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455 lines
14 KiB
455 lines
14 KiB
// Copyright 2015 Google Inc. All Rights Reserved. |
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// |
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// Use of this source code is governed by a BSD-style license |
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// that can be found in the COPYING file in the root of the source |
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// tree. An additional intellectual property rights grant can be found |
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// in the file PATENTS. All contributing project authors may |
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// be found in the AUTHORS file in the root of the source tree. |
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// ----------------------------------------------------------------------------- |
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// |
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// Author: Mislav Bradac (mislavm@google.com) |
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// |
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#include "./delta_palettization_enc.h" |
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#ifdef WEBP_EXPERIMENTAL_FEATURES |
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#include "../webp/types.h" |
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#include "../dsp/lossless.h" |
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#define MK_COL(r, g, b) (((r) << 16) + ((g) << 8) + (b)) |
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// Format allows palette up to 256 entries, but more palette entries produce |
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// bigger entropy. In the future it will probably be useful to add more entries |
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// that are far from the origin of the palette or choose remaining entries |
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// dynamically. |
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#define DELTA_PALETTE_SIZE 226 |
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// Palette used for delta_palettization. Entries are roughly sorted by distance |
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// of their signed equivalents from the origin. |
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static const uint32_t kDeltaPalette[DELTA_PALETTE_SIZE] = { |
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MK_COL(0u, 0u, 0u), |
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MK_COL(255u, 255u, 255u), |
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MK_COL(1u, 1u, 1u), |
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MK_COL(254u, 254u, 254u), |
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MK_COL(2u, 2u, 2u), |
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MK_COL(4u, 4u, 4u), |
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MK_COL(252u, 252u, 252u), |
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MK_COL(250u, 0u, 0u), |
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MK_COL(0u, 250u, 0u), |
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MK_COL(0u, 0u, 250u), |
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MK_COL(6u, 0u, 0u), |
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MK_COL(0u, 6u, 0u), |
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MK_COL(0u, 0u, 6u), |
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MK_COL(0u, 0u, 248u), |
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MK_COL(0u, 0u, 8u), |
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MK_COL(0u, 248u, 0u), |
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MK_COL(0u, 248u, 248u), |
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MK_COL(0u, 248u, 8u), |
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MK_COL(0u, 8u, 0u), |
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MK_COL(0u, 8u, 248u), |
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MK_COL(0u, 8u, 8u), |
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MK_COL(8u, 8u, 8u), |
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MK_COL(248u, 0u, 0u), |
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MK_COL(248u, 0u, 248u), |
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MK_COL(248u, 0u, 8u), |
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MK_COL(248u, 248u, 0u), |
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MK_COL(248u, 8u, 0u), |
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MK_COL(8u, 0u, 0u), |
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MK_COL(8u, 0u, 248u), |
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MK_COL(8u, 0u, 8u), |
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MK_COL(8u, 248u, 0u), |
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MK_COL(8u, 8u, 0u), |
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MK_COL(23u, 23u, 23u), |
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MK_COL(13u, 13u, 13u), |
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MK_COL(232u, 232u, 232u), |
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MK_COL(244u, 244u, 244u), |
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MK_COL(245u, 245u, 250u), |
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MK_COL(50u, 50u, 50u), |
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MK_COL(204u, 204u, 204u), |
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MK_COL(236u, 236u, 236u), |
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MK_COL(16u, 16u, 16u), |
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MK_COL(240u, 16u, 16u), |
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MK_COL(16u, 240u, 16u), |
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MK_COL(240u, 240u, 16u), |
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MK_COL(16u, 16u, 240u), |
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MK_COL(240u, 16u, 240u), |
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MK_COL(16u, 240u, 240u), |
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MK_COL(240u, 240u, 240u), |
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MK_COL(0u, 0u, 232u), |
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MK_COL(0u, 232u, 0u), |
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MK_COL(232u, 0u, 0u), |
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MK_COL(0u, 0u, 24u), |
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MK_COL(0u, 24u, 0u), |
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MK_COL(24u, 0u, 0u), |
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MK_COL(32u, 32u, 32u), |
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MK_COL(224u, 32u, 32u), |
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MK_COL(32u, 224u, 32u), |
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MK_COL(224u, 224u, 32u), |
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MK_COL(32u, 32u, 224u), |
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MK_COL(224u, 32u, 224u), |
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MK_COL(32u, 224u, 224u), |
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MK_COL(224u, 224u, 224u), |
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MK_COL(0u, 0u, 176u), |
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MK_COL(0u, 0u, 80u), |
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MK_COL(0u, 176u, 0u), |
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MK_COL(0u, 176u, 176u), |
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MK_COL(0u, 176u, 80u), |
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MK_COL(0u, 80u, 0u), |
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MK_COL(0u, 80u, 176u), |
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MK_COL(0u, 80u, 80u), |
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MK_COL(176u, 0u, 0u), |
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MK_COL(176u, 0u, 176u), |
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MK_COL(176u, 0u, 80u), |
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MK_COL(176u, 176u, 0u), |
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MK_COL(176u, 80u, 0u), |
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MK_COL(80u, 0u, 0u), |
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MK_COL(80u, 0u, 176u), |
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MK_COL(80u, 0u, 80u), |
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MK_COL(80u, 176u, 0u), |
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MK_COL(80u, 80u, 0u), |
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MK_COL(0u, 0u, 152u), |
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MK_COL(0u, 0u, 104u), |
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MK_COL(0u, 152u, 0u), |
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MK_COL(0u, 152u, 152u), |
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MK_COL(0u, 152u, 104u), |
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MK_COL(0u, 104u, 0u), |
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MK_COL(0u, 104u, 152u), |
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MK_COL(0u, 104u, 104u), |
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MK_COL(152u, 0u, 0u), |
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MK_COL(152u, 0u, 152u), |
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MK_COL(152u, 0u, 104u), |
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MK_COL(152u, 152u, 0u), |
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MK_COL(152u, 104u, 0u), |
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MK_COL(104u, 0u, 0u), |
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MK_COL(104u, 0u, 152u), |
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MK_COL(104u, 0u, 104u), |
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MK_COL(104u, 152u, 0u), |
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MK_COL(104u, 104u, 0u), |
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MK_COL(216u, 216u, 216u), |
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MK_COL(216u, 216u, 40u), |
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MK_COL(216u, 216u, 176u), |
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MK_COL(216u, 216u, 80u), |
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MK_COL(216u, 40u, 216u), |
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MK_COL(216u, 40u, 40u), |
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MK_COL(216u, 40u, 176u), |
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MK_COL(216u, 40u, 80u), |
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MK_COL(216u, 176u, 216u), |
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MK_COL(216u, 176u, 40u), |
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MK_COL(216u, 176u, 176u), |
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MK_COL(216u, 176u, 80u), |
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MK_COL(216u, 80u, 216u), |
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MK_COL(216u, 80u, 40u), |
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MK_COL(216u, 80u, 176u), |
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MK_COL(216u, 80u, 80u), |
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MK_COL(40u, 216u, 216u), |
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MK_COL(40u, 216u, 40u), |
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MK_COL(40u, 216u, 176u), |
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MK_COL(40u, 216u, 80u), |
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MK_COL(40u, 40u, 216u), |
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MK_COL(40u, 40u, 40u), |
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MK_COL(40u, 40u, 176u), |
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MK_COL(40u, 40u, 80u), |
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MK_COL(40u, 176u, 216u), |
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MK_COL(40u, 176u, 40u), |
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MK_COL(40u, 176u, 176u), |
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MK_COL(40u, 176u, 80u), |
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MK_COL(40u, 80u, 216u), |
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MK_COL(40u, 80u, 40u), |
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MK_COL(40u, 80u, 176u), |
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MK_COL(40u, 80u, 80u), |
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MK_COL(80u, 216u, 216u), |
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MK_COL(80u, 216u, 40u), |
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MK_COL(80u, 216u, 176u), |
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MK_COL(80u, 216u, 80u), |
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MK_COL(80u, 40u, 216u), |
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MK_COL(80u, 40u, 40u), |
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MK_COL(80u, 40u, 176u), |
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MK_COL(80u, 40u, 80u), |
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MK_COL(80u, 176u, 216u), |
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MK_COL(80u, 176u, 40u), |
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MK_COL(80u, 176u, 176u), |
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MK_COL(80u, 176u, 80u), |
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MK_COL(80u, 80u, 216u), |
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MK_COL(80u, 80u, 40u), |
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MK_COL(80u, 80u, 176u), |
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MK_COL(80u, 80u, 80u), |
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MK_COL(0u, 0u, 192u), |
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MK_COL(0u, 0u, 64u), |
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MK_COL(0u, 0u, 128u), |
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MK_COL(0u, 192u, 0u), |
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MK_COL(0u, 192u, 192u), |
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MK_COL(0u, 192u, 64u), |
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MK_COL(0u, 192u, 128u), |
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MK_COL(0u, 64u, 0u), |
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MK_COL(0u, 64u, 192u), |
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MK_COL(0u, 64u, 64u), |
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MK_COL(0u, 64u, 128u), |
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MK_COL(0u, 128u, 0u), |
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MK_COL(0u, 128u, 192u), |
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MK_COL(0u, 128u, 64u), |
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MK_COL(0u, 128u, 128u), |
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MK_COL(176u, 216u, 216u), |
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MK_COL(176u, 216u, 40u), |
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MK_COL(176u, 216u, 176u), |
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MK_COL(176u, 216u, 80u), |
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MK_COL(176u, 40u, 216u), |
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MK_COL(176u, 40u, 40u), |
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MK_COL(176u, 40u, 176u), |
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MK_COL(176u, 40u, 80u), |
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MK_COL(176u, 176u, 216u), |
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MK_COL(176u, 176u, 40u), |
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MK_COL(176u, 176u, 176u), |
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MK_COL(176u, 176u, 80u), |
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MK_COL(176u, 80u, 216u), |
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MK_COL(176u, 80u, 40u), |
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MK_COL(176u, 80u, 176u), |
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MK_COL(176u, 80u, 80u), |
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MK_COL(192u, 0u, 0u), |
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MK_COL(192u, 0u, 192u), |
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MK_COL(192u, 0u, 64u), |
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MK_COL(192u, 0u, 128u), |
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MK_COL(192u, 192u, 0u), |
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MK_COL(192u, 192u, 192u), |
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MK_COL(192u, 192u, 64u), |
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MK_COL(192u, 192u, 128u), |
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MK_COL(192u, 64u, 0u), |
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MK_COL(192u, 64u, 192u), |
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MK_COL(192u, 64u, 64u), |
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MK_COL(192u, 64u, 128u), |
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MK_COL(192u, 128u, 0u), |
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MK_COL(192u, 128u, 192u), |
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MK_COL(192u, 128u, 64u), |
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MK_COL(192u, 128u, 128u), |
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MK_COL(64u, 0u, 0u), |
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MK_COL(64u, 0u, 192u), |
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MK_COL(64u, 0u, 64u), |
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MK_COL(64u, 0u, 128u), |
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MK_COL(64u, 192u, 0u), |
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MK_COL(64u, 192u, 192u), |
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MK_COL(64u, 192u, 64u), |
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MK_COL(64u, 192u, 128u), |
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MK_COL(64u, 64u, 0u), |
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MK_COL(64u, 64u, 192u), |
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MK_COL(64u, 64u, 64u), |
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MK_COL(64u, 64u, 128u), |
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MK_COL(64u, 128u, 0u), |
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MK_COL(64u, 128u, 192u), |
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MK_COL(64u, 128u, 64u), |
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MK_COL(64u, 128u, 128u), |
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MK_COL(128u, 0u, 0u), |
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MK_COL(128u, 0u, 192u), |
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MK_COL(128u, 0u, 64u), |
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MK_COL(128u, 0u, 128u), |
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MK_COL(128u, 192u, 0u), |
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MK_COL(128u, 192u, 192u), |
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MK_COL(128u, 192u, 64u), |
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MK_COL(128u, 192u, 128u), |
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MK_COL(128u, 64u, 0u), |
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MK_COL(128u, 64u, 192u), |
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MK_COL(128u, 64u, 64u), |
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MK_COL(128u, 64u, 128u), |
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MK_COL(128u, 128u, 0u), |
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MK_COL(128u, 128u, 192u), |
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MK_COL(128u, 128u, 64u), |
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MK_COL(128u, 128u, 128u), |
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}; |
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#undef MK_COL |
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//------------------------------------------------------------------------------ |
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// TODO(skal): move the functions to dsp/lossless.c when the correct |
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// granularity is found. For now, we'll just copy-paste some useful bits |
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// here instead. |
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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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const uint32_t red_and_blue = (*a & 0x00ff00ffu) + (b & 0x00ff00ffu); |
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*a = (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu); |
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} |
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static WEBP_INLINE uint32_t Clip255(uint32_t a) { |
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if (a < 256) { |
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return a; |
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} |
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// return 0, when a is a negative integer. |
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// return 255, when a is positive. |
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return ~a >> 24; |
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} |
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// Delta palettization functions. |
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static WEBP_INLINE int Square(int x) { |
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return x * x; |
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} |
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static WEBP_INLINE uint32_t Intensity(uint32_t a) { |
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return |
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30 * ((a >> 16) & 0xff) + |
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59 * ((a >> 8) & 0xff) + |
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11 * ((a >> 0) & 0xff); |
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} |
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static uint32_t CalcDist(uint32_t predicted_value, uint32_t actual_value, |
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uint32_t palette_entry) { |
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int i; |
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uint32_t distance = 0; |
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AddPixelsEq(&predicted_value, palette_entry); |
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for (i = 0; i < 32; i += 8) { |
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const int32_t av = (actual_value >> i) & 0xff; |
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const int32_t pv = (predicted_value >> i) & 0xff; |
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distance += Square(pv - av); |
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} |
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// We sum square of intensity difference with factor 10, but because Intensity |
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// returns 100 times real intensity we need to multiply differences of colors |
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// by 1000. |
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distance *= 1000u; |
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distance += Square(Intensity(predicted_value) |
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- Intensity(actual_value)); |
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return distance; |
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} |
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static uint32_t Predict(int x, int y, uint32_t* image) { |
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const uint32_t t = (y == 0) ? ARGB_BLACK : image[x]; |
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const uint32_t l = (x == 0) ? ARGB_BLACK : image[x - 1]; |
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const uint32_t p = |
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(((((t >> 24) & 0xff) + ((l >> 24) & 0xff)) / 2) << 24) + |
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(((((t >> 16) & 0xff) + ((l >> 16) & 0xff)) / 2) << 16) + |
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(((((t >> 8) & 0xff) + ((l >> 8) & 0xff)) / 2) << 8) + |
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(((((t >> 0) & 0xff) + ((l >> 0) & 0xff)) / 2) << 0); |
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if (x == 0 && y == 0) return ARGB_BLACK; |
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if (x == 0) return t; |
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if (y == 0) return l; |
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return p; |
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} |
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static WEBP_INLINE int AddSubtractComponentFullWithCoefficient( |
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int a, int b, int c) { |
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return Clip255(a + ((b - c) >> 2)); |
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} |
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static WEBP_INLINE uint32_t ClampedAddSubtractFullWithCoefficient( |
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uint32_t c0, uint32_t c1, uint32_t c2) { |
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const int a = AddSubtractComponentFullWithCoefficient( |
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c0 >> 24, c1 >> 24, c2 >> 24); |
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const int r = AddSubtractComponentFullWithCoefficient((c0 >> 16) & 0xff, |
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(c1 >> 16) & 0xff, |
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(c2 >> 16) & 0xff); |
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const int g = AddSubtractComponentFullWithCoefficient((c0 >> 8) & 0xff, |
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(c1 >> 8) & 0xff, |
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(c2 >> 8) & 0xff); |
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const int b = AddSubtractComponentFullWithCoefficient( |
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c0 & 0xff, c1 & 0xff, c2 & 0xff); |
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return ((uint32_t)a << 24) | (r << 16) | (g << 8) | b; |
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} |
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//------------------------------------------------------------------------------ |
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// Find palette entry with minimum error from difference of actual pixel value |
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// and predicted pixel value. Propagate error of pixel to its top and left pixel |
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// in src array. Write predicted_value + palette_entry to new_image. Return |
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// index of best palette entry. |
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static int FindBestPaletteEntry(uint32_t src, uint32_t predicted_value, |
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const uint32_t palette[], int palette_size) { |
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int i; |
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int idx = 0; |
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uint32_t best_distance = CalcDist(predicted_value, src, palette[0]); |
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for (i = 1; i < palette_size; ++i) { |
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const uint32_t distance = CalcDist(predicted_value, src, palette[i]); |
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if (distance < best_distance) { |
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best_distance = distance; |
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idx = i; |
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} |
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} |
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return idx; |
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} |
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static void ApplyBestPaletteEntry(int x, int y, |
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uint32_t new_value, uint32_t palette_value, |
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uint32_t* src, int src_stride, |
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uint32_t* new_image) { |
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AddPixelsEq(&new_value, palette_value); |
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if (x > 0) { |
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src[x - 1] = ClampedAddSubtractFullWithCoefficient(src[x - 1], |
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new_value, src[x]); |
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} |
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if (y > 0) { |
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src[x - src_stride] = |
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ClampedAddSubtractFullWithCoefficient(src[x - src_stride], |
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new_value, src[x]); |
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} |
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new_image[x] = new_value; |
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} |
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//------------------------------------------------------------------------------ |
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// Main entry point |
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static WebPEncodingError ApplyDeltaPalette(uint32_t* src, uint32_t* dst, |
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uint32_t src_stride, |
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uint32_t dst_stride, |
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const uint32_t* palette, |
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int palette_size, |
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int width, int height, |
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int num_passes) { |
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int x, y; |
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WebPEncodingError err = VP8_ENC_OK; |
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uint32_t* new_image = (uint32_t*)WebPSafeMalloc(width, sizeof(*new_image)); |
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uint8_t* const tmp_row = (uint8_t*)WebPSafeMalloc(width, sizeof(*tmp_row)); |
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if (new_image == NULL || tmp_row == NULL) { |
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err = VP8_ENC_ERROR_OUT_OF_MEMORY; |
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goto Error; |
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} |
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while (num_passes--) { |
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uint32_t* cur_src = src; |
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uint32_t* cur_dst = dst; |
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for (y = 0; y < height; ++y) { |
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for (x = 0; x < width; ++x) { |
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const uint32_t predicted_value = Predict(x, y, new_image); |
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tmp_row[x] = FindBestPaletteEntry(cur_src[x], predicted_value, |
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palette, palette_size); |
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ApplyBestPaletteEntry(x, y, predicted_value, palette[tmp_row[x]], |
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cur_src, src_stride, new_image); |
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} |
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for (x = 0; x < width; ++x) { |
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cur_dst[x] = palette[tmp_row[x]]; |
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} |
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cur_src += src_stride; |
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cur_dst += dst_stride; |
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} |
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} |
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Error: |
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WebPSafeFree(new_image); |
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WebPSafeFree(tmp_row); |
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return err; |
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} |
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// replaces enc->argb_ by a palettizable approximation of it, |
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// and generates optimal enc->palette_[] |
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WebPEncodingError WebPSearchOptimalDeltaPalette(VP8LEncoder* const enc) { |
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const WebPPicture* const pic = enc->pic_; |
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uint32_t* src = pic->argb; |
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uint32_t* dst = enc->argb_; |
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const int width = pic->width; |
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const int height = pic->height; |
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WebPEncodingError err = VP8_ENC_OK; |
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memcpy(enc->palette_, kDeltaPalette, sizeof(kDeltaPalette)); |
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enc->palette_[DELTA_PALETTE_SIZE - 1] = src[0] - 0xff000000u; |
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enc->palette_size_ = DELTA_PALETTE_SIZE; |
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err = ApplyDeltaPalette(src, dst, pic->argb_stride, enc->current_width_, |
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enc->palette_, enc->palette_size_, |
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width, height, 2); |
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if (err != VP8_ENC_OK) goto Error; |
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Error: |
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return err; |
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} |
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#else // !WEBP_EXPERIMENTAL_FEATURES |
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WebPEncodingError WebPSearchOptimalDeltaPalette(VP8LEncoder* const enc) { |
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(void)enc; |
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return VP8_ENC_ERROR_INVALID_CONFIGURATION; |
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} |
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#endif // WEBP_EXPERIMENTAL_FEATURES
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