rtpdec: Emit timestamps for packets before the first RTCP packet, too

Emitted timestamps in each stream start from 0, for the first received
RTP packet. Once an RTCP packet is received, that one is used for
sync, emitting timestamps that fit seamlessly into the earlier ones.

Originally committed as revision 26187 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rtpdec.c

@@ -123,9 +123,13 @@ static int rtcp_parse_packet(RTPDemuxContext *s, const unsigned char *buf, int l
             payload_len = (AV_RB16(buf + 2) + 1) * 4;
 
             s->last_rtcp_ntp_time = AV_RB64(buf + 8);
-            if (s->first_rtcp_ntp_time == AV_NOPTS_VALUE)
-                s->first_rtcp_ntp_time = s->last_rtcp_ntp_time;
             s->last_rtcp_timestamp = AV_RB32(buf + 16);
+            if (s->first_rtcp_ntp_time == AV_NOPTS_VALUE) {
+                s->first_rtcp_ntp_time = s->last_rtcp_ntp_time;
+                if (!s->base_timestamp)
+                    s->base_timestamp = s->last_rtcp_timestamp;
+                s->rtcp_ts_offset = s->last_rtcp_timestamp - s->base_timestamp;
+            }
 
             buf += payload_len;
             len -= payload_len;
@@ -440,8 +444,15 @@ static void finalize_packet(RTPDemuxContext *s, AVPacket *pkt, uint32_t timestam
         delta_timestamp = timestamp - s->last_rtcp_timestamp;
         /* convert to the PTS timebase */
         addend = av_rescale(s->last_rtcp_ntp_time - s->first_rtcp_ntp_time, s->st->time_base.den, (uint64_t)s->st->time_base.num << 32);
-        pkt->pts = s->range_start_offset + addend + delta_timestamp;
+        pkt->pts = s->range_start_offset + s->rtcp_ts_offset + addend +
+                   delta_timestamp;
+        return;
     }
+    if (timestamp == RTP_NOTS_VALUE)
+        return;
+    if (!s->base_timestamp)
+        s->base_timestamp = timestamp;
+    pkt->pts = s->range_start_offset + timestamp - s->base_timestamp;
 }
 
 static int rtp_parse_packet_internal(RTPDemuxContext *s, AVPacket *pkt,

libavformat/rtpdec.h

@@ -172,6 +172,7 @@ struct RTPDemuxContext {
     int64_t last_rtcp_ntp_time;    // TODO: move into statistics
     int64_t first_rtcp_ntp_time;   // TODO: move into statistics
     uint32_t last_rtcp_timestamp;  // TODO: move into statistics
+    int64_t rtcp_ts_offset;
 
     /* rtcp sender statistics */
     unsigned int packet_count;     // TODO: move into statistics (outgoing)

libavformat/rtsp.c

@@ -1617,11 +1617,21 @@ int ff_rtsp_fetch_packet(AVFormatContext *s, AVPacket *pkt)
                  * in order to map their timestamp origin to the same ntp time
                  * as this one. */
                 int i;
+                AVStream *st = NULL;
+                if (rtsp_st->stream_index >= 0)
+                    st = s->streams[rtsp_st->stream_index];
                 for (i = 0; i < rt->nb_rtsp_streams; i++) {
                     RTPDemuxContext *rtpctx2 = rt->rtsp_streams[i]->transport_priv;
-                    if (rtpctx2 &&
-                        rtpctx2->first_rtcp_ntp_time == AV_NOPTS_VALUE)
+                    AVStream *st2 = NULL;
+                    if (rt->rtsp_streams[i]->stream_index >= 0)
+                        st2 = s->streams[rt->rtsp_streams[i]->stream_index];
+                    if (rtpctx2 && st && st2 &&
+                        rtpctx2->first_rtcp_ntp_time == AV_NOPTS_VALUE) {
                         rtpctx2->first_rtcp_ntp_time = rtpctx->first_rtcp_ntp_time;
+                        rtpctx2->rtcp_ts_offset = av_rescale_q(
+                            rtpctx->rtcp_ts_offset, st->time_base,
+                            st2->time_base);
+                    }
                 }
             }
             if (ret == -RTCP_BYE) {

libavformat/rtspdec.c

@@ -67,6 +67,8 @@ static int rtsp_read_play(AVFormatContext *s)
                 if (reply->range_start != AV_NOPTS_VALUE) {
                     rtpctx->last_rtcp_ntp_time  = AV_NOPTS_VALUE;
                     rtpctx->first_rtcp_ntp_time = AV_NOPTS_VALUE;
+                    rtpctx->base_timestamp      = 0;
+                    rtpctx->rtcp_ts_offset      = 0;
                     if (st)
                         rtpctx->range_start_offset =
                             av_rescale_q(reply->range_start, AV_TIME_BASE_Q,