diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index 78e5051e1e..74edebf41c 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -780,7 +780,7 @@ resync:
             else
                 ast->frame_offset++;
         }
-        ast->remaining -= size;
+        ast->remaining -= err;
         if(!ast->remaining){
             avi->stream_index= -1;
             ast->packet_size= 0;