diff --git a/libavformat/avidec.c b/libavformat/avidec.c
index fdd796c55a..e338ddbb7c 100644
--- a/libavformat/avidec.c
+++ b/libavformat/avidec.c
@@ -538,8 +538,8 @@ static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
                 get_le32(pb);
                 get_le32(pb);
 
-                active_aspect.num= get_le16(pb);
                 active_aspect.den= get_le16(pb);
+                active_aspect.num= get_le16(pb);
                 active.num       = get_le32(pb);
                 active.den       = get_le32(pb);
                 get_le32(pb); //nbFieldsPerFrame
diff --git a/libavformat/avienc.c b/libavformat/avienc.c
index 6e8901ea8e..35fee28ed4 100644
--- a/libavformat/avienc.c
+++ b/libavformat/avienc.c
@@ -297,8 +297,8 @@ static int avi_write_header(AVFormatContext *s)
             put_le32(pb, lrintf(1.0/av_q2d(stream->time_base)));
             put_le32(pb, stream->width );
             put_le32(pb, stream->height);
-            put_le16(pb, num);
             put_le16(pb, den);
+            put_le16(pb, num);
             put_le32(pb, stream->width );
             put_le32(pb, stream->height);
             put_le32(pb, 1); //progressive FIXME