Signed-off-by: Nicolas George <geo...@nsup.org> --- libavutil/pixfmt.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
Note: we have log2_chroma_h = 2 for yuv410p, meaning each chroma pixel is 4×4 luma pixels, but everywhere I look on the web, ilcuding: https://en.wikipedia.org/wiki/Chroma_subsampling I find that it is supposed to be 4×2, and we should set log2_chroma_h = 1. Who is right? Regards, -- Nicolas George diff --git a/libavutil/pixfmt.h b/libavutil/pixfmt.h index 2d3927cc3f..3d0f92ed4d 100644 --- a/libavutil/pixfmt.h +++ b/libavutil/pixfmt.h @@ -60,6 +60,23 @@ * For all the 8 bits per pixel formats, an RGB32 palette is in data[1] like * for pal8. This palette is filled in automatically by the function * allocating the picture. + * + * @par + * Summary of the naming conventions for YUV formats: + * 444 422 440 420 411 410 + * ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╋━┿━┿━┿━╋ ╋━┿━┿━┿━╋ + * ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╂─╂─╂─╂─╂ ╂─┼─╂─┼─╂ ╋━┿━┿━┿━╋ ╂─┼─┼─┼─╂ + * ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╋━┿━┿━┿━╋ ╂─┼─┼─┼─╂ + * ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╂─╂─╂─╂─╂ ╂─┼─╂─┼─╂ ╋━┿━┿━┿━╋ ╂─┼─┼─┼─╂ + * ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╋━╋━╋━╋━╋ ╋━┿━╋━┿━╋ ╋━┿━┿━┿━╋ ╋━┿━┿━┿━╋ + * where + * ┼─┼ = luma pixel ╋━╋ = chroma pixel + * ┼─┼ ╋━╋ + * + * yuv4ab → + * log2_chroma_w = log₂(4/a) + * log2_chroma_h = b == a ? 0 : b == 0 ? log2_chroma_w : unused + * i.e. a = horizontally, number of luma pixels for four chroma pixels */ enum AVPixelFormat { AV_PIX_FMT_NONE = -1, -- 2.35.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
