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https://github.com/webmproject/libwebp.git
synced 2024-12-27 06:08:21 +01:00
revamp VP8LColorSpaceTransform() a bit
-> remove the 'color_transform' multiplier, use more constants, etc. This function is particularly critical, mostly because of GetBestColorTransformForTile(). Loop is a bit faster (maybe ~1%) Change-Id: I90c96a3437cafb184773acef55c77e40c224388f
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skal
parent
0c7cc4ca20
commit
32aeaf115a
@ -363,6 +363,9 @@ float VP8LFastLog2Slow(int v) {
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//------------------------------------------------------------------------------
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// Image transforms.
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// Mostly used to reduce code size + readability
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static WEBP_INLINE int GetMin(int a, int b) { return (a > b) ? b : a; }
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// In-place sum of each component with mod 256.
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static WEBP_INLINE void AddPixelsEq(uint32_t* a, uint32_t b) {
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const uint32_t alpha_and_green = (*a & 0xff00ff00u) + (b & 0xff00ff00u);
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@ -567,10 +570,8 @@ static int GetBestPredictorForTile(int width, int height,
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const int col_start = tile_x << bits;
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const int row_start = tile_y << bits;
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const int tile_size = 1 << bits;
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const int ymax = (tile_size <= height - row_start) ?
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tile_size : height - row_start;
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const int xmax = (tile_size <= width - col_start) ?
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tile_size : width - col_start;
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const int ymax = GetMin(tile_size, height - row_start);
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const int xmax = GetMin(tile_size, width - col_start);
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int histo[4][256];
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float best_diff = MAX_DIFF_COST;
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int best_mode = 0;
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@ -622,10 +623,8 @@ static void CopyTileWithPrediction(int width, int height,
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const int col_start = tile_x << bits;
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const int row_start = tile_y << bits;
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const int tile_size = 1 << bits;
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const int ymax = (tile_size <= height - row_start) ?
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tile_size : height - row_start;
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const int xmax = (tile_size <= width - col_start) ?
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tile_size : width - col_start;
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const int ymax = GetMin(tile_size, height - row_start);
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const int xmax = GetMin(tile_size, width - col_start);
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const PredictorFunc pred_func = kPredictors[mode];
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const uint32_t* current_row = argb_scratch;
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@ -899,16 +898,10 @@ static Multipliers GetBestColorTransformForTile(
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int green_to_red;
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int green_to_blue;
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int red_to_blue;
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int all_x_max = tile_x_offset + max_tile_size;
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int all_y_max = tile_y_offset + max_tile_size;
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const int all_x_max = GetMin(tile_x_offset + max_tile_size, xsize);
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const int all_y_max = GetMin(tile_y_offset + max_tile_size, ysize);
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Multipliers best_tx;
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MultipliersClear(&best_tx);
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if (all_x_max > xsize) {
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all_x_max = xsize;
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}
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if (all_y_max > ysize) {
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all_y_max = ysize;
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}
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for (green_to_red = -64; green_to_red <= 64; green_to_red += halfstep) {
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int histo[256] = { 0 };
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@ -985,96 +978,74 @@ static Multipliers GetBestColorTransformForTile(
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}
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static void CopyTileWithColorTransform(int xsize, int ysize,
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int tile_x, int tile_y, int bits,
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int tile_x, int tile_y,
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int max_tile_size,
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Multipliers color_transform,
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uint32_t* const argb) {
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int y;
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int xscan = 1 << bits;
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int yscan = 1 << bits;
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tile_x <<= bits;
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tile_y <<= bits;
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if (xscan > xsize - tile_x) {
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xscan = xsize - tile_x;
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}
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if (yscan > ysize - tile_y) {
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yscan = ysize - tile_y;
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}
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yscan += tile_y;
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for (y = tile_y; y < yscan; ++y) {
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int ix = y * xsize + tile_x;
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const int end_ix = ix + xscan;
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for (; ix < end_ix; ++ix) {
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argb[ix] = TransformColor(&color_transform, argb[ix], 0);
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uint32_t* argb) {
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const int xscan = GetMin(max_tile_size, xsize - tile_x);
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int yscan = GetMin(max_tile_size, ysize - tile_y);
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argb += tile_y * xsize + tile_x;
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while (yscan-- > 0) {
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int x;
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for (x = 0; x < xscan; ++x) {
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argb[x] = TransformColor(&color_transform, argb[x], 0);
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}
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argb += xsize;
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}
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}
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void VP8LColorSpaceTransform(int width, int height, int bits, int step,
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uint32_t* const argb, uint32_t* image) {
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const int max_tile_size = 1 << bits;
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int tile_xsize = VP8LSubSampleSize(width, bits);
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int tile_ysize = VP8LSubSampleSize(height, bits);
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const int tile_xsize = VP8LSubSampleSize(width, bits);
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const int tile_ysize = VP8LSubSampleSize(height, bits);
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int accumulated_red_histo[256] = { 0 };
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int accumulated_blue_histo[256] = { 0 };
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int tile_y;
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int tile_x;
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Multipliers prevX;
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Multipliers prevY;
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MultipliersClear(&prevY);
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MultipliersClear(&prevX);
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int tile_x, tile_y;
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Multipliers prev_x, prev_y;
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MultipliersClear(&prev_y);
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MultipliersClear(&prev_x);
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for (tile_y = 0; tile_y < tile_ysize; ++tile_y) {
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for (tile_x = 0; tile_x < tile_xsize; ++tile_x) {
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Multipliers color_transform;
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int all_x_max;
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int y;
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const int tile_y_offset = tile_y * max_tile_size;
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const int tile_x_offset = tile_x * max_tile_size;
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const int tile_y_offset = tile_y * max_tile_size;
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const int all_x_max = GetMin(tile_x_offset + max_tile_size, width);
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const int all_y_max = GetMin(tile_y_offset + max_tile_size, height);
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const int offset = tile_y * tile_xsize + tile_x;
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if (tile_y != 0) {
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ColorCodeToMultipliers(image[tile_y * tile_xsize + tile_x - 1], &prevX);
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ColorCodeToMultipliers(image[(tile_y - 1) * tile_xsize + tile_x],
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&prevY);
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} else if (tile_x != 0) {
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ColorCodeToMultipliers(image[tile_y * tile_xsize + tile_x - 1], &prevX);
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ColorCodeToMultipliers(image[offset - tile_xsize], &prev_y);
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}
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color_transform =
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GetBestColorTransformForTile(tile_x, tile_y, bits,
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prevX, prevY,
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step, width, height,
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&accumulated_red_histo[0],
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&accumulated_blue_histo[0],
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argb);
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image[tile_y * tile_xsize + tile_x] =
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MultipliersToColorCode(&color_transform);
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CopyTileWithColorTransform(width, height, tile_x, tile_y, bits,
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color_transform, argb);
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prev_x = GetBestColorTransformForTile(tile_x, tile_y, bits,
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prev_x, prev_y,
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step, width, height,
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&accumulated_red_histo[0],
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&accumulated_blue_histo[0],
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argb);
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image[offset] = MultipliersToColorCode(&prev_x);
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CopyTileWithColorTransform(width, height,
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tile_x_offset, tile_y_offset, max_tile_size,
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prev_x, argb);
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// Gather accumulated histogram data.
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all_x_max = tile_x_offset + max_tile_size;
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if (all_x_max > width) {
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all_x_max = width;
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}
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for (y = 0; y < max_tile_size; ++y) {
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int ix;
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int all_x;
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int all_y = tile_y_offset + y;
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if (all_y >= height) {
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break;
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}
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ix = all_y * width + tile_x_offset;
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for (all_x = tile_x_offset; all_x < all_x_max; ++all_x, ++ix) {
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for (y = tile_y_offset; y < all_y_max; ++y) {
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int ix = y * width + tile_x_offset;
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const int ix_end = ix + all_x_max - tile_x_offset;
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for (; ix < ix_end; ++ix) {
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const uint32_t pix = argb[ix];
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if (ix >= 2 &&
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argb[ix] == argb[ix - 2] &&
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argb[ix] == argb[ix - 1]) {
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pix == argb[ix - 2] &&
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pix == argb[ix - 1]) {
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continue; // repeated pixels are handled by backward references
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}
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if (ix >= width + 2 &&
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argb[ix - 2] == argb[ix - width - 2] &&
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argb[ix - 1] == argb[ix - width - 1] &&
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argb[ix] == argb[ix - width]) {
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pix == argb[ix - width]) {
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continue; // repeated pixels are handled by backward references
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}
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++accumulated_red_histo[(argb[ix] >> 16) & 0xff];
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++accumulated_blue_histo[argb[ix] & 0xff];
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++accumulated_red_histo[(pix >> 16) & 0xff];
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++accumulated_blue_histo[(pix >> 0) & 0xff];
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}
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}
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}
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