mirror of https://github.com/jorio/Pomme.git
94 lines
3.2 KiB
C++
94 lines
3.2 KiB
C++
#include "PommeSound.h"
|
|
|
|
// Conversion tables to obtain 16-bit PCM from 8-bit a-law/mu-law.
|
|
// These tables are valid for *-law input bytes [0...127].
|
|
// For inputs [-127...-1], mirror the table and negate the output.
|
|
//
|
|
// These tables were generated using alaw2linear() and ulaw2linear()
|
|
// from ffmpeg/libavcodec/pcm_tablegen.h.
|
|
|
|
static const int16_t alawToPCM[128] = {
|
|
-5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
|
|
-7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
|
|
-2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
|
|
-3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
|
|
-22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944,
|
|
-30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136,
|
|
-11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472,
|
|
-15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568,
|
|
-344, -328, -376, -360, -280, -264, -312, -296,
|
|
-472, -456, -504, -488, -408, -392, -440, -424,
|
|
-88, -72, -120, -104, -24, -8, -56, -40,
|
|
-216, -200, -248, -232, -152, -136, -184, -168,
|
|
-1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
|
|
-1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
|
|
-688, -656, -752, -720, -560, -528, -624, -592,
|
|
-944, -912, -1008, -976, -816, -784, -880, -848,
|
|
};
|
|
|
|
static const int16_t ulawToPCM[128] = {
|
|
-32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956,
|
|
-23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764,
|
|
-15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412,
|
|
-11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316,
|
|
-7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140,
|
|
-5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
|
|
-3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004,
|
|
-2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980,
|
|
-1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
|
|
-1372, -1308, -1244, -1180, -1116, -1052, -988, -924,
|
|
-876, -844, -812, -780, -748, -716, -684, -652,
|
|
-620, -588, -556, -524, -492, -460, -428, -396,
|
|
-372, -356, -340, -324, -308, -292, -276, -260,
|
|
-244, -228, -212, -196, -180, -164, -148, -132,
|
|
-120, -112, -104, -96, -88, -80, -72, -64,
|
|
-56, -48, -40, -32, -24, -16, -8, -0,
|
|
};
|
|
|
|
Pomme::Sound::xlaw::xlaw(uint32_t codecFourCC)
|
|
{
|
|
switch (codecFourCC)
|
|
{
|
|
case 'ulaw':
|
|
xlawToPCM = ulawToPCM;
|
|
break;
|
|
case 'alaw':
|
|
xlawToPCM = alawToPCM;
|
|
break;
|
|
default:
|
|
throw std::runtime_error("unknown xlaw fourCC");
|
|
}
|
|
}
|
|
|
|
void Pomme::Sound::xlaw::Decode(
|
|
const int nChannels,
|
|
const std::span<const char> input,
|
|
const std::span<char> output)
|
|
{
|
|
(void) nChannels;
|
|
|
|
if (2 * input.size() != output.size())
|
|
{
|
|
throw std::runtime_error("ulaw: incorrect input/output buffer sizes");
|
|
}
|
|
|
|
const std::span<int16_t> out16(
|
|
reinterpret_cast<int16_t*>(output.data()),
|
|
input.size());
|
|
|
|
for (size_t i = 0; i < input.size(); i++)
|
|
{
|
|
int8_t b = input[i]; // SIGNED!
|
|
if (b < 0)
|
|
{
|
|
// Mirror table and negate output
|
|
out16[i] = -xlawToPCM[128 + b];
|
|
}
|
|
else
|
|
{
|
|
out16[i] = xlawToPCM[b];
|
|
}
|
|
}
|
|
}
|
|
|