[FFmpeg-devel] [PATCH 3/3] avformat/movenc: Add support for AVIF muxing
Vignesh Venkatasubramanian
vigneshv at google.com
Thu Apr 14 00:35:58 EEST 2022
On Wed, Apr 13, 2022 at 2:04 PM Andreas Rheinhardt
<andreas.rheinhardt at outlook.com> wrote:
>
> Vignesh Venkatasubramanian:
> > On Mon, Mar 21, 2022 at 1:46 PM Andreas Rheinhardt
> > <andreas.rheinhardt at outlook.com> wrote:
> >>
> >> Vignesh Venkatasubramanian:
> >>> Add an AVIF muxer by re-using the existing the mov/mp4 muxer.
> >>>
> >>> AVIF Specifiation: https://aomediacodec.github.io/av1-avif
> >>>
> >>> Sample usage for still image:
> >>> ffmpeg -i image.png -c:v libaom-av1 -avif-image 1 image.avif
> >>>
> >>> Sample usage for animated AVIF image:
> >>> ffmpeg -i video.mp4 animated.avif
> >>>
> >>> We can re-use any of the AV1 encoding options that will make
> >>> sense for image encoding (like bitrate, tiles, encoding speed,
> >>> etc).
> >>>
> >>> The files generated by this muxer has been verified to be valid
> >>> AVIF files by the following:
> >>> 1) Displays on Chrome (both still and animated images).
> >>> 2) Displays on Firefox (only still images, firefox does not support
> >>> animated AVIF yet).
> >>> 3) Verfied to be valid by Compliance Warden:
> >>> https://github.com/gpac/ComplianceWarden
> >>>
> >>> Fixes the encoder/muxer part of Trac Ticket #7621
> >>>
> >>> Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
> >>> ---
> >>> configure | 1 +
> >>> libavformat/allformats.c | 1 +
> >>> libavformat/movenc.c | 341 ++++++++++++++++++++++++++++++++++++---
> >>> libavformat/movenc.h | 5 +
> >>> 4 files changed, 322 insertions(+), 26 deletions(-)
> >>>
> >>> diff --git a/configure b/configure
> >>> index 8c69ab0c86..6d7020e96b 100755
> >>> --- a/configure
> >>> +++ b/configure
> >>> @@ -3390,6 +3390,7 @@ asf_stream_muxer_select="asf_muxer"
> >>> av1_demuxer_select="av1_frame_merge_bsf av1_parser"
> >>> avi_demuxer_select="riffdec exif"
> >>> avi_muxer_select="riffenc"
> >>> +avif_muxer_select="mov_muxer"
> >>> caf_demuxer_select="iso_media"
> >>> caf_muxer_select="iso_media"
> >>> dash_muxer_select="mp4_muxer"
> >>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> >>> index d066a7745b..400c17afbd 100644
> >>> --- a/libavformat/allformats.c
> >>> +++ b/libavformat/allformats.c
> >>> @@ -81,6 +81,7 @@ extern const AVOutputFormat ff_au_muxer;
> >>> extern const AVInputFormat ff_av1_demuxer;
> >>> extern const AVInputFormat ff_avi_demuxer;
> >>> extern const AVOutputFormat ff_avi_muxer;
> >>> +extern const AVOutputFormat ff_avif_muxer;
> >>> extern const AVInputFormat ff_avisynth_demuxer;
> >>> extern const AVOutputFormat ff_avm2_muxer;
> >>> extern const AVInputFormat ff_avr_demuxer;
> >>> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> >>> index 1a746a67fd..ff41579300 100644
> >>> --- a/libavformat/movenc.c
> >>> +++ b/libavformat/movenc.c
> >>> @@ -1303,7 +1303,7 @@ static int mov_write_av1c_tag(AVIOContext *pb, MOVTrack *track)
> >>>
> >>> avio_wb32(pb, 0);
> >>> ffio_wfourcc(pb, "av1C");
> >>> - ff_isom_write_av1c(pb, track->vos_data, track->vos_len, 1);
> >>> + ff_isom_write_av1c(pb, track->vos_data, track->vos_len, track->mode != MODE_AVIF);
> >>> return update_size(pb, pos);
> >>> }
> >>>
> >>> @@ -2004,12 +2004,13 @@ static int mov_write_colr_tag(AVIOContext *pb, MOVTrack *track, int prefer_icc)
> >>> }
> >>> }
> >>>
> >>> - /* We should only ever be called by MOV or MP4. */
> >>> - av_assert0(track->mode == MODE_MOV || track->mode == MODE_MP4);
> >>> + /* We should only ever be called for MOV, MP4 and AVIF. */
> >>> + av_assert0(track->mode == MODE_MOV || track->mode == MODE_MP4 ||
> >>> + track->mode == MODE_AVIF);
> >>>
> >>> avio_wb32(pb, 0); /* size */
> >>> ffio_wfourcc(pb, "colr");
> >>> - if (track->mode == MODE_MP4)
> >>> + if (track->mode == MODE_MP4 || track->mode == MODE_AVIF)
> >>> ffio_wfourcc(pb, "nclx");
> >>> else
> >>> ffio_wfourcc(pb, "nclc");
> >>> @@ -2019,7 +2020,7 @@ static int mov_write_colr_tag(AVIOContext *pb, MOVTrack *track, int prefer_icc)
> >>> avio_wb16(pb, track->par->color_primaries);
> >>> avio_wb16(pb, track->par->color_trc);
> >>> avio_wb16(pb, track->par->color_space);
> >>> - if (track->mode == MODE_MP4) {
> >>> + if (track->mode == MODE_MP4 || track->mode == MODE_AVIF) {
> >>> int full_range = track->par->color_range == AVCOL_RANGE_JPEG;
> >>> avio_w8(pb, full_range << 7);
> >>> }
> >>> @@ -2085,7 +2086,7 @@ static void find_compressor(char * compressor_name, int len, MOVTrack *track)
> >>> || (track->par->width == 1440 && track->par->height == 1080)
> >>> || (track->par->width == 1920 && track->par->height == 1080);
> >>>
> >>> - if (track->mode == MODE_MOV &&
> >>> + if ((track->mode == MODE_AVIF || track->mode == MODE_MOV) &&
> >>> (encoder = av_dict_get(track->st->metadata, "encoder", NULL, 0))) {
> >>> av_strlcpy(compressor_name, encoder->value, 32);
> >>> } else if (track->par->codec_id == AV_CODEC_ID_MPEG2VIDEO && xdcam_res) {
> >>> @@ -2106,6 +2107,25 @@ static void find_compressor(char * compressor_name, int len, MOVTrack *track)
> >>> }
> >>> }
> >>>
> >>> +static int mov_write_ccst_tag(AVIOContext *pb)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + // Write sane defaults:
> >>> + // all_ref_pics_intra = 0 : all samples can use any type of reference.
> >>> + // intra_pred_used = 1 : intra prediction may or may not be used.
> >>> + // max_ref_per_pic = 15 : reserved value to indicate that any number of
> >>> + // reference images can be used.
> >>> + uint8_t ccstValue = (0 << 7) | /* all_ref_pics_intra */
> >>> + (1 << 6) | /* intra_pred_used */
> >>> + (15 << 2); /* max_ref_per_pic */
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "ccst");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_w8(pb, ccstValue);
> >>> + avio_wb24(pb, 0); /* reserved */
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> static int mov_write_video_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContext *mov, MOVTrack *track)
> >>> {
> >>> int ret = AVERROR_BUG;
> >>> @@ -2123,6 +2143,8 @@ static int mov_write_video_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContex
> >>> avio_wb32(pb, 0); /* size */
> >>> if (mov->encryption_scheme != MOV_ENC_NONE) {
> >>> ffio_wfourcc(pb, "encv");
> >>> + } else if (track->mode == MODE_AVIF) {
> >>> + ffio_wfourcc(pb, "av01");
> >>> } else {
> >>> avio_wl32(pb, track->tag); // store it byteswapped
> >>> }
> >>> @@ -2239,7 +2261,7 @@ static int mov_write_video_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContex
> >>> else
> >>> av_log(mov->fc, AV_LOG_WARNING, "Not writing 'gama' atom. Format is not MOV.\n");
> >>> }
> >>> - if (track->mode == MODE_MOV || track->mode == MODE_MP4) {
> >>> + if (track->mode == MODE_MOV || track->mode == MODE_MP4 || track->mode == MODE_AVIF) {
> >>> int has_color_info = track->par->color_primaries != AVCOL_PRI_UNSPECIFIED &&
> >>> track->par->color_trc != AVCOL_TRC_UNSPECIFIED &&
> >>> track->par->color_space != AVCOL_SPC_UNSPECIFIED;
> >>> @@ -2291,6 +2313,9 @@ static int mov_write_video_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContex
> >>> if (avid)
> >>> avio_wb32(pb, 0);
> >>>
> >>> + if (track->mode == MODE_AVIF)
> >>> + mov_write_ccst_tag(pb);
> >>> +
> >>> return update_size(pb, pos);
> >>> }
> >>>
> >>> @@ -2792,7 +2817,10 @@ static int mov_write_hdlr_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra
> >>>
> >>> if (track) {
> >>> hdlr = (track->mode == MODE_MOV) ? "mhlr" : "\0\0\0\0";
> >>> - if (track->par->codec_type == AVMEDIA_TYPE_VIDEO) {
> >>> + if (track->mode == MODE_AVIF) {
> >>> + hdlr_type = "pict";
> >>> + descr = "ffmpeg";
> >>> + } else if (track->par->codec_type == AVMEDIA_TYPE_VIDEO) {
> >>> hdlr_type = "vide";
> >>> descr = "VideoHandler";
> >>> } else if (track->par->codec_type == AVMEDIA_TYPE_AUDIO) {
> >>> @@ -2859,6 +2887,131 @@ static int mov_write_hdlr_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra
> >>> return update_size(pb, pos);
> >>> }
> >>>
> >>> +static int mov_write_pitm_tag(AVIOContext *pb, int item_id)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "pitm");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_wb16(pb, item_id); /* item_id */
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> +static int mov_write_iloc_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "iloc");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_w8(pb, (4 << 4) + 4); /* offset_size(4) and length_size(4) */
> >>> + avio_w8(pb, 0); /* base_offset_size(4) and reserved(4) */
> >>> + avio_wb16(pb, 1); /* item_count */
> >>> +
> >>> + avio_wb16(pb, 1); /* item_id */
> >>> + avio_wb16(pb, 0); /* data_reference_index */
> >>> + avio_wb16(pb, 1); /* extent_count */
> >>> + mov->avif_extent_pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* extent_offset (written later) */
> >>> + // For animated AVIF, we simply write the first packet's size.
> >>> + avio_wb32(pb, mov->avif_extent_length); /* extent_length */
> >>> +
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> +static int mov_write_iinf_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t infe_pos;
> >>> + int64_t iinf_pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "iinf");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_wb16(pb, 1); /* entry_count */
> >>> +
> >>> + infe_pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "infe");
> >>> + avio_w8(pb, 0x2); /* Version */
> >>> + avio_wb24(pb, 0); /* flags */
> >>> + avio_wb16(pb, 1); /* item_id */
> >>> + avio_wb16(pb, 0); /* item_protection_index */
> >>> + avio_write(pb, "av01", 4); /* item_type */
> >>> + avio_write(pb, "Color\0", 6); /* item_name */
> >>> + update_size(pb, infe_pos);
> >>> +
> >>> + return update_size(pb, iinf_pos);
> >>> +}
> >>> +
> >>> +static int mov_write_ispe_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "ispe");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_wb32(pb, s->streams[0]->codecpar->width); /* image_width */
> >>> + avio_wb32(pb, s->streams[0]->codecpar->height); /* image_height */
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> +
> >>> +static int mov_write_pixi_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + int num_channels = av_pix_fmt_count_planes(s->streams[0]->codecpar->format);
> >>
> >> Is the number of planes really the correct number here? After all, for a
> >> muxer (instead of a decoder) it does not matter whether the chroma
> >> planes are interleaved like in AV_PIX_FMT_NV12 or not like in
> >> AV_PIX_FMT_YUV420P. You should better use pixdesc->nb_components.
> >>
> >
> > Done.
> >
> >>> + const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(s->streams[0]->codecpar->format);
> >>> + int i;
> >>
> >> We allow and use "for (int i = 0;" from C99 to save lines like these.
> >>
> >
> > Done.
> >
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "pixi");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_w8(pb, num_channels); /* num_channels */
> >>> + for (i = 0; i < num_channels; ++i) {
> >>> + avio_w8(pb, pixdesc->comp[i].depth); /* bits_per_channel */
> >>> + }
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> +static int mov_write_ipco_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "ipco");
> >>> + mov_write_ispe_tag(pb, mov, s);
> >>> + mov_write_pixi_tag(pb, mov, s);
> >>> + mov_write_av1c_tag(pb, &mov->tracks[0]);
> >>> + mov_write_colr_tag(pb, &mov->tracks[0], 0);
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> +static int mov_write_ipma_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "ipma");
> >>> + avio_wb32(pb, 0); /* Version & flags */
> >>> + avio_wb32(pb, 1); /* entry_count */
> >>> + avio_wb16(pb, 1); /* item_ID */
> >>> + avio_w8(pb, 4); /* association_count */
> >>> +
> >>> + // ispe association.
> >>> + avio_w8(pb, 1); /* essential and property_index */
> >>> + // pixi association.
> >>> + avio_w8(pb, 2); /* essential and property_index */
> >>> + // av1C association.
> >>> + avio_w8(pb, 0x80 | 3); /* essential and property_index */
> >>> + // colr association.
> >>> + avio_w8(pb, 4); /* essential and property_index */
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> +static int mov_write_iprp_tag(AVIOContext *pb, MOVMuxContext *mov, AVFormatContext *s)
> >>> +{
> >>> + int64_t pos = avio_tell(pb);
> >>> + avio_wb32(pb, 0); /* size */
> >>> + ffio_wfourcc(pb, "iprp");
> >>> + mov_write_ipco_tag(pb, mov, s);
> >>> + mov_write_ipma_tag(pb, mov, s);
> >>> + return update_size(pb, pos);
> >>> +}
> >>> +
> >>> static int mov_write_hmhd_tag(AVIOContext *pb)
> >>> {
> >>> /* This atom must be present, but leaving the values at zero
> >>> @@ -3056,7 +3209,7 @@ static int mov_write_tkhd_tag(AVIOContext *pb, MOVMuxContext *mov,
> >>> display_matrix = NULL;
> >>> }
> >>>
> >>> - if (track->flags & MOV_TRACK_ENABLED)
> >>> + if (track->flags & MOV_TRACK_ENABLED || track->mode == MODE_AVIF)
> >>> flags |= MOV_TKHD_FLAG_ENABLED;
> >>>
> >>> if (track->mode == MODE_ISM)
> >>> @@ -3104,7 +3257,7 @@ static int mov_write_tkhd_tag(AVIOContext *pb, MOVMuxContext *mov,
> >>> if (st && (track->par->codec_type == AVMEDIA_TYPE_VIDEO ||
> >>> track->par->codec_type == AVMEDIA_TYPE_SUBTITLE)) {
> >>> int64_t track_width_1616;
> >>> - if (track->mode == MODE_MOV) {
> >>> + if (track->mode == MODE_MOV || track->mode == MODE_AVIF) {
> >>> track_width_1616 = track->par->width * 0x10000ULL;
> >>> } else {
> >>> track_width_1616 = av_rescale(st->sample_aspect_ratio.num,
> >>> @@ -3439,7 +3592,8 @@ static int mov_write_trak_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContext
> >>> mov_write_tapt_tag(pb, track);
> >>> }
> >>> }
> >>> - mov_write_track_udta_tag(pb, mov, st);
> >>> + if (track->mode != MODE_AVIF)
> >>> + mov_write_track_udta_tag(pb, mov, st);
> >>> track->entry = entry_backup;
> >>> track->chunkCount = chunk_backup;
> >>> return update_size(pb, pos);
> >>> @@ -3914,8 +4068,15 @@ static int mov_write_meta_tag(AVIOContext *pb, MOVMuxContext *mov,
> >>> mov_write_mdta_hdlr_tag(pb, mov, s);
> >>> mov_write_mdta_keys_tag(pb, mov, s);
> >>> mov_write_mdta_ilst_tag(pb, mov, s);
> >>> - }
> >>> - else {
> >>> + } else if (mov->mode == MODE_AVIF) {
> >>> + mov_write_hdlr_tag(s, pb, &mov->tracks[0]);
> >>> + // We always write the primary item id as 1 since only one track is
> >>> + // supported for AVIF.
> >>> + mov_write_pitm_tag(pb, 1);
> >>> + mov_write_iloc_tag(pb, mov, s);
> >>> + mov_write_iinf_tag(pb, mov, s);
> >>> + mov_write_iprp_tag(pb, mov, s);
> >>> + } else {
> >>> /* iTunes metadata tag */
> >>> mov_write_itunes_hdlr_tag(pb, mov, s);
> >>> mov_write_ilst_tag(pb, mov, s);
> >>> @@ -4245,10 +4406,11 @@ static int mov_write_moov_tag(AVIOContext *pb, MOVMuxContext *mov,
> >>> }
> >>>
> >>> mov_write_mvhd_tag(pb, mov);
> >>> - if (mov->mode != MODE_MOV && !mov->iods_skip)
> >>> + if (mov->mode != MODE_MOV && mov->mode != MODE_AVIF && !mov->iods_skip)
> >>> mov_write_iods_tag(pb, mov);
> >>> for (i = 0; i < mov->nb_streams; i++) {
> >>> - if (mov->tracks[i].entry > 0 || mov->flags & FF_MOV_FLAG_FRAGMENT) {
> >>> + if (mov->tracks[i].entry > 0 || mov->flags & FF_MOV_FLAG_FRAGMENT ||
> >>> + mov->mode == MODE_AVIF) {
> >>> int ret = mov_write_trak_tag(s, pb, mov, &(mov->tracks[i]), i < s->nb_streams ? s->streams[i] : NULL);
> >>> if (ret < 0)
> >>> return ret;
> >>> @@ -4259,7 +4421,7 @@ static int mov_write_moov_tag(AVIOContext *pb, MOVMuxContext *mov,
> >>>
> >>> if (mov->mode == MODE_PSP)
> >>> mov_write_uuidusmt_tag(pb, s);
> >>> - else
> >>> + else if (mov->mode != MODE_AVIF)
> >>> mov_write_udta_tag(pb, mov, s);
> >>>
> >>> return update_size(pb, pos);
> >>> @@ -5002,6 +5164,9 @@ static void mov_write_ftyp_tag_internal(AVIOContext *pb, AVFormatContext *s,
> >>> else if (mov->mode == MODE_3GP) {
> >>> ffio_wfourcc(pb, has_h264 ? "3gp6" : "3gp4");
> >>> minor = has_h264 ? 0x100 : 0x200;
> >>> + } else if (mov->mode == MODE_AVIF) {
> >>> + ffio_wfourcc(pb, mov->is_animated_avif ? "avis" : "avif");
> >>> + minor = 0;
> >>> } else if (mov->mode & MODE_3G2) {
> >>> ffio_wfourcc(pb, has_h264 ? "3g2b" : "3g2a");
> >>> minor = has_h264 ? 0x20000 : 0x10000;
> >>> @@ -5065,6 +5230,31 @@ static int mov_write_ftyp_tag(AVIOContext *pb, AVFormatContext *s)
> >>> // compatible brand a second time.
> >>> if (mov->mode == MODE_ISM) {
> >>> ffio_wfourcc(pb, "piff");
> >>> + } else if (mov->mode == MODE_AVIF) {
> >>> + const AVPixFmtDescriptor *pix_fmt_desc =
> >>> + av_pix_fmt_desc_get(s->streams[0]->codecpar->format);
> >>> + const int depth = pix_fmt_desc->comp[0].depth;
> >>> + if (mov->is_animated_avif) {
> >>> + // For animated AVIF, major brand is "avis". Add "avif" as a
> >>> + // compatible brand.
> >>> + ffio_wfourcc(pb, "avif");
> >>> + ffio_wfourcc(pb, "msf1");
> >>> + ffio_wfourcc(pb, "iso8");
> >>> + }
> >>> + ffio_wfourcc(pb, "mif1");
> >>> + ffio_wfourcc(pb, "miaf");
> >>> + if (depth == 8 || depth == 10) {
> >>> + // MA1B and MA1A brands are based on AV1 profile. Short hand for
> >>> + // computing that is based on chroma subsampling type. 420 chroma
> >>> + // subsampling is MA1B. 444 chroma subsampling is MA1A.
> >>> + if (pix_fmt_desc->log2_chroma_w == 0 && pix_fmt_desc->log2_chroma_h == 0) {
> >>> + // 444 chroma subsampling.
> >>> + ffio_wfourcc(pb, "MA1A");
> >>> + } else {
> >>> + // 420 chroma subsampling.
> >>> + ffio_wfourcc(pb, "MA1B");
> >>> + }
> >>> + }
> >>> } else if (mov->mode != MODE_MOV) {
> >>> // We add tfdt atoms when fragmenting, signal this with the iso6 compatible
> >>> // brand, if not already the major brand. This is compatible with users that
> >>> @@ -5669,7 +5859,7 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
> >>> if (ret < 0)
> >>> return ret;
> >>>
> >>> - if (mov->flags & FF_MOV_FLAG_FRAGMENT) {
> >>> + if (mov->flags & FF_MOV_FLAG_FRAGMENT || mov->mode == MODE_AVIF) {
> >>> int ret;
> >>> if (mov->moov_written || mov->flags & FF_MOV_FLAG_EMPTY_MOOV) {
> >>> if (mov->frag_interleave && mov->fragments > 0) {
> >>> @@ -5802,7 +5992,9 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
> >>> }
> >>> }
> >>> } else if (par->codec_id == AV_CODEC_ID_AV1) {
> >>> - if (trk->hint_track >= 0 && trk->hint_track < mov->nb_streams) {
> >>> + if (trk->mode == MODE_AVIF) {
> >>
> >> Why this? AVIF requires that AVI-in-ISOBMFF sample format is honoured
> >> and this contains e.g. "OBUs of type OBU_TEMPORAL_DELIMITER,
> >> OBU_PADDING, or OBU_REDUNDANT_FRAME_HEADER SHOULD NOT be used".
> >> ff_av1_filter_obus(_buf)? merely ensures that these OBUs are stripped away.
> >>
> >> If the aim of this check is to disallow hint tracks or so, then it fails
> >> (all it does is ensuring that both the ordinary track as well as the
> >> hint track get data that might contain OBUs that should not be there).
> >>
> >
> > Done. I had to update the extent offset code here as well.
> >
> >>> + avio_write(pb, pkt->data, pkt->size);
> >>> + } else if (trk->hint_track >= 0 && trk->hint_track < mov->nb_streams) {
> >>> ret = ff_av1_filter_obus_buf(pkt->data, &reformatted_data,
> >>> &size, &offset);
> >>> if (ret < 0)
> >>> @@ -6230,6 +6422,10 @@ fail:
> >>> }
> >>> }
> >>>
> >>> + if (trk->mode == MODE_AVIF && !mov->avif_extent_length) {
> >>> + mov->avif_extent_length = pkt->size;
> >>> + }
> >>> +
> >>> return mov_write_single_packet(s, pkt);
> >>> }
> >>> }
> >>> @@ -6569,11 +6765,15 @@ static int mov_init(AVFormatContext *s)
> >>> else if (IS_MODE(ipod, IPOD)) mov->mode = MODE_IPOD;
> >>> else if (IS_MODE(ismv, ISMV)) mov->mode = MODE_ISM;
> >>> else if (IS_MODE(f4v, F4V)) mov->mode = MODE_F4V;
> >>> + else if (IS_MODE(avif, AVIF)) mov->mode = MODE_AVIF;
> >>> #undef IS_MODE
> >>>
> >>> if (mov->flags & FF_MOV_FLAG_DELAY_MOOV)
> >>> mov->flags |= FF_MOV_FLAG_EMPTY_MOOV;
> >>>
> >>> + if (mov->mode == MODE_AVIF)
> >>> + mov->flags |= FF_MOV_FLAG_DELAY_MOOV;
> >>> +
> >>> /* Set the FRAGMENT flag if any of the fragmentation methods are
> >>> * enabled. */
> >>> if (mov->max_fragment_duration || mov->max_fragment_size ||
> >>> @@ -6654,11 +6854,25 @@ static int mov_init(AVFormatContext *s)
> >>> /* Non-seekable output is ok if using fragmentation. If ism_lookahead
> >>> * is enabled, we don't support non-seekable output at all. */
> >>> if (!(s->pb->seekable & AVIO_SEEKABLE_NORMAL) &&
> >>> - (!(mov->flags & FF_MOV_FLAG_FRAGMENT) || mov->ism_lookahead)) {
> >>> + (!(mov->flags & FF_MOV_FLAG_FRAGMENT) || mov->ism_lookahead ||
> >>> + mov->mode == MODE_AVIF)) {
> >>> av_log(s, AV_LOG_ERROR, "muxer does not support non seekable output\n");
> >>> return AVERROR(EINVAL);
> >>> }
> >>>
> >>> + /* AVIF output must have exactly one video stream */
> >>> + if (mov->mode == MODE_AVIF) {
> >>> + if (s->nb_streams > 1) {
> >>> + av_log(s, AV_LOG_ERROR, "AVIF output requires exactly one stream\n");
> >>> + return AVERROR(EINVAL);
> >>> + }
> >>> + if (s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO) {
> >>> + av_log(s, AV_LOG_ERROR, "AVIF output requires one video stream\n");
> >>> + return AVERROR(EINVAL);
> >>> + }
> >>> + }
> >>> +
> >>> +
> >>> mov->nb_streams = s->nb_streams;
> >>> if (mov->mode & (MODE_MP4|MODE_MOV|MODE_IPOD) && s->nb_chapters)
> >>> mov->chapter_track = mov->nb_streams++;
> >>> @@ -6797,12 +7011,13 @@ static int mov_init(AVFormatContext *s)
> >>> pix_fmt == AV_PIX_FMT_MONOWHITE ||
> >>> pix_fmt == AV_PIX_FMT_MONOBLACK;
> >>> }
> >>> - if (track->par->codec_id == AV_CODEC_ID_VP9 ||
> >>> - track->par->codec_id == AV_CODEC_ID_AV1) {
> >>> - if (track->mode != MODE_MP4) {
> >>> - av_log(s, AV_LOG_ERROR, "%s only supported in MP4.\n", avcodec_get_name(track->par->codec_id));
> >>> - return AVERROR(EINVAL);
> >>> - }
> >>> + if (track->par->codec_id == AV_CODEC_ID_VP9 && track->mode != MODE_MP4) {
> >>> + av_log(s, AV_LOG_ERROR, "%s only supported in MP4.\n", avcodec_get_name(track->par->codec_id));
> >>> + return AVERROR(EINVAL);
> >>> + } else if (track->par->codec_id == AV_CODEC_ID_AV1 &&
> >>> + track->mode != MODE_MP4 && track->mode != MODE_AVIF) {
> >>> + av_log(s, AV_LOG_ERROR, "%s only supported in MP4 and AVIF.\n", avcodec_get_name(track->par->codec_id));
> >>> + return AVERROR(EINVAL);
> >>> } else if (track->par->codec_id == AV_CODEC_ID_VP8) {
> >>> /* altref frames handling is not defined in the spec as of version v1.0,
> >>> * so just forbid muxing VP8 streams altogether until a new version does */
> >>> @@ -7003,7 +7218,7 @@ static int mov_write_header(AVFormatContext *s)
> >>> FF_MOV_FLAG_FRAG_EVERY_FRAME)) &&
> >>> !mov->max_fragment_duration && !mov->max_fragment_size)
> >>> mov->flags |= FF_MOV_FLAG_FRAG_KEYFRAME;
> >>> - } else {
> >>> + } else if (mov->mode != MODE_AVIF) {
> >>> if (mov->flags & FF_MOV_FLAG_FASTSTART)
> >>> mov->reserved_header_pos = avio_tell(pb);
> >>> mov_write_mdat_tag(pb, mov);
> >>> @@ -7291,6 +7506,48 @@ static int mov_check_bitstream(AVFormatContext *s, AVStream *st,
> >>> return ret;
> >>> }
> >>>
> >>> +static int avif_write_trailer(AVFormatContext *s)
> >>> +{
> >>> + AVIOContext *pb = s->pb;
> >>> + MOVMuxContext *mov = s->priv_data;
> >>> + int64_t pos_backup, mdat_pos;
> >>> + uint8_t *buf;
> >>> + int buf_size, moov_size;
> >>> + int i;
> >>> +
> >>> + if (mov->moov_written) return 0;
> >>> +
> >>> + mov->is_animated_avif = s->streams[0]->nb_frames > 1;
> >>> + mov_write_identification(pb, s);
> >>> + mov_write_meta_tag(pb, mov, s);
> >>> +
> >>> + moov_size = get_moov_size(s);
> >>> + for (i = 0; i < mov->nb_streams; i++)
> >>> + mov->tracks[i].data_offset = avio_tell(pb) + moov_size + 8;
> >>
> >> Don't call avio_tell() in a loop (and I wonder whether this loop is even
> >> necessary given that s->nb_streams is checked to be one).
> >>
> >
> > Removed the loop. I was thinking about potentially supporting multiple
> > output tracks in the future (for alpha channel for example), but this
> > code would not work in that case any way.
> >
> >>> +
> >>> + if (mov->is_animated_avif) {
> >>> + int ret;
> >>> + if ((ret = mov_write_moov_tag(pb, mov, s)) < 0)
> >>> + return ret;
> >>> + }
> >>> +
> >>> + buf_size = avio_get_dyn_buf(mov->mdat_buf, &buf);
> >>> + avio_wb32(pb, buf_size + 8);
> >>> + ffio_wfourcc(pb, "mdat");
> >>> + mdat_pos = avio_tell(pb);
> >>> +
> >>> + avio_write(pb, buf, buf_size);
> >>> + ffio_free_dyn_buf(&mov->mdat_buf);
> >>
> >> Unnecessary: This will be freed in mov_free().
> >>
> >
> > Removed.
> >
> >>> +
> >>> + // write extent offset.
> >>> + pos_backup = avio_tell(pb);
> >>> + avio_seek(pb, mov->avif_extent_pos, SEEK_SET);
> >>> + avio_wb32(pb, mdat_pos); /* rewrite offset */
> >>
> >> What guarantees that this fits into 32bits?
> >>
> >
> > Added a check to fail if it does not fit in 32-bits.
> >
> >>> + avio_seek(pb, pos_backup, SEEK_SET);
> >>> +
> >>> + return 0;
> >>> +}
> >>> +
> >>> #if CONFIG_TGP_MUXER || CONFIG_TG2_MUXER
> >>> static const AVCodecTag codec_3gp_tags[] = {
> >>> { AV_CODEC_ID_H263, MKTAG('s','2','6','3') },
> >>> @@ -7373,6 +7630,20 @@ static const AVCodecTag codec_f4v_tags[] = {
> >>> { AV_CODEC_ID_NONE, 0 },
> >>> };
> >>>
> >>> +#if CONFIG_AVIF_MUXER
> >>> +static const AVCodecTag codec_avif_tags[] = {
> >>> + { AV_CODEC_ID_AV1, MKTAG('a','v','0','1') },
> >>> + { AV_CODEC_ID_NONE, 0 },
> >>> +};
> >>> +static const AVCodecTag *const codec_avif_tags_list[] = { codec_avif_tags, NULL };
> >>> +
> >>> +static const AVClass mov_avif_muxer_class = {
> >>> + .class_name = "avif muxer",
> >>> + .item_name = av_default_item_name,
> >>> + .version = LIBAVUTIL_VERSION_INT,
> >>> +};
> >>
> >> It's not mandatory for a muxer to have a private class; it is only
> >> necessary for options. If you do not have options (like here), then the
> >> AVClass is useless.
> >> I actually wanted that you support the options that make sense for AVIF
> >> and I dislike that the avif muxer uses a different write_trailer than
> >> every other muxer here (which is the reason why e.g. the faststart
> >> option is not supported by it). Is it really so different?
> >> Furthermore, given that you don't use the same AVClass as everyone else,
> >> the values for fields that are AVOpt-enabled are zero; and this does not
> >> always coincide with the default value of the relevant option. See e.g.
> >> skip_iods, iods_audio_profile, iods_video_profile etc. movie_timescale
> >> will even be set to a value that is outside of its legal range. I don't
> >> know whether this can lead to any divide-by-zero crashes or asserts, but
> >> it is certainly very fragile.
> >>
> >
> > Hmm, i see a couple of solutions here:
> > 1) Use the same private class as the MOV muxer and document that not
> > all options are supported when the format is AVIF. I think there are
> > already cases within this file where not all muxers may support all
> > the options.
> > 2) Leave it as-is since the code always checks for AVIF mode first and
> > then does the rest, so the defaults of the non-relevant options should
> > not matter. But i agree that this is very fragile. One way to ensure
> > future changes don't break this structure is to add a fate test.
> >
>
> Can you tell which options (if enabled) would work and which would not
> work or would create spec-incompliant output?
>
The following options will make sense for AVIF (and may just work
as-is, i am not sure of this): write_colr, prefer_icc,
video_track_timescale and a few other generic MOV options like
use_stream_ids_as_track_ids, empty_hdlr_name, and brand.
> > Please let me know what you think.
> >
> > About using a separate write_trailer function, i can re-use the
> > existing mov_write_trailer but it will mostly be a special case for
> > AVIF mode with the code in avif_write_trailer, so i thought it was
> > cleaner to have a separate function anyway. I am not sure if there are
> > any other implications because of this. If you prefer that i move it
> > into mov_write_trailer, please let me know and i can do that as well.
> >
>
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--
Vignesh
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