lavf: add use_wallclock_as_timestamps

This may fix Ticket730

Reviewed-by: Nicolas George <nicolas.george@normalesup.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/avformat.h

@@ -1100,6 +1100,14 @@ typedef struct AVFormatContext {
      */
     int max_chunk_size;
 
+    /**
+     * forces the use of wallclock timestamps as pts/dts of packets
+     * This has undefined results in the presence of B frames.
+     * - encoding: unused
+     * - decoding: Set by user via AVOptions (NO direct access)
+     */
+    int use_wallclock_as_timestamps;
+
     /*****************************************************************
      * All fields below this line are not part of the public API. They
      * may not be used outside of libavformat and can be changed and

libavformat/options_table.h

@@ -70,6 +70,7 @@ static const AVOption options[]={
 {"careful",    "consider things that violate the spec and have not been seen in the wild as errors", 0, AV_OPT_TYPE_CONST, {.dbl = AV_EF_CAREFUL }, INT_MIN, INT_MAX, D, "err_detect"},
 {"compliant",  "consider all spec non compliancies as errors", 0, AV_OPT_TYPE_CONST, {.dbl = AV_EF_COMPLIANT }, INT_MIN, INT_MAX, D, "err_detect"},
 {"aggressive", "consider things that a sane encoder shouldnt do as an error", 0, AV_OPT_TYPE_CONST, {.dbl = AV_EF_AGGRESSIVE }, INT_MIN, INT_MAX, D, "err_detect"},
+{"use_wallclock_as_timestamps", "use wallclock as timestamps", OFFSET(use_wallclock_as_timestamps), AV_OPT_TYPE_INT, {.dbl = 0}, 0, INT_MAX-1, D},
 {NULL},
 };
 

libavformat/utils.c

@@ -776,6 +776,9 @@ int ff_read_packet(AVFormatContext *s, AVPacket *pkt)
             if(s->subtitle_codec_id)st->codec->codec_id= s->subtitle_codec_id;
             break;
         }
+        /* TODO: audio: time filter; video: frame reordering (pts != dts) */
+        if (s->use_wallclock_as_timestamps)
+            pkt->dts = pkt->pts = av_rescale_q(av_gettime(), AV_TIME_BASE_Q, st->time_base);
 
         if(!pktl && st->request_probe <= 0)
             return ret;