[FFmpeg-devel] [PATCH] lavf/matroska: Export codecdelay and seekpreroll as metadata tags

[Vignesh Venkatasubramanian]

This patch exports the values of Codec Delay and Seek Preroll
container elements as metadata tags.

Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
---
 libavformat/matroskadec.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 76c610b..62b95f1 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -163,6 +163,8 @@ typedef struct {
     uint64_t default_duration;
     uint64_t flag_default;
     uint64_t flag_forced;
+    uint64_t codec_delay;
+    uint64_t seek_preroll;
     MatroskaTrackVideo video;
     MatroskaTrackAudio audio;
     MatroskaTrackOperation operation;
@@ -410,6 +412,8 @@ static EbmlSyntax matroska_track[] = {
     { MATROSKA_ID_TRACKOPERATION,       EBML_NEST, 0, offsetof(MatroskaTrack,operation), {.n=matroska_track_operation} },
     { MATROSKA_ID_TRACKCONTENTENCODINGS,EBML_NEST, 0, 0, {.n=matroska_track_encodings} },
     { MATROSKA_ID_TRACKMAXBLKADDID,     EBML_UINT, 0, offsetof(MatroskaTrack,max_block_additional_id) },
+    { MATROSKA_ID_CODECDELAY,           EBML_UINT, 0, offsetof(MatroskaTrack,codec_delay) },
+    { MATROSKA_ID_SEEKPREROLL,          EBML_UINT, 0, offsetof(MatroskaTrack,seek_preroll) },
     { MATROSKA_ID_TRACKFLAGENABLED,     EBML_NONE },
     { MATROSKA_ID_TRACKFLAGLACING,      EBML_NONE },
     { MATROSKA_ID_CODECNAME,            EBML_NONE },
@@ -1821,6 +1825,21 @@ static int matroska_read_header(AVFormatContext *s)
             }
         }
 
+        /* export codec delay and seek preroll as metadata tags */
+        if (track->codec_delay > 0) {
+            char codec_delay[25];
+            snprintf(codec_delay, sizeof(codec_delay), "%"PRIu64,
+                     track->codec_delay);
+            av_dict_set(&st->metadata, "codec_delay", codec_delay, 0);
+        }
+
+        if (track->seek_preroll > 0) {
+            char seek_preroll[25];
+            snprintf(seek_preroll, sizeof(seek_preroll), "%"PRIu64,
+                     track->seek_preroll);
+            av_dict_set(&st->metadata, "seek_preroll", seek_preroll, 0);
+        }
+
         if (track->type == MATROSKA_TRACK_TYPE_VIDEO) {
             MatroskaTrackPlane *planes = track->operation.combine_planes.elem;
 
-- 
1.8.4