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Speedup WebP lossless compression for low effort (m=0) mode with following:

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- Disable Cross-Color transform.
- Evaluate predictors #11 (paeth), #12 and #13 only.

Change-Id: I857264c85c61c3957d4fb45ae32d261d947c8bed
This commit is contained in:
Pascal Massimino 2014-12-17 11:52:11 +01:00
parent 9275d91c79
commit 31a9cf6417
3 changed files with 16 additions and 10 deletions
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9
src/dsp/lossless.c
View File

@ -758,9 +758,12 @@ static WEBP_INLINE void UpdateHisto(int histo_argb[4][256], uint32_t argb) {
static int GetBestPredictorForTile(int width, int height,
int tile_x, int tile_y, int bits,
int low_effort,
const int accumulated[4][256],
const uint32_t* const argb_scratch) {
const int kNumPredModes = 14;
const int kPredModePaeth = 11;
const int start_mode = low_effort ? kPredModePaeth : 0;
const int col_start = tile_x << bits;
const int row_start = tile_y << bits;
const int tile_size = 1 << bits;
@ -769,7 +772,7 @@ static int GetBestPredictorForTile(int width, int height,
float best_diff = MAX_DIFF_COST;
int best_mode = 0;
int mode;
for (mode = 0; mode < kNumPredModes; ++mode) {
for (mode = start_mode; mode < kNumPredModes; ++mode) {
const uint32_t* current_row = argb_scratch;
const VP8LPredictorFunc pred_func = VP8LPredictors[mode];
float cur_diff;
@ -839,7 +842,7 @@ static void CopyTileWithPrediction(int width, int height,
}
}
void VP8LResidualImage(int width, int height, int bits,
void VP8LResidualImage(int width, int height, int bits, int low_effort,
uint32_t* const argb, uint32_t* const argb_scratch,
uint32_t* const image) {
const int max_tile_size = 1 << bits;
@ -870,7 +873,7 @@ void VP8LResidualImage(int width, int height, int bits,
all_x_max = width;
}
pred = GetBestPredictorForTile(width, height, tile_x, tile_y, bits,
(const int (*)[256])histo,
low_effort, (const int (*)[256])histo,
argb_scratch);
image[tile_y * tiles_per_row + tile_x] = 0xff000000u | (pred << 8);
CopyTileWithPrediction(width, height, tile_x, tile_y, bits, pred,

2
src/dsp/lossless.h
View File

@ -98,7 +98,7 @@ void VP8LColorIndexInverseTransformAlpha(
const struct VP8LTransform* const transform, int y_start, int y_end,
const uint8_t* src, uint8_t* dst);
void VP8LResidualImage(int width, int height, int bits,
void VP8LResidualImage(int width, int height, int bits, int low_effort,
uint32_t* const argb, uint32_t* const argb_scratch,
uint32_t* const image);

15
src/enc/vp8l.c
View File

@ -341,7 +341,7 @@ static int AnalyzeAndInit(VP8LEncoder* const enc, WebPImageHint image_hint) {
if (!enc->use_palette_) {
if (image_hint == WEBP_HINT_PHOTO) {
enc->use_predict_ = 1;
enc->use_cross_color_ = 1;
enc->use_cross_color_ = (method > 0);
} else {
double non_pred_entropy, pred_entropy;
if (!AnalyzeEntropy(pic->argb, width, height, pic->argb_stride,
@ -350,7 +350,7 @@ static int AnalyzeAndInit(VP8LEncoder* const enc, WebPImageHint image_hint) {
}
if (pred_entropy < 0.95 * non_pred_entropy) {
enc->use_predict_ = 1;
enc->use_cross_color_ = 1;
enc->use_cross_color_ = (method > 0);
}
}
}
@ -919,14 +919,15 @@ static void ApplySubtractGreen(VP8LEncoder* const enc, int width, int height,
}
static WebPEncodingError ApplyPredictFilter(const VP8LEncoder* const enc,
int width, int height, int quality,
int width, int height,
int quality, int low_effort,
VP8LBitWriter* const bw) {
const int pred_bits = enc->transform_bits_;
const int transform_width = VP8LSubSampleSize(width, pred_bits);
const int transform_height = VP8LSubSampleSize(height, pred_bits);
VP8LResidualImage(width, height, pred_bits, enc->argb_, enc->argb_scratch_,
enc->transform_data_);
VP8LResidualImage(width, height, pred_bits, low_effort, enc->argb_,
enc->argb_scratch_, enc->transform_data_);
VP8LPutBits(bw, TRANSFORM_PRESENT, 1);
VP8LPutBits(bw, PREDICTOR_TRANSFORM, 2);
assert(pred_bits >= 2);
@ -1207,6 +1208,7 @@ WebPEncodingError VP8LEncodeStream(const WebPConfig* const config,
VP8LBitWriter* const bw) {
WebPEncodingError err = VP8_ENC_OK;
const int quality = (int)config->quality;
const int low_effort = (config->method == 0);
const int width = picture->width;
const int height = picture->height;
VP8LEncoder* const enc = VP8LEncoderNew(config, picture);
@ -1279,7 +1281,8 @@ WebPEncodingError VP8LEncodeStream(const WebPConfig* const config,
}
}
#endif // WEBP_EXPERIMENTAL_FEATURES
err = ApplyPredictFilter(enc, enc->current_width_, height, quality, bw);
err = ApplyPredictFilter(enc, enc->current_width_, height, quality,
low_effort, bw);
if (err != VP8_ENC_OK) {
WebPSafeFree(copy_buffer);
goto Error;