Extract video clip using ffmpeg

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I recently needed to extract a 30 second video clip, and remove the audio, from a 2 hour mkv video.

If you are on macOS,  you need to get a copy of ffmpeg, the steps are:

  1. Download the statically linked pre-compiled binary as a dmg from this page:
    https://evermeet.cx/ffmpeg/The links to the DMG are quite small and appear under the large green buttons that download the .7z files.  Look closely.
  2. If the disk image does not automatically mount, double click the downloaded .dmg file to mount the disk image
  3. Open Applications > Utilities > Terminal
  4. Enter this command to make sure the /usr/local/bin directory exists:
    sudo mkdir /usr/local/bin
  5. Enter this command to install the ffmpeg binary into the correct location (if your version of ffmpeg is different you may need to change 4.0.1 to something else):
    sudo cp /Volumes/FFmpeg\ 4.0.1/ffmpeg /usr/local/bin

Now that you have ffmpeg installed, the Terminal command to extract the video using ffmpeg looks like this:

ffmpeg -ss HH:MM:SS.FFF -i movie.mkv -t 00:30 -qscale 0 -an out.mp4

Where HH:MMSS:FFF was the starting time code (in my case it was 2 hours, 8 minutes and 3 seconds or 02:08:03.000 into the video).

The other setting explained:

-i movie.mkv was the input video

-t 00:30 was the duration that I wanted to extract

-qscale 0 was to preserve the video quality

-an was to remove the audio

Of course it being ffmpeg you can use an input movie in a variety of different formats, it just so happened mine was an mkv

Update 2018-09-20


Since making the original post, I have developed a GUI front end to ffmpeg and ffprobe to make the process a lot simpler. You can click on the App name to download the Calvert Clipper.

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