diff --git a/libavcodec/dsputil.c b/libavcodec/dsputil.c
index 0500872036..a04b8a400a 100644
--- a/libavcodec/dsputil.c
+++ b/libavcodec/dsputil.c
@@ -3573,7 +3573,7 @@ static void diff_bytes_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w){
         dst[i+0] = src1[i+0]-src2[i+0];
 }
 
-static void add_hfyu_median_prediction_c(uint8_t *dst, const uint8_t *src1, uint8_t *diff, int w, int *left, int *left_top){
+static void add_hfyu_median_prediction_c(uint8_t *dst, const uint8_t *src1, const uint8_t *diff, int w, int *left, int *left_top){
     int i;
     uint8_t l, lt;
 
@@ -3590,7 +3590,7 @@ static void add_hfyu_median_prediction_c(uint8_t *dst, const uint8_t *src1, uint
     *left_top= lt;
 }
 
-static void sub_hfyu_median_prediction_c(uint8_t *dst, const uint8_t *src1, uint8_t *src2, int w, int *left, int *left_top){
+static void sub_hfyu_median_prediction_c(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, int w, int *left, int *left_top){
     int i;
     uint8_t l, lt;
 
diff --git a/libavcodec/dsputil.h b/libavcodec/dsputil.h
index ab791f53cb..c097461c4a 100644
--- a/libavcodec/dsputil.h
+++ b/libavcodec/dsputil.h
@@ -347,8 +347,8 @@ typedef struct DSPContext {
      * subtract huffyuv's variant of median prediction
      * note, this might read from src1[-1], src2[-1]
      */
-    void (*sub_hfyu_median_prediction)(uint8_t *dst, const uint8_t *src1, uint8_t *src2, int w, int *left, int *left_top);
-    void (*add_hfyu_median_prediction)(uint8_t *dst, const uint8_t *top, uint8_t *diff, int w, int *left, int *left_top);
+    void (*sub_hfyu_median_prediction)(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, int w, int *left, int *left_top);
+    void (*add_hfyu_median_prediction)(uint8_t *dst, const uint8_t *top, const uint8_t *diff, int w, int *left, int *left_top);
     int  (*add_hfyu_left_prediction)(uint8_t *dst, const uint8_t *src, int w, int left);
     void (*add_hfyu_left_prediction_bgr32)(uint8_t *dst, const uint8_t *src, int w, int *red, int *green, int *blue);
     /* this might write to dst[w] */
diff --git a/libavcodec/x86/dsputil_mmx.c b/libavcodec/x86/dsputil_mmx.c
index 3f6f1dae6b..af33707df0 100644
--- a/libavcodec/x86/dsputil_mmx.c
+++ b/libavcodec/x86/dsputil_mmx.c
@@ -597,7 +597,7 @@ static void add_bytes_l2_mmx(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w){
 }
 
 #if HAVE_7REGS && HAVE_TEN_OPERANDS
-static void add_hfyu_median_prediction_cmov(uint8_t *dst, uint8_t *top, uint8_t *diff, int w, int *left, int *left_top) {
+static void add_hfyu_median_prediction_cmov(uint8_t *dst, const uint8_t *top, const uint8_t *diff, int w, int *left, int *left_top) {
     x86_reg w2 = -w;
     x86_reg x;
     int l = *left & 0xff;
@@ -2384,9 +2384,9 @@ static void float_to_int16_sse2(int16_t *dst, const float *src, long len){
 void ff_float_to_int16_interleave6_sse(int16_t *dst, const float **src, int len);
 void ff_float_to_int16_interleave6_3dnow(int16_t *dst, const float **src, int len);
 void ff_float_to_int16_interleave6_3dn2(int16_t *dst, const float **src, int len);
-void ff_add_hfyu_median_prediction_mmx2(uint8_t *dst, uint8_t *top, uint8_t *diff, int w, int *left, int *left_top);
-int  ff_add_hfyu_left_prediction_ssse3(uint8_t *dst, uint8_t *src, int w, int left);
-int  ff_add_hfyu_left_prediction_sse4(uint8_t *dst, uint8_t *src, int w, int left);
+void ff_add_hfyu_median_prediction_mmx2(uint8_t *dst, const uint8_t *top, const uint8_t *diff, int w, int *left, int *left_top);
+int  ff_add_hfyu_left_prediction_ssse3(uint8_t *dst, const uint8_t *src, int w, int left);
+int  ff_add_hfyu_left_prediction_sse4(uint8_t *dst, const uint8_t *src, int w, int left);
 void ff_x264_deblock_v_luma_sse2(uint8_t *pix, int stride, int alpha, int beta, int8_t *tc0);
 void ff_x264_deblock_h_luma_sse2(uint8_t *pix, int stride, int alpha, int beta, int8_t *tc0);
 void ff_x264_deblock_v8_luma_intra_mmxext(uint8_t *pix, int stride, int alpha, int beta);
diff --git a/libavcodec/x86/dsputil_yasm.asm b/libavcodec/x86/dsputil_yasm.asm
index d071186f5c..c3a23a9cb2 100644
--- a/libavcodec/x86/dsputil_yasm.asm
+++ b/libavcodec/x86/dsputil_yasm.asm
@@ -99,7 +99,7 @@ FLOAT_TO_INT16_INTERLEAVE6 3dn2
 
 
 
-; void ff_add_hfyu_median_prediction_mmx2(uint8_t *dst, uint8_t *top, uint8_t *diff, int w, int *left, int *left_top)
+; void ff_add_hfyu_median_prediction_mmx2(uint8_t *dst, const uint8_t *top, const uint8_t *diff, int w, int *left, int *left_top)
 cglobal add_hfyu_median_prediction_mmx2, 6,6,0, dst, top, diff, w, left, left_top
     movq    mm0, [topq]
     movq    mm2, mm0
@@ -197,7 +197,7 @@ cglobal add_hfyu_median_prediction_mmx2, 6,6,0, dst, top, diff, w, left, left_to
     RET
 %endmacro
 
-; int ff_add_hfyu_left_prediction(uint8_t *dst, uint8_t *src, int w, int left)
+; int ff_add_hfyu_left_prediction(uint8_t *dst, const uint8_t *src, int w, int left)
 INIT_MMX
 cglobal add_hfyu_left_prediction_ssse3, 3,3,7, dst, src, w, left
 .skip_prologue:
diff --git a/libavcodec/x86/dsputilenc_mmx.c b/libavcodec/x86/dsputilenc_mmx.c
index a7fafe0605..3ee2c38d00 100644
--- a/libavcodec/x86/dsputilenc_mmx.c
+++ b/libavcodec/x86/dsputilenc_mmx.c
@@ -902,7 +902,7 @@ static void diff_bytes_mmx(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w){
         dst[i+0] = src1[i+0]-src2[i+0];
 }
 
-static void sub_hfyu_median_prediction_mmx2(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w, int *left, int *left_top){
+static void sub_hfyu_median_prediction_mmx2(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, int w, int *left, int *left_top){
     x86_reg i=0;
     uint8_t l, lt;