dashdemux: implement get_presentation_offset.

To account for presentationTimeOffset as per section 7.2.1 .

https://bugzilla.gnome.org/show_bug.cgi?id=745455

ext/dash/gstdashdemux.c

@@ -282,6 +282,17 @@ gst_dash_demux_get_live_seek_range (GstAdaptiveDemux * demux, gint64 * start,
   return TRUE;
 }
 
+static GstClockTime
+gst_dash_demux_get_presentation_offset (GstAdaptiveDemux * demux,
+    GstAdaptiveDemuxStream * stream)
+{
+  GstDashDemuxStream *dashstream = (GstDashDemuxStream *) stream;
+  GstDashDemux *dashdemux = GST_DASH_DEMUX_CAST (demux);
+
+  return gst_mpd_parser_get_stream_presentation_offset (dashdemux->client,
+      dashstream->index);
+}
+
 static void
 gst_dash_demux_class_init (GstDashDemuxClass * klass)
 {
@@ -361,6 +372,8 @@ gst_dash_demux_class_init (GstDashDemuxClass * klass)
   gstadaptivedemux_class->stream_free = gst_dash_demux_stream_free;
   gstadaptivedemux_class->get_live_seek_range =
       gst_dash_demux_get_live_seek_range;
+  gstadaptivedemux_class->get_presentation_offset =
+      gst_dash_demux_get_presentation_offset;
 }
 
 static void

ext/dash/gstmpdparser.c

@@ -3140,19 +3140,31 @@ gst_mpd_client_setup_representation (GstMpdClient * client,
         return FALSE;
       }
     } else {
+      GstMultSegmentBaseType *mult_seg =
+          stream->cur_seg_template->MultSegBaseType;
       /* build segment list */
-      i = stream->cur_seg_template->MultSegBaseType->startNumber;
+      i = mult_seg->startNumber;
       start = 0;
       start_time = PeriodStart;
 
       GST_LOG ("Building media segment list using this template: %s",
           stream->cur_seg_template->media);
-      if (stream->cur_seg_template->MultSegBaseType->SegmentTimeline) {
+      stream->presentationTimeOffset =
+          mult_seg->SegBaseType->presentationTimeOffset * GST_SECOND;
+
+      /* Avoid dividing by zero */
+      if (mult_seg->SegBaseType->timescale)
+        stream->presentationTimeOffset /= mult_seg->SegBaseType->timescale;
+
+      GST_LOG ("Setting stream's presentation time offset to %" GST_TIME_FORMAT,
+          GST_TIME_ARGS (stream->presentationTimeOffset));
+
+      if (mult_seg->SegmentTimeline) {
         GstSegmentTimelineNode *timeline;
         GstSNode *S;
         GList *list;
 
-        timeline = stream->cur_seg_template->MultSegBaseType->SegmentTimeline;
+        timeline = mult_seg->SegmentTimeline;
         gst_mpdparser_init_active_stream_segments (stream);
         for (list = g_queue_peek_head_link (&timeline->S); list;
             list = g_list_next (list)) {
@@ -3162,8 +3174,7 @@ gst_mpd_client_setup_representation (GstMpdClient * client,
           GST_LOG ("Processing S node: d=%" G_GUINT64_FORMAT " r=%u t=%"
               G_GUINT64_FORMAT, S->d, S->r, S->t);
           duration = S->d * GST_SECOND;
-          timescale =
+          timescale = mult_seg->SegBaseType->timescale;
-              stream->cur_seg_template->MultSegBaseType->SegBaseType->timescale;
           if (timescale > 1)
             duration /= timescale;
           if (S->t > 0) {
@@ -3583,6 +3594,20 @@ gst_mpd_client_get_next_fragment_timestamp (GstMpdClient * client,
   return TRUE;
 }
 
+GstClockTime
+gst_mpd_parser_get_stream_presentation_offset (GstMpdClient * client,
+    guint stream_idx)
+{
+  GstActiveStream *stream = NULL;
+
+  g_return_val_if_fail (client != NULL, FALSE);
+  g_return_val_if_fail (client->active_streams != NULL, FALSE);
+  stream = g_list_nth_data (client->active_streams, stream_idx);
+  g_return_val_if_fail (stream != NULL, FALSE);
+
+  return stream->presentationTimeOffset;
+}
+
 gboolean
 gst_mpd_client_get_next_fragment (GstMpdClient * client,
     guint indexStream, GstMediaFragmentInfo * fragment)

ext/dash/gstmpdparser.h

@@ -456,6 +456,7 @@ struct _GstActiveStream
   GstSegmentTemplateNode *cur_seg_template;   /* active segment template */
   guint segment_idx;                          /* index of next sequence chunk */
   GPtrArray *segments;                        /* array of GstMediaSegment */
+  GstClockTime presentationTimeOffset;        /* presentation time offset of the current segment */
 };
 
 struct _GstMpdClient
@@ -503,6 +504,7 @@ gboolean gst_mpd_client_seek_to_time (GstMpdClient * client, GDateTime * time);
 GstDateTime *gst_mpd_client_add_time_difference (GstDateTime * t1, gint64 usecs);
 gint gst_mpd_client_get_segment_index_at_time (GstMpdClient *client, GstActiveStream * stream, const GstDateTime *time);
 gint gst_mpd_client_check_time_position (GstMpdClient * client, GstActiveStream * stream, GstClockTime ts, gint64 * diff);
+GstClockTime gst_mpd_parser_get_stream_presentation_offset (GstMpdClient *client, guint stream_idx);
 
 /* Period selection */
 guint gst_mpd_client_get_period_index_at_time (GstMpdClient * client, GstDateTime * time);