ons 2023-09-06 klockan 11:38 -0300 skrev James Almer: > Signed-off-by: James Almer <jamr...@gmail.com> > --- > This is an initial proof of concept for AVStream groups, something > that's > needed for quite a few existing and upcoming formats that lavf has no > way to > currently export. Said formats define a single video or audio stream > composed > by merging several individualy multiplexed streams within a media > file. > This is the case of HEIF, a format defining a tiled image where each > tile is a > separate image (either hevc, av1, etc) all of which need to be > decoded > individualy and then stitched together for presentation using > container level > information;
I remember this blocking HEIF as a GSoC project. Honestly the way that format is designed is immensely horrible. > MPEG-TS programs, currently exported as > AVProgram, which this new general purpose API would replace. I can foresee this being a nuisance for users accustomed to AVProgram. Also this feature borders on NLE territory. Not necessarily a bad thing, but FFmpeg is overall poorly architectured for NLE stuff. I believe I raised this issue back when lavfi was proposed, it being wholly unsuitable for NLE work. > +typedef struct AVStreamGroup { > + /** > + * A class for @ref avoptions. Set on stream creation. > + */ > + const AVClass *av_class; > + > + /** > + * Group index in AVFormatContext. > + */ > + int index; > + > + /** > + * Format-specific group ID. > + * decoding: set by libavformat > + * encoding: set by the user, replaced by libavformat if left > unset > + */ > + int id; > + > + /** > + * Codec parameters associated with this stream group. Allocated > and freed > + * by libavformat in avformat_new_stream_group() and > avformat_free_context() > + * respectively. > + * > + * - demuxing: filled by libavformat on stream group creation or > in > + * avformat_find_stream_info() > + * - muxing: filled by the caller before avformat_write_header() > + */ > + AVCodecParameters *codecpar; > + > + void *priv_data; > + > + /** > + * Number of elements in AVStreamGroup.stream_index. > + * > + * Set by av_stream_group_add_stream() and > av_stream_group_new_stream(), must not > + * be modified by any other code. > + */ > + int nb_stream_indexes; > + > + /** > + * A list of indexes of streams in the group. New entries are > created with > + * av_stream_group_add_stream() and > av_stream_group_new_stream(). > + * > + * - demuxing: entries are created by libavformat in > avformat_open_input(). > + * If AVFMTCTX_NOHEADER is set in ctx_flags, then > new entries may also > + * appear in av_read_frame(). > + * - muxing: entries are created by the user before > avformat_write_header(). > + * > + * Freed by libavformat in avformat_free_context(). > + */ > + int *stream_index; > +} AVStreamGroup; I see no provisions for attaching metadata, for example HEIF stitching. Putting it in coderpar seems wrong, since it is container-level metadata. We could just have an HEIF specific struct as container metadata. /Tomas _______________________________________________ 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".