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entropy_coding.hpp
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entropy_coding.hpp
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#ifndef ENTROPY_CODING_HEADER
#define ENTROPY_CODING_HEADER
#include "rans_byte.h"
#include "symbolstats.hpp"
void entropyCoding_map(
uint8_t* filtered_bytes,
uint32_t width,
uint32_t height,
SymbolStats* table,
uint8_t contextNumber,
uint32_t entropyWidth,
uint32_t entropyHeight,
uint8_t*& outPointer
){
uint32_t entropyWidth_block = (width + entropyWidth - 1)/entropyWidth;
uint32_t entropyHeight_block = (height + entropyHeight - 1)/entropyHeight;
RansEncSymbol esyms[contextNumber][256];
for(size_t context = 0;context < contextNumber;context++){
for(size_t i=0; i < 256; i++) {
RansEncSymbolInit(&esyms[context][i], table[context].cum_freqs[i], table[context].freqs[i], 16);
}
}
printf("starting entropy coding\n");
RansState rans;
RansEncInit(&rans);
for(size_t index=width*height;index--;){
size_t tileIndex = tileIndexFromPixel(
index,
width,
entropyWidth,
entropyWidth_block,
entropyHeight_block
);
RansEncPutSymbol(&rans, &outPointer, esyms[tileIndex] + filtered_bytes[index]);//index == context here, but that's not generally true. Use a map lookup!
}
RansEncFlush(&rans, &outPointer);
}
void entropyCoding_map(
uint8_t* filtered_bytes,
uint32_t width,
uint32_t height,
SymbolStats* table,
uint8_t* entropyImage,
uint8_t contextNumber,
uint32_t entropyWidth,
uint32_t entropyHeight,
uint8_t*& outPointer
){
uint32_t entropyWidth_block = (width + entropyWidth - 1)/entropyWidth;
uint32_t entropyHeight_block = (height + entropyHeight - 1)/entropyHeight;
RansEncSymbol esyms[contextNumber][256];
for(size_t context = 0;context < contextNumber;context++){
for(size_t i=0; i < 256; i++) {
RansEncSymbolInit(&esyms[context][i], table[context].cum_freqs[i], table[context].freqs[i], 16);
}
}
printf("starting entropy coding\n");
RansState rans;
RansEncInit(&rans);
for(size_t index=width*height;index--;){
size_t tileIndex = tileIndexFromPixel(
index,
width,
entropyWidth,
entropyWidth_block,
entropyHeight_block
);
RansEncPutSymbol(&rans, &outPointer, esyms[entropyImage[tileIndex]] + filtered_bytes[index]);
}
RansEncFlush(&rans, &outPointer);
}
#endif //ENTROPY_CODING