I'm not super familiar with AV1/AVIF but I do have extensive experience using h264 for desktop streaming, and all major implementations support 444 in hardware and software, and I doubt more advanced codecs/image formats have a limitation like this. Asked ChatGPT and it also claimed there's no problem with 444 and AVIF/AV1.

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lgkrnkglwn 4 hours ago | parent | next [-]

Then chatgpt missed an obvious issue, nvidia definitely have had shortcomings in the hardware implementation of coder/decoders only supporting 420 in nvenc/nvdec. One obvious problem with that was that it affected premiere.

	▲	torginus 3 hours ago \| parent [-]
		We have been using NVENC with 444 and h264 in production going back years and HW as old as Turing. But it turns out you are right, 444 decoding with H264 doesn't seem to be supported up until recently: https://developer.nvidia.com/video-encode-decode-support-mat... Never noticed, seems like a strange omission, but in any case doesn't seem to apply to newer codecs like AV1.

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jaffathecake 3 hours ago | parent | prev [-]

I'm pretty sure 444 h264 fails to decode on iOS Safari due to poor support in the hardware decoder.