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samvera / hydra-derivatives

Derivative generation for Samvera repositories
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Use more universally-compatible pixel format for mp4 derivatives #223

Open conorom opened 4 years ago

conorom commented 4 years ago

Recently we uploaded a lot of videos to Fulcrum that used a pixel format incompatible with playback in Safari.

Because FFmpeg persists the input file's tracks' parameters where applicable, the transcoded mp4 (the one requested by Safari) was not playable in Safari.

This is a weird thing to track down, but seems to be a fairly well known issue. Given that the playback derivatives should be as universally-viewable as possible, it seems like the pix_fmt flag should be added in mp4 creation to ensure a user's file will produce playable derivs.

Should be a quick change to make, if others agree. Just adding -pix_fmt yuv420p there.

Links: https://changelog.addpipe.com/fixed-rare-issue-with-recordings-not-playing-in-safari-149750 https://stackoverflow.com/a/54335942 https://superuser.com/a/1413330 https://video.stackexchange.com/a/24584 https://stackoverflow.com/questions/32829514/which-pixel-format-for-web-mp4-video https://tools.lib.umich.edu/jira/browse/HELIO-3433

no-reply commented 4 years ago

this seems like a good addition.

it might be nice to make these options more readily configurable by users in general.