[FFmpeg-devel] [PATCH] avformat/demux: in case of no timestamps, calculate dts based on previous dts and duration

["zhilizhao(赵志立)"]

> On May 5, 2023, at 19:31, Jan Ekström <jeebjp at gmail.com> wrote:
> 
> From: Martin Machalek <martin.machalek at 24i.com>
> 
> Adds DTS to packets which would otherwise break tbr calculation
> within libavformat, as well as packet rate calculation in ffmpeg.
> 
> An example of such input would be an MPEG-TS stream where a whole
> GOP is put into a single PES packet.
> 
> Co-authored-by: Jan Ekström <jan.ekstrom at 24i.com>
> 
> Signed-off-by: Jan Ekström <jan.ekstrom at 24i.com>
> ---
> libavformat/demux.c | 5 +++++
> 1 file changed, 5 insertions(+)
> 
> diff --git a/libavformat/demux.c b/libavformat/demux.c
> index 06de71cd6e..9a4ab28679 100644
> --- a/libavformat/demux.c
> +++ b/libavformat/demux.c
> @@ -1098,6 +1098,11 @@ static void compute_pkt_fields(AVFormatContext *s, AVStream *st,
>     if (!onein_oneout)
>         // This should happen on the first packet
>         update_initial_timestamps(s, pkt->stream_index, pkt->dts, pkt->pts, pkt);
> +
> +    if (pkt->dts == AV_NOPTS_VALUE && !is_relative(sti->cur_dts) &&
> +        sti->cur_dts != AV_NOPTS_VALUE && pkt->duration > 0)
> +        pkt->dts = sti->cur_dts + pkt->duration;
> +

It’s possible that the next dts < pkt->dts, how to prevent non-monotonic increasing?

>     if (pkt->dts > sti->cur_dts)
>         sti->cur_dts = pkt->dts;
> 
> -- 
> 2.40.1
> 
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