ffmpeg: add support for specifically setting an input start TS

Additionally do not reset the start timestamp if this option is set for an input.
jeeb · Feb 15, 2018 · 369a722 · 369a722
1 parent aa62808
commit 369a722
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Showing 3 changed files with 13 additions and 2 deletions.
diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
@@ -4385,7 +4385,7 @@ static int process_input(int file_index)
     pkt_dts = av_rescale_q_rnd(pkt.dts, ist->st->time_base, AV_TIME_BASE_Q, AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX);
     if ((ist->dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO ||
          ist->dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) &&
-        pkt_dts != AV_NOPTS_VALUE && ist->next_dts == AV_NOPTS_VALUE && !copy_ts
+        pkt_dts != AV_NOPTS_VALUE && ist->next_dts == AV_NOPTS_VALUE && !copy_ts && !ifile->set_start_time
         && (is->iformat->flags & AVFMT_TS_DISCONT) && ifile->last_ts != AV_NOPTS_VALUE) {
         int64_t delta   = pkt_dts - ifile->last_ts;
         if (delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||

diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
@@ -116,6 +116,7 @@ typedef struct OptionsContext {
 
     /* input options */
     int64_t input_ts_offset;
+    int64_t input_ts_start;
     int loop;
     int rate_emu;
     int accurate_seek;
@@ -402,6 +403,7 @@ typedef struct InputFile {
     int64_t input_ts_offset;
 
     int64_t ts_offset;
+    int64_t set_start_time;
     int64_t last_ts;
     int64_t start_time;   /* user-specified start time in AV_TIME_BASE or AV_NOPTS_VALUE */
     int seek_timestamp;

diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
@@ -1153,7 +1153,13 @@ static int open_input_file(OptionsContext *o, const char *filename)
     f->start_time = o->start_time;
     f->recording_time = o->recording_time;
     f->input_ts_offset = o->input_ts_offset;
-    f->ts_offset  = o->input_ts_offset - (copy_ts ? (start_at_zero && ic->start_time != AV_NOPTS_VALUE ? ic->start_time : 0) : timestamp);
+
+    if (o->input_ts_start) {
+        f->set_start_time = o->input_ts_start;
+        f->ts_offset = o->input_ts_start - (ic->start_time != AV_NOPTS_VALUE ? ic->start_time : 0);
+    } else {
+        f->ts_offset  = o->input_ts_offset - (copy_ts ? (start_at_zero && ic->start_time != AV_NOPTS_VALUE ? ic->start_time : 0) : timestamp);
+    }
     f->nb_streams = ic->nb_streams;
     f->rate_emu   = o->rate_emu;
     f->accurate_seek = o->accurate_seek;
@@ -3350,6 +3356,9 @@ const OptionDef options[] = {
     { "itsscale",       HAS_ARG | OPT_DOUBLE | OPT_SPEC |
                         OPT_EXPERT | OPT_INPUT,                      { .off = OFFSET(ts_scale) },
         "set the input ts scale", "scale" },
+    { "its_start_point",      HAS_ARG | OPT_TIME | OPT_OFFSET |
+                        OPT_EXPERT | OPT_INPUT,                      { .off = OFFSET(input_ts_start) },
+        "set the input ts start point", "time_off" },
     { "timestamp",      HAS_ARG | OPT_PERFILE | OPT_OUTPUT,          { .func_arg = opt_recording_timestamp },
         "set the recording timestamp ('now' to set the current time)", "time" },
     { "metadata",       HAS_ARG | OPT_STRING | OPT_SPEC | OPT_OUTPUT, { .off = OFFSET(metadata) },