[FFmpeg-devel] [PATCH 25/29] fftools/ffmpeg_demux: set the timebase on demuxed packets

[James Almer]

On 4/9/2023 11:08 AM, Anton Khirnov wrote:
> Simplifies tracking what timebase are the timestamps in. Will be useful
> in following commits.
> ---
>   fftools/ffmpeg_demux.c | 16 +++++++++-------
>   1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/fftools/ffmpeg_demux.c b/fftools/ffmpeg_demux.c
> index f2da0826ad..7ff57273c9 100644
> --- a/fftools/ffmpeg_demux.c
> +++ b/fftools/ffmpeg_demux.c
> @@ -194,15 +194,17 @@ static void ts_fixup(Demuxer *d, AVPacket *pkt, int *repeat_pict)
>       const int64_t start_time = ifile->start_time_effective;
>       int64_t duration;
>   
> +    pkt->time_base = ist->st->time_base;

Might be a good future-proof idea to check first if pkt->time_base is 
already set or not. The doxy says demuxers themselves may start doing so 
at some point.

> +
>   #define SHOW_TS_DEBUG(tag_)                                             \
>       if (debug_ts) {                                                     \
>           av_log(ist, AV_LOG_INFO, "%s -> ist_index:%d:%d type:%s "       \
>                  "pkt_pts:%s pkt_pts_time:%s pkt_dts:%s pkt_dts_time:%s duration:%s duration_time:%s\n", \
>                  tag_, ifile->index, pkt->stream_index,                   \
>                  av_get_media_type_string(ist->st->codecpar->codec_type), \
> -               av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &ist->st->time_base), \
> -               av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &ist->st->time_base), \
> -               av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, &ist->st->time_base)); \
> +               av_ts2str(pkt->pts), av_ts2timestr(pkt->pts, &pkt->time_base), \
> +               av_ts2str(pkt->dts), av_ts2timestr(pkt->dts, &pkt->time_base), \
> +               av_ts2str(pkt->duration), av_ts2timestr(pkt->duration, &pkt->time_base)); \
>       }
>   
>       SHOW_TS_DEBUG("demuxer");
> @@ -211,7 +213,7 @@ static void ts_fixup(Demuxer *d, AVPacket *pkt, int *repeat_pict)
>           ist->st->pts_wrap_bits < 64) {
>           int64_t stime, stime2;
>   
> -        stime = av_rescale_q(start_time, AV_TIME_BASE_Q, ist->st->time_base);
> +        stime = av_rescale_q(start_time, AV_TIME_BASE_Q, pkt->time_base);
>           stime2= stime + (1ULL<<ist->st->pts_wrap_bits);
>           ist->wrap_correction_done = 1;
>   
> @@ -226,16 +228,16 @@ static void ts_fixup(Demuxer *d, AVPacket *pkt, int *repeat_pict)
>       }
>   
>       if (pkt->dts != AV_NOPTS_VALUE)
> -        pkt->dts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, ist->st->time_base);
> +        pkt->dts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, pkt->time_base);
>       if (pkt->pts != AV_NOPTS_VALUE)
> -        pkt->pts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, ist->st->time_base);
> +        pkt->pts += av_rescale_q(ifile->ts_offset, AV_TIME_BASE_Q, pkt->time_base);
>   
>       if (pkt->pts != AV_NOPTS_VALUE)
>           pkt->pts *= ds->ts_scale;
>       if (pkt->dts != AV_NOPTS_VALUE)
>           pkt->dts *= ds->ts_scale;
>   
> -    duration = av_rescale_q(d->duration, d->time_base, ist->st->time_base);
> +    duration = av_rescale_q(d->duration, d->time_base, pkt->time_base);
>       if (pkt->pts != AV_NOPTS_VALUE) {
>           pkt->pts += duration;
>           ds->max_pts = FFMAX(pkt->pts, ds->max_pts);