cog/Libraries/MAC/Files/Source/MACLib/Old/AntiPredictorFast.cpp

89 lines
2.3 KiB
C++
Executable File

#include "All.h"
#ifdef BACKWARDS_COMPATIBILITY
#include "Anti-Predictor.h"
#ifdef ENABLE_COMPRESSION_MODE_FAST
void CAntiPredictorFast0000To3320::AntiPredict(int *pInputArray, int *pOutputArray, int NumberOfElements) {
//short frame handling
if (NumberOfElements < 32) {
memcpy(pOutputArray, pInputArray, NumberOfElements * 4);
return;
}
//the initial
pOutputArray[0] = pInputArray[0];
pOutputArray[1] = pInputArray[1] + pOutputArray[0];
pOutputArray[2] = pInputArray[2] + pOutputArray[1];
pOutputArray[3] = pInputArray[3] + pOutputArray[2];
pOutputArray[4] = pInputArray[4] + pOutputArray[3];
pOutputArray[5] = pInputArray[5] + pOutputArray[4];
pOutputArray[6] = pInputArray[6] + pOutputArray[5];
pOutputArray[7] = pInputArray[7] + pOutputArray[6];
//the rest
int p, pw;
int m = 4000;
int *ip, *op, *op1;
op1 = &pOutputArray[7];
p = (*op1 * 2) - pOutputArray[6];
pw = (p * m) >> 12;
for (op = &pOutputArray[8], ip = &pInputArray[8]; ip < &pInputArray[NumberOfElements]; ip++, op++, op1++) {
*op = *ip + pw;
//adjust m
if (*ip > 0)
m += (p > 0) ? 4 : -4;
else if (*ip < 0)
m += (p > 0) ? -4 : 4;
p = (*op * 2) - *op1;
pw = (p * m) >> 12;
}
}
///////note: no output - overwrites input/////////////////
void CAntiPredictorFast3320ToCurrent::AntiPredict(int *pInputArray, int *pOutputArray, int NumberOfElements) {
//short frame handling
if (NumberOfElements < 3) {
return;
}
//variable declares
int p;
int m = 375;
int *ip;
int IP2 = pInputArray[1];
int IP3 = pInputArray[0];
int OP1 = pInputArray[1];
//the decompression loop (order 2 followed by order 1)
for (ip = &pInputArray[2]; ip < &pInputArray[NumberOfElements]; ip++) {
//make a prediction for order 2
p = IP2 + IP2 - IP3;
//rollback the values
IP3 = IP2;
IP2 = *ip + ((p * m) >> 9);
//adjust m for the order 2
(*ip ^ p) > 0 ? m++ : m--;
//set the output value
*ip = IP2 + OP1;
OP1 = *ip;
}
}
#endif // #ifdef ENABLE_COMPRESSION_MODE_FAST
#endif // #ifdef BACKWARDS_COMPATIBILITY