ffmpeg: Use input packet duration in vfr/cfr code if available and valid

Fixes Ticket3052

1 files changed, 8 insertions, 0 deletions

diff --git a/ffmpeg.c b/ffmpeg.c
index 0f4b2aa254..3b24cf99da 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -893,6 +893,14 @@ static void do_video_out(AVFormatContext *s,
     if(ist && ist->st->start_time != AV_NOPTS_VALUE && ist->st->first_dts != AV_NOPTS_VALUE && ost->frame_rate.num)
         duration = 1/(av_q2d(ost->frame_rate) * av_q2d(enc->time_base));
 
+    if (!ost->filters_script &&
+        !ost->filters &&
+        next_picture &&
+        ist &&
+        lrintf(av_frame_get_pkt_duration(next_picture) * av_q2d(ist->st->time_base) / av_q2d(enc->time_base)) > 0) {
+        duration = lrintf(av_frame_get_pkt_duration(next_picture) * av_q2d(ist->st->time_base) / av_q2d(enc->time_base));
+    }
+
     sync_ipts = next_picture->pts;
     delta0 = sync_ipts - ost->sync_opts;
     delta  = delta0 + duration;