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Extracting frames from a video with ffmpeg very slow if not using jpeg
(discuss.tchncs.de)
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h.264 (the compression algorithm the video uses) and jpeg are entirely different, so it does have to re-encode
Actually they both use Discrete Cosign Transform!
PNGs use DEFLATE which is a generic compression standard that exhaustively searches for smaller ways to compact the data.
I would recommend comparing the quality of images of different formats against eachother to see if there is noticeable lossyness.
If the PNGs are indeed better, try to set the initial compression of the PNGs to "zero" and come back later to "crush" them smaller.
Even if they use the same technique, they're entirely different algorithms and h.264 also takes information from multiple different frames, which is why the video is 1.7gb but a folder with each frame saved as a png is over 300gb.
The formats with the best compression, where it might be fine, are jpeg xl and webp, as far as I know. They're even slower tho because they're so CPU intensive and only use one thread.
Setting the png compression to 0 doesn't help because the bottleneck for png is the hard drives write speed. I already tried that.
Yeah, that makes sense. There might be some useful interface in VAAPI?