On 4/9/2019 8:22 PM, Baptiste Coudurier wrote: > Hi James, > >> On Apr 9, 2019, at 4:09 PM, James Almer <jamr...@gmail.com> wrote: >> >>> […] >> >> Ok so, the only fields you need from the sps are constraint_set_flags, >> frame_mbs_only_flag, bit_depth_luma, profile_idc, level_idc and sar, >> meaning you don't even need to parse the sps until the very end (sar is >> the furthest value, and right at the beginning of vui_parameters). >> I'd very much prefer if we can avoid making >> ff_h264_decode_seq_parameter_set() avpriv and with it H264ParamSets part >> of the ABI, so i think it's worth copying the required bitstream parsing >> code at least until the beginning of vui_parameters. It was done for >> hevc and av1, so it can be done for h264 as well. > > Since vui parsing is needed, that would be the entire > "ff_h264_decode_seq_parameter_set()” function.
If you only need up to sar, then yo don't need to parse the entire VUI. > > I disagree with the copying. I also disagree with the copying for AVC1 and > HEVC btw. Using avpriv opens a whole can of worms that will be unpredictable in the future. Just look at recent commits like f4ea930a119298c6110ee4e3d24219a66e27e230 that started storing previously skipped values. If hevc_pc was made avpriv for isombff/matroska muxing purposes and its structs part of the ABI, this wouldn't have been possible until a major bump. sps parsing can and should be done in libavformat for this. Otherwise you'll be constraining future development in other areas. So please, take libavcodec/cbs_h264* and libavformat/av1.c as basis and write a simple sps parser that takes the raw bitstream values and does nothing else. You only need six values. > > — > Baptiste > _______________________________________________ > 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". > _______________________________________________ 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".