splitmuxsrc: Avoid stall when parts get out of sync

When one part moves ahead of the others - due to excessive
downstream queueing, or really small input files - then
we can end up activating parts more than once. That can lead to
effects like shutting down pad tasks prematurely.

https://bugzilla.gnome.org/show_bug.cgi?id=772138

3 files changed, 29 insertions, 14 deletions

diff --git a/gst/multifile/gstsplitmuxpartreader.c b/gst/multifile/gstsplitmuxpartreader.c
index 5e98166d4..16d78bed7 100644
--- a/gst/multifile/gstsplitmuxpartreader.c
+++ b/gst/multifile/gstsplitmuxpartreader.c
@@ -1185,6 +1185,18 @@ gst_splitmux_part_reader_activate (GstSplitMuxPartReader * reader,
   return TRUE;
 }
 
+gboolean
+gst_splitmux_part_reader_is_active (GstSplitMuxPartReader * part)
+{
+  gboolean ret;
+
+  SPLITMUX_PART_LOCK (part);
+  ret = part->active;
+  SPLITMUX_PART_UNLOCK (part);
+
+  return ret;
+}
+
 void
 gst_splitmux_part_reader_deactivate (GstSplitMuxPartReader * reader)
 {
diff --git a/gst/multifile/gstsplitmuxpartreader.h b/gst/multifile/gstsplitmuxpartreader.h
index 593d8ae02..95d920fc5 100644
--- a/gst/multifile/gstsplitmuxpartreader.h
+++ b/gst/multifile/gstsplitmuxpartreader.h
@@ -103,6 +103,7 @@ gboolean gst_splitmux_part_is_eos (GstSplitMuxPartReader *reader);
 
 gboolean gst_splitmux_part_reader_activate (GstSplitMuxPartReader *part, GstSegment *seg);
 void gst_splitmux_part_reader_deactivate (GstSplitMuxPartReader *part);
+gboolean gst_splitmux_part_reader_is_active (GstSplitMuxPartReader *part);
 
 gboolean gst_splitmux_part_reader_src_query (GstSplitMuxPartReader *part, GstPad *src_pad, GstQuery * query);
 void gst_splitmux_part_reader_set_start_offset (GstSplitMuxPartReader *part, GstClockTime offset);
diff --git a/gst/multifile/gstsplitmuxsrc.c b/gst/multifile/gstsplitmuxsrc.c
index 6cd9e1f6f..5fb7de698 100644
--- a/gst/multifile/gstsplitmuxsrc.c
+++ b/gst/multifile/gstsplitmuxsrc.c
@@ -931,21 +931,23 @@ gst_splitmux_end_of_part (GstSplitMuxSrc * splitmux, SplitMuxSrcPad * splitpad)
         (GstPad *) (splitpad));
 
     if (splitmux->cur_part != next_part) {
-      GstSegment tmp;
-      /* If moving backward into a new part, set stop
-       * to -1 to ensure we play the entire file - workaround
-       * a bug in qtdemux that misses bits at the end */
-      gst_segment_copy_into (&splitmux->play_segment, &tmp);
-      if (tmp.rate < 0)
-        tmp.stop = -1;
-
-      /* This is the first pad to move to the new part, activate it */
+      if (!gst_splitmux_part_reader_is_active (splitpad->reader)) {
+        GstSegment tmp;
+        /* If moving backward into a new part, set stop
+         * to -1 to ensure we play the entire file - workaround
+         * a bug in qtdemux that misses bits at the end */
+        gst_segment_copy_into (&splitmux->play_segment, &tmp);
+        if (tmp.rate < 0)
+          tmp.stop = -1;
+
+        /* This is the first pad to move to the new part, activate it */
+        GST_DEBUG_OBJECT (splitpad,
+            "First pad to change part. Activating part %d with seg %"
+            GST_SEGMENT_FORMAT, next_part, &tmp);
+        if (!gst_splitmux_part_reader_activate (splitpad->reader, &tmp))
+          goto error;
+      }
       splitmux->cur_part = next_part;
-      GST_DEBUG_OBJECT (splitpad,
-          "First pad to change part. Activating part %d with seg %"
-          GST_SEGMENT_FORMAT, next_part, &tmp);
-      if (!gst_splitmux_part_reader_activate (splitpad->reader, &tmp))
-        goto error;
     }
     res = TRUE;
   }