diff --git a/libavcodec/mpegvideo.h b/libavcodec/mpegvideo.h
index 023e657004458fb3c979dd5054de9dcfecb44033..d8eebc3bbfc10a0debaaa62f346d87c630922207 100644
--- a/libavcodec/mpegvideo.h
+++ b/libavcodec/mpegvideo.h
@@ -909,7 +909,11 @@ void mpeg4_pred_ac(MpegEncContext * s, DCTELEM *block, int n,
                    int dir);
 void ff_set_mpeg4_time(MpegEncContext * s, int picture_number);
 void mpeg4_encode_picture_header(MpegEncContext *s, int picture_number);
+#ifdef CONFIG_ENCODERS
 void h263_encode_init(MpegEncContext *s);
+#else
+static void h263_encode_init(MpegEncContext *s) {assert(0);}
+#endif
 void h263_decode_init_vlc(MpegEncContext *s);
 int h263_decode_picture_header(MpegEncContext *s);
 int ff_h263_decode_gob_header(MpegEncContext *s);
diff --git a/libavcodec/snow.h b/libavcodec/snow.h
index 26b30abe57aad6c2cfdb286b7540ef1b4dadfcdc..8dfabf563e080b9a795f9bce2a5c6ac6adf04c56 100644
--- a/libavcodec/snow.h
+++ b/libavcodec/snow.h
@@ -125,9 +125,13 @@ extern void ff_snow_vertical_compose97i(DWTELEM *b0, DWTELEM *b1, DWTELEM *b2, D
 extern void ff_snow_horizontal_compose97i(DWTELEM *b, int width);
 extern void ff_snow_inner_add_yblock(uint8_t *obmc, const int obmc_stride, uint8_t * * block, int b_w, int b_h, int src_x, int src_y, int src_stride, slice_buffer * sb, int add, uint8_t * dst8);
 
+#ifdef CONFIG_SNOW_ENCODER
 int w53_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h);
 int w97_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h);
-
+#else
+static int w53_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h) {assert (0);}
+static int w97_32_c(void *v, uint8_t * pix1, uint8_t * pix2, int line_size, int h) {assert (0);}
+#endif
 
 /* C bits used by mmx/sse2/altivec */