[FFmpeg-cvslog] ffmpeg: Use filter graph output frame rate also for frame duration estimation

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Fri Jan 16 20:15:15 2015 +0100| [d3d9a00bcdfd5fc81d4640489555a3a41c82b303] | committer: Michael Niedermayer

ffmpeg: Use filter graph output frame rate also for frame duration estimation

Previously the duration was sometimes wrong, this addition
limits the value and improves which frames are choosen when
reducing the frame rate

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=d3d9a00bcdfd5fc81d4640489555a3a41c82b303
---

 ffmpeg.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/ffmpeg.c b/ffmpeg.c
index 909dd68..0a39274 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -895,6 +895,7 @@ static void do_video_out(AVFormatContext *s,
     double duration = 0;
     int frame_size = 0;
     InputStream *ist = NULL;
+    AVFilterContext *filter = ost->filter->filter;
 
     if (ost->source_index >= 0)
         ist = input_streams[ost->source_index];
@@ -902,6 +903,13 @@ 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));
 
+    // We take the conservative approuch here and take the minimum even though
+    // this should be correct on its own but a value too small is harmless, one
+    // too big can lead to errors
+    if (filter->inputs[0]->frame_rate.num > 0 &&
+        filter->inputs[0]->frame_rate.den > 0)
+        duration = FFMIN(duration, 1/(av_q2d(filter->inputs[0]->frame_rate) * av_q2d(enc->time_base)));
+
     if (!ost->filters_script &&
         !ost->filters &&
         next_picture &&