From b0bb1d353925c935d93f37706f21d8b199505ec5 Mon Sep 17 00:00:00 2001
From: Vincent Penquerc'h <vincent.penquerch@collabora.co.uk>
Date: Sat, 22 Oct 2011 20:29:26 +0100
Subject: [PATCH] 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
---
 ext/ogg/gstoggdemux.c | 71 +++++++++++++++++++++++++------------------
 1 file changed, 42 insertions(+), 29 deletions(-)

diff --git a/ext/ogg/gstoggdemux.c b/ext/ogg/gstoggdemux.c
index 3afbd91976..16bcf6c23e 100644
--- 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));
+          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_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);
+            ogg->push_state = PUSH_BISECT2;
+            best = gst_ogg_demux_estimate_bisection_target (ogg, 1.0f);
+          }
         }
       }
     }