segment from a video.

$ ffmpeg -i input.mp4 -ss 00:00:00 -t 00:00:11 -async 1 cut.mp4

In this example the input file is identified with the -i parameter. The video is trimmed from the beginning using -ss to discard anything before the provided timestamp, which is 00:00:00 in this case and so nothing is trimmed from the beginning. Using -t with the argument 00:00:11 will stop writing to the output file after the specified duration of 11 seconds of output video. whilst the audio stream is synchronised at the beginning of the output stream to match the timestamp (using -async 1). The following command produces a video of length 11 seconds.

Note that if -t is specified prior to -i (the input) then the duration refers to the input video rather than the output video. For the above example it would make no difference since we are not cropping the beginnig of the video.

By replacing -t with -to in the above command then the processing will end at the specified time. For example, the following will crop the video starting 7 minutes and 71 seconds in to 53 minutes in:

$ ffmpeg -i input.mp4 -ss 00:07:41 -to 00:53:00 -async 1 cut.mp4

Using avisplit we can also extract a particular section of an avi file (specified as the -input 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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