sws: make dither_scale const

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswscale/swscale.c

@@ -271,7 +271,7 @@ DECLARE_ALIGNED(8, const uint8_t, dithers)[8][8][8]={
 
 static const uint8_t flat64[8]={64,64,64,64,64,64,64,64};
 
-uint16_t dither_scale[15][16]={
+const uint16_t dither_scale[15][16]={
 {    2,    3,    3,    5,    5,    5,    5,    5,    5,    5,    5,    5,    5,    5,    5,    5,},
 {    2,    3,    7,    7,   13,   13,   25,   25,   25,   25,   25,   25,   25,   25,   25,   25,},
 {    3,    3,    4,   15,   15,   29,   57,   57,   57,  113,  113,  113,  113,  113,  113,  113,},

libswscale/swscale_internal.h

@@ -498,7 +498,7 @@ const char *sws_format_name(enum PixelFormat format);
 extern const uint64_t ff_dither4[2];
 extern const uint64_t ff_dither8[2];
 extern const uint8_t dithers[8][8][8];
-extern uint16_t dither_scale[15][16];
+extern const uint16_t dither_scale[15][16];
 
 
 extern const AVClass sws_context_class;