oggdemux: skip the second bisection when possible

If we already saw the keyframes that we need to find,
we do not need to bisect to find them.

This will always be the case for streams with audio only,
where each frame acts as a keyframe, but will occasionally
also happen for streams with video.

https://bugzilla.gnome.org/show_bug.cgi?id=662475

diff --git a/ext/ogg/gstoggdemux.c b/ext/ogg/gstoggdemux.c
index 3afbd91..16bcf6c 100644 (file)
--- a/ext/ogg/gstoggdemux.c
+++ b/ext/ogg/gstoggdemux.c
@@ -1333,6 +1333,25 @@ gst_ogg_demux_estimate_seek_quality (GstOggDemux * ogg)
   return seek_quality;
 }
 
+static void
+gst_ogg_demux_update_bisection_stats (GstOggDemux * ogg)
+{
+  GST_INFO_OBJECT (ogg, "Bisection needed %d + %d steps",
+      ogg->push_bisection_steps[0], ogg->push_bisection_steps[1]);
+  ogg->stats_bisection_steps[0] += ogg->push_bisection_steps[0];
+  ogg->stats_bisection_steps[1] += ogg->push_bisection_steps[1];
+  if (ogg->stats_bisection_max_steps[0] < ogg->push_bisection_steps[0])
+    ogg->stats_bisection_max_steps[0] = ogg->push_bisection_steps[0];
+  if (ogg->stats_bisection_max_steps[1] < ogg->push_bisection_steps[1])
+    ogg->stats_bisection_max_steps[1] = ogg->push_bisection_steps[1];
+  ogg->stats_nbisections++;
+  GST_INFO_OBJECT (ogg,
+      "So far, %.2f + %.2f bisections needed per seek (max %d + %d)",
+      ogg->stats_bisection_steps[0] / (float) ogg->stats_nbisections,
+      ogg->stats_bisection_steps[1] / (float) ogg->stats_nbisections,
+      ogg->stats_bisection_max_steps[0], ogg->stats_bisection_max_steps[1]);
+}
+
 static gboolean
 gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
 {
@@ -1533,21 +1552,7 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
                any queued pages into the stream so we start decoding there */
             ogg->push_state = PUSH_PLAYING;
           }
-          GST_INFO_OBJECT (ogg, "Bisection needed %d + %d steps",
-              ogg->push_bisection_steps[0], ogg->push_bisection_steps[1]);
-          ogg->stats_bisection_steps[0] += ogg->push_bisection_steps[0];
-          ogg->stats_bisection_steps[1] += ogg->push_bisection_steps[1];
-          if (ogg->stats_bisection_max_steps[0] < ogg->push_bisection_steps[0])
-            ogg->stats_bisection_max_steps[0] = ogg->push_bisection_steps[0];
-          if (ogg->stats_bisection_max_steps[1] < ogg->push_bisection_steps[1])
-            ogg->stats_bisection_max_steps[1] = ogg->push_bisection_steps[1];
-          ogg->stats_nbisections++;
-          GST_INFO_OBJECT (ogg,
-              "So far, %.2f + %.2f bisections needed per seek (max %d + %d)",
-              ogg->stats_bisection_steps[0] / (float) ogg->stats_nbisections,
-              ogg->stats_bisection_steps[1] / (float) ogg->stats_nbisections,
-              ogg->stats_bisection_max_steps[0],
-              ogg->stats_bisection_max_steps[1]);
+          gst_ogg_demux_update_bisection_stats (ogg);
         }
       }
     } else if (ogg->push_state == PUSH_LINEAR1) {
@@ -1561,22 +1566,30 @@ gst_ogg_pad_handle_push_mode_state (GstOggPad * pad, ogg_page * page)
             GST_TIME_ARGS (pad->push_kf_time));
         earliest_keyframe_time = gst_ogg_demux_get_earliest_keyframe_time (ogg);
         if (earliest_keyframe_time != GST_CLOCK_TIME_NONE) {
-          GST_INFO_OBJECT (ogg,
-              "All non sparse streams now have a previous keyframe time,"
-              "bisecting again to %" GST_TIME_FORMAT,
-              GST_TIME_ARGS (earliest_keyframe_time));
-
-          ogg->push_seek_time_target = earliest_keyframe_time;
-          ogg->push_offset0 = 0;
-          ogg->push_time0 = ogg->push_start_time;
-          ogg->push_offset1 = ogg->push_last_seek_offset;
-          ogg->push_time1 = ogg->push_last_seek_time;
-          ogg->push_prev_seek_time = GST_CLOCK_TIME_NONE;
-          ogg->seek_secant = FALSE;
-          ogg->seek_undershot = FALSE;
-
-          ogg->push_state = PUSH_BISECT2;
-          best = gst_ogg_demux_estimate_bisection_target (ogg, 1.0f);
+          if (earliest_keyframe_time > ogg->push_last_seek_time) {
+            GST_INFO_OBJECT (ogg,
+                "All non sparse streams now have a previous keyframe time, "
+                "and we already decoded it, switching to playing");
+            ogg->push_state = PUSH_PLAYING;
+            gst_ogg_demux_update_bisection_stats (ogg);
+          } else {
+            GST_INFO_OBJECT (ogg,
+                "All non sparse streams now have a previous keyframe time, "
+                "bisecting again to %" GST_TIME_FORMAT,
+                GST_TIME_ARGS (earliest_keyframe_time));
+
+            ogg->push_seek_time_target = earliest_keyframe_time;
+            ogg->push_offset0 = 0;
+            ogg->push_time0 = ogg->push_start_time;
+            ogg->push_offset1 = ogg->push_last_seek_offset;
+            ogg->push_time1 = ogg->push_last_seek_time;
+            ogg->push_prev_seek_time = GST_CLOCK_TIME_NONE;
+            ogg->seek_secant = FALSE;
+            ogg->seek_undershot = FALSE;
+
+            ogg->push_state = PUSH_BISECT2;
+            best = gst_ogg_demux_estimate_bisection_target (ogg, 1.0f);
+          }
         }
       }
     }