On Sat, Mar 31, 2018 at 8:09 PM, Jan Ekström <jee...@gmail.com> wrote:
> With certain types of input and the filter chain getting re-initialized
> or re-configured, multiple nullptr AVSubtitles can get pushed into
> sub2video_update() in a row from sub2video_heartbeat.
>
> This causes end_pts, and on the next round pts, to become INT64_MAX,
> latter of which signals EOF in framesync, leading to complete loss of
> subtitles from that point on.
>
> Thus, check that the sub2video.end_pts is smaller than INT64_MAX
> in a similar fashion to sub2video_flush before sending out the
> nullptr AVSubtitle. This keeps premature EOFs from happening in
> framesync and the subtitle overlay is kept past the filter chain
> re-initializations/configurations.
> ---
> fftools/ffmpeg.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 4724f62fff..d3bc382dec 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -285,7 +285,8 @@ static void sub2video_heartbeat(InputStream *ist, int64_t
> pts)
> /* do not send the heartbeat frame if the subtitle is already ahead
> */
> if (pts2 <= ist2->sub2video.last_pts)
> continue;
> - if (pts2 >= ist2->sub2video.end_pts ||
> !ist2->sub2video.frame->data[0])
> + if (pts2 >= ist2->sub2video.end_pts ||
> + (!ist2->sub2video.frame->data[0] && ist2->sub2video.end_pts <
> INT64_MAX))
> sub2video_update(ist2, NULL);
> for (j = 0, nb_reqs = 0; j < ist2->nb_filters; j++)
> nb_reqs +=
> av_buffersrc_get_nb_failed_requests(ist2->filters[j]->filter);
> --
> 2.14.3
>
A diff which I utilized to help with testing this. I can share a
sample to test this over on IRC.
Jan
---
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -247,10 +247,17 @@ void sub2video_update(InputStream *ist, AVSubtitle *sub)
end_pts = av_rescale_q(sub->pts + sub->end_display_time * 1000LL,
AV_TIME_BASE_Q, ist->st->time_base);
num_rects = sub->num_rects;
+ av_log(ist->dec_ctx, AV_LOG_WARNING,
+ "normal AVSubtitle: utilized values: pts=%"PRId64",
end_pts=%"PRId64", "
+ "num_rects=%d\n",
+ pts, end_pts, num_rects);
} else {
pts = ist->sub2video.end_pts;
end_pts = INT64_MAX;
num_rects = 0;
+ av_log(ist->dec_ctx, AV_LOG_WARNING,
+ "nullptr AVSubtitle: utilized values: pts=%"PRId64",
end_pts=%"PRId64"\n",
+ pts, end_pts);
}
if (sub2video_get_blank_frame(ist) < 0) {
av_log(ist->dec_ctx, AV_LOG_ERROR,
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