[FFmpeg-devel] [PATCH] ffmpeg: fix implementation of updated input start time
Gyan Doshi
ffmpeg at gyani.pro
Tue Sep 27 07:40:56 EEST 2022
The current adjustment of input start times just adjusts the tsoffset.
And it does so, by resetting the tsoffset to nullify the new start time.
This leads to breakage of -copyts, ignoring of user_ts_offset, breaking
of -isync as well as breaking wrap correction.
Fixed by taking cognizance of these parameters, and by correcting start
times just before sync offsets are applied.
---
fftools/ffmpeg.c | 24 +-------------------
fftools/ffmpeg.h | 5 ++++-
fftools/ffmpeg_demux.c | 4 ++--
fftools/ffmpeg_opt.c | 50 +++++++++++++++++++++++++++++++++++++-----
4 files changed, 52 insertions(+), 31 deletions(-)
diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 0e1477299d..fabb0fb952 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -1898,7 +1898,7 @@ static void do_streamcopy(InputStream *ist, OutputStream *ost, const AVPacket *p
start_time = 0;
if (copy_ts) {
start_time += f->start_time != AV_NOPTS_VALUE ? f->start_time : 0;
- start_time += start_at_zero ? 0 : f->ctx->start_time;
+ start_time += start_at_zero ? 0 : f->enabled_start_time;
}
if (ist->pts >= f->recording_time + start_time) {
close_output_stream(ost);
@@ -3323,28 +3323,6 @@ static int transcode_init(void)
input_streams[j + ifile->ist_index]->start = av_gettime_relative();
}
- // Correct starttime based on the enabled streams
- for (i = 0; i < nb_input_files; i++) {
- InputFile *ifile = input_files[i];
- AVFormatContext *is = ifile->ctx;
- int64_t new_start_time = INT64_MAX;
-
- if (is->start_time == AV_NOPTS_VALUE ||
- !(is->iformat->flags & AVFMT_TS_DISCONT))
- continue;
-
- for (int j = 0; j < is->nb_streams; j++) {
- AVStream *st = is->streams[j];
- if(st->discard == AVDISCARD_ALL || st->start_time == AV_NOPTS_VALUE)
- continue;
- new_start_time = FFMIN(new_start_time, av_rescale_q(st->start_time, st->time_base, AV_TIME_BASE_Q));
- }
- if (new_start_time > is->start_time) {
- av_log(is, AV_LOG_VERBOSE, "Correcting start time by %"PRId64"\n", new_start_time - is->start_time);
- ifile->ts_offset = -new_start_time;
- }
- }
-
/* init input streams */
for (i = 0; i < nb_input_streams; i++)
if ((ret = init_input_stream(i, error, sizeof(error))) < 0)
diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
index ede0b2bd96..b93c2427b6 100644
--- a/fftools/ffmpeg.h
+++ b/fftools/ffmpeg.h
@@ -439,7 +439,10 @@ typedef struct InputFile {
AVRational time_base; /* time base of the duration */
int64_t input_ts_offset;
int input_sync_ref;
-
+ /**
+ * Effective format start time based on enabled streams.
+ */
+ int64_t enabled_start_time;
int64_t ts_offset;
/**
* Extra timestamp offset added by discontinuity handling.
diff --git a/fftools/ffmpeg_demux.c b/fftools/ffmpeg_demux.c
index 6e89f5999a..6125181f81 100644
--- a/fftools/ffmpeg_demux.c
+++ b/fftools/ffmpeg_demux.c
@@ -120,7 +120,7 @@ static int seek_to_start(InputFile *ifile)
static void ts_fixup(InputFile *ifile, AVPacket *pkt, int *repeat_pict)
{
InputStream *ist = input_streams[ifile->ist_index + pkt->stream_index];
- const int64_t start_time = ifile->ctx->start_time;
+ const int64_t start_time = ifile->enabled_start_time;
int64_t duration;
if (debug_ts) {
@@ -367,7 +367,7 @@ int ifile_get_packet(InputFile *f, AVPacket **pkt)
if (f->readrate || f->rate_emu) {
int i;
int64_t file_start = copy_ts * (
- (f->ctx->start_time != AV_NOPTS_VALUE ? f->ctx->start_time * !start_at_zero : 0) +
+ (f->enabled_start_time != AV_NOPTS_VALUE ? f->enabled_start_time * !start_at_zero : 0) +
(f->start_time != AV_NOPTS_VALUE ? f->start_time : 0)
);
float scale = f->rate_emu ? 1.0 : f->readrate;
diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c
index 5febe319e4..8df322c31c 100644
--- a/fftools/ffmpeg_opt.c
+++ b/fftools/ffmpeg_opt.c
@@ -293,6 +293,44 @@ static int parse_and_set_vsync(const char *arg, int *vsync_var, int file_idx, in
return 0;
}
+/* Correct input file start times based on enabled streams */
+static int correct_input_start_times(void)
+{
+ for (int i = 0; i < nb_input_files; i++) {
+ InputFile *ifile = input_files[i];
+ AVFormatContext *is = ifile->ctx;
+ int64_t new_start_time = INT64_MAX, diff, abs_start_seek;
+
+ ifile->enabled_start_time = is->start_time;
+
+ if (is->start_time == AV_NOPTS_VALUE ||
+ !(is->iformat->flags & AVFMT_TS_DISCONT))
+ continue;
+
+ for (int j = 0; j < is->nb_streams; j++) {
+ AVStream *st = is->streams[j];
+ if(st->discard == AVDISCARD_ALL || st->start_time == AV_NOPTS_VALUE)
+ continue;
+ new_start_time = FFMIN(new_start_time, av_rescale_q(st->start_time, st->time_base, AV_TIME_BASE_Q));
+ }
+
+ diff = new_start_time - is->start_time;
+ if (diff) {
+ av_log(NULL, AV_LOG_VERBOSE, "Correcting start time of Input #%d by %"PRId64" us.\n", i, diff);
+ ifile->enabled_start_time = new_start_time;
+ if (copy_ts && start_at_zero)
+ ifile->ts_offset = -new_start_time;
+ else if (!copy_ts) {
+ abs_start_seek = is->start_time + (ifile->start_time != AV_NOPTS_VALUE) ? ifile->start_time : 0;
+ ifile->ts_offset = abs_start_seek > new_start_time ? -abs_start_seek : -new_start_time;
+ }
+ ifile->ts_offset += ifile->input_ts_offset;
+ }
+ }
+
+ return 0;
+}
+
static int apply_sync_offsets(void)
{
for (int i = 0; i < nb_input_files; i++) {
@@ -321,9 +359,9 @@ static int apply_sync_offsets(void)
if (self->ctx->start_time_realtime != AV_NOPTS_VALUE && ref->ctx->start_time_realtime != AV_NOPTS_VALUE) {
self_start_time = self->ctx->start_time_realtime;
ref_start_time = ref->ctx->start_time_realtime;
- } else if (self->ctx->start_time != AV_NOPTS_VALUE && ref->ctx->start_time != AV_NOPTS_VALUE) {
- self_start_time = self->ctx->start_time;
- ref_start_time = ref->ctx->start_time;
+ } else if (self->enabled_start_time != AV_NOPTS_VALUE && ref->enabled_start_time != AV_NOPTS_VALUE) {
+ self_start_time = self->enabled_start_time;
+ ref_start_time = ref->enabled_start_time;
} else {
start_times_set = 0;
}
@@ -3747,8 +3785,6 @@ int ffmpeg_parse_options(int argc, char **argv)
goto fail;
}
- apply_sync_offsets();
-
/* create the complex filtergraphs */
ret = init_complex_filters();
if (ret < 0) {
@@ -3763,6 +3799,10 @@ int ffmpeg_parse_options(int argc, char **argv)
goto fail;
}
+ correct_input_start_times();
+
+ apply_sync_offsets();
+
check_filter_outputs();
fail:
--
2.36.1
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