qtdemux: handling zero segment-duration edit list

Based on document ISO_IEC_14496-12, edit list box can have
segment duration as zero. It does not imply that media_start equals to
media_stop. But, it just indicates a sample which should be presented
at the first. This patch derives segment duration using media_time
and duration of file. And set derived duration to segment-duration.

https://bugzilla.gnome.org/show_bug.cgi?id=760781

diff --git a/gst/isomp4/qtdemux.c b/gst/isomp4/qtdemux.c
index cbba39b..f0b368b 100644 (file)
--- a/gst/isomp4/qtdemux.c
+++ b/gst/isomp4/qtdemux.c
@@ -8019,24 +8019,40 @@ qtdemux_parse_segments (GstQTDemux * qtdemux, QtDemuxStream * stream,
       guint64 media_time;
       QtDemuxSegment *segment;
       guint32 rate_int;
+      GstClockTime media_start = GST_CLOCK_TIME_NONE;
 
       media_time = QT_UINT32 (buffer + 20 + i * 12);
       duration = QT_UINT32 (buffer + 16 + i * 12);
 
+      if (media_time != G_MAXUINT32)
+        media_start = QTSTREAMTIME_TO_GSTTIME (stream, media_time);
+
       segment = &stream->segments[count++];
 
       /* time and duration expressed in global timescale */
       segment->time = stime;
       /* add non scaled values so we don't cause roundoff errors */
-      time += duration;
-      stime = QTTIME_TO_GSTTIME (qtdemux, time);
+      if (duration) {
+        time += duration;
+        stime = QTTIME_TO_GSTTIME (qtdemux, time);
+        segment->duration = stime - segment->time;
+      } else {
+        /* zero duration does not imply media_start == media_stop
+         * but, only specify media_start.*/
+        stime = QTTIME_TO_GSTTIME (qtdemux, qtdemux->duration);
+        if (GST_CLOCK_TIME_IS_VALID (stime) && media_time != G_MAXUINT32
+            && stime >= media_start) {
+          segment->duration = stime - media_start;
+        } else {
+          segment->duration = GST_CLOCK_TIME_NONE;
+        }
+      }
       segment->stop_time = stime;
-      segment->duration = stime - segment->time;
 
       segment->trak_media_start = media_time;
       /* media_time expressed in stream timescale */
       if (media_time != G_MAXUINT32) {
-        segment->media_start = QTSTREAMTIME_TO_GSTTIME (stream, media_time);
+        segment->media_start = media_start;
         segment->media_stop = segment->media_start + segment->duration;
         media_segments_count++;
       } else {