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Increase the transform bits if possible.

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This brings minor size improvements because repetitive values in
the transform images are easily explainable through LZ77. Still,
it makes an upcoming pull request a bit more stable.

Change-Id: I1c7135675cb59b5e27ca960738d74465f10d0deb
This commit is contained in:
Vincent Rabaud
2024-05-17 09:28:29 +02:00
parent 1bf198a22b
commit 971a03d820
3 changed files with 98 additions and 28 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
src/enc/vp8l_enc.c
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@ -1071,26 +1071,27 @@ static int ApplyPredictFilter(VP8LEncoder* const enc, int width, int height,
int quality, int low_effort,
int used_subtract_green, VP8LBitWriter* const bw,
int percent_range, int* const percent) {
const int pred_bits = enc->predictor_transform_bits_;
const int transform_width = VP8LSubSampleSize(width, pred_bits);
const int transform_height = VP8LSubSampleSize(height, pred_bits);
const int min_bits = enc->predictor_transform_bits_;
int best_bits;
// we disable near-lossless quantization if palette is used.
const int near_lossless_strength =
enc->use_palette_ ? 100 : enc->config_->near_lossless;
if (!VP8LResidualImage(
width, height, pred_bits, low_effort, enc->argb_, enc->argb_scratch_,
enc->transform_data_, near_lossless_strength, enc->config_->exact,
used_subtract_green, enc->pic_, percent_range / 2, percent)) {
if (!VP8LResidualImage(width, height, min_bits, low_effort, enc->argb_,
enc->argb_scratch_, enc->transform_data_,
near_lossless_strength, enc->config_->exact,
used_subtract_green, enc->pic_, percent_range / 2,
percent, &best_bits)) {
return 0;
}
VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2);
assert(pred_bits >= MIN_TRANSFORM_BITS && pred_bits <= MAX_TRANSFORM_BITS);
VP8LPutBits(bw, pred_bits - MIN_TRANSFORM_BITS, NUM_TRANSFORM_BITS);
assert(best_bits >= MIN_TRANSFORM_BITS && best_bits <= MAX_TRANSFORM_BITS);
VP8LPutBits(bw, best_bits - MIN_TRANSFORM_BITS, NUM_TRANSFORM_BITS);
enc->predictor_transform_bits_ = best_bits;
return EncodeImageNoHuffman(
bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
(VP8LBackwardRefs*)&enc->refs_[0], transform_width, transform_height,
bw, enc->transform_data_, &enc->hash_chain_, &enc->refs_[0],
VP8LSubSampleSize(width, best_bits), VP8LSubSampleSize(height, best_bits),
quality, low_effort, enc->pic_, percent_range - percent_range / 2,
percent);
}
@ -1099,24 +1100,22 @@ static int ApplyCrossColorFilter(VP8LEncoder* const enc, int width, int height,
int quality, int low_effort,
VP8LBitWriter* const bw, int percent_range,
int* const percent) {
const int ccolor_transform_bits = enc->cross_color_transform_bits_;
const int transform_width = VP8LSubSampleSize(width, ccolor_transform_bits);
const int transform_height = VP8LSubSampleSize(height, ccolor_transform_bits);
const int min_bits = enc->cross_color_transform_bits_;
int best_bits;
if (!VP8LColorSpaceTransform(width, height, ccolor_transform_bits, quality,
enc->argb_, enc->transform_data_, enc->pic_,
percent_range / 2, percent)) {
if (!VP8LColorSpaceTransform(width, height, min_bits, quality, enc->argb_,
enc->transform_data_, enc->pic_,
percent_range / 2, percent, &best_bits)) {
return 0;
}
VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
VP8LPutBits(bw, CROSS_COLOR_TRANSFORM, 2);
assert(ccolor_transform_bits >= MIN_TRANSFORM_BITS &&
ccolor_transform_bits <= MAX_TRANSFORM_BITS);
VP8LPutBits(bw, ccolor_transform_bits - MIN_TRANSFORM_BITS,
NUM_TRANSFORM_BITS);
assert(best_bits >= MIN_TRANSFORM_BITS && best_bits <= MAX_TRANSFORM_BITS);
VP8LPutBits(bw, best_bits - MIN_TRANSFORM_BITS, NUM_TRANSFORM_BITS);
enc->cross_color_transform_bits_ = best_bits;
return EncodeImageNoHuffman(
bw, enc->transform_data_, (VP8LHashChain*)&enc->hash_chain_,
(VP8LBackwardRefs*)&enc->refs_[0], transform_width, transform_height,
bw, enc->transform_data_, &enc->hash_chain_, &enc->refs_[0],
VP8LSubSampleSize(width, best_bits), VP8LSubSampleSize(height, best_bits),
quality, low_effort, enc->pic_, percent_range - percent_range / 2,
percent);
}