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1 #include "pfc-lite.h"
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2 #include "audio_sample.h"
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3 #include "primitives.h"
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4 #include "byte_order.h"
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5
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6 namespace pfc {
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7 float audio_math::decodeFloat24ptr(const void* sourcePtr) {
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8 PFC_STATIC_ASSERT(pfc::byte_order_is_little_endian);
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9 union {
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10 uint8_t bytes[4];
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11 float v;
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12 } u;
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13 const uint8_t* s = reinterpret_cast<const uint8_t*>(sourcePtr);
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14 u.bytes[0] = 0;
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15 u.bytes[1] = s[0];
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16 u.bytes[2] = s[1];
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17 u.bytes[3] = s[2];
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18 return u.v;
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19 }
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20 float audio_math::decodeFloat24ptrbs(const void* sourcePtr) {
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21 PFC_STATIC_ASSERT(pfc::byte_order_is_little_endian);
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22 union {
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23 uint8_t bytes[4];
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24 float v;
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25 } u;
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26 const uint8_t* s = reinterpret_cast<const uint8_t*>(sourcePtr);
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27 u.bytes[0] = 0;
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28 u.bytes[1] = s[2];
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29 u.bytes[2] = s[1];
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30 u.bytes[3] = s[0];
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31 return u.v;
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32 }
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33
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34 float audio_math::decodeFloat16(uint16_t source) {
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35 const unsigned fractionBits = 10;
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36 const unsigned widthBits = 16;
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37 typedef uint16_t source_t;
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38
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39 /* typedef uint64_t out_t; typedef double retval_t;
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40 enum {
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41 outExponent = 11,
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42 outFraction = 52,
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43 outExponentShift = (1 << (outExponent-1))-1
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44 };*/
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45
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46 typedef uint32_t out_t; typedef float retval_t;
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47 enum {
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48 outExponent = 8,
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49 outFraction = 23,
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50 outExponentShift = (1 << (outExponent - 1)) - 1
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51 };
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52
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53 const unsigned exponentBits = widthBits - fractionBits - 1;
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54 // 1 bit sign | exponent | fraction
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55 source_t fraction = source & (((source_t)1 << fractionBits) - 1);
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56 source >>= fractionBits;
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57 int exponent = (int)(source & (((source_t)1 << exponentBits) - 1)) - (int)((1 << (exponentBits - 1)) - 1);
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58 source >>= exponentBits;
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59
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60 if constexpr (outExponent + outExponentShift <= 0) return 0;
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61
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62 out_t output = (out_t)(source & 1);
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63 output <<= outExponent;
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64 output |= (unsigned)(exponent + outExponentShift) & ((1 << outExponent) - 1);
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65 output <<= outFraction;
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66 int shift = (int)outFraction - (int)fractionBits;
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67 if (shift < 0) output |= (out_t)(fraction >> -shift);
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68 else output |= (out_t)(fraction << shift);
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69 return *(retval_t*)&output / pfc::audio_math::float16scale;
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70 }
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71
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72 unsigned audio_math::bitrate_kbps(uint64_t fileSize, double duration) {
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73 if (fileSize > 0 && duration > 0) return (unsigned)floor((double)fileSize * 8 / (duration * 1000) + 0.5);
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74 return 0;
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75 }
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76 }
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