From c1a705acbc216e35a07fffc2c3405538b4a46ef2 Mon Sep 17 00:00:00 2001
From: Mark Nauwelaerts <mark.nauwelaerts@collabora.co.uk>
Date: Thu, 12 Aug 2010 10:02:56 +0200
Subject: [PATCH] streamsynchronizer: send preroll buffer when delaying preroll
 eos

That is, if eos is received which will not be forwarded, and the stream
has not yet seen any data, then send a buffer to preroll downstream
(which might otherwise be accomplished by the eos event).
---
 gst/playback/gststreamsynchronizer.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/gst/playback/gststreamsynchronizer.c b/gst/playback/gststreamsynchronizer.c
index ecf53bf26e..5899559b40 100644
--- a/gst/playback/gststreamsynchronizer.c
+++ b/gst/playback/gststreamsynchronizer.c
@@ -67,6 +67,7 @@ typedef struct
   gboolean new_stream;
   gboolean drop_discont;
   gboolean is_eos;
+  gboolean seen_data;
 
   gint64 running_time_diff;
 } GstStream;
@@ -446,6 +447,7 @@ gst_stream_synchronizer_sink_event (GstPad * pad, GstEvent * event)
         stream->wait = FALSE;
         stream->new_stream = FALSE;
         stream->drop_discont = FALSE;
+        stream->seen_data = FALSE;
       }
       GST_STREAM_SYNCHRONIZER_UNLOCK (self);
       break;
@@ -454,7 +456,9 @@ gst_stream_synchronizer_sink_event (GstPad * pad, GstEvent * event)
       GstStream *stream;
       GList *l;
       gboolean all_eos = TRUE;
+      gboolean seen_data;
       GSList *pads = NULL;
+      GstPad *srcpad;
 
       GST_STREAM_SYNCHRONIZER_LOCK (self);
       stream = gst_pad_get_element_private (pad);
@@ -463,6 +467,9 @@ gst_stream_synchronizer_sink_event (GstPad * pad, GstEvent * event)
         stream->is_eos = TRUE;
       }
 
+      seen_data = stream->seen_data;
+      srcpad = gst_object_ref (stream->srcpad);
+
       for (l = self->streams; l; l = l->next) {
         GstStream *ostream = l->data;
 
@@ -496,7 +503,17 @@ gst_stream_synchronizer_sink_event (GstPad * pad, GstEvent * event)
           epad = g_slist_next (epad);
         }
         g_slist_free (pads);
+      } else {
+        /* if EOS, but no data has passed, then send something to replace EOS
+         * for preroll purposes */
+        if (!seen_data) {
+          GstBuffer *buf = gst_buffer_new ();
+
+          GST_BUFFER_FLAG_SET (buf, GST_BUFFER_FLAG_PREROLL);
+          gst_pad_push (srcpad, buf);
+        }
       }
+      gst_object_unref (srcpad);
       goto done;
       break;
     }
@@ -563,6 +580,7 @@ gst_stream_synchronizer_sink_chain (GstPad * pad, GstBuffer * buffer)
   GST_STREAM_SYNCHRONIZER_LOCK (self);
   stream = gst_pad_get_element_private (pad);
 
+  stream->seen_data = TRUE;
   if (stream && stream->drop_discont) {
     buffer = gst_buffer_make_metadata_writable (buffer);
     GST_BUFFER_FLAG_UNSET (buffer, GST_BUFFER_FLAG_DISCONT);