Visualise differences between two clips with FFmpeg lut2

Guide ID: art_01M6W48RV7S5P0486ZSFZK6VA1

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Guide title

Visualise differences between two clips with FFmpeg lut2

Coverage

For editors and technical artists who want a quick visual map of where two versions of a clip differ, such as an original and a re-encode. It gives three ready expressions taken from the FFmpeg manual. Based on the documentation only; no command was run, and it is not a numeric quality measure.

Example

Hypothetical and not run: compare an original clip with its re-encode, expecting matching areas to come out black and differing areas bright, then judge where the bright regions fall.

Useful starting points

• A lossy re-encode often lights up much of the map, because every nonzero difference is marked at full value. That alone is not a fault.
• Strange colours in a map made from YUV footage usually mean an RGB-oriented expression was used. Match the expression to the input format.
• Check that both clips start together and share size and frame rate before reading the map; misaligned inputs make it meaningless.