On 7/30/2018 2:03 AM, Steve Lhomme wrote: > On 26/07/2018 03:11, James Almer wrote: >> Make sure to not write forbidden OBUs to CodecPrivate, and do the same >> with >> unnecessary OBUs for packets. > > Does this include reordering the OBUs ? The first one must be the > Sequence Header OBU. Also it must be the only one of that kind.
No, it doesn't. I can make that change, but why does it matter if it's the first? Why can't a metadata OBU be before a Seq Header? isobmff doesn't care what's first, only what's in. A parser is currently forced to know how to read OBUs anyway, and it could just skip any metadata obu before the sequence header. For that matter, i do agree with https://github.com/AOMediaCodec/av1-isobmff/issues/7#issuecomment-406257234 and https://github.com/AOMediaCodec/av1-isobmff/issues/46#issuecomment-406516226 that perhaps av1C should, much like hvcC, avcC and in it's own way also vpcC, contain a bunch of header bytes listing some basic information (and therefore the entire thing, sans atom size and fourcc, be included in CodecPrivate verbatim). Things like profile, level, and maybe number of OBUs, before the raw OBUs. As an extra benefit than simply removing the requirement for demuxers to parse OBUs that may even only be in sample data just to see if the file can be decoded (firing up a hardware decoder can be expensive), it would also give us a way to identify the source of the bitstream (mp4/mkv vs ivf/raw/annexb/etc), for example for the purpose of inserting the extradata Seq Header if not present on key frames (Matroska allows to remove it, but isobmff in section 2.5 seems to want a sync sample to be a fully compliant RAP without the need of extradata obus, despite the description in section 2.4.4), achieved by writing and using an av1_mp4tolobf bsf or similar, which would then be included where needed instead of the naive dump_extradata one from patch 2/5 of this set, for example. > >> >> Signed-off-by: James Almer <jamr...@gmail.com> >> --- >> libavformat/matroskaenc.c | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c >> index b7ff1950d3..816ddd059a 100644 >> --- a/libavformat/matroskaenc.c >> +++ b/libavformat/matroskaenc.c >> @@ -21,6 +21,7 @@ >> #include <stdint.h> >> +#include "av1.h" >> #include "avc.h" >> #include "hevc.h" >> #include "avformat.h" >> @@ -769,6 +770,9 @@ static int >> mkv_write_native_codecprivate(AVFormatContext *s, AVIOContext *pb, >> ff_isom_write_hvcc(dyn_cp, par->extradata, >> par->extradata_size, 0); >> return 0; >> + case AV_CODEC_ID_AV1: >> + return ff_isom_write_av1c(dyn_cp, par->extradata, >> + par->extradata_size); >> case AV_CODEC_ID_ALAC: >> if (par->extradata_size < 36) { >> av_log(s, AV_LOG_ERROR, >> @@ -2120,6 +2124,8 @@ static void mkv_write_block(AVFormatContext *s, >> AVIOContext *pb, >> (AV_RB24(par->extradata) == 1 || >> AV_RB32(par->extradata) == 1)) >> /* extradata is Annex B, assume the bitstream is too and >> convert it */ >> ff_hevc_annexb2mp4_buf(pkt->data, &data, &size, 0, NULL); >> + else if (par->codec_id == AV_CODEC_ID_AV1) >> + ff_av1_filter_obus_buf(pkt->data, &data, &size); >> else if (par->codec_id == AV_CODEC_ID_WAVPACK) { >> int ret = mkv_strip_wavpack(pkt->data, &data, &size); >> if (ret < 0) { >> -- >> 2.18.0 >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
