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DEFINITIONS
This source file includes following definitions.
- writeADPCMData
- main
/*
* raw2adpcm converts a raw sound data to adpcm compressed.
* This is based on adpcm.cpp found at http://www.openswf.org .
* The original code is the code posted on news:forums.macromedia.com by Jonathan Gay.
*/
#include <stdio.h>
#include <stdlib.h>
#include "../src/blocks/input.h"
#include "../src/blocks/output.h"
#include "../src/libming.h"
/*
* ADPCM tables
*/
static const int piIndexTable2[2] =
{
-1, 2,
};
static const int piIndexTable3[4] =
{
-1, -1, 2, 4,
};
static const int piIndexTable4[8] =
{
-1, -1, -1, -1, 2, 4, 6, 8,
};
static const int piIndexTable5[16] =
{
-1, -1, -1, -1, -1, -1, -1, -1, 1, 2, 4, 6, 8, 10, 13, 16,
};
static const int* ppiIndexTables[] =
{
piIndexTable2,
piIndexTable3,
piIndexTable4,
piIndexTable5
};
static const int piStepSizeTable[89] =
{
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};
void writeADPCMData(short *samples, int stereo, int sample_count, SWFOutput output) {
int nBits = 4; /* number of bits per ADPCM sample */
int iSignBit = 1 << (nBits-1); /* Sign bit mask */
const int* piIndexTable = ppiIndexTables[nBits-2]; /* Select index table to use */
int iValPred[2] = {0, 0}; /* Predicted output value(s) */
int iIndex[2] = {0, 0}; /* Indeces int StepSizeTable */
int iStep[2] = {0, 0}; /* Step size */
int iSampleCount = sample_count; /* Number of samples. */
int iChannelCount = 1 + stereo; /* Number of channels (mono, stereo) */
short* psSample = samples; /* Pointer to start of 16-bit/sample data */
int i;
/* Write number of bits per ADPCM sample */
SWFOutput_writeBits(output, nBits-2, 2);
for (i=0; i < iSampleCount; i++) {
if ((i & 0xfff) == 0) {
int c;
for (c=0; c<iChannelCount; c++) {
/* First sample in the block, so no delta */
short sSample = *psSample++;
int iDiff;
/* Write full 16-bit sample */
SWFOutput_writeSBits(output, (int)sSample, 16); /* XXX - should be swapped? */
iValPred[c] = sSample;
/* Calculate initial index & step */
if (iSampleCount == 1) /* XXX - stereo OK? */
iDiff = abs(*psSample - sSample);
else
iDiff = abs(*(psSample+1) - sSample);
for (iIndex[c]=0; iIndex[c] < 88; iIndex[c]++)
if (iDiff <= piStepSizeTable[iIndex[c]])
break;
if (iIndex[c] > 63)
iIndex[c] = 63;
iStep[c] = piStepSizeTable[iIndex[c]];
/* Write initial index into StepSizeTable */
SWFOutput_writeBits(output, (int)iIndex[c], 6);
}
} else {
int c;
for (c=0; c<iChannelCount; c++) {
short sSample = *psSample++;
int iDiff, iSign, iDelta, iVPDiff;
int k;
/* Step 1 - compute difference with previous value */
iDiff = sSample - iValPred[c];
/* Make iDiff absolute value */
iSign = (iDiff < 0) ? iSignBit : 0;
if (iSign)
iDiff = (-iDiff);
/*
* Step 2 - Divide and clamp
* Note:
* This code *approximately* computes:
* iDelta = iDiff*4/iStep;
* iVPDiff = (iDelta+0.5)*iStep/4;
* but in shift step bits are dropped. The net result of this is
* that even if you have fast mul/div hardware you cannot put it to
* good use since the fixup would be too expensive.
*/
iDelta = 0;
iVPDiff = (iStep[c] >> (nBits-1));
for (k = nBits-2; k >= 0; k--, iStep[c] >>= 1) {
if (iDiff >= iStep[c]) {
iDelta |= (1<<k);
iVPDiff += iStep[c];
if (k > 0)
iDiff -= iStep[c];
}
}
/* Step 3 - Update previous value */
if (iSign)
iValPred[c] -= iVPDiff;
else
iValPred[c] += iVPDiff;
/* Step 4 - Clamp previous value to 16 bits */
if (iValPred[c] > 32767)
iValPred[c] = 32767;
else if (iValPred[c] < -32768)
iValPred[c] = -32768;
/* Step 5 - Assemble value, update index and step values */
iIndex[c] += piIndexTable[iDelta];
iDelta |= iSign; /* Or with iSign *after* indexing */
/* Clamp StepSizeTable index */
if (iIndex[c] < 0) iIndex[c] = 0;
if (iIndex[c] > 88) iIndex[c] = 88;
iStep[c] = piStepSizeTable[iIndex[c]];
/* Step 6 - Output value */
SWFOutput_writeBits(output, iDelta, nBits);
}
}
}
}
int main(int argc, char *argv[])
{
FILE *fp_in, *fp_out;
SWFInput input;
SWFOutput output;
int bits16;
int stereo;
int sample_count;
short *samples, *i_sample;
int i;
if (argc < 3) {
printf(
"%s converts a raw sound data to adpcm compressed.\n"
"\n"
"Usage:\n"
"%s in out [16bit] [stereo]\n"
"\n"
"in : the filename of input file, raw sound data\n"
"out : the filename of output file, ADPCM compressed\n"
"16bit : bits per sample 0=8bit 1=16bit default=1=16bit\n"
"stereo : number of channels 0=mono 1=stereo default=1=stereo\n"
, argv[0], argv[0]);
exit(0);
}
fp_in = fopen(argv[1], "rb");
if (!fp_in) {
fprintf(stderr, "file '%s' cannot open.\n", argv[1]);
exit(1);
}
fp_out = fopen(argv[2], "wb");
if (!fp_out) {
fprintf(stderr, "file '%s' cannnot open.\n", argv[2]);
exit(1);
}
bits16 = 1;
if (argc > 3) bits16 = atoi(argv[3]);
stereo = 1;
if (argc > 4) stereo = atoi(argv[4]);
/* read RAW sound data */
input = newSWFInput_file(fp_in);
sample_count = SWFInput_length(input) / (1+bits16) / (1+stereo);
samples = malloc(sizeof(short) * sample_count * (1+stereo));
i_sample = samples;
for (i=0; i<sample_count*(1+stereo); i++) {
if (bits16 == 0) {
*i_sample = (short)SWFInput_getChar(input);
} else {
*i_sample = (short)SWFInput_getSInt16(input);
}
i_sample++;
}
destroySWFInput(input);
fclose(fp_in);
/* create a SWFOutput */
output = newSWFOutput();
writeADPCMData(samples, stereo, sample_count, output);
/* write to file */
SWFOutput_writeToMethod(output, fileOutputMethod, fp_out);
fclose(fp_out);
exit(0);
}