diff --git a/libavformat/yop.c b/libavformat/yop.c
index 8f140ce..8498c74 100644
--- a/libavformat/yop.c
+++ b/libavformat/yop.c
@@ -105,6 +105,8 @@ static int yop_read_header(AVFormatContext *s)
 
     yop->palette_size       = video_dec->extradata[0] * 3 + 4;
     yop->audio_block_length = AV_RL16(video_dec->extradata + 6);
+    
+    video_dec->bit_rate     = 8 * (yop->frame_size - yop->audio_block_length) * frame_rate;
 
     // 1840 samples per frame, 1 nibble per sample; hence 1840/2 = 920
     if (yop->audio_block_length < 920 ||