[FFmpeg-devel] [PATCH] fftools/ffmpeg: Fix EOF pts for libavfilter in send_filter_eof()

[Paul B Mahol]

On 9/11/22, Li-Heng Chen <lihengc at netflix.com> wrote:
> When input is video bitstream (e.g. *.264) with framerate set by -r,
> ist->pts could be a nonsense value.
>
> In libavfilter/vf_fps, the pts value of EOF from above is compared to pts
> derived from inlink. The wrong EOF pts may trigger a bug, where ffmpeg keeps
> writting the last video frame to the output. This bug can be easily
> reproduced by the ffmpeg cmd below (h264 bitstreams in fate-suite can
> reproduce this issue):
>
> ffmpeg -r num_in/den_in -i bitstream -vf fps=num_out/den_out -f rawvideo
> out.yuv
>
> Example: ffmpeg -r 24/1 -i fate-suite/h264/bbc2.sample.h264 -vf fps=24/1 -f
> rawvideo out.yuv
> Signed-off-by: Li-Heng Chen <lihengc at netflix.com>
> ---
> fftools/ffmpeg.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 0e1477299d..e9a986c95b 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -2383,6 +2383,9 @@ static int send_filter_eof(InputStream *ist)
>     int64_t pts = av_rescale_q_rnd(ist->pts, AV_TIME_BASE_Q,
> ist->st->time_base,
>                                    AV_ROUND_NEAR_INF |
> AV_ROUND_PASS_MINMAX);
>
> +    if(ist->framerate.num)
> +        pts = ist->cfr_next_pts;
> +

Style is wrong

>     for (i = 0; i < ist->nb_filters; i++) {
>         ret = ifilter_send_eof(ist->filters[i], pts);
>         if (ret < 0)
> --
> 2.32.1 (Apple Git-133)
>
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