From 037e21b578d56057a205bd07422b53f3c1d1e7e8 Mon Sep 17 00:00:00 2001
From: Wim Taymans <wtaymans@redhat.com>
Date: Thu, 26 Dec 2013 16:28:59 +0100
Subject: [PATCH] session-media: calculate start-time

---
 gst/rtsp-server/rtsp-session-media.c    | 45 ++++++++++++++++++++++++-
 gst/rtsp-server/rtsp-stream-transport.c |  8 +++--
 gst/rtsp-server/rtsp-stream-transport.h |  3 +-
 3 files changed, 51 insertions(+), 5 deletions(-)

diff --git a/gst/rtsp-server/rtsp-session-media.c b/gst/rtsp-server/rtsp-session-media.c
index e49e4262c4..78faeedfce 100644
--- a/gst/rtsp-server/rtsp-session-media.c
+++ b/gst/rtsp-server/rtsp-session-media.c
@@ -248,15 +248,51 @@ gst_rtsp_session_media_get_rtpinfo (GstRTSPSessionMedia * media)
   GstRTSPSessionMediaPrivate *priv;
   GString *rtpinfo = NULL;
   GstRTSPStreamTransport *transport;
+  GstRTSPStream *stream;
   guint i, n_streams;
+  GstClockTime earliest = GST_CLOCK_TIME_NONE;
 
   g_return_val_if_fail (GST_IS_RTSP_SESSION_MEDIA (media), NULL);
 
   priv = media->priv;
   g_mutex_lock (&priv->lock);
 
+  if (gst_rtsp_media_get_status (priv->media) != GST_RTSP_MEDIA_STATUS_PREPARED)
+    goto not_prepared;
+
   n_streams = priv->transports->len;
 
+  /* first step, take lowest running-time from all streams */
+  GST_LOG_OBJECT (media, "determining start time among %d transports",
+      n_streams);
+
+  for (i = 0; i < n_streams; i++) {
+    GstClockTime running_time;
+
+    transport = g_ptr_array_index (priv->transports, i);
+    if (transport == NULL) {
+      GST_DEBUG_OBJECT (media, "ignoring unconfigured transport %d", i);
+      continue;
+    }
+
+    stream = gst_rtsp_stream_transport_get_stream (transport);
+    if (!gst_rtsp_stream_get_rtpinfo (stream, NULL, NULL, &running_time))
+      continue;
+
+    GST_LOG_OBJECT (media, "running time of %d stream: %" GST_TIME_FORMAT, i,
+        GST_TIME_ARGS (running_time));
+
+    if (!GST_CLOCK_TIME_IS_VALID (earliest)) {
+      earliest = running_time;
+    } else {
+      earliest = MIN (earliest, running_time);
+    }
+  }
+
+  GST_LOG_OBJECT (media, "media start time: %" GST_TIME_FORMAT,
+      GST_TIME_ARGS (earliest));
+
+  /* next step, scale all rtptime of all streams to lowest running-time */
   GST_LOG_OBJECT (media, "collecting RTP info for %d transports", n_streams);
 
   for (i = 0; i < n_streams; i++) {
@@ -268,7 +304,8 @@ gst_rtsp_session_media_get_rtpinfo (GstRTSPSessionMedia * media)
       continue;
     }
 
-    stream_rtpinfo = gst_rtsp_stream_transport_get_rtpinfo (transport);
+    stream_rtpinfo =
+        gst_rtsp_stream_transport_get_rtpinfo (transport, earliest);
     if (stream_rtpinfo == NULL)
       goto stream_rtpinfo_missing;
 
@@ -291,6 +328,12 @@ gst_rtsp_session_media_get_rtpinfo (GstRTSPSessionMedia * media)
   return g_string_free (rtpinfo, FALSE);
 
   /* ERRORS */
+not_prepared:
+  {
+    g_mutex_unlock (&priv->lock);
+    GST_ERROR_OBJECT (media, "media was not prepared");
+    return NULL;
+  }
 stream_rtpinfo_missing:
   {
     g_mutex_unlock (&priv->lock);
diff --git a/gst/rtsp-server/rtsp-stream-transport.c b/gst/rtsp-server/rtsp-stream-transport.c
index faacc4a653..9c1f9c21d3 100644
--- a/gst/rtsp-server/rtsp-stream-transport.c
+++ b/gst/rtsp-server/rtsp-stream-transport.c
@@ -313,14 +313,16 @@ gst_rtsp_stream_transport_get_url (GstRTSPStreamTransport * trans)
  /**
  * gst_rtsp_stream_transport_get_rtpinfo:
  * @trans: a #GstRTSPStreamTransport
+ * @start_time: a star time
  *
- * Get the RTPInfo string for @trans.
+ * Get the RTPInfo string for @trans and @start_time.
  *
- * Returns: the RTPInfo string for @trans. g_free() after
+ * Returns: the RTPInfo string for @trans and @start_time. g_free() after
  * usage.
  */
 gchar *
-gst_rtsp_stream_transport_get_rtpinfo (GstRTSPStreamTransport * trans)
+gst_rtsp_stream_transport_get_rtpinfo (GstRTSPStreamTransport * trans,
+    GstClockTime start_time)
 {
   GstRTSPStreamTransportPrivate *priv;
   gchar *url_str;
diff --git a/gst/rtsp-server/rtsp-stream-transport.h b/gst/rtsp-server/rtsp-stream-transport.h
index 3a5e5793dd..7735ee718f 100644
--- a/gst/rtsp-server/rtsp-stream-transport.h
+++ b/gst/rtsp-server/rtsp-stream-transport.h
@@ -100,7 +100,8 @@ void                     gst_rtsp_stream_transport_set_url       (GstRTSPStreamT
 const GstRTSPUrl *       gst_rtsp_stream_transport_get_url       (GstRTSPStreamTransport *trans);
 
 
-gchar *                  gst_rtsp_stream_transport_get_rtpinfo   (GstRTSPStreamTransport *trans);
+gchar *                  gst_rtsp_stream_transport_get_rtpinfo   (GstRTSPStreamTransport *trans,
+                                                                  GstClockTime start_time);
 
 void                     gst_rtsp_stream_transport_set_callbacks (GstRTSPStreamTransport *trans,
                                                                   GstRTSPSendFunc send_rtp,