Check a return value for error.

diff --git a/src/lib/ffmpeg_file_encoder.cc b/src/lib/ffmpeg_file_encoder.cc
index 30dcdb94cc299b0031583eee5218a6de9c23a84a..32a0e0f8620f3741ab09bd6c7456305541692130 100644 (file)
--- a/src/lib/ffmpeg_file_encoder.cc
+++ b/src/lib/ffmpeg_file_encoder.cc
@@ -394,7 +394,8 @@ FFmpegFileEncoder::flush ()
                }
        }
 
-       av_write_trailer (_format_context);
+       auto const r = av_write_trailer(_format_context);
+       DCPOMATIC_ASSERT(r == 0);
 }