Cut part from video file starting from startpos to endpos (ffmpeg)

Question

I have a video file of 30 minutes, but I want to extract a video from 00:09:23 to 00:25:33. I can define the startposition with -ss, but I couldn't find one for the end position. Any help please?

Answer 1

The other answer are partly right. However, to just extract a part of a video, and not re-encode it while doing so, you can't use the -sameq option. Forget that one, it just tries to get the same quality from an input, while unnecessarily increasing the output file size, when in fact you can just copy the video. In general, using -sameq is really bad advice. Therefore, use -vcodec copy.

So, this would mean:

ffmpeg -i in.mp4 -ss [start] -t [duration] -vcodec copy -acodec copy out.mp4

However, there's still one drawback. The video will be decoded until it reaches the position implied by -ss. This can take a long time, especially for really long videos.

For additional speed when doing this, you can supply the -ss option before -i. This way, the decoder will first seek to the position and then start decoding:

ffmpeg -ss [start] -i in.mp4 -t [duration] -vcodec copy -acodec copy out.mp4

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If you have an edit list of in and out points, and want to convert these into in points with duration, you can use this Ruby script I wrote, which calculates the difference:

require "Time"
def time_diff(time1_str, time2_str)
  t = Time.at( Time.parse(time2_str) - Time.parse(time1_str) )
  (t - t.gmt_offset).strftime("%H:%M:%S.%L")
end

For example:

time_diff("00:09:23.000", "00:25:33.000")
=> "00:16:10.000" 

Answer 2

I use the following syntax to cut video with ffmpef:

ffmpeg -sameq -ss [start_seconds] -t [duration_seconds] -i [input_file] [outputfile]

-t is used to set the duration in seconds - you can't specify the end time but this should work for you.

Answer 3

You can use this

ffmpeg -sameq -ss clip_start -t duration  -i  original.ogg  clip.ogg

Here you have to give duration of video. ie. 00:25:33-00:09:23