oggdemux: Fix seeking before the first frame.

The previous code was setting keytarget to target
to make sure the keyframe found for each pad was
indeed before the target.

Then if target == keytarget, it assumed a keyframe had been
found, which was not the case if target was before the first frame
in the file.

This patch checks that a keyframe was indeed found, and if not
seeks to 0, without bisecting again.

Assuming default gst qa assets in $HOME/gst-validate

seek_before_first_frame.scenario:

description, seek=true, handles-states=true
pause, playback-time=0.0
seek, playback-time=0.0, start=0.0, flags=accurate+flush
seek, playback-time=0.0, start=0.01, flags=accurate+flush
seek, playback-time=0.0, start=0.1, flags=accurate+flush

GST_DEBUG=*theoradec*:2 gst-validate-1.0 playbin \
uri=file://$HOME/gst-validate/gst-qa-assets/medias/ogg/vorbis_theora.0.ogg \
--set-scenario seek_before_first_frame.scenario

https://bugzilla.gnome.org/show_bug.cgi?id=741097

diff --git a/ext/ogg/gstoggdemux.c b/ext/ogg/gstoggdemux.c
index 2a98e20..b6b7f70 100644 (file)
--- a/ext/ogg/gstoggdemux.c
+++ b/ext/ogg/gstoggdemux.c
@@ -2984,6 +2984,7 @@ gst_ogg_demux_do_seek (GstOggDemux * ogg, GstSegment * segment,
   GstFlowReturn ret;
   gint i, pending;
   gint serialno = 0;
+  gboolean found_keyframe = FALSE;
 
   position = segment->position;
 
@@ -3114,6 +3115,7 @@ gst_ogg_demux_do_seek (GstOggDemux * ogg, GstSegment * segment,
       if (keyframe_time < keytarget) {
         serialno = pad->map.serialno;
         keytarget = keyframe_time;
+        found_keyframe = TRUE;
       }
     }
 
@@ -3127,6 +3129,10 @@ gst_ogg_demux_do_seek (GstOggDemux * ogg, GstSegment * segment,
   if (segment->rate < 0.0)
     goto done;
 
+  /* No keyframe found, no need to bisect again, keytarget == target here */
+  if (!found_keyframe)
+    best = 0;
+
   if (keytarget != target) {
     GST_LOG_OBJECT (ogg, "final seek to target %" GST_TIME_FORMAT,
         GST_TIME_ARGS (keytarget));