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Fix dithering for float to int case when float values are greater than 0db. Also made DITHER_LOOP macro more readable but did not change content

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mchinen 2012-02-05 10:31:18 +00:00
parent 07e3469c9e
commit 54f7e4590b
1 changed files with 17 additions and 4 deletions
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21
src/Dither.cpp
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@ -76,7 +76,13 @@ const float Dither::SHAPED_BS[] = { 2.033f, -2.165f, 1.959f, -1.590f, 0.6149f };
// Dereference sample pointer and convert to float sample
#define FROM_INT16(ptr) (*((short*)(ptr)) / CONVERT_DIV16)
#define FROM_INT24(ptr) (*(( int*)(ptr)) / CONVERT_DIV24)
#define FROM_FLOAT(ptr) (*((float*)(ptr)))
// For float, we internally allow values greater than 1.0, which
// would blow up the dithering to int values. FROM_FLOAT is
// only used to dither to int, so clip here.
#define FROM_FLOAT(ptr) (*((float*)(ptr)) > 1.0 ? 1.0 : \
*((float*)(ptr)) < -1.0 ? -1.0 : \
*((float*)(ptr)))
// Promote sample to range of specified type, keep it float, though
#define PROMOTE_TO_INT16(sample) ((sample) * CONVERT_DIV16)
@ -106,9 +112,16 @@ const float Dither::SHAPED_BS[] = { 2.033f, -2.165f, 1.959f, -1.590f, 0.6149f };
// Implement a dithering loop
// Note: The variable 'x' is needed for the STORE_... macros
#define DITHER_LOOP(dither, store, load, dst, dstFormat, src, srcFormat, len, stride) \
do { char *d, *s; unsigned int i; int x; for (d = (char*)dst, s = (char*)src, i = 0; i < len; \
i++, d += SAMPLE_SIZE(dstFormat), s += SAMPLE_SIZE(srcFormat) * stride) \
DITHER_STEP(dither, store, load, d, s); } while (0)
do { \
char *d, *s; \
unsigned int i; \
int x; \
for (d = (char*)dst, s = (char*)src, i = 0; \
i < len; \
i++, d += SAMPLE_SIZE(dstFormat), \
s += SAMPLE_SIZE(srcFormat) * stride) \
DITHER_STEP(dither, store, load, d, s); \
} while (0)
// Shortcuts to dithering loops
#define DITHER_INT24_TO_INT16(dither, dst, src, len, stride) \