[FFmpeg-devel] [PATCH 1/2] avformat/mov: Rework the AVIF parser to handle multiple items
James Zern
jzern at google.com
Tue Aug 2 19:54:41 EEST 2022
Andreas,
On Thu, Jul 28, 2022 at 11:25 AM Vignesh Venkatasubramanian
<vigneshv-at-google.com at ffmpeg.org> wrote:
>
> Stores the item ids of all the items found in the file and
> processes the primary item at the end of the meta box. This patch
> does not change any behavior. It sets up the code for parsing
> alpha channel (and possibly images with 'grid') in follow up
> patches.
>
> Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
> ---
> libavformat/isom.h | 6 ++
> libavformat/mov.c | 143 +++++++++++++++++++++++++++------------------
> 2 files changed, 92 insertions(+), 57 deletions(-)
>
Any more comments on this one?
> diff --git a/libavformat/isom.h b/libavformat/isom.h
> index f05c2d9c28..9d8646d2ea 100644
> --- a/libavformat/isom.h
> +++ b/libavformat/isom.h
> @@ -318,6 +318,12 @@ typedef struct MOVContext {
> uint32_t max_stts_delta;
> int is_still_picture_avif;
> int primary_item_id;
> + struct {
> + int item_id;
> + int extent_length;
> + int64_t extent_offset;
> + } *avif_info;
> + int avif_info_size;
> } MOVContext;
>
> int ff_mp4_read_descr_len(AVIOContext *pb);
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index a09a762d91..6ee6ed0950 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -4698,6 +4698,69 @@ static int mov_read_custom(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> return ret;
> }
>
> +static int avif_add_stream(MOVContext *c, int item_id)
> +{
> + MOVStreamContext *sc;
> + AVStream *st;
> + int item_index = -1;
> + for (int i = 0; i < c->avif_info_size; i++)
> + if (c->avif_info[i].item_id == item_id) {
> + item_index = i;
> + break;
> + }
> + if (item_index < 0)
> + return AVERROR_INVALIDDATA;
> + st = avformat_new_stream(c->fc, NULL);
> + if (!st)
> + return AVERROR(ENOMEM);
> + st->id = c->fc->nb_streams;
> + sc = av_mallocz(sizeof(MOVStreamContext));
> + if (!sc)
> + return AVERROR(ENOMEM);
> +
> + st->priv_data = sc;
> + st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> + st->codecpar->codec_id = AV_CODEC_ID_AV1;
> + sc->ffindex = st->index;
> + c->trak_index = st->index;
> + st->avg_frame_rate.num = st->avg_frame_rate.den = 1;
> + st->time_base.num = st->time_base.den = 1;
> + st->nb_frames = 1;
> + sc->time_scale = 1;
> + sc = st->priv_data;
> + sc->pb = c->fc->pb;
> + sc->pb_is_copied = 1;
> +
> + // Populate the necessary fields used by mov_build_index.
> + sc->stsc_count = 1;
> + sc->stsc_data = av_malloc_array(1, sizeof(*sc->stsc_data));
> + if (!sc->stsc_data)
> + return AVERROR(ENOMEM);
> + sc->stsc_data[0].first = 1;
> + sc->stsc_data[0].count = 1;
> + sc->stsc_data[0].id = 1;
> + sc->chunk_count = 1;
> + sc->chunk_offsets = av_malloc_array(1, sizeof(*sc->chunk_offsets));
> + if (!sc->chunk_offsets)
> + return AVERROR(ENOMEM);
> + sc->sample_count = 1;
> + sc->sample_sizes = av_malloc_array(1, sizeof(*sc->sample_sizes));
> + if (!sc->sample_sizes)
> + return AVERROR(ENOMEM);
> + sc->stts_count = 1;
> + sc->stts_data = av_malloc_array(1, sizeof(*sc->stts_data));
> + if (!sc->stts_data)
> + return AVERROR(ENOMEM);
> + sc->stts_data[0].count = 1;
> + // Not used for still images. But needed by mov_build_index.
> + sc->stts_data[0].duration = 0;
> + sc->sample_sizes[0] = c->avif_info[item_index].extent_length;
> + sc->chunk_offsets[0] = c->avif_info[item_index].extent_offset;
> +
> + mov_build_index(c, st);
> + return 0;
> +}
> +
> static int mov_read_meta(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> {
> while (atom.size > 8) {
> @@ -4707,9 +4770,23 @@ static int mov_read_meta(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> tag = avio_rl32(pb);
> atom.size -= 4;
> if (tag == MKTAG('h','d','l','r')) {
> + int ret;
> avio_seek(pb, -8, SEEK_CUR);
> atom.size += 8;
> - return mov_read_default(c, pb, atom);
> + if ((ret = mov_read_default(c, pb, atom)) < 0)
> + return ret;
> + if (c->is_still_picture_avif) {
> + int ret;
> + // Add a stream for the YUV planes (primary item).
> + if ((ret = avif_add_stream(c, c->primary_item_id)) < 0)
> + return ret;
> + // For still AVIF images, the meta box contains all the
> + // necessary information that would generally be provided by the
> + // moov box. So simply mark that we have found the moov box so
> + // that parsing can continue.
> + c->found_moov = 1;
> + }
> + return ret;
> }
> }
> return 0;
> @@ -7478,8 +7555,6 @@ static int mov_read_iloc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> int item_count, extent_count;
> uint64_t base_offset, extent_offset, extent_length;
> uint8_t value;
> - AVStream *st;
> - MOVStreamContext *sc;
>
> if (!c->is_still_picture_avif) {
> // * For non-avif, we simply ignore the iloc box.
> @@ -7493,27 +7568,6 @@ static int mov_read_iloc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> return 0;
> }
>
> - st = avformat_new_stream(c->fc, NULL);
> - if (!st)
> - return AVERROR(ENOMEM);
> - st->id = c->fc->nb_streams;
> - sc = av_mallocz(sizeof(MOVStreamContext));
> - if (!sc)
> - return AVERROR(ENOMEM);
> -
> - st->priv_data = sc;
> - st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> - st->codecpar->codec_id = AV_CODEC_ID_AV1;
> - sc->ffindex = st->index;
> - c->trak_index = st->index;
> - st->avg_frame_rate.num = st->avg_frame_rate.den = 1;
> - st->time_base.num = st->time_base.den = 1;
> - st->nb_frames = 1;
> - sc->time_scale = 1;
> - sc = st->priv_data;
> - sc->pb = c->fc->pb;
> - sc->pb_is_copied = 1;
> -
> version = avio_r8(pb);
> avio_rb24(pb); // flags.
>
> @@ -7529,34 +7583,17 @@ static int mov_read_iloc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> }
> item_count = (version < 2) ? avio_rb16(pb) : avio_rb32(pb);
>
> - // Populate the necessary fields used by mov_build_index.
> - sc->stsc_count = 1;
> - sc->stsc_data = av_malloc_array(1, sizeof(*sc->stsc_data));
> - if (!sc->stsc_data)
> - return AVERROR(ENOMEM);
> - sc->stsc_data[0].first = 1;
> - sc->stsc_data[0].count = 1;
> - sc->stsc_data[0].id = 1;
> - sc->chunk_count = 1;
> - sc->chunk_offsets = av_malloc_array(1, sizeof(*sc->chunk_offsets));
> - if (!sc->chunk_offsets)
> + c->avif_info = av_malloc_array(item_count, sizeof(*c->avif_info));
> + if (!c->avif_info)
> return AVERROR(ENOMEM);
> - sc->sample_count = 1;
> - sc->sample_sizes = av_malloc_array(1, sizeof(*sc->sample_sizes));
> - if (!sc->sample_sizes)
> - return AVERROR(ENOMEM);
> - sc->stts_count = 1;
> - sc->stts_data = av_malloc_array(1, sizeof(*sc->stts_data));
> - if (!sc->stts_data)
> - return AVERROR(ENOMEM);
> - sc->stts_data[0].count = 1;
> - // Not used for still images. But needed by mov_build_index.
> - sc->stts_data[0].duration = 0;
> + c->avif_info_size = item_count;
>
> for (int i = 0; i < item_count; i++) {
> int item_id = (version < 2) ? avio_rb16(pb) : avio_rb32(pb);
> if (avio_feof(pb))
> return AVERROR_INVALIDDATA;
> + c->avif_info[i].item_id = item_id;
> +
> if (version > 0)
> avio_rb16(pb); // construction_method.
> avio_rb16(pb); // data_reference_index.
> @@ -7572,20 +7609,11 @@ static int mov_read_iloc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
> if (rb_size(pb, &extent_offset, offset_size) < 0 ||
> rb_size(pb, &extent_length, length_size) < 0)
> return AVERROR_INVALIDDATA;
> - if (item_id == c->primary_item_id) {
> - sc->sample_sizes[0] = extent_length;
> - sc->chunk_offsets[0] = base_offset + extent_offset;
> - }
> + c->avif_info[i].extent_length = extent_length;
> + c->avif_info[i].extent_offset = base_offset + extent_offset;
> }
> }
>
> - mov_build_index(c, st);
> -
> - // For still AVIF images, the iloc box contains all the necessary
> - // information that would generally be provided by the moov box. So simply
> - // mark that we have found the moov box so that parsing can continue.
> - c->found_moov = 1;
> -
> return atom.size;
> }
>
> @@ -8189,6 +8217,7 @@ static int mov_read_close(AVFormatContext *s)
>
> av_freep(&mov->aes_decrypt);
> av_freep(&mov->chapter_tracks);
> + av_freep(&mov->avif_info);
>
> return 0;
> }
> --
> 2.37.1.455.g008518b4e5-goog
>
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