decklinksink: Wait for the pipeline clock instead of the decklink clock

Otherwise we're going to starve other elements if the decklink clock
is slower than the pipeline clock, or starts much later.

Of course this will still cause problems if the decklink clock and ours are
completely out of sync, or running at a very different rate. But this at least
works better now.

1 files changed, 21 insertions, 0 deletions

diff --git a/sys/decklink/gstdecklinksink.cpp b/sys/decklink/gstdecklinksink.cpp
index 50c9438d5..fc1cda3c5 100644
--- a/sys/decklink/gstdecklinksink.cpp
+++ b/sys/decklink/gstdecklinksink.cpp
@@ -454,6 +454,9 @@ gst_decklink_sink_videosink_chain (GstPad * pad, GstObject * parent,
   GstClockTime timestamp, duration;
   GstClockTime running_time;
   GstClockTime running_time_duration;
+  GstClock *clock;
+  GstClockID clock_id;
+  GstClockTime base_time;
 
   decklinksink = GST_DECKLINK_SINK (parent);
 
@@ -492,6 +495,7 @@ gst_decklink_sink_videosink_chain (GstPad * pad, GstObject * parent,
   running_time_duration = gst_segment_to_running_time (&decklinksink->video_segment, GST_FORMAT_TIME, timestamp + duration) - running_time;
   gst_buffer_unref (buffer);
 
+#if 0
   g_mutex_lock (&decklinksink->mutex);
   /* FIXME: This is not correct as it assumes that the decklink clock
    * has the exact same value as the pipeline clock at any time. Not
@@ -500,10 +504,27 @@ gst_decklink_sink_videosink_chain (GstPad * pad, GstObject * parent,
   while (decklinksink->queued_frames > 2 && !decklinksink->stop) {
     g_cond_wait (&decklinksink->cond, &decklinksink->mutex);
   }
+#else
+  /* XXX: Wait until the pipeline clock reaches our running time to
+   * throttle filling the decklinksink internal queue */
+  clock = gst_element_get_clock (GST_ELEMENT (decklinksink));
+  base_time = gst_element_get_base_time (GST_ELEMENT (decklinksink));
+  if (clock) {
+    if (base_time != GST_CLOCK_TIME_NONE) {
+      clock_id = gst_clock_new_single_shot_id (clock, base_time + running_time);
+      gst_clock_id_wait (clock_id, NULL);
+      gst_clock_id_unref (clock_id);
+    }
+
+    gst_object_unref (clock);
+  }
+#endif
   if (!decklinksink->stop) {
     decklinksink->queued_frames++;
   }
+#if 0
   g_mutex_unlock (&decklinksink->mutex);
+#endif
 
   if (!decklinksink->stop) {
     ret = decklinksink->output->ScheduleVideoFrame (frame,