[FFmpeg-devel] [RFC] mpegts: Provide a monotonic timestamp to the outside world

[Harald Axmann]

Am 29.10.2012 23:59, schrieb Carl Eugen Hoyos:
> Harald Axmann <harald.axmann <at> hotmail.com> writes:
>
>> The new version of the patch (still against XBMC's
>> FFmpeg) is attached, please check it.
> Just FYI:
> Four hunks of the current patch cannot be applied
> to git head.
>
> [...]

Sorry, I know. The patch was against current XBMC's FFmpeg, as I use 
this for development, as long as my proposals are not approved.

The patch attached now should work against git head. But I still have to 
test it.
-------------- next part --------------
diff --git a/libavformat/utils.c b/libavformat/utils.c
index fb5742b..0145118 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -78,6 +78,21 @@ static int is_relative(int64_t ts) {
     return ts > (RELATIVE_TS_BASE - (1LL<<48));
 }
 
+/**
+ * Wrap a given time stamp, if there is an indication for an overflow
+ *
+ * @param st stream
+ * @param timestamp the time stamp to wrap
+ * @return resulting time stamp
+ */
+static int64_t wrap_timestamp(AVStream *st, int64_t timestamp)
+{
+    if (st->first_dts != AV_NOPTS_VALUE && timestamp != AV_NOPTS_VALUE &&
+        timestamp < st->first_dts - 60*st->time_base.den)
+        return timestamp + (1LL<<st->pts_wrap_bits);
+    return timestamp;
+}
+
 /** head of registered input format linked list */
 static AVInputFormat *first_iformat = NULL;
 /** head of registered output format linked list */
@@ -739,6 +754,8 @@ int ff_read_packet(AVFormatContext *s, AVPacket *pkt)
         }
 
         st= s->streams[pkt->stream_index];
+        pkt->dts = wrap_timestamp(st, pkt->dts);
+        pkt->pts = wrap_timestamp(st, pkt->pts);
 
         force_codec_ids(s, st);
 
@@ -1614,6 +1631,7 @@ int ff_add_index_entry(AVIndexEntry **index_entries,
 int av_add_index_entry(AVStream *st,
                        int64_t pos, int64_t timestamp, int size, int distance, int flags)
 {
+    timestamp = wrap_timestamp(st, timestamp);
     return ff_add_index_entry(&st->index_entries, &st->nb_index_entries,
                               &st->index_entries_allocated_size, pos,
                               timestamp, size, distance, flags);
@@ -1660,6 +1678,12 @@ int av_index_search_timestamp(AVStream *st, int64_t wanted_timestamp,
                                      wanted_timestamp, flags);
 }
 
+static int64_t ff_read_timestamp(AVFormatContext *s, int stream_index, int64_t *ppos, int64_t pos_limit,
+                                 int64_t (*read_timestamp)(struct AVFormatContext *, int , int64_t *, int64_t ))
+{
+    return wrap_timestamp(s->streams[stream_index], read_timestamp(s, stream_index, ppos, pos_limit));
+}
+
 int ff_seek_frame_binary(AVFormatContext *s, int stream_index, int64_t target_ts, int flags)
 {
     AVInputFormat *avif= s->iformat;
@@ -1735,7 +1759,7 @@ int64_t ff_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts,
 
     if(ts_min == AV_NOPTS_VALUE){
         pos_min = s->data_offset;
-        ts_min = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
+        ts_min = ff_read_timestamp(s, stream_index, &pos_min, INT64_MAX, read_timestamp);
         if (ts_min == AV_NOPTS_VALUE)
             return -1;
     }
@@ -1751,7 +1775,7 @@ int64_t ff_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts,
         pos_max = filesize - 1;
         do{
             pos_max -= step;
-            ts_max = read_timestamp(s, stream_index, &pos_max, pos_max + step);
+            ts_max = ff_read_timestamp(s, stream_index, &pos_max, pos_max + step, read_timestamp);
             step += step;
         }while(ts_max == AV_NOPTS_VALUE && pos_max >= step);
         if (ts_max == AV_NOPTS_VALUE)
@@ -1759,7 +1783,7 @@ int64_t ff_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts,
 
         for(;;){
             int64_t tmp_pos= pos_max + 1;
-            int64_t tmp_ts= read_timestamp(s, stream_index, &tmp_pos, INT64_MAX);
+            int64_t tmp_ts= ff_read_timestamp(s, stream_index, &tmp_pos, INT64_MAX, read_timestamp);
             if(tmp_ts == AV_NOPTS_VALUE)
                 break;
             ts_max= tmp_ts;
@@ -1806,7 +1830,7 @@ int64_t ff_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts,
             pos= pos_limit;
         start_pos= pos;
 
-        ts = read_timestamp(s, stream_index, &pos, INT64_MAX); //may pass pos_limit instead of -1
+        ts = ff_read_timestamp(s, stream_index, &pos, INT64_MAX, read_timestamp); //may pass pos_limit instead of -1
         if(pos == pos_max)
             no_change++;
         else
@@ -1835,9 +1859,9 @@ int64_t ff_gen_search(AVFormatContext *s, int stream_index, int64_t target_ts,
     ts  = (flags & AVSEEK_FLAG_BACKWARD) ?  ts_min :  ts_max;
 #if 0
     pos_min = pos;
-    ts_min = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
+    ts_min = ff_read_timestamp(s, stream_index, &pos_min, INT64_MAX, read_timestamp);
     pos_min++;
-    ts_max = read_timestamp(s, stream_index, &pos_min, INT64_MAX);
+    ts_max = ff_read_timestamp(s, stream_index, &pos_min, INT64_MAX, read_timestamp);
     av_dlog(s, "pos=0x%"PRIx64" %s<=%s<=%s\n",
             pos, av_ts2str(ts_min), av_ts2str(target_ts), av_ts2str(ts_max));
 #endif