@@ -832,6 +832,13 @@ typedef struct AVStream {

      * its lifetime differs from info which is why its not in that structure.

      */

     int nb_decoded_frames;

+

+    /**

+     * Timestamp offset added to timestamps before muxing

+     * NOT PART OF PUBLIC API

+     */

+    int64_t mux_ts_offset;

+

 } AVStream;

 #define AV_PROGRAM_RUNNING 1

@@ -1111,6 +1118,17 @@ typedef struct AVFormatContext {

      */

     int use_wallclock_as_timestamps;

+    /**

+     * Avoids negative timestamps during muxing

+     *  0 -> allow negative timestamps

+     *  1 -> avoid negative timestamps

+     * -1 -> choose automatically (default)

+     * Note, this is only works when interleave_packet_per_dts is in use

+     * - encoding: Set by user via AVOptions (NO direct access)

+     * - decoding: unused

+     */

+    int avoid_negative_ts;

+

     /*****************************************************************

      * 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

@@ -71,6 +71,7 @@ static const AVOption options[]={

 {"compliant",  "consider all spec non compliancies as errors", 0, AV_OPT_TYPE_CONST, {.i64 = 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, {.i64 = 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, {.i64 = 0}, 0, INT_MAX-1, D},

+{"avoid_negative_ts", "avoid negative timestamps", OFFSET(avoid_negative_ts), AV_OPT_TYPE_INT, {.i64 = -1}, -1, 1, E},

 {NULL},

 };

@@ -3699,16 +3699,36 @@ int ff_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,

         }

     }

     if(stream_count && flush){

+        AVStream *st;

         pktl= s->packet_buffer;

         *out= pktl->pkt;

+        st = s->streams[out->stream_index];

         s->packet_buffer= pktl->next;

         if(!s->packet_buffer)

             s->packet_buffer_end= NULL;

-        if(s->streams[out->stream_index]->last_in_packet_buffer == pktl)

-            s->streams[out->stream_index]->last_in_packet_buffer= NULL;

+        if(st->last_in_packet_buffer == pktl)

+            st->last_in_packet_buffer= NULL;

         av_freep(&pktl);

+

+        if (s->avoid_negative_ts > 0) {

+            if (out->dts != AV_NOPTS_VALUE) {

+                if (!st->mux_ts_offset && out->dts < 0) {

+                    for(i=0; i < s->nb_streams; i++) {

+                        s->streams[i]->mux_ts_offset =

+                            av_rescale_q_rnd(-out->dts,

+                                             st->time_base,

+                                             s->streams[i]->time_base,

+                                             AV_ROUND_UP);

+                    }

+                }

+                out->dts += st->mux_ts_offset;

+            }

+            if (out->pts != AV_NOPTS_VALUE)

+                out->pts += st->mux_ts_offset;

+        }

+

         return 1;

     }else{

         av_init_packet(out);

@@ -30,7 +30,7 @@

 #include "libavutil/avutil.h"

 #define LIBAVFORMAT_VERSION_MAJOR 54

-#define LIBAVFORMAT_VERSION_MINOR 28

+#define LIBAVFORMAT_VERSION_MINOR 29

 #define LIBAVFORMAT_VERSION_MICRO 101

 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \