diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 46bb014..00268c6 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -4521,7 +4521,7 @@ static int process_input(int file_index)
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
- && (is->iformat->flags & AVFMT_TS_DISCONT) && ifile->last_ts != AV_NOPTS_VALUE) {
+ && (is->iformat->flags & AVFMT_TS_DISCONT) && ifile->last_ts != AV_NOPTS_VALUE && !force_dts_monotonicity) {
int64_t delta = pkt_dts - ifile->last_ts;
if (delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||
delta > 1LL*dts_delta_threshold*AV_TIME_BASE){
@@ -4559,7 +4559,7 @@ static int process_input(int file_index)
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 &&
- !disable_discontinuity_correction) {
+ !disable_discontinuity_correction && !force_dts_monotonicity) {
int64_t delta = pkt_dts - ist->next_dts;
if (is->iformat->flags & AVFMT_TS_DISCONT) {
if (delta < -1LL*dts_delta_threshold*AV_TIME_BASE ||
@@ -4597,6 +4597,43 @@ static int process_input(int file_index)
if (pkt->dts != AV_NOPTS_VALUE)
ifile->last_ts = av_rescale_q(pkt->dts, ist->st->time_base, AV_TIME_BASE_Q);
+ if ((ist->dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO ||
+ ist->dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) &&
+ (pkt->pts != AV_NOPTS_VALUE || pkt->dts != AV_NOPTS_VALUE) &&
+ force_dts_monotonicity) {
+ int64_t ff_pts_error = 0;
+ int64_t ff_dts_error = 0;
+ int64_t ff_dts_threshold = av_rescale_q(dts_monotonicity_threshold, AV_TIME_BASE_Q, ist->st->time_base);
+
+ // adjust the incoming packet by the accumulated monotonicity error
+ if (pkt->pts != AV_NOPTS_VALUE) {
+ pkt->pts += ifile->ff_timestamp_monotonicity_offset;
+ if (ist->next_pts != AV_NOPTS_VALUE) {
+ ff_pts_error = av_rescale_q(ist->next_pts, AV_TIME_BASE_Q, ist->st->time_base) - pkt->pts;
+ }
+ }
+ if (pkt->dts != AV_NOPTS_VALUE) {
+ pkt->dts += ifile->ff_timestamp_monotonicity_offset;
+ if (ist->next_dts != AV_NOPTS_VALUE) {
+ ff_dts_error = av_rescale_q(ist->next_dts, AV_TIME_BASE_Q, ist->st->time_base) - pkt->dts;
+ }
+ }
+
+ if (ff_dts_error > 0 || ff_dts_error < (-ff_dts_threshold) || ff_pts_error < (-ff_dts_threshold)) {
+ if (pkt->dts == AV_NOPTS_VALUE /*|| ist->next_dts != AV_NOPTS_VALUE*/) {
+ pkt->pts += ff_pts_error;
+ ifile->ff_timestamp_monotonicity_offset += ff_pts_error;
+ av_log(is, AV_LOG_INFO, "Incoming PTS error %"PRId64", offsetting subsequent timestamps by %"PRId64" to correct\n", ff_pts_error, ifile->ff_timestamp_monotonicity_offset);
+ }
+ else {
+ pkt->pts += ff_dts_error;
+ pkt->dts += ff_dts_error;
+ ifile->ff_timestamp_monotonicity_offset += ff_dts_error;
+ av_log(is, AV_LOG_INFO, "Incoming DTS error %"PRId64", offsetting subsequent timestamps by %"PRId64" to correct\n", ff_dts_error, ifile->ff_timestamp_monotonicity_offset);
+ }
+ }
+ }
+
if (debug_ts) {
av_log(NULL, AV_LOG_INFO, "demuxer+ffmpeg -> ist_index:%d type:%s pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s off:%s off_time:%s\n",
ifile->ist_index + pkt->stream_index, av_get_media_type_string(ist->dec_ctx->codec_type),
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index 606f2af..87775d4 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -428,6 +428,10 @@ typedef struct InputFile {
int joined; /* the thread has been joined */
int thread_queue_size; /* maximum number of queued packets */
#endif
+
+ // A value added to inbound timestamps to prevent them from going "backward" in cases such as HLS discontinuities
+ int64_t ff_timestamp_monotonicity_offset;
+
} InputFile;
enum forced_keyframes_const {
@@ -605,6 +609,9 @@ extern float audio_drift_threshold;
extern float dts_delta_threshold;
extern float dts_error_threshold;
+extern int dts_monotonicity_threshold;
+extern int force_dts_monotonicity;
+
extern int audio_volume;
extern int audio_sync_method;
extern int video_sync_method;
diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index 807e783..8389bce 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -151,6 +151,9 @@ float audio_drift_threshold = 0.1;
float dts_delta_threshold = 10;
float dts_error_threshold = 3600*30;
+int dts_monotonicity_threshold = AV_TIME_BASE;
+int force_dts_monotonicity = 0;
+
int audio_volume = 256;
int audio_sync_method = 0;
int video_sync_method = VSYNC_AUTO;
@@ -1274,6 +1277,7 @@ static int open_input_file(OptionsContext *o, const char *filename)
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);
+ f->ff_timestamp_monotonicity_offset = 0;
f->nb_streams = ic->nb_streams;
f->rate_emu = o->rate_emu;
f->accurate_seek = o->accurate_seek;
@@ -3538,6 +3542,10 @@ const OptionDef options[] = {
{ "apad", OPT_STRING | HAS_ARG | OPT_SPEC |
OPT_OUTPUT, { .off = OFFSET(apad) },
"audio pad", "" },
+ { "force_dts_monotonicity", OPT_BOOL | OPT_EXPERT, { &force_dts_monotonicity },
+ "correct dts monotonicity errors" },
+ { "dts_monotonicity_threshold", HAS_ARG | OPT_INT | OPT_EXPERT, { &dts_monotonicity_threshold },
+ "dts correction threshold for forward jumps", "microseconds" },
{ "dts_delta_threshold", HAS_ARG | OPT_FLOAT | OPT_EXPERT, { &dts_delta_threshold },
"timestamp discontinuity delta threshold", "threshold" },
{ "dts_error_threshold", HAS_ARG | OPT_FLOAT | OPT_EXPERT, { &dts_error_threshold },