diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index a09bebd57c..87a5e7cf00 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -1328,7 +1328,7 @@ static int avi_read_idx1(AVFormatContext *s, int size)
         st = s->streams[index];
         ast = st->priv_data;
 
-        if(first_packet && first_packet_pos && len) {
+        if (first_packet && first_packet_pos) {
             data_offset = first_packet_pos - pos;
             first_packet = 0;
         }