[FFmpeg-devel] [PATCH v3 1/2] Parse and process ogg/flac comments in chained bitstreams.

[Romain Beauxis]

libavformat/oggparseflac: Parse ogg/flac comments in new ogg packets,
add them to ogg stream new_metadata.

libavcodec/flacdec: Process AV_PKT_DATA_METADATA_UPDATE on new packets,
add them as new metadata on the new decoded audio frame.


---
 libavcodec/flacdec.c       | 20 +++++++++++++++++++-
 libavformat/oggparseflac.c | 28 ++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/libavcodec/flacdec.c b/libavcodec/flacdec.c
index ad921a1bd1..337f3e1702 100644
--- a/libavcodec/flacdec.c
+++ b/libavcodec/flacdec.c
@@ -68,6 +68,8 @@ typedef struct FLACContext {
     unsigned int decoded_buffer_size_33bps;
     int buggy_lpc;                          ///< use workaround for old lavc encoded files
 
+    AVDictionary *pending_metadata;
+
     FLACDSPContext dsp;
 } FLACContext;
 
@@ -718,6 +720,8 @@ static int flac_decode_frame(AVCodecContext *avctx, AVFrame *frame,
     int buf_size = avpkt->size;
     FLACContext *s = avctx->priv_data;
     int bytes_read = 0;
+    const uint8_t *side_metadata;
+    size_t size;
     int ret;
 
     *got_frame_ptr = 0;
@@ -728,7 +732,14 @@ static int flac_decode_frame(AVCodecContext *avctx, AVFrame *frame,
     }
 
     if (buf_size > 0 && (*buf & 0x7F) == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
-        av_log(s->avctx, AV_LOG_DEBUG, "skipping vorbis comment\n");
+        /* New metadata */
+        side_metadata = av_packet_get_side_data(avpkt, AV_PKT_DATA_METADATA_UPDATE, &size);
+        if (side_metadata) {
+            av_dict_free(&s->pending_metadata);
+            ret = av_packet_unpack_dictionary(side_metadata, size, &s->pending_metadata);
+            if (ret < 0)
+                return ret;
+        }
         return buf_size;
     }
 
@@ -788,6 +799,12 @@ static int flac_decode_frame(AVCodecContext *avctx, AVFrame *frame,
                buf_size - bytes_read, buf_size);
     }
 
+
+    if (s->pending_metadata) {
+        av_dict_copy(&frame->metadata, s->pending_metadata, AV_DICT_APPEND);
+        av_dict_free(&s->pending_metadata);
+    }
+
     *got_frame_ptr = 1;
 
     return bytes_read;
@@ -799,6 +816,7 @@ static av_cold int flac_decode_close(AVCodecContext *avctx)
 
     av_freep(&s->decoded_buffer);
     av_freep(&s->decoded_buffer_33bps);
+    av_dict_free(&s->pending_metadata);
 
     return 0;
 }
diff --git a/libavformat/oggparseflac.c b/libavformat/oggparseflac.c
index f25ed9cc15..3810806112 100644
--- a/libavformat/oggparseflac.c
+++ b/libavformat/oggparseflac.c
@@ -78,6 +78,32 @@ flac_header (AVFormatContext * s, int idx)
     return 1;
 }
 
+static int
+flac_packet (AVFormatContext * s, int idx)
+{
+    struct ogg *ogg = s->priv_data;
+    struct ogg_stream *os = ogg->streams + idx;
+    AVDictionary *new_metadata = NULL;
+    int ret;
+
+    if (os->psize > 0 && os->buf[os->pstart] &&
+        (os->buf[os->pstart] & 0x7F) == FLAC_METADATA_TYPE_VORBIS_COMMENT) {
+        ret = ff_vorbis_comment(s, &new_metadata, os->buf + os->pstart + 4,
+                                os->psize - 4, 1);
+
+        if (ret < 0)
+            return ret;
+
+        os->new_metadata = av_packet_pack_dictionary(new_metadata, &os->new_metadata_size);
+        av_dict_free(&new_metadata);
+
+        if (!os->new_metadata)
+            return AVERROR(ENOMEM);
+    }
+
+    return 0;
+}
+
 static int
 old_flac_header (AVFormatContext * s, int idx)
 {
@@ -130,6 +156,7 @@ const struct ogg_codec ff_flac_codec = {
     .magic = "\177FLAC",
     .magicsize = 5,
     .header = flac_header,
+    .packet = flac_packet,
     .nb_header = 2,
 };
 
@@ -137,5 +164,6 @@ const struct ogg_codec ff_old_flac_codec = {
     .magic = "fLaC",
     .magicsize = 4,
     .header = old_flac_header,
+    .packet = flac_packet,
     .nb_header = 0,
 };
-- 
2.39.5 (Apple Git-154)