[FFmpeg-cvslog] rtpdec: unwrap RTP timestamps for PTS calculation

[John Brooks]

ffmpeg | branch: master | John Brooks <john.brooks at bluecherry.net> | Thu Nov 17 08:50:12 2011 -0700| [12348ca25e0bf44bf4530745753e938fc54e7ae3] | committer: Martin Storsjö

rtpdec: unwrap RTP timestamps for PTS calculation

The timestamp field in RTPDemuxContext was unused before this.

Signed-off-by: Martin Storsjö <martin at martin.st>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=12348ca25e0bf44bf4530745753e938fc54e7ae3
---

 libavformat/rtpdec.c  |    8 +++++++-
 libavformat/rtpdec.h  |    1 +
 libavformat/rtspdec.c |    2 ++
 3 files changed, 10 insertions(+), 1 deletions(-)

diff --git a/libavformat/rtpdec.c b/libavformat/rtpdec.c
index a5ec1ca..94fa0f1 100644
--- a/libavformat/rtpdec.c
+++ b/libavformat/rtpdec.c
@@ -439,7 +439,13 @@ static void finalize_packet(RTPDemuxContext *s, AVPacket *pkt, uint32_t timestam
 
     if (!s->base_timestamp)
         s->base_timestamp = timestamp;
-    pkt->pts = s->range_start_offset + timestamp - s->base_timestamp;
+    /* assume that the difference is INT32_MIN < x < INT32_MAX, but allow the first timestamp to exceed INT32_MAX */
+    if (!s->timestamp)
+        s->unwrapped_timestamp += timestamp;
+    else
+        s->unwrapped_timestamp += (int32_t)(timestamp - s->timestamp);
+    s->timestamp = timestamp;
+    pkt->pts = s->unwrapped_timestamp + s->range_start_offset - s->base_timestamp;
 }
 
 static int rtp_parse_packet_internal(RTPDemuxContext *s, AVPacket *pkt,
diff --git a/libavformat/rtpdec.h b/libavformat/rtpdec.h
index d58eddd..eb1e62d 100644
--- a/libavformat/rtpdec.h
+++ b/libavformat/rtpdec.h
@@ -151,6 +151,7 @@ struct RTPDemuxContext {
     uint32_t timestamp;
     uint32_t base_timestamp;
     uint32_t cur_timestamp;
+    int64_t  unwrapped_timestamp;
     int64_t  range_start_offset;
     int max_payload_size;
     struct MpegTSContext *ts;   /* only used for MP2T payloads */
diff --git a/libavformat/rtspdec.c b/libavformat/rtspdec.c
index c453b82..1b4982f 100644
--- a/libavformat/rtspdec.c
+++ b/libavformat/rtspdec.c
@@ -52,6 +52,8 @@ static int rtsp_read_play(AVFormatContext *s)
                 rtpctx->last_rtcp_ntp_time  = AV_NOPTS_VALUE;
                 rtpctx->first_rtcp_ntp_time = AV_NOPTS_VALUE;
                 rtpctx->base_timestamp      = 0;
+                rtpctx->timestamp           = 0;
+                rtpctx->unwrapped_timestamp = 0;
                 rtpctx->rtcp_ts_offset      = 0;
             }
         }