this post was submitted on 14 Jul 2024
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I'm trying to extract the frames of a video as individual images but it's really slow, except when I'm using jpeg. The obvious issue with jpegs is the data loss from the compression, I want the images to be lossless. Extracting them as jpegs manages about 50-70 fps but as pngs it's only 4 fps and it seems to continue getting slower, after 1 minute of the 11 minute video it's only 3.5 fps.

I suspect it's because I'm doing this on an external 5tb hard drive, connected over USB 3.0 and the write speed can't keep up. So my idea was to use a different image format. I tried lossless jpeg xl and lossless webp but both of them are even slower, only managing to extract at about 0.5 fps or something. I have no idea why that's so slow, the files are a lot smaller than png, so it can't be because of the write speed.

I would appreciate it if anyone could help me with this.

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[–] OfCourseNot@fedia.io -2 points 4 months ago (1 children)

PNG is a good format for graphics, lettering, logos... not photography so unless your video is some cartoons you're using png compression for something is not meant for.

[–] Static_Rocket@lemmy.world 3 points 4 months ago* (last edited 4 months ago)

I agree that you're not really leveraging any features of PNG like you would using JPEG or RAW here, but saying it's not meant for this use is an odd way to phrase it. There's nothing inherently wrong with wanting lossless compression on an image...