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Diffstat (limited to 'drivers/webp/enc/near_lossless.c')
-rw-r--r-- | drivers/webp/enc/near_lossless.c | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/drivers/webp/enc/near_lossless.c b/drivers/webp/enc/near_lossless.c deleted file mode 100644 index f4ab91f571..0000000000 --- a/drivers/webp/enc/near_lossless.c +++ /dev/null @@ -1,122 +0,0 @@ -// Copyright 2014 Google Inc. All Rights Reserved. -// -// Use of this source code is governed by a BSD-style license -// that can be found in the COPYING file in the root of the source -// tree. An additional intellectual property rights grant can be found -// in the file PATENTS. All contributing project authors may -// be found in the AUTHORS file in the root of the source tree. -// ----------------------------------------------------------------------------- -// -// Near-lossless image preprocessing adjusts pixel values to help -// compressibility with a guarantee of maximum deviation between original and -// resulting pixel values. -// -// Author: Jyrki Alakuijala (jyrki@google.com) -// Converted to C by Aleksander Kramarz (akramarz@google.com) - -#include <assert.h> -#include <stdlib.h> - -#include "../dsp/lossless.h" -#include "../utils/utils.h" -#include "./vp8enci.h" - -#define MIN_DIM_FOR_NEAR_LOSSLESS 64 -#define MAX_LIMIT_BITS 5 - -// Quantizes the value up or down to a multiple of 1<<bits (or to 255), -// choosing the closer one, resolving ties using bankers' rounding. -static int FindClosestDiscretized(int a, int bits) { - const int mask = (1 << bits) - 1; - const int biased = a + (mask >> 1) + ((a >> bits) & 1); - assert(bits > 0); - if (biased > 0xff) return 0xff; - return biased & ~mask; -} - -// Applies FindClosestDiscretized to all channels of pixel. -static uint32_t ClosestDiscretizedArgb(uint32_t a, int bits) { - return - (FindClosestDiscretized(a >> 24, bits) << 24) | - (FindClosestDiscretized((a >> 16) & 0xff, bits) << 16) | - (FindClosestDiscretized((a >> 8) & 0xff, bits) << 8) | - (FindClosestDiscretized(a & 0xff, bits)); -} - -// Checks if distance between corresponding channel values of pixels a and b -// is within the given limit. -static int IsNear(uint32_t a, uint32_t b, int limit) { - int k; - for (k = 0; k < 4; ++k) { - const int delta = - (int)((a >> (k * 8)) & 0xff) - (int)((b >> (k * 8)) & 0xff); - if (delta >= limit || delta <= -limit) { - return 0; - } - } - return 1; -} - -static int IsSmooth(const uint32_t* const prev_row, - const uint32_t* const curr_row, - const uint32_t* const next_row, - int ix, int limit) { - // Check that all pixels in 4-connected neighborhood are smooth. - return (IsNear(curr_row[ix], curr_row[ix - 1], limit) && - IsNear(curr_row[ix], curr_row[ix + 1], limit) && - IsNear(curr_row[ix], prev_row[ix], limit) && - IsNear(curr_row[ix], next_row[ix], limit)); -} - -// Adjusts pixel values of image with given maximum error. -static void NearLossless(int xsize, int ysize, uint32_t* argb, - int limit_bits, uint32_t* copy_buffer) { - int x, y; - const int limit = 1 << limit_bits; - uint32_t* prev_row = copy_buffer; - uint32_t* curr_row = prev_row + xsize; - uint32_t* next_row = curr_row + xsize; - memcpy(copy_buffer, argb, xsize * 2 * sizeof(argb[0])); - - for (y = 1; y < ysize - 1; ++y) { - uint32_t* const curr_argb_row = argb + y * xsize; - uint32_t* const next_argb_row = curr_argb_row + xsize; - memcpy(next_row, next_argb_row, xsize * sizeof(argb[0])); - for (x = 1; x < xsize - 1; ++x) { - if (!IsSmooth(prev_row, curr_row, next_row, x, limit)) { - curr_argb_row[x] = ClosestDiscretizedArgb(curr_row[x], limit_bits); - } - } - { - // Three-way swap. - uint32_t* const temp = prev_row; - prev_row = curr_row; - curr_row = next_row; - next_row = temp; - } - } -} - -int VP8ApplyNearLossless(int xsize, int ysize, uint32_t* argb, int quality) { - int i; - uint32_t* const copy_buffer = - (uint32_t*)WebPSafeMalloc(xsize * 3, sizeof(*copy_buffer)); - const int limit_bits = VP8LNearLosslessBits(quality); - assert(argb != NULL); - assert(limit_bits >= 0); - assert(limit_bits <= MAX_LIMIT_BITS); - if (copy_buffer == NULL) { - return 0; - } - // For small icon images, don't attempt to apply near-lossless compression. - if (xsize < MIN_DIM_FOR_NEAR_LOSSLESS && ysize < MIN_DIM_FOR_NEAR_LOSSLESS) { - WebPSafeFree(copy_buffer); - return 1; - } - - for (i = limit_bits; i != 0; --i) { - NearLossless(xsize, ysize, argb, i, copy_buffer); - } - WebPSafeFree(copy_buffer); - return 1; -} |