Add timestamp computation if values are exported by decoder.

Patch by Ivan Schreter, schreter gmx net

Originally committed as revision 17574 to svn://svn.ffmpeg.org/ffmpeg/trunk

2 files changed, 33 insertions, 2 deletions

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index 6308940ce5..cf455da9e5 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -22,8 +22,8 @@
 #define AVFORMAT_AVFORMAT_H
 
 #define LIBAVFORMAT_VERSION_MAJOR 52
-#define LIBAVFORMAT_VERSION_MINOR 29
-#define LIBAVFORMAT_VERSION_MICRO  2
+#define LIBAVFORMAT_VERSION_MINOR 30
+#define LIBAVFORMAT_VERSION_MICRO  0
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \
@@ -494,6 +494,16 @@ typedef struct AVStream {
     const uint8_t *cur_ptr;
     int cur_len;
     AVPacket cur_pkt;
+
+    // Timestamp generation support:
+    /**
+     * Timestamp corresponding to the last dts sync point.
+     *
+     * Initialized when AVCodecParserContext.dts_sync_point >= 0 and
+     * a DTS is received from the underlying container. Otherwise set to
+     * AV_NOPTS_VALUE by default.
+     */
+    int64_t reference_dts;
 } AVStream;
 
 #define AV_PROGRAM_RUNNING 1
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 61f74c3c18..073e6dacdc 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -834,6 +834,25 @@ static void compute_pkt_fields(AVFormatContext *s, AVStream *st,
             pkt->dts += offset;
     }
 
+    if (pc && pc->dts_sync_point >= 0) {
+        // we have synchronization info from the parser
+        int64_t den = st->codec->time_base.den * (int64_t) st->time_base.num;
+        if (den > 0) {
+            int64_t num = st->codec->time_base.num * (int64_t) st->time_base.den;
+            if (pkt->dts != AV_NOPTS_VALUE) {
+                // got DTS from the stream, update reference timestamp
+                st->reference_dts = pkt->dts - pc->dts_ref_dts_delta * num / den;
+                pkt->pts = pkt->dts + pc->pts_dts_delta * num / den;
+            } else if (st->reference_dts != AV_NOPTS_VALUE) {
+                // compute DTS based on reference timestamp
+                pkt->dts = st->reference_dts + pc->dts_ref_dts_delta * num / den;
+                pkt->pts = pkt->dts + pc->pts_dts_delta * num / den;
+            }
+            if (pc->dts_sync_point > 0)
+                st->reference_dts = pkt->dts; // new reference
+        }
+    }
+
     /* This may be redundant, but it should not hurt. */
     if(pkt->dts != AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE && pkt->pts > pkt->dts)
         presentation_delayed = 1;
@@ -1157,6 +1176,7 @@ static void av_read_frame_flush(AVFormatContext *s)
         }
         st->last_IP_pts = AV_NOPTS_VALUE;
         st->cur_dts = AV_NOPTS_VALUE; /* we set the current DTS to an unspecified origin */
+        st->reference_dts = AV_NOPTS_VALUE;
         /* fail safe */
         st->cur_ptr = NULL;
         st->cur_len = 0;
@@ -2332,6 +2352,7 @@ AVStream *av_new_stream(AVFormatContext *s, int id)
     st->last_IP_pts = AV_NOPTS_VALUE;
     for(i=0; i<MAX_REORDER_DELAY+1; i++)
         st->pts_buffer[i]= AV_NOPTS_VALUE;
+    st->reference_dts = AV_NOPTS_VALUE;
 
     st->sample_aspect_ratio = (AVRational){0,1};