[FFmpeg-devel] [PATCH 2/4] ffmpeg: use reordered duration for stream PTS.

[Hendrik Leppkes]

On Thu, Apr 6, 2017 at 10:44 AM, Nicolas George <george at nsup.org> wrote:
> Signed-off-by: Nicolas George <george at nsup.org>
> ---
>  ffmpeg.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
>
> Unchanged. Necessary for the next patches.
>
>
> diff --git a/ffmpeg.c b/ffmpeg.c
> index 4db8ea82ac..41f1f076ca 100644
> --- a/ffmpeg.c
> +++ b/ffmpeg.c
> @@ -2357,7 +2357,7 @@ static int decode_audio(InputStream *ist, AVPacket *pkt, int *got_output,
>      return err < 0 ? err : ret;
>  }
>
> -static int decode_video(InputStream *ist, AVPacket *pkt, int *got_output, int eof,
> +static int decode_video(InputStream *ist, AVPacket *pkt, int *got_output, int *duration_pts, int eof,
>                          int *decode_failed)
>  {
>      AVFrame *decoded_frame;
> @@ -2448,6 +2448,7 @@ static int decode_video(InputStream *ist, AVPacket *pkt, int *got_output, int eo
>      ist->hwaccel_retrieved_pix_fmt = decoded_frame->format;
>
>      best_effort_timestamp= av_frame_get_best_effort_timestamp(decoded_frame);
> +    *duration_pts = decoded_frame->pkt_duration;
>
>      if (ist->framerate.num)
>          best_effort_timestamp = ist->cfr_next_pts++;
> @@ -2618,6 +2619,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
>      // while we have more to decode or while the decoder did output something on EOF
>      while (ist->decoding_needed) {
>          int duration_dts = 0;
> +        int duration_pts = 0;
>          int got_output = 0;
>          int decode_failed = 0;
>
> @@ -2630,7 +2632,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
>                                     &decode_failed);
>              break;
>          case AVMEDIA_TYPE_VIDEO:
> -            ret = decode_video    (ist, repeating ? NULL : &avpkt, &got_output, !pkt,
> +            ret = decode_video    (ist, repeating ? NULL : &avpkt, &got_output, &duration_pts, !pkt,
>                                     &decode_failed);
>              if (!repeating || !pkt || got_output) {
>                  if (pkt && pkt->duration) {
> @@ -2649,7 +2651,7 @@ static int process_input_packet(InputStream *ist, const AVPacket *pkt, int no_eo
>              }
>
>              if (got_output)
> -                ist->next_pts += duration_dts; //FIXME the duration is not correct in some cases
> +                ist->next_pts += av_rescale_q(duration_pts, ist->st->time_base, AV_TIME_BASE_Q);
>              break;
>          case AVMEDIA_TYPE_SUBTITLE:
>              if (repeating)
> --
> 2.11.0
>

As was pointed out before, pkt_duration is often missing or incorrect.
At the very last falling back to the old logic if its unset seems
sensible.

- Hendrik