assrender: fix seeking backwards

Use proper API to flush libass events when we do
a flushing seek, and also do it in FLUSH_STOP
rather than FLUSH_START, so we can be sure
streaming has stopped.

Fixes seeking back in time.

Something seems to have changed in libass that
renders the old manual way of flushing events
ineffective and libass then seems to ignore
timestamps that are older than the ones last
seen then if we do it the old way.

Fixes #916

1 files changed, 5 insertions, 12 deletions

diff --git a/ext/assrender/gstassrender.c b/ext/assrender/gstassrender.c
index 65617bb7d..52f9740e9 100644
--- a/ext/assrender/gstassrender.c
+++ b/ext/assrender/gstassrender.c
@@ -1741,7 +1741,6 @@ gst_ass_render_query_video (GstPad * pad, GstObject * parent, GstQuery * query)
 static gboolean
 gst_ass_render_event_text (GstPad * pad, GstObject * parent, GstEvent * event)
 {
-  gint i;
   gboolean ret = FALSE;
   GstAssRender *render = GST_ASS_RENDER (parent);
 
@@ -1812,6 +1811,11 @@ gst_ass_render_event_text (GstPad * pad, GstObject * parent, GstEvent * event)
       break;
     }
     case GST_EVENT_FLUSH_STOP:
+      g_mutex_lock (&render->ass_mutex);
+      if (render->ass_track) {
+        ass_flush_events (render->ass_track);
+      }
+      g_mutex_unlock (&render->ass_mutex);
       GST_ASS_RENDER_LOCK (render);
       GST_INFO_OBJECT (render, "text flush stop");
       render->subtitle_flushing = FALSE;
@@ -1824,17 +1828,6 @@ gst_ass_render_event_text (GstPad * pad, GstObject * parent, GstEvent * event)
       break;
     case GST_EVENT_FLUSH_START:
       GST_DEBUG_OBJECT (render, "text flush start");
-      g_mutex_lock (&render->ass_mutex);
-      if (render->ass_track) {
-        /* delete any events on the ass_track */
-        for (i = 0; i < render->ass_track->n_events; i++) {
-          GST_DEBUG_OBJECT (render, "deleted event with eid %i", i);
-          ass_free_event (render->ass_track, i);
-        }
-        render->ass_track->n_events = 0;
-        GST_DEBUG_OBJECT (render, "done flushing");
-      }
-      g_mutex_unlock (&render->ass_mutex);
       GST_ASS_RENDER_LOCK (render);
       render->subtitle_flushing = TRUE;
       GST_ASS_RENDER_BROADCAST (render);