[FFmpeg-devel] [PATCH 25/26] lavc/h264: Add common code for level handling

Mark Thompson sw at jkqxz.net
Wed May 2 02:25:54 EEST 2018

On 27/04/18 06:42, Xiang, Haihao wrote:
> Just for curious, will you have the common code for H.265 level handling too?

I've written some matching the H.264 code, but it's not yet complete because I haven't come up with a clean way to deal with all of the different subprofiles.

For example, decoding code doesn't really care at all about the difference between all of the different YUV 4:4:4 subprofiles ("Main 4:4:4", "High Throughput 4:4:4", "Screen-Extended Main 4:4:4", "Screen-Extended High Throughput 4:4:4", "Main 4:4:4 Intra", "Main 4:4:4 Still Picture") - it only cares about whether it supports the individually-flagged features used by a stream or not (and indeed that's reflected in the current libavcodec support, which doesn't bother to explicitly distinguish RExt subprofiles at all).  On the other hand, they do all have different properties when considered for level constraints (notably table A.8), and so need to be fully identified in any code handling that properly.

- Mark

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