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> Burning subtitles into the video implies re-encoding In principle, would it be possible to only re-encode the macroblocks affected by the subtitles, leaving
by twic 6y ago
> Burning subtitles into the video implies re-encoding
In principle, would it be possible to only re-encode the macroblocks affected by the subtitles, leaving the rest of the frame bit-for-bit identical?
It's been a long time since i read a video encoding specification, so i don't know if things still work this way.
- beagle3 6y agoMuch harder than it sounds because future macroblocks depend on present ones, and motion vectors mean that over a few seconds, transitive dependency can reach the entire image (and does in panned and zoomed shots) Can possibly work, but depending on movie content might not save all that much encoding.
- _Gyan_ 6y agoWhat would be much better would be to encode an overlay raster stream, which the player can then composite at runtime, like they do with text subtitles. Much faster to encode. Can be toggled. But players need to support it.
- danielheath 6y agoYeah, but the whole point of the exercise is to see subtitles on players that don't even support subtitles; they're definitely not going to support an overlay stream.