[FFmpeg-devel] [PATCH v2 2/2] ffmpeg: fix implementation of updated input start time
Gyan Doshi
ffmpeg at gyani.pro
Tue Nov 1 15:48:03 EET 2022
Plan to apply set in 24h , barring objections.
On 2022-10-30 01:34 am, Gyan Doshi wrote:
> Any objections?
>
> On 2022-10-25 09:28 pm, Gyan Doshi wrote:
>> Ping.
>>
>> On 2022-10-21 10:01 pm, Gyan Doshi wrote:
>>> 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 input_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 | 2 +-
>>> fftools/ffmpeg.h | 5 ++++-
>>> fftools/ffmpeg_demux.c | 4 ++--
>>> fftools/ffmpeg_opt.c | 33 +++++++++++++++++++++++----------
>>> 4 files changed, 30 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
>>> index 0fe582be3b..c564b2649e 100644
>>> --- a/fftools/ffmpeg.c
>>> +++ b/fftools/ffmpeg.c
>>> @@ -1815,7 +1815,7 @@ 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->start_time_effective;
>>> }
>>> if (ist->pts >= f->recording_time + start_time) {
>>> close_output_stream(ost);
>>> diff --git a/fftools/ffmpeg.h b/fftools/ffmpeg.h
>>> index 5966cac60e..2d97ccaa15 100644
>>> --- a/fftools/ffmpeg.h
>>> +++ b/fftools/ffmpeg.h
>>> @@ -447,7 +447,10 @@ 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 start_time_effective;
>>> 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..220fda56da 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->start_time_effective;
>>> 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->start_time_effective !=
>>> AV_NOPTS_VALUE ? f->start_time_effective * !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 28b7d4dc27..a6fa9b7801 100644
>>> --- a/fftools/ffmpeg_opt.c
>>> +++ b/fftools/ffmpeg_opt.c
>>> @@ -216,13 +216,15 @@ int parse_and_set_vsync(const char *arg, int
>>> *vsync_var, int file_idx, int st_id
>>> return 0;
>>> }
>>> +/* Correct input file start times based on enabled streams */
>>> static void correct_input_start_times(void)
>>> {
>>> - // Correct starttime based on the enabled streams
>>> 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;
>>> + int64_t new_start_time = INT64_MAX, diff, abs_start_seek;
>>> +
>>> + ifile->start_time_effective = is->start_time;
>>> if (is->start_time == AV_NOPTS_VALUE ||
>>> !(is->iformat->flags & AVFMT_TS_DISCONT))
>>> @@ -234,9 +236,20 @@ static void correct_input_start_times(void)
>>> 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;
>>> +
>>> + 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->start_time_effective = 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;
>>> + } else if (copy_ts)
>>> + ifile->ts_offset = 0;
>>> +
>>> + ifile->ts_offset += ifile->input_ts_offset;
>>> }
>>> }
>>> }
>>> @@ -269,9 +282,9 @@ 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->start_time_effective != AV_NOPTS_VALUE &&
>>> ref->start_time_effective != AV_NOPTS_VALUE) {
>>> + self_start_time = self->start_time_effective;
>>> + ref_start_time = ref->start_time_effective;
>>> } else {
>>> start_times_set = 0;
>>> }
>>> @@ -1918,8 +1931,6 @@ int ffmpeg_parse_options(int argc, char **argv)
>>> goto fail;
>>> }
>>> - apply_sync_offsets();
>>> -
>>> /* create the complex filtergraphs */
>>> ret = init_complex_filters();
>>> if (ret < 0) {
>>> @@ -1936,6 +1947,8 @@ int ffmpeg_parse_options(int argc, char **argv)
>>> correct_input_start_times();
>>> + apply_sync_offsets();
>>> +
>>> check_filter_outputs();
>>> fail:
>>
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