From 22ffac707e52ce58c0bd71857fe1353f453f78e0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Reimar=20D=C3=B6ffinger?= <Reimar.Doeffinger@gmx.de>
Date: Sun, 23 Jul 2006 18:19:33 +0000
Subject: [PATCH] Try to find out correct start time to make seeking faster and
 add some extra checks to make sure the seeking function will not hang
 forever.

Originally committed as revision 5814 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavformat/avformat.h |  1 +
 libavformat/ogg2.c     | 36 ++++++++++++++++++++++++++++++++----
 libavformat/utils.c    |  2 +-
 3 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index df87339e8b..8fec18deee 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -472,6 +472,7 @@ int av_index_search_timestamp(AVStream *st, int64_t timestamp, int flags);
 int av_add_index_entry(AVStream *st,
                        int64_t pos, int64_t timestamp, int size, int distance, int flags);
 int av_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags);
+void av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp);
 
 /* media file output */
 int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap);
diff --git a/libavformat/ogg2.c b/libavformat/ogg2.c
index 2af5a4f9aa..254415b7a3 100644
--- a/libavformat/ogg2.c
+++ b/libavformat/ogg2.c
@@ -201,7 +201,6 @@ ogg_new_stream (AVFormatContext * s, uint32_t serial)
         return AVERROR_NOMEM;
 
     av_set_pts_info(st, 64, 1, 1000000);
-    st->start_time = 0;
 
     return idx;
 }
@@ -495,6 +494,16 @@ ogg_get_length (AVFormatContext * s)
 
     ogg->size = size;
     ogg_restore (s, 0);
+    ogg_save (s);
+    while (ogg_read_page (s, &i)) {
+        if (i == idx && ogg->streams[i].granule != -1 && ogg->streams[i].granule != 0)
+            break;
+    }
+    if (i == idx) {
+        s->streams[idx]->start_time = ogg_gptopts (s, idx, ogg->streams[idx].granule);
+        s->streams[idx]->duration -= s->streams[idx]->start_time;
+    }
+    ogg_restore (s, 0);
 
     return 0;
 }
@@ -572,12 +581,14 @@ ogg_read_seek (AVFormatContext * s, int stream_index, int64_t target_ts,
     ogg_t *ogg = s->priv_data;
     ByteIOContext *bc = &s->pb;
     uint64_t min = 0, max = ogg->size;
-    uint64_t tmin = 0, tmax = st->duration;
+    uint64_t tmin = st->start_time, tmax = st->start_time + st->duration;
     int64_t pts = AV_NOPTS_VALUE;
 
     ogg_save (s);
 
-    while (min <= max){
+    if ((uint64_t)target_ts < tmin || target_ts < 0)
+        target_ts = tmin;
+    while (min <= max && tmin < tmax){
         uint64_t p = min + (max - min) * (target_ts - tmin) / (tmax - tmin);
         int i = -1;
 
@@ -599,9 +610,25 @@ ogg_read_seek (AVFormatContext * s, int stream_index, int64_t target_ts,
             break;
 
         if (pts > target_ts){
+            if (max == p && tmax == pts) {
+                // probably our tmin is wrong, causing us to always end up too late in the file
+                tmin = (target_ts + tmin + 1) / 2;
+                if (tmin == target_ts) {
+                    url_fseek(bc, min, SEEK_SET);
+                    break;
+                }
+            }
             max = p;
             tmax = pts;
         }else{
+            if (min == p && tmin == pts) {
+                // probably our tmax is wrong, causing us to always end up too early in the file
+                tmax = (target_ts + tmax) / 2;
+                if (tmax == target_ts) {
+                    url_fseek(bc, max, SEEK_SET);
+                    break;
+                }
+            }
             min = p;
             tmin = pts;
         }
@@ -615,7 +642,8 @@ ogg_read_seek (AVFormatContext * s, int stream_index, int64_t target_ts,
         pts = AV_NOPTS_VALUE;
     }
 
-    return pts;
+    av_update_cur_dts(s, st, pts);
+    return 0;
 
 #if 0
     //later...
diff --git a/libavformat/utils.c b/libavformat/utils.c
index 2c882faf44..cefce88abc 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -1097,7 +1097,7 @@ static void av_read_frame_flush(AVFormatContext *s)
  * @param timestamp new dts expressed in time_base of param ref_st
  * @param ref_st reference stream giving time_base of param timestamp
  */
-static void av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp){
+void av_update_cur_dts(AVFormatContext *s, AVStream *ref_st, int64_t timestamp){
     int i;
 
     for(i = 0; i < s->nb_streams; i++) {