[FFmpeg-devel] [PATCH v2 2/2] ffmpeg: fix implementation of updated input start time
Gyan Doshi
ffmpeg at gyani.pro
Thu Nov 3 11:27:49 EET 2022
Pushed as
93faba449c0dc9d953d9aeb381f03728ff66e2cb..5ccd4d306054cec839e9078203a3b3892a3372a2
On 2022-11-01 07:18 pm, Gyan Doshi wrote:
> 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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