Some codecs, like h264, require the width and height be divisible by 2. Scaling ... | Hacker News

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		runlevel1 on June 1, 2022 \| parent \| context \| favorite \| on: Ffmpeg Buddy Some codecs, like h264, require the width and height be divisible by 2. Scaling with -1 will sometimes fail because of that. If you use -2 instead it will adjust so that it is even.[^1] For example: `ffmpeg -i input.mp4 -vf scale=720:-2 output.mp4` [1]: https://trac.ffmpeg.org/wiki/Scaling#KeepingtheAspectRatio

hombre_fatal on June 1, 2022 [–]

It reminds me of a similar quirk where scaling by a single pixel extra in either dimension can introduce disproportional blurriness, so one solution is to pad by a 1px wide border on the would-be odd dimension.

This has saved me a lot: https://stackoverflow.com/a/53024964/511200

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