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FFmpeg Open Source CLI

FFmpeg is a powerful command line interface (CLI) that handles audio and video processing tasks. I like to think of FFmpeg as a "Swiss army knife" for media processing, due to its wide range of capabilities.

FFmpeg Use Cases

  • Record your desktop
  • Convert between different file formats (eg mkv to mp4)
  • Capture Real-Time Streaming Protocol (RTSP) streams from security cameras and record to disk
  • Resize video resolution and bitrate

Resize Video Resolution

To change the resolution of a video, using FFmpeg, use the scale video filter. There are several different scale filters, in fact, but the most basic one is simply called scale. The -vf parameter is used to apply a filter to an input video stream. The -y parameter simply allows overwriting of the destination file, if it already exists.

ffmpeg -y -i source.mp4 -vf scale=width=1280:height=720 output.mp4

Crop Video

Sometimes you only care about a certain section of video, from a camera stream. This is especially true for security cameras, where the wide lens angle can capture a wider area than is necessary to monitor specific items. You can use the crop video filter to crop the contents of a video.

If you specify the x and y parameters, without specifying the w (width) and h (height) parameters, the filter will fail to operate. FFmpeg will ignore the filter but continue to process other valid filters.

ffmpeg -y -i source.mp4 -vf crop=x=1500:y=800:w=500:h=300 -t 5 output.mkv
wThe width of the video to capture
hThe height of the video to capture
xThe left starting edge to capture from
yThe top starting edge to capture from