diff --git a/libavfilter/gradfun.h b/libavfilter/gradfun.h
index 3dacbcb252..3c01085b83 100644
--- a/libavfilter/gradfun.h
+++ b/libavfilter/gradfun.h
@@ -33,16 +33,16 @@ typedef struct {
     int chroma_r;  ///< blur radius for the chroma planes
     uint16_t *buf; ///< holds image data for blur algorithm passed into filter.
     /// DSP functions.
-    void (*filter_line) (uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers);
-    void (*blur_line) (uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width);
+    void (*filter_line) (uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers);
+    void (*blur_line) (uint16_t *dc, uint16_t *buf, const uint16_t *buf1, const uint8_t *src, int src_linesize, int width);
 } GradFunContext;
 
-void ff_gradfun_filter_line_c(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers);
-void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width);
+void ff_gradfun_filter_line_c(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers);
+void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, const uint16_t *buf1, const uint8_t *src, int src_linesize, int width);
 
-void ff_gradfun_filter_line_mmx2(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers);
-void ff_gradfun_filter_line_ssse3(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers);
+void ff_gradfun_filter_line_mmx2(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers);
+void ff_gradfun_filter_line_ssse3(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers);
 
-void ff_gradfun_blur_line_sse2(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width);
+void ff_gradfun_blur_line_sse2(uint16_t *dc, uint16_t *buf, const uint16_t *buf1, const uint8_t *src, int src_linesize, int width);
 
 #endif /* AVFILTER_GRADFUN_H */
diff --git a/libavfilter/vf_gradfun.c b/libavfilter/vf_gradfun.c
index 83ed3d79e4..32dd3c1072 100644
--- a/libavfilter/vf_gradfun.c
+++ b/libavfilter/vf_gradfun.c
@@ -49,7 +49,7 @@ DECLARE_ALIGNED(16, static const uint16_t, dither)[8][8] = {
     {0x54,0x34,0x4C,0x2C,0x52,0x32,0x4A,0x2A},
 };
 
-void ff_gradfun_filter_line_c(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers)
+void ff_gradfun_filter_line_c(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers)
 {
     int x;
     for (x = 0; x < width; x++, dc += x & 1) {
@@ -63,7 +63,7 @@ void ff_gradfun_filter_line_c(uint8_t *dst, uint8_t *src, uint16_t *dc, int widt
     }
 }
 
-void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width)
+void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, const uint16_t *buf1, const uint8_t *src, int src_linesize, int width)
 {
     int x, v, old;
     for (x = 0; x < width; x++) {
@@ -74,7 +74,7 @@ void ff_gradfun_blur_line_c(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t
     }
 }
 
-static void filter(GradFunContext *ctx, uint8_t *dst, uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r)
+static void filter(GradFunContext *ctx, uint8_t *dst, const uint8_t *src, int width, int height, int dst_linesize, int src_linesize, int r)
 {
     int bstride = FFALIGN(width, 16) / 2;
     int y;
diff --git a/libavfilter/vf_unsharp.c b/libavfilter/vf_unsharp.c
index 7aa7a43651..fa75de5d94 100644
--- a/libavfilter/vf_unsharp.c
+++ b/libavfilter/vf_unsharp.c
@@ -63,7 +63,7 @@ typedef struct {
     FilterParam chroma; ///< chroma parameters (width, height, amount)
 } UnsharpContext;
 
-static void unsharpen(uint8_t *dst, uint8_t *src, int dst_stride, int src_stride, int width, int height, FilterParam *fp)
+static void unsharpen(uint8_t *dst, const uint8_t *src, int dst_stride, int src_stride, int width, int height, FilterParam *fp)
 {
     uint32_t **sc = fp->sc;
     uint32_t sr[(MAX_SIZE * MAX_SIZE) - 1], tmp1, tmp2;
@@ -96,7 +96,7 @@ static void unsharpen(uint8_t *dst, uint8_t *src, int dst_stride, int src_stride
                 tmp1 = sc[z + 1][x + fp->steps_x] + tmp2; sc[z + 1][x + fp->steps_x] = tmp2;
             }
             if (x >= fp->steps_x && y >= fp->steps_y) {
-                uint8_t* srx = src - fp->steps_y * src_stride + x - fp->steps_x;
+                const uint8_t* srx = src - fp->steps_y * src_stride + x - fp->steps_x;
                 uint8_t* dsx = dst - fp->steps_y * dst_stride + x - fp->steps_x;
 
                 res = (int32_t)*srx + ((((int32_t) * srx - (int32_t)((tmp1 + fp->halfscale) >> fp->scalebits)) * fp->amount) >> 16);
diff --git a/libavfilter/x86/gradfun.c b/libavfilter/x86/gradfun.c
index 894a44b9ff..05d4a6fd6e 100644
--- a/libavfilter/x86/gradfun.c
+++ b/libavfilter/x86/gradfun.c
@@ -23,7 +23,7 @@
 DECLARE_ALIGNED(16, static const uint16_t, pw_7f)[8] = {0x7F,0x7F,0x7F,0x7F,0x7F,0x7F,0x7F,0x7F};
 DECLARE_ALIGNED(16, static const uint16_t, pw_ff)[8] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
 
-void ff_gradfun_filter_line_mmx2(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers)
+void ff_gradfun_filter_line_mmx2(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers)
 {
 #if HAVE_MMX
     intptr_t x;
@@ -71,7 +71,7 @@ void ff_gradfun_filter_line_mmx2(uint8_t *dst, uint8_t *src, uint16_t *dc, int w
 #endif
 }
 
-void ff_gradfun_filter_line_ssse3(uint8_t *dst, uint8_t *src, uint16_t *dc, int width, int thresh, const uint16_t *dithers)
+void ff_gradfun_filter_line_ssse3(uint8_t *dst, const uint8_t *src, const uint16_t *dc, int width, int thresh, const uint16_t *dithers)
 {
 #if HAVE_SSSE3
     intptr_t x;
@@ -118,7 +118,7 @@ void ff_gradfun_filter_line_ssse3(uint8_t *dst, uint8_t *src, uint16_t *dc, int
 #endif // HAVE_SSSE3
 }
 
-void ff_gradfun_blur_line_sse2(uint16_t *dc, uint16_t *buf, uint16_t *buf1, uint8_t *src, int src_linesize, int width)
+void ff_gradfun_blur_line_sse2(uint16_t *dc, uint16_t *buf, const uint16_t *buf1, const uint8_t *src, int src_linesize, int width)
 {
 #if HAVE_SSE
 #define BLURV(load)\
diff --git a/libavformat/mmst.c b/libavformat/mmst.c
index 7b0af6c320..a3db288b35 100644
--- a/libavformat/mmst.c
+++ b/libavformat/mmst.c
@@ -152,7 +152,7 @@ static int send_command_packet(MMSTContext *mmst)
     return 0;
 }
 
-static void mms_put_utf16(MMSContext *mms, uint8_t *src)
+static void mms_put_utf16(MMSContext *mms, const uint8_t *src)
 {
     AVIOContext bic;
     int size = mms->write_out_ptr - mms->out_buffer;
diff --git a/libavformat/mov.c b/libavformat/mov.c
index a41b8ce73d..26e7a3a2df 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1689,13 +1689,13 @@ static void mov_build_index(MOVContext *mov, AVStream *st)
     }
 }
 
-static int mov_open_dref(AVIOContext **pb, char *src, MOVDref *ref)
+static int mov_open_dref(AVIOContext **pb, const char *src, MOVDref *ref)
 {
     /* try relative path, we do not try the absolute because it can leak information about our
        system to an attacker */
     if (ref->nlvl_to > 0 && ref->nlvl_from > 0) {
         char filename[1024];
-        char *src_path;
+        const char *src_path;
         int i, l;
 
         /* find a source dir */