mirror of
https://github.com/ScrelliCopter/VGM-Tools
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58 lines
1.8 KiB
C
58 lines
1.8 KiB
C
/* libadpcma.c (C) 2023 a dinosaur (zlib)
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Original ADPCM to PCM converter v 1.01 By MARTINEZ Fabrice aka SNK of SUPREMACY */
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#include "adpcm.h"
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#include "util.h"
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#include <math.h>
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#include <stdlib.h>
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#include <stdio.h>
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#define ADPCMA_VOLUME_RATE 1
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#define ADPCMA_DECODE_RANGE 1024
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#define ADPCMA_DECODE_MIN (-(ADPCMA_DECODE_RANGE * ADPCMA_VOLUME_RATE))
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#define ADPCMA_DECODE_MAX ((ADPCMA_DECODE_RANGE * ADPCMA_VOLUME_RATE) - 1)
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void adpcmAInit(AdpcmADecoderState* decoder)
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{
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for (int step = 0; step <= 48; step++)
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{
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int stepval = floor(16.0 * pow(11.0 / 10.0, step) * ADPCMA_VOLUME_RATE);
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// Loop over all nibbles and compute the difference
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for (int nib = 0; nib < 16; nib++)
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{
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int value = stepval * ((nib & 0x07) * 2 + 1) / 8;
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decoder->jediTable[step * 16 + nib] = (nib & 0x08) ? -value : value;
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}
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}
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decoder->delta = 0;
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decoder->cursignal = 0;
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}
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static const int decodeTableA1[16] =
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{
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-1 * 16, -1 * 16, -1 * 16, -1 * 16, 2 * 16, 5 * 16, 7 * 16, 9 * 16,
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-1 * 16, -1 * 16, -1 * 16, -1 * 16, 2 * 16, 5 * 16, 7 * 16, 9 * 16
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};
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void adpcmADecode(AdpcmADecoderState* decoder, const char* restrict in, short* restrict out, int len)
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{
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for (int i = 0; i < len * 2; ++i)
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{
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int data = (!(i & 0x1) ? ((*in) >> 4) : (*in++)) & 0x0F;
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int oldsignal = decoder->cursignal;
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decoder->cursignal = CLAMP(decoder->cursignal + decoder->jediTable[data + decoder->delta],
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ADPCMA_DECODE_MIN, ADPCMA_DECODE_MAX);
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decoder->delta = CLAMP(decoder->delta + decodeTableA1[data], 0 * 16, 48 * 16);
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if (abs(oldsignal - decoder->cursignal) > 2500)
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{
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fprintf(stderr, "WARNING: Suspicious signal evolution %06x,%06x pos:%06x delta:%06x\n",
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oldsignal, decoder->cursignal, i % len, decoder->delta);
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fprintf(stderr, "data:%02x dx:%08x\n",
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data, decoder->jediTable[data + decoder->delta]);
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}
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*(out++) = (decoder->cursignal & 0xffff) * 32;
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}
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}
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