@@ -751,7 +751,9 @@ static void do_subtitle_out(AVFormatContext *s,

         nb = 1;

     /* shift timestamp to honor -ss and make check_recording_time() work with -t */

-    pts = sub->pts - output_files[ost->file_index]->start_time;

+    pts = sub->pts;

+    if (output_files[ost->file_index]->start_time != AV_NOPTS_VALUE)

+        pts -= output_files[ost->file_index]->start_time;

     for (i = 0; i < nb; i++) {

         ost->sync_opts = av_rescale_q(pts, AV_TIME_BASE_Q, enc->time_base);

         if (!check_recording_time(ost))

@@ -1070,10 +1072,11 @@ static int reap_filters(void)

             }

             frame_pts = AV_NOPTS_VALUE;

             if (filtered_frame->pts != AV_NOPTS_VALUE) {

+                int64_t start_time = (of->start_time == AV_NOPTS_VALUE) ? 0 : of->start_time;

                 filtered_frame->pts = frame_pts = av_rescale_q(filtered_frame->pts,

                                                 ost->filter->filter->inputs[0]->time_base,

                                                 ost->st->codec->time_base) -

-                                    av_rescale_q(of->start_time,

+                                    av_rescale_q(start_time,

                                                 AV_TIME_BASE_Q,

                                                 ost->st->codec->time_base);

             }

@@ -1377,7 +1380,7 @@ static int check_output_constraints(InputStream *ist, OutputStream *ost)

     if (ost->source_index != ist_index)

         return 0;

-    if (of->start_time && ist->pts < of->start_time)

+    if (of->start_time != AV_NOPTS_VALUE && ist->pts < of->start_time)

         return 0;

     return 1;

@@ -1386,8 +1389,9 @@ static int check_output_constraints(InputStream *ist, OutputStream *ost)

 static void do_streamcopy(InputStream *ist, OutputStream *ost, const AVPacket *pkt)

 {

     OutputFile *of = output_files[ost->file_index];

-    int64_t ost_tb_start_time = av_rescale_q(of->start_time, AV_TIME_BASE_Q, ost->st->time_base);

-    int64_t ist_tb_start_time = av_rescale_q(of->start_time, AV_TIME_BASE_Q, ist->st->time_base);

+    int64_t start_time = (of->start_time == AV_NOPTS_VALUE) ? 0 : of->start_time;

+    int64_t ost_tb_start_time = av_rescale_q(start_time, AV_TIME_BASE_Q, ost->st->time_base);

+    int64_t ist_tb_start_time = av_rescale_q(start_time, AV_TIME_BASE_Q, ist->st->time_base);

     AVPicture pict;

     AVPacket opkt;

@@ -1398,7 +1402,7 @@ static void do_streamcopy(InputStream *ist, OutputStream *ost, const AVPacket *p

         return;

     if (pkt->pts == AV_NOPTS_VALUE) {

-        if (!ost->frame_number && ist->pts < of->start_time &&

+        if (!ost->frame_number && ist->pts < start_time &&

             !ost->copy_prior_start)

             return;

     } else {

@@ -1408,7 +1412,7 @@ static void do_streamcopy(InputStream *ist, OutputStream *ost, const AVPacket *p

     }

     if (of->recording_time != INT64_MAX &&

-        ist->pts >= of->recording_time + of->start_time) {

+        ist->pts >= of->recording_time + start_time) {

         close_output_stream(ost);

         return;

     }

@@ -286,11 +286,11 @@ static int insert_trim(OutputStream *ost, AVFilterContext **last_filter, int *pa

     char filter_name[128];

     int ret = 0;

-    if (of->recording_time == INT64_MAX && !of->start_time)

+    if (of->recording_time == INT64_MAX && of->start_time == AV_NOPTS_VALUE)

         return 0;

     // Use with duration and without output starttime is buggy with trim filters

-    if (!of->start_time)

+    if (of->start_time == AV_NOPTS_VALUE)

         return 0;

     trim = avfilter_get_by_name(name);

@@ -310,7 +310,7 @@ static int insert_trim(OutputStream *ost, AVFilterContext **last_filter, int *pa

         ret = av_opt_set_double(ctx, "duration", (double)of->recording_time / 1e6,

                                 AV_OPT_SEARCH_CHILDREN);

     }

-    if (ret >= 0 && of->start_time) {

+    if (ret >= 0 && of->start_time != AV_NOPTS_VALUE) {

         ret = av_opt_set_double(ctx, "start", (double)of->start_time / 1e6,

                                 AV_OPT_SEARCH_CHILDREN);

     }

@@ -147,6 +147,7 @@ static void init_options(OptionsContext *o, int is_input)

         o->recording_time = INT64_MAX;

     o->stop_time = INT64_MAX;

     o->mux_max_delay  = 0.7;

+    o->start_time     = AV_NOPTS_VALUE;

     o->limit_filesize = UINT64_MAX;

     o->chapters_input_file = INT_MAX;

 }

@@ -824,13 +825,13 @@ static int open_input_file(OptionsContext *o, const char *filename)

         exit_program(1);

     }

-    timestamp = o->start_time;

+    timestamp = (o->start_time == AV_NOPTS_VALUE) ? 0 : o->start_time;

     /* add the stream start time */

     if (ic->start_time != AV_NOPTS_VALUE)

         timestamp += ic->start_time;

     /* if seeking requested, we execute it */

-    if (o->start_time != 0) {

+    if (o->start_time != AV_NOPTS_VALUE) {

         ret = avformat_seek_file(ic, -1, INT64_MIN, timestamp, timestamp, 0);

         if (ret < 0) {

             av_log(NULL, AV_LOG_WARNING, "%s: could not seek to position %0.3f\n",

@@ -1451,7 +1452,8 @@ static int copy_chapters(InputFile *ifile, OutputFile *ofile, int copy_metadata)

     for (i = 0; i < is->nb_chapters; i++) {

         AVChapter *in_ch = is->chapters[i], *out_ch;

-        int64_t ts_off   = av_rescale_q(ofile->start_time - ifile->ts_offset,

+        int64_t start_time = (ofile->start_time == AV_NOPTS_VALUE) ? 0 : ofile->start_time;

+        int64_t ts_off   = av_rescale_q(start_time - ifile->ts_offset,

                                        AV_TIME_BASE_Q, in_ch->time_base);

         int64_t rt       = (ofile->recording_time == INT64_MAX) ? INT64_MAX :

                            av_rescale_q(ofile->recording_time, AV_TIME_BASE_Q, in_ch->time_base);

@@ -1586,11 +1588,12 @@ static int open_output_file(OptionsContext *o, const char *filename)

     }

     if (o->stop_time != INT64_MAX && o->recording_time == INT64_MAX) {

-        if (o->stop_time <= o->start_time) {

+        int64_t start_time = o->start_time == AV_NOPTS_VALUE ? 0 : o->start_time;

+        if (o->stop_time <= start_time) {

             av_log(NULL, AV_LOG_WARNING, "-to value smaller than -ss; ignoring -to.\n");

             o->stop_time = INT64_MAX;

         } else {

-            o->recording_time = o->stop_time - o->start_time;

+            o->recording_time = o->stop_time - start_time;

         }

     }