[FFmpeg-devel] [PATCH 1/1] avformat/matroska: fully parse stsd atom in v_quicktime tracks

[Stanislav Ionascu]

Per matroska spec, v_quicktime contains the complete stsd atom, after
the mandatory size + fourcc. By properly parsing the hvcc sub-atoms of
the track, it becomes possible to demux/decode mp4/mov tracks stored as is
in matroska containers.

Also dvh1 in stsd in matroska is more likely hevc codec than dv.

Signed-off-by: Stanislav Ionascu <stanislav.ionascu at gmail.com>
---
 libavformat/matroskadec.c | 51 +++++++++++++++++++++++++++------------
 1 file changed, 36 insertions(+), 15 deletions(-)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 4e20f15792..88bc89c545 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2473,25 +2473,46 @@ static int matroska_parse_tracks(AVFormatContext *s)
         } else if (!strcmp(track->codec_id, "V_QUICKTIME") &&
                    (track->codec_priv.size >= 21)          &&
                    (track->codec_priv.data)) {
+            MOVStreamContext *msc;
+            MOVContext *mc = NULL;
+            AVIOContext *stsd_ctx = NULL;
+            void *priv_data;
+            int nb_streams;
             int ret = get_qt_codec(track, &fourcc, &codec_id);
             if (ret < 0)
                 return ret;
-            if (codec_id == AV_CODEC_ID_NONE && AV_RL32(track->codec_priv.data+4) == AV_RL32("SMI ")) {
-                fourcc = MKTAG('S','V','Q','3');
-                codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
+            av_log(matroska->ctx, AV_LOG_TRACE,
+                   "FourCC found %s.\n", av_fourcc2str(fourcc));
+            priv_data = st->priv_data;
+            nb_streams = s->nb_streams;
+            mc = av_mallocz(sizeof(*mc));
+            if (!mc)
+                return AVERROR(ENOMEM);
+            stsd_ctx = avio_alloc_context(track->codec_priv.data,
+                                track->codec_priv.size,
+                                0, NULL, NULL, NULL, NULL);
+            if (!stsd_ctx)
+                return AVERROR(ENOMEM);
+            mc->fc = s;
+            st->priv_data = msc = av_mallocz(sizeof(MOVStreamContext));
+            if (!msc) {
+                av_free(mc);
+                st->priv_data = priv_data;
+                return AVERROR(ENOMEM);
             }
-            if (codec_id == AV_CODEC_ID_NONE)
-                av_log(matroska->ctx, AV_LOG_ERROR,
-                       "mov FourCC not found %s.\n", av_fourcc2str(fourcc));
-            if (track->codec_priv.size >= 86) {
-                bit_depth = AV_RB16(track->codec_priv.data + 82);
-                ffio_init_context(&b, track->codec_priv.data,
-                                  track->codec_priv.size,
-                                  0, NULL, NULL, NULL, NULL);
-                if (ff_get_qtpalette(codec_id, &b, track->palette)) {
-                    bit_depth &= 0x1F;
-                    track->has_palette = 1;
-                }
+            /* ff_mov_read_stsd_entries updates stream s->nb_streams-1,
+             * so set it temporarily to indicate which stream to update. */
+            s->nb_streams = st->index + 1;
+            ff_mov_read_stsd_entries(mc, stsd_ctx, 1);
+            av_free(msc);
+            av_free(mc);
+            avio_context_free(&stsd_ctx);
+            st->priv_data = priv_data;
+            s->nb_streams = nb_streams;
+
+            // dvh1 in mkv is likely HEVC
+            if (st->codecpar->codec_tag == MKTAG('d','v','h','1')) {
+                codec_id = AV_CODEC_ID_HEVC;
             }
         } else if (codec_id == AV_CODEC_ID_PCM_S16BE) {
             switch (track->audio.bitdepth) {
-- 
2.20.1