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Convert VP8LFastSLog2 to fixed point

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Speedups: 1% with '-lossless', 2% with '-lossless -q 100 -m6'

Change-Id: I1d79ea8e3e9e4bac7bcea4d7cbcc1bd56273988e
This commit is contained in:
Vincent Rabaud
2024-07-09 15:44:18 +02:00
parent 66408c2c7c
commit fb444b692b
7 changed files with 128 additions and 260 deletions
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7
src/enc/predictor_enc.c
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@ -57,7 +57,9 @@ static float PredictionCostSpatialHistogram(
// Compute the new cost if 'tile' is added to 'accumulate' but also add the
// cost of the current histogram to guide the spatial predictor selection.
// Basically, favor low entropy, locally and globally.
retval += VP8LCombinedShannonEntropy(&tile[i * 256], &accumulated[i * 256]);
retval += (float)VP8LCombinedShannonEntropy(&tile[i * 256],
&accumulated[i * 256]) /
(1ll << LOG_2_PRECISION_BITS);
}
// Favor keeping the areas locally similar.
if (mode == left_mode) retval -= kSpatialPredictorBias;
@ -541,7 +543,8 @@ static float PredictionCostCrossColor(const uint32_t accumulated[256],
// Favor low entropy, locally and globally.
// Favor small absolute values for PredictionCostSpatial
static const float kExpValue = 2.4f;
return VP8LCombinedShannonEntropy(counts, accumulated) +
return (float)VP8LCombinedShannonEntropy(counts, accumulated) /
(1ll << LOG_2_PRECISION_BITS) +
PredictionCostBias(counts, 3, kExpValue);
}