> On Apr 9, 2019, at 4:51 PM, James Almer <jamr...@gmail.com> wrote: > > 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.
It still requires copying the entire ff_h264_decode_seq_parameter_set(), even though the sub functions are not needed. >> >> 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. When did the sharing policy between avformat and avcodec (in the sense avformat using avcodec) change ? It seems perfectly natural to me to have libavformat require the libavcodec version that it was compiled with, and check it at runtime. > > 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. I disagree with the copying and we will need more opinions on this to settle the argument, maybe a vote. — 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".
