diff --git a/libavcodec/bmp.c b/libavcodec/bmp.c
index f286aebecf..e621c68ea9 100644
--- a/libavcodec/bmp.c
+++ b/libavcodec/bmp.c
@@ -1,5 +1,5 @@
 /*
- * BMP image format
+ * BMP image format decoder
  * Copyright (c) 2005 Mans Rullgard
  *
  * This file is part of FFmpeg.
@@ -22,17 +22,7 @@
 #include "avcodec.h"
 #include "bitstream.h"
 #include "bswap.h"
-
-typedef struct BMPContext {
-    AVFrame picture;
-} BMPContext;
-
-typedef enum {
-    BMP_RGB         =0,
-    BMP_RLE8        =1,
-    BMP_RLE4        =2,
-    BMP_BITFIELDS   =3,
-} BiCompression;
+#include "bmp.h"
 
 #define read16(bits) bswap_16(get_bits(bits, 16))
 #define read32(bits) bswap_32(get_bits_long(bits, 32))
diff --git a/libavcodec/bmp.h b/libavcodec/bmp.h
new file mode 100644
index 0000000000..cf6ace8451
--- /dev/null
+++ b/libavcodec/bmp.h
@@ -0,0 +1,31 @@
+/*
+ * internals for BMP codecs
+ * Copyright (c) 2005 Mans Rullgard
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+typedef struct BMPContext {
+    AVFrame picture;
+} BMPContext;
+
+typedef enum {
+    BMP_RGB         =0,
+    BMP_RLE8        =1,
+    BMP_RLE4        =2,
+    BMP_BITFIELDS   =3,
+} BiCompression;