diff --git a/libswresample/rematrix.c b/libswresample/rematrix.c
index 5929ae4098..ed2d9fd883 100644
--- a/libswresample/rematrix.c
+++ b/libswresample/rematrix.c
@@ -494,13 +494,13 @@ av_cold int swri_rematrix_init(SwrContext *s){
         }
         *((int*)s->native_one) = 32768;
         if (maxsum <= 32768) {
-            s->mix_1_1_f = (mix_1_1_func_type*)copy_s16;
-            s->mix_2_1_f = (mix_2_1_func_type*)sum2_s16;
-            s->mix_any_f = (mix_any_func_type*)get_mix_any_func_s16(s);
+            s->mix_1_1_f = copy_s16;
+            s->mix_2_1_f = sum2_s16;
+            s->mix_any_f = get_mix_any_func_s16(s);
         } else {
-            s->mix_1_1_f = (mix_1_1_func_type*)copy_clip_s16;
-            s->mix_2_1_f = (mix_2_1_func_type*)sum2_clip_s16;
-            s->mix_any_f = (mix_any_func_type*)get_mix_any_func_clip_s16(s);
+            s->mix_1_1_f = copy_clip_s16;
+            s->mix_2_1_f = sum2_clip_s16;
+            s->mix_any_f = get_mix_any_func_clip_s16(s);
         }
     }else if(s->midbuf.fmt == AV_SAMPLE_FMT_FLTP){
         s->native_matrix = av_calloc(nb_in * nb_out, sizeof(float));
@@ -511,9 +511,9 @@ av_cold int swri_rematrix_init(SwrContext *s){
             for (j = 0; j < nb_in; j++)
                 ((float*)s->native_matrix)[i * nb_in + j] = s->matrix[i][j];
         *((float*)s->native_one) = 1.0;
-        s->mix_1_1_f = (mix_1_1_func_type*)copy_float;
-        s->mix_2_1_f = (mix_2_1_func_type*)sum2_float;
-        s->mix_any_f = (mix_any_func_type*)get_mix_any_func_float(s);
+        s->mix_1_1_f = copy_float;
+        s->mix_2_1_f = sum2_float;
+        s->mix_any_f = get_mix_any_func_float(s);
     }else if(s->midbuf.fmt == AV_SAMPLE_FMT_DBLP){
         s->native_matrix = av_calloc(nb_in * nb_out, sizeof(double));
         s->native_one    = av_mallocz(sizeof(double));
@@ -523,9 +523,9 @@ av_cold int swri_rematrix_init(SwrContext *s){
             for (j = 0; j < nb_in; j++)
                 ((double*)s->native_matrix)[i * nb_in + j] = s->matrix[i][j];
         *((double*)s->native_one) = 1.0;
-        s->mix_1_1_f = (mix_1_1_func_type*)copy_double;
-        s->mix_2_1_f = (mix_2_1_func_type*)sum2_double;
-        s->mix_any_f = (mix_any_func_type*)get_mix_any_func_double(s);
+        s->mix_1_1_f = copy_double;
+        s->mix_2_1_f = sum2_double;
+        s->mix_any_f = get_mix_any_func_double(s);
     }else if(s->midbuf.fmt == AV_SAMPLE_FMT_S32P){
         s->native_one    = av_mallocz(sizeof(int));
         if (!s->native_one)
@@ -545,9 +545,9 @@ av_cold int swri_rematrix_init(SwrContext *s){
             }
         }
         *((int*)s->native_one) = 32768;
-        s->mix_1_1_f = (mix_1_1_func_type*)copy_s32;
-        s->mix_2_1_f = (mix_2_1_func_type*)sum2_s32;
-        s->mix_any_f = (mix_any_func_type*)get_mix_any_func_s32(s);
+        s->mix_1_1_f = copy_s32;
+        s->mix_2_1_f = sum2_s32;
+        s->mix_any_f = get_mix_any_func_s32(s);
     }else
         av_assert0(0);
     //FIXME quantize for integeres
diff --git a/libswresample/rematrix_template.c b/libswresample/rematrix_template.c
index d4726c4dbb..62ba3e53bf 100644
--- a/libswresample/rematrix_template.c
+++ b/libswresample/rematrix_template.c
@@ -49,9 +49,12 @@
 #    define RENAME(x) x ## _s32
 #endif
 
-typedef void (RENAME(mix_any_func_type))(SAMPLE **out, const SAMPLE **in1, COEFF *coeffp, integer len);
-
-static void RENAME(sum2)(SAMPLE *out, const SAMPLE *in1, const SAMPLE *in2, COEFF *coeffp, integer index1, integer index2, integer len){
+static void RENAME(sum2)(void *out_, const void *in1_, const void *in2_,
+                         void *coeffp_, integer index1, integer index2, integer len)
+{
+    const SAMPLE *in1 = in1_, *in2 = in2_;
+    const COEFF *coeffp = coeffp_;
+    SAMPLE *out = out_;
     int i;
     INTER coeff1 = coeffp[index1];
     INTER coeff2 = coeffp[index2];
@@ -60,14 +63,22 @@ static void RENAME(sum2)(SAMPLE *out, const SAMPLE *in1, const SAMPLE *in2, COEF
         out[i] = R(coeff1*in1[i] + coeff2*in2[i]);
 }
 
-static void RENAME(copy)(SAMPLE *out, const SAMPLE *in, COEFF *coeffp, integer index, integer len){
+static void RENAME(copy)(void *out_, const void *in_, void *coeffp_, integer index, integer len)
+{
+    const COEFF *coeffp = coeffp_;
+    const SAMPLE *in = in_;
+    SAMPLE *out = out_;
     int i;
     INTER coeff = coeffp[index];
     for(i=0; i<len; i++)
         out[i] = R(coeff*in[i]);
 }
 
-static void RENAME(mix6to2)(SAMPLE **out, const SAMPLE **in, COEFF *coeffp, integer len){
+static void RENAME(mix6to2)(uint8_t **out_, const uint8_t **in_, void *coeffp_, integer len)
+{
+    const SAMPLE *const *const in = (const SAMPLE *const *)in_;
+    SAMPLE *const *const out = (SAMPLE *const*)out_;
+    const COEFF *coeffp = coeffp_;
     int i;
 
     for(i=0; i<len; i++) {
@@ -77,7 +88,11 @@ static void RENAME(mix6to2)(SAMPLE **out, const SAMPLE **in, COEFF *coeffp, inte
     }
 }
 
-static void RENAME(mix8to2)(SAMPLE **out, const SAMPLE **in, COEFF *coeffp, integer len){
+static void RENAME(mix8to2)(uint8_t **out_, const uint8_t **in_, void *coeffp_, integer len)
+{
+    const SAMPLE *const *const in = (const SAMPLE *const *)in_;
+    SAMPLE *const *const out = (SAMPLE *const*)out_;
+    const COEFF *coeffp = coeffp_;
     int i;
 
     for(i=0; i<len; i++) {
@@ -87,7 +102,8 @@ static void RENAME(mix8to2)(SAMPLE **out, const SAMPLE **in, COEFF *coeffp, inte
     }
 }
 
-static RENAME(mix_any_func_type) *RENAME(get_mix_any_func)(SwrContext *s){
+static mix_any_func_type *RENAME(get_mix_any_func)(SwrContext *s)
+{
     if (  !av_channel_layout_compare(&s->out_ch_layout, &(AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO)
        && (   !av_channel_layout_compare(&s->in_ch_layout, &(AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT1)
            || !av_channel_layout_compare(&s->in_ch_layout, &(AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT1_BACK))