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Merge "Unify some entropy functions."

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This commit is contained in:
James Zern 2015-12-17 22:35:29 +00:00 committed by Gerrit Code Review
commit 99a01f4f8b
4 changed files with 107 additions and 142 deletions
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25
src/dsp/lossless.h
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@ -216,12 +216,9 @@ typedef struct { // small struct to hold counters
int streaks[2][2]; // [zero/non-zero][streak<3 / streak>=3]
} VP8LStreaks;
typedef VP8LStreaks (*VP8LCostCountFunc)(const uint32_t* population,
int length);
typedef VP8LStreaks (*VP8LCostCombinedCountFunc)(const uint32_t* X,
const uint32_t* Y, int length);
extern VP8LCostCountFunc VP8LHuffmanCostCount;
extern VP8LCostCombinedCountFunc VP8LHuffmanCostCombinedCount;
typedef struct { // small struct to hold bit entropy results
@ -234,14 +231,28 @@ typedef struct { // small struct to hold bit entropy results
void VP8LBitEntropyInit(VP8LBitEntropy* const entropy);
// Get the combined symbol entropy for the distributions 'X' and 'Y'.
// Get the combined symbol bit entropy and Huffman cost stats for the
// distributions 'X' and 'Y'. Those results can then be refined according to
// codec specific heuristics.
void VP8LGetCombinedEntropyUnrefined(const uint32_t* const X,
const uint32_t* const Y, int length,
VP8LBitEntropy* bit_entropy,
VP8LStreaks* stats);
VP8LBitEntropy* const bit_entropy,
VP8LStreaks* const stats);
// Get the entropy for the distribution 'X'.
void VP8LGetEntropyUnrefined(const uint32_t* const X, int length,
VP8LBitEntropy* const bit_entropy,
VP8LStreaks* const stats);
void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n,
VP8LBitEntropy* entropy);
VP8LBitEntropy* const entropy);
typedef void (*GetEntropyUnrefinedHelperFunc)(uint32_t val, int i,
uint32_t* const val_prev,
int* const i_prev,
VP8LBitEntropy* const bit_entropy,
VP8LStreaks* const stats);
// Internal function used by VP8LGet*EntropyUnrefined.
extern GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper;
typedef void (*VP8LHistogramAddFunc)(const VP8LHistogram* const a,
const VP8LHistogram* const b,

132
src/dsp/lossless_enc.c
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@ -442,7 +442,7 @@ void VP8LBitEntropyInit(VP8LBitEntropy* const entropy) {
}
void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n,
VP8LBitEntropy* entropy) {
VP8LBitEntropy* const entropy) {
int i;
VP8LBitEntropyInit(entropy);
@ -461,69 +461,70 @@ void VP8LBitsEntropyUnrefined(const uint32_t* const array, int n,
entropy->entropy += VP8LFastSLog2(entropy->sum);
}
void VP8LGetCombinedEntropyUnrefined(const uint32_t* const X,
const uint32_t* const Y, int length,
VP8LBitEntropy* bit_entropy,
VP8LStreaks* stats) {
int i;
// Bit entropy variables.
int i_prev;
uint32_t xy;
// Huffman cost variables.
int streak = 0;
uint32_t xy_prev;
memset(stats, 0, sizeof(*stats));
VP8LBitEntropyInit(bit_entropy);
// Treat the first value for the huffman cost: this is keeping the original
// behavior, even though there is no first streak.
// TODO(vrabaud): study proper behavior
xy = X[0] + Y[0];
++stats->streaks[xy != 0][0];
xy_prev = xy;
i_prev = 0;
for (i = 1; i < length; ++i) {
xy = X[i] + Y[i];
// Process data by streaks for both bit entropy and huffman cost.
if (xy != xy_prev) {
streak = i - i_prev;
static WEBP_INLINE void GetEntropyUnrefinedHelper(
uint32_t val, int i, uint32_t* const val_prev, int* const i_prev,
VP8LBitEntropy* const bit_entropy, VP8LStreaks* const stats) {
const int streak = i - *i_prev;
// Gather info for the bit entropy.
if (xy_prev != 0) {
bit_entropy->sum += xy_prev * streak;
if (*val_prev != 0) {
bit_entropy->sum += (*val_prev) * streak;
bit_entropy->nonzeros += streak;
bit_entropy->entropy -= VP8LFastSLog2(xy_prev) * streak;
if (bit_entropy->max_val < xy_prev) {
bit_entropy->max_val = xy_prev;
bit_entropy->nonzero_code = *i_prev;
bit_entropy->entropy -= VP8LFastSLog2(*val_prev) * streak;
if (bit_entropy->max_val < *val_prev) {
bit_entropy->max_val = *val_prev;
}
}
// Gather info for the huffman cost.
stats->counts[xy != 0] += (streak > 3);
stats->streaks[xy != 0][(streak > 3)] += streak;
// Gather info for the Huffman cost.
stats->counts[*val_prev != 0] += (streak > 3);
stats->streaks[*val_prev != 0][(streak > 3)] += streak;
xy_prev = xy;
i_prev = i;
}
*val_prev = val;
*i_prev = i;
}
// Finish off the last streak for bit entropy.
if (xy != 0) {
streak = i - i_prev;
bit_entropy->sum += xy * streak;
bit_entropy->nonzeros += streak;
bit_entropy->entropy -= VP8LFastSLog2(xy) * streak;
if (bit_entropy->max_val < xy) {
bit_entropy->max_val = xy;
void VP8LGetEntropyUnrefined(const uint32_t* const X, int length,
VP8LBitEntropy* const bit_entropy,
VP8LStreaks* const stats) {
int i;
int i_prev = 0;
uint32_t x_prev = X[0];
memset(stats, 0, sizeof(*stats));
VP8LBitEntropyInit(bit_entropy);
for (i = 1; i < length; ++i) {
const uint32_t x = X[i];
if (x != x_prev) {
VP8LGetEntropyUnrefinedHelper(x, i, &x_prev, &i_prev, bit_entropy, stats);
}
}
// Huffman cost is not updated with the last streak to keep original behavior.
// TODO(vrabaud): study proper behavior
VP8LGetEntropyUnrefinedHelper(0, i, &x_prev, &i_prev, bit_entropy, stats);
bit_entropy->entropy += VP8LFastSLog2(bit_entropy->sum);
}
void VP8LGetCombinedEntropyUnrefined(const uint32_t* const X,
const uint32_t* const Y, int length,
VP8LBitEntropy* const bit_entropy,
VP8LStreaks* const stats) {
int i = 1;
int i_prev = 0;
uint32_t xy_prev = X[0] + Y[0];
memset(stats, 0, sizeof(*stats));
VP8LBitEntropyInit(bit_entropy);
for (i = 1; i < length; ++i) {
const uint32_t xy = X[i] + Y[i];
if (xy != xy_prev) {
VP8LGetEntropyUnrefinedHelper(xy, i, &xy_prev, &i_prev, bit_entropy,
stats);
}
}
VP8LGetEntropyUnrefinedHelper(0, i, &xy_prev, &i_prev, bit_entropy, stats);
bit_entropy->entropy += VP8LFastSLog2(bit_entropy->sum);
}
@ -1093,27 +1094,6 @@ static double ExtraCostCombined(const uint32_t* X, const uint32_t* Y,
return cost;
}
// Returns the various RLE counts
static VP8LStreaks HuffmanCostCount(const uint32_t* population, int length) {
int i;
int streak = 0;
VP8LStreaks stats;
memset(&stats, 0, sizeof(stats));
for (i = 0; i < length - 1; ++i) {
++streak;
if (population[i] == population[i + 1]) {
continue;
}
stats.counts[population[i] != 0] += (streak > 3);
stats.streaks[population[i] != 0][(streak > 3)] += streak;
streak = 0;
}
++streak;
stats.counts[population[i] != 0] += (streak > 3);
stats.streaks[population[i] != 0][(streak > 3)] += streak;
return stats;
}
//------------------------------------------------------------------------------
static void HistogramAdd(const VP8LHistogram* const a,
@ -1165,7 +1145,7 @@ VP8LCostFunc VP8LExtraCost;
VP8LCostCombinedFunc VP8LExtraCostCombined;
VP8LCombinedShannonEntropyFunc VP8LCombinedShannonEntropy;
VP8LCostCountFunc VP8LHuffmanCostCount;
GetEntropyUnrefinedHelperFunc VP8LGetEntropyUnrefinedHelper;
VP8LHistogramAddFunc VP8LHistogramAdd;
@ -1197,7 +1177,7 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInit(void) {
VP8LExtraCostCombined = ExtraCostCombined;
VP8LCombinedShannonEntropy = CombinedShannonEntropy;
VP8LHuffmanCostCount = HuffmanCostCount;
VP8LGetEntropyUnrefinedHelper = GetEntropyUnrefinedHelper;
VP8LHistogramAdd = HistogramAdd;

69
src/dsp/lossless_enc_mips32.c
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@ -213,51 +213,31 @@ static double ExtraCostCombined(const uint32_t* const X,
);
// Returns the various RLE counts
static VP8LStreaks HuffmanCostCount(const uint32_t* population, int length) {
int i;
int streak = 0;
VP8LStreaks stats;
int* const pstreaks = &stats.streaks[0][0];
int* const pcnts = &stats.counts[0];
static WEBP_INLINE void GetEntropyUnrefinedHelper(
uint32_t val, int i, uint32_t* const val_prev, int* const i_prev,
VP8LBitEntropy* const bit_entropy, VP8LStreaks* const stats) {
int* const pstreaks = &stats->streaks[0][0];
int* const pcnts = &stats->counts[0];
int temp0, temp1, temp2, temp3;
memset(&stats, 0, sizeof(stats));
for (i = 0; i < length - 1; ++i) {
++streak;
if (population[i] == population[i + 1]) {
continue;
}
temp0 = (population[i] != 0);
HUFFMAN_COST_PASS
streak = 0;
}
++streak;
temp0 = (population[i] != 0);
HUFFMAN_COST_PASS
const int streak = i - *i_prev;
return stats;
// Gather info for the bit entropy.
if (*val_prev != 0) {
bit_entropy->sum += (*val_prev) * streak;
bit_entropy->nonzeros += streak;
bit_entropy->nonzero_code = *i_prev;
bit_entropy->entropy -= VP8LFastSLog2(*val_prev) * streak;
if (bit_entropy->max_val < *val_prev) {
bit_entropy->max_val = *val_prev;
}
}
static VP8LStreaks HuffmanCostCombinedCount(const uint32_t* X,
const uint32_t* Y, int length) {
int i;
int streak = 0;
uint32_t xy_prev = 0xffffffff;
VP8LStreaks stats;
int* const pstreaks = &stats.streaks[0][0];
int* const pcnts = &stats.counts[0];
int temp0, temp1, temp2, temp3;
memset(&stats, 0, sizeof(stats));
for (i = 0; i < length; ++i) {
const uint32_t xy = X[i] + Y[i];
++streak;
if (xy != xy_prev) {
temp0 = (xy != 0);
// Gather info for the Huffman cost.
temp0 = (*val_prev != 0);
HUFFMAN_COST_PASS
streak = 0;
xy_prev = xy;
}
}
return stats;
*val_prev = val;
*i_prev = i;
}
#define ASM_START \
@ -395,14 +375,7 @@ WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitMIPS32(void) {
VP8LFastLog2Slow = FastLog2Slow;
VP8LExtraCost = ExtraCost;
VP8LExtraCostCombined = ExtraCostCombined;
VP8LHuffmanCostCount = HuffmanCostCount;
// TODO(mips team): rewrite VP8LGetCombinedEntropy (which used to use
// HuffmanCostCombinedCount) with MIPS optimizations
#if 0
VP8LHuffmanCostCombinedCount = HuffmanCostCombinedCount;
#else
(void)HuffmanCostCombinedCount;
#endif
VP8LGetEntropyUnrefinedHelper = GetEntropyUnrefinedHelper;
VP8LHistogramAdd = HistogramAdd;
}

21
src/enc/histogram.c
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@ -221,18 +221,19 @@ static double FinalHuffmanCost(const VP8LStreaks* const stats) {
return retval;
}
// Trampolines
static double HuffmanCost(const uint32_t* const population, int length) {
const VP8LStreaks stats = VP8LHuffmanCostCount(population, length);
return FinalHuffmanCost(&stats);
}
// Get the symbol entropy for the distribution 'population'.
// Set 'trivial_sym', if there's only one symbol present in the distribution.
static double PopulationCost(const uint32_t* const population, int length,
uint32_t* const trivial_sym) {
return VP8LBitsEntropy(population, length, trivial_sym) +
HuffmanCost(population, length);
VP8LBitEntropy bit_entropy;
VP8LStreaks stats;
VP8LGetEntropyUnrefined(population, length, &bit_entropy, &stats);
if (trivial_sym != NULL) {
*trivial_sym = (bit_entropy.nonzeros == 1) ? bit_entropy.nonzero_code
: VP8L_NON_TRIVIAL_SYM;
}
return BitsEntropyRefine(&bit_entropy) + FinalHuffmanCost(&stats);
}
static WEBP_INLINE double GetCombinedEntropy(const uint32_t* const X,
@ -363,8 +364,8 @@ static void UpdateDominantCostRange(
static void UpdateHistogramCost(VP8LHistogram* const h) {
uint32_t alpha_sym, red_sym, blue_sym;
const double alpha_cost = PopulationCost(h->alpha_, NUM_LITERAL_CODES,
&alpha_sym);
const double alpha_cost =
PopulationCost(h->alpha_, NUM_LITERAL_CODES, &alpha_sym);
const double distance_cost =
PopulationCost(h->distance_, NUM_DISTANCE_CODES, NULL) +
VP8LExtraCost(h->distance_, NUM_DISTANCE_CODES);