[FFmpeg-devel] [PATCH] matroska: Set CodecDelay and SeekPreroll in the AVStream

[Vignesh Venkatasubramanian]

This patch exports the values of Codec Delay and Seek Preroll
container elements as in the AVStream structure. The seek_preroll
field has been added to the AVStream struct and the minor version
of libavformat has been bumped.

Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
---
 libavformat/avformat.h    |  3 +++
 libavformat/matroskadec.c | 14 ++++++++++++++
 libavformat/version.h     |  2 +-
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index b18eb3f..94acd86 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -888,6 +888,9 @@ typedef struct AVStream {
      */
     int pts_wrap_behavior;
 
+    /* Number of samples to skip after a discontinuity */
+    int seek_preroll;
+
 } AVStream;
 
 AVRational av_stream_get_r_frame_rate(const AVStream *s);
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 76c610b..85cb459 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 },
@@ -1871,6 +1875,16 @@ static int matroska_read_header(AVFormatContext *s)
             st->codec->bits_per_coded_sample = track->audio.bitdepth;
             if (st->codec->codec_id != AV_CODEC_ID_AAC)
             st->need_parsing = AVSTREAM_PARSE_HEADERS;
+            if (track->codec_delay > 0) {
+                st->skip_samples = av_rescale_q(track->codec_delay,
+                                                (AVRational){1, 1000000000},
+                                                (AVRational){1, st->codec->sample_rate});
+            }
+            if (track->seek_preroll > 0) {
+                st->seek_preroll = av_rescale_q(track->seek_preroll,
+                                                (AVRational){1, 1000000000},
+                                                (AVRational){1, st->codec->sample_rate});
+            }
         } else if (codec_id == AV_CODEC_ID_WEBVTT) {
             st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
 
diff --git a/libavformat/version.h b/libavformat/version.h
index fb82f34..32e76c7 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -30,7 +30,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFORMAT_VERSION_MAJOR 55
-#define LIBAVFORMAT_VERSION_MINOR 18
+#define LIBAVFORMAT_VERSION_MINOR 19
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
-- 
1.8.4