ffmpeg: check for unconnected outputs

Fixes e.g.:

ffmpeg -f lavfi -i testsrc -f lavfi -i testsrc -filter_complex "[0:v][1:v]psnr[out]" -f null none

1 files changed, 1 insertions, 0 deletions

diff --git a/ffmpeg.h b/ffmpeg.h
index 4d0456c1fb..d34561275a 100644
--- a/ffmpeg.h
+++ b/ffmpeg.h
@@ -638,6 +638,7 @@ void choose_sample_fmt(AVStream *st, AVCodec *codec);
 
 int configure_filtergraph(FilterGraph *fg);
 int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out);
+void check_filter_outputs(void);
 int ist_in_filtergraph(FilterGraph *fg, InputStream *ist);
 int filtergraph_is_simple(FilterGraph *fg);
 int init_simple_filtergraph(InputStream *ist, OutputStream *ost);