diff --git a/ffmpeg.c b/ffmpeg.c
index 59999b8c6f..af0a3cc78c 100644
--- a/ffmpeg.c
+++ b/ffmpeg.c
@@ -1292,6 +1292,7 @@ static int av_encode(AVFormatContext **output_files,
                         /* force the input stream PTS */
                         av_write_frame(os, ost->index, data_buf, data_size);
 			ost->st->codec.frame_number++;
+			ost->frame_number++;
                     }
                 }
             }