FFmpeg cheatsheet

FFmpeg is ideal for processing video (and audio). If you are dealing with video files, FFmpeg is likely a useful tool. The documentation of FFmpeg is very limited. This cheatsheet lists some common usage of FFmpeg. DISCLAIMER: May contain errors and/or misconceptions, always check the documentation and thoroughly test the result.

General usage

FFmpeg takes input and processes it into an output, and has the following general usage:

• <INPUT>: For example, /dev/video0 for webcam; pipe:0 to read from stdin (standard input); or /path/to/file.mp4 to read from a file.
• <OUTPUT>: For example, /path/to/file.mp4 to write to a file; pipe:1 to write to stdout (standard output).

The order of the input and output options is usually not important.

Input options

• -re: Prevent reading from input as fast as possible, but limit reading speed to the realtime framerate of the output (optionally use with the -r output option to set a custom framerate).
• -f v4l2: Default for any /dev/video* device.
  -f video4linux2: Alias for v4l2.
  • -input_format: The pixelformat of the device: mjpeg, yuyv422, etc. FFmpeg will try to change the device's output pixelformat automatically, which succeeds as long as the device supports the given format. To discover formats, try: ffmpeg -f video4linux2 -list_formats all -i /dev/video0.
• -f rawvideo: Take raw video frames input (without container).
  • -pixel_format yuv420p: Pixel format: yuv420p, rgb24, gray8, etc.
  • -video_size 1280x720: Resolution: 1280x720, 1920x1080, etc.
  • -framerate 15: Framerate: 15, 25, 30, etc.

Output options

• -y: Force overwrite <OUTPUT> without interactive prompt (answer y to prompt).
• -r 15: Set a custom framerate for the output. This will skip/drop frames if input is faster, and duplicate frames if input is slower.
• -f rawvideo: Output raw video frames (without container).
  • -pix_fmt yuv420p: Pixel format: yuv420p, rgb24, gray8, etc.
  • -s 1280x720: Resolution: 1280x720, 1920x1080, etc.
  • -r 15: Framerate: 15, 25, 30, etc.

Examples

List all possible values for the input_format input option that the given webcam supports:

This is the FFmpeg-interpreted equivalent of v4l2-ctl --list-formats-ext -d /dev/video0. Note that FFmpeg will try to negotiate an input format based on your input options with the input device.