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Switch ExtraCost to ints and implement it in SSE.

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The histograms count the occurrences of len/dist in entropy images.
Those (at most (1<<14) by (1<<14)) are sub-sampled by at least
MIN_HUFFMAN_BITS == 2, hence at most 24 bits in a histogram value.
At most, we multiply by 19 (because the longest histogram is of
size 40 and we do 40>>1, cf code) for the bit cost. So it all fits
in 32 bits.

Change-Id: Ife24b035f54794851ff31f2fac07901f724c6d7f
This commit is contained in:
Vincent Rabaud
2023-05-31 15:41:43 +02:00
parent 15b365083d
commit 828b4ce062
5 changed files with 94 additions and 37 deletions
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6
src/dsp/lossless.h
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@ -182,9 +182,9 @@ extern VP8LPredictorAddSubFunc VP8LPredictorsSub_C[16];
// -----------------------------------------------------------------------------
// Huffman-cost related functions.
typedef float (*VP8LCostFunc)(const uint32_t* population, int length);
typedef float (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y,
int length);
typedef uint32_t (*VP8LCostFunc)(const uint32_t* population, int length);
typedef uint32_t (*VP8LCostCombinedFunc)(const uint32_t* X, const uint32_t* Y,
int length);
typedef float (*VP8LCombinedShannonEntropyFunc)(const int X[256],
const int Y[256]);