74 lines
2.1 KiB
C++
74 lines
2.1 KiB
C++
#include "pfc.h"
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namespace pfc {
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audio_sample audio_math::decodeFloat24ptr(const void * sourcePtr) {
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PFC_STATIC_ASSERT(pfc::byte_order_is_little_endian);
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union {
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uint8_t bytes[4];
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float v;
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} u;
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const uint8_t * s = reinterpret_cast<const uint8_t*>(sourcePtr);
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u.bytes[0] = 0;
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u.bytes[1] = s[0];
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u.bytes[2] = s[1];
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u.bytes[3] = s[2];
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return u.v;
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}
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audio_sample audio_math::decodeFloat24ptrbs(const void * sourcePtr) {
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PFC_STATIC_ASSERT(pfc::byte_order_is_little_endian);
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union {
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uint8_t bytes[4];
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float v;
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} u;
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const uint8_t * s = reinterpret_cast<const uint8_t*>(sourcePtr);
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u.bytes[0] = 0;
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u.bytes[1] = s[2];
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u.bytes[2] = s[1];
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u.bytes[3] = s[0];
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return u.v;
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}
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audio_sample audio_math::decodeFloat16(uint16_t source) {
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const unsigned fractionBits = 10;
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const unsigned widthBits = 16;
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typedef uint16_t source_t;
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/* typedef uint64_t out_t; typedef double retval_t;
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enum {
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outExponent = 11,
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outFraction = 52,
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outExponentShift = (1 << (outExponent-1))-1
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};*/
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typedef uint32_t out_t; typedef float retval_t;
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enum {
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outExponent = 8,
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outFraction = 23,
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outExponentShift = (1 << (outExponent-1))-1
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};
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const unsigned exponentBits = widthBits - fractionBits - 1;
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// 1 bit sign | exponent | fraction
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source_t fraction = source & (((source_t)1 << fractionBits)-1);
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source >>= fractionBits;
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int exponent = (int)( source & (((source_t)1 << exponentBits)-1) ) - (int)((1 << (exponentBits-1))-1);
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source >>= exponentBits;
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if (outExponent + outExponentShift <= 0) return 0;
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out_t output = (out_t)( source&1 );
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output <<= outExponent;
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output |= (unsigned) (exponent + outExponentShift) & ( (1<<outExponent) - 1 );
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output <<= outFraction;
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int shift = (int) outFraction - (int) fractionBits;
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if (shift < 0) output |= (out_t) (fraction >> -shift);
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else output |= (out_t) (fraction << shift);
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return *(retval_t*)&output / pfc::audio_math::float16scale;
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}
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unsigned audio_math::bitrate_kbps(uint64_t fileSize, double duration) {
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if (fileSize > 0 && duration > 0) return (unsigned)floor((double)fileSize * 8 / (duration * 1000) + 0.5);
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return 0;
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}
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}
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