videoaggregator: If getting a timeout before having caps, just advance our position

This can happen if this is a live pipeline and no source produced any buffer
and sent no caps until an output buffer should've been produced according to the
latency.

This fix is similar in spirit to commit be7034d1 by Sebastian for audiomixer.

1 files changed, 40 insertions, 2 deletions

diff --git a/gst-libs/gst/video/gstvideoaggregator.c b/gst-libs/gst/video/gstvideoaggregator.c
index 005edcaa7..871103f4d 100644
--- a/gst-libs/gst/video/gstvideoaggregator.c
+++ b/gst-libs/gst/video/gstvideoaggregator.c
@@ -760,6 +760,13 @@ gst_videoaggregator_update_src_caps (GstVideoAggregator * vagg)
             GST_VIDEO_AGGREGATOR_GET_CLASS (vagg)->negotiated_caps (vagg, caps);
     }
     gst_caps_unref (caps);
+  } else {
+    /* We couldn't decide the output video info because the sinkpads don't have
+     * all the caps yet, so we mark the pad as needing a reconfigure. This
+     * allows aggregate() to skip ahead a bit and try again later. */
+    GST_DEBUG_OBJECT (vagg, "Couldn't decide output video info");
+    gst_pad_mark_reconfigure (agg->srcpad);
+    ret = FALSE;
   }
 
 done:
@@ -1261,8 +1268,39 @@ gst_videoaggregator_aggregate (GstAggregator * agg, gboolean timeout)
       ret = gst_videoaggregator_update_src_caps (vagg);
 
     if (!ret) {
-      GST_VIDEO_AGGREGATOR_UNLOCK (vagg);
-      return GST_FLOW_NOT_NEGOTIATED;
+      if (timeout && gst_pad_needs_reconfigure (agg->srcpad)) {
+        guint64 frame_duration;
+        gint fps_d, fps_n;
+
+        GST_DEBUG_OBJECT (vagg,
+            "Got timeout before receiving any caps, don't output anything");
+
+        if (agg->segment.position == -1) {
+          if (agg->segment.rate > 0.0)
+            agg->segment.position = agg->segment.start;
+          else
+            agg->segment.position = agg->segment.stop;
+        }
+
+        /* Advance position */
+        fps_d = GST_VIDEO_INFO_FPS_D (&vagg->info) ?
+            GST_VIDEO_INFO_FPS_D (&vagg->info) : 1;
+        fps_n = GST_VIDEO_INFO_FPS_N (&vagg->info) ?
+            GST_VIDEO_INFO_FPS_N (&vagg->info) : 25;
+        /* Default to 25/1 if no "best fps" is known */
+        frame_duration = gst_util_uint64_scale (GST_SECOND, fps_d, fps_n);
+        if (agg->segment.rate > 0.0)
+          agg->segment.position += frame_duration;
+        else if (agg->segment.position > frame_duration)
+          agg->segment.position -= frame_duration;
+        else
+          agg->segment.position = 0;
+        GST_VIDEO_AGGREGATOR_UNLOCK (vagg);
+        return GST_FLOW_OK;
+      } else {
+        GST_VIDEO_AGGREGATOR_UNLOCK (vagg);
+        return GST_FLOW_NOT_NEGOTIATED;
+      }
     }
   }