avfilter/vf_fps: make sure the fifo is not empty before using it

Fixes Ticket2905

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit cdd5df8189ff1537f7abe8defe971f80602cc2d2)

Conflicts:

	libavfilter/vf_fps.c

1 files changed, 1 insertions, 1 deletions

diff --git a/libavfilter/vf_fps.c b/libavfilter/vf_fps.c
index d12070c49a..1be055b6b4 100644
--- a/libavfilter/vf_fps.c
+++ b/libavfilter/vf_fps.c
@@ -193,7 +193,7 @@ static void end_frame(AVFilterLink *inlink)
     }
 
     /* now wait for the next timestamp */
-    if (buf->pts == AV_NOPTS_VALUE) {
+    if (buf->pts == AV_NOPTS_VALUE || av_fifo_size(s->fifo) <= 0) {
         write_to_fifo(s->fifo, buf);
         return;
     }