h264parse: Set srcpad caps before forwarding newsegment

This holds all newsegement and most other events till there is enough
data to set srcpad caps, so that the downstream link is properly
negotiated before data starts flowing.

https://bugzilla.gnome.org/show_bug.cgi?id=635205

gst/h264parse/gsth264parse.c

@@ -1016,6 +1016,14 @@ gst_h264_parse_reset (GstH264Parse * h264parse)
   h264parse->picture_start = FALSE;
   h264parse->idr_offset = -1;
 
+  if (h264parse->pending_segment)
+    gst_event_unref (h264parse->pending_segment);
+  h264parse->pending_segment = NULL;
+
+  g_list_foreach (h264parse->pending_events, (GFunc) gst_event_unref, NULL);
+  g_list_free (h264parse->pending_events);
+  h264parse->pending_events = NULL;
+
   gst_caps_replace (&h264parse->src_caps, NULL);
 }
 
@@ -1040,6 +1048,13 @@ gst_h264_parse_finalize (GObject * object)
       g_slice_free (GstH264Pps, h264parse->pps_buffers[i]);
   }
 
+  if (h264parse->pending_segment)
+    gst_event_replace (&h264parse->pending_segment, NULL);
+
+  g_list_foreach (h264parse->pending_events, (GFunc) gst_event_unref, NULL);
+  g_list_free (h264parse->pending_events);
+  h264parse->pending_events = NULL;
+
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
@@ -1369,8 +1384,10 @@ gst_h264_parse_update_src_caps (GstH264Parse * h264parse, GstCaps * caps)
   /* save as new caps, caps will be set when pushing data */
   /* avoid replacing caps by a mere identical copy, thereby triggering
    * negotiating (which e.g. some container might not appreciate) */
-  if (modified)
+  if (modified) {
     gst_caps_replace (&h264parse->src_caps, src_caps);
+    gst_pad_set_caps (h264parse->srcpad, h264parse->src_caps);
+  }
   gst_caps_unref (src_caps);
 
   return TRUE;
@@ -1599,6 +1616,23 @@ gst_h264_parse_push_buffer (GstH264Parse * h264parse, GstBuffer * buf)
 {
   GstFlowReturn ret = GST_FLOW_OK;
 
+  /* We can send pending events if this is the first call, since we now have
+   * caps for the srcpad */
+  if (G_UNLIKELY (h264parse->pending_segment != NULL)) {
+    gst_pad_push_event (h264parse->srcpad, h264parse->pending_segment);
+    h264parse->pending_segment = NULL;
+
+    if (G_UNLIKELY (h264parse->pending_events != NULL)) {
+      GList *l;
+
+      for (l = h264parse->pending_events; l != NULL; l = l->next)
+        gst_pad_push_event (h264parse->srcpad, GST_EVENT (l->data));
+
+      g_list_free (h264parse->pending_events);
+      h264parse->pending_events = NULL;
+    }
+  }
+
   /* start of picture is good time to slip in codec_data NALUs
    * (when outputting NALS and transforming to bytestream) */
   if (G_UNLIKELY (h264parse->codec_nals && h264parse->picture_start)) {
@@ -2583,6 +2617,11 @@ gst_h264_parse_sink_event (GstPad * pad, GstEvent * event)
       break;
     case GST_EVENT_EOS:
       GST_DEBUG_OBJECT (h264parse, "received EOS");
+      if (h264parse->pending_segment) {
+        /* Send pending newsegment before EOS */
+        gst_pad_push_event (h264parse->srcpad, h264parse->pending_segment);
+        h264parse->pending_segment = NULL;
+      }
       if (h264parse->segment.rate < 0.0) {
         gst_h264_parse_chain_reverse (h264parse, TRUE, NULL);
         gst_h264_parse_flush_decode (h264parse);
@@ -2595,6 +2634,7 @@ gst_h264_parse_sink_event (GstPad * pad, GstEvent * event)
       GstFormat format;
       gint64 start, stop, pos;
       gboolean update;
+      GstEvent **ev;
 
       gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
           &format, &start, &stop, &pos);
@@ -2604,17 +2644,35 @@ gst_h264_parse_sink_event (GstPad * pad, GstEvent * event)
           rate, applied_rate, format, start, stop, pos);
 
       GST_DEBUG_OBJECT (h264parse,
-          "Pushing newseg rate %g, applied rate %g, format %d, start %"
+          "Keeping newseg rate %g, applied rate %g, format %d, start %"
           G_GINT64_FORMAT ", stop %" G_GINT64_FORMAT ", pos %" G_GINT64_FORMAT,
           rate, applied_rate, format, start, stop, pos);
 
+      ev = &h264parse->pending_segment;
+      gst_event_replace (ev, event);
+      gst_event_unref (event);
+      res = TRUE;
+      break;
+    }
+    case GST_EVENT_FLUSH_START:
+    {
       res = gst_pad_push_event (h264parse->srcpad, event);
       break;
     }
     default:
-      res = gst_pad_push_event (h264parse->srcpad, event);
-      break;
+    {
+      if (G_UNLIKELY (h264parse->src_caps == NULL ||
+              h264parse->pending_segment)) {
+        /* We don't yet have enough data to set caps on the srcpad, so collect
+         * non-critical events till we do */
+        h264parse->pending_events = g_list_append (h264parse->pending_events,
+            event);
+        res = TRUE;
+      } else
+        res = gst_pad_push_event (h264parse->srcpad, event);
 
+      break;
+    }
   }
   gst_object_unref (h264parse);
 

gst/h264parse/gsth264parse.h

@@ -137,6 +137,9 @@ struct _GstH264Parse
   GstBuffer *pps_nals[MAX_PPS_COUNT];
 
   GstCaps *src_caps;
+
+  GstEvent *pending_segment;
+  GList *pending_events;
 };
 
 struct _GstH264ParseClass