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dd1c3873fe
For low-color images, it may be better to not use color-palettes. Users should treat this as one another hint (as with Photo & Picture) and another parameter for tuning the compression density. The optimum compression can still be obtained by running (outer loop) compression with all possible tunable parameters. Change-Id: Icb1a4face2a84774e16e801aee4a8ae97e232e8a
133 lines
4.0 KiB
C
133 lines
4.0 KiB
C
// Copyright 2011 Google Inc. All Rights Reserved.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// Coding tools configuration
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include "../webp/encode.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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//------------------------------------------------------------------------------
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// WebPConfig
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//------------------------------------------------------------------------------
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int WebPConfigInitInternal(WebPConfig* config,
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WebPPreset preset, float quality, int version) {
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if (WEBP_ABI_IS_INCOMPATIBLE(version, WEBP_ENCODER_ABI_VERSION)) {
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return 0; // caller/system version mismatch!
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}
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if (config == NULL) return 0;
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config->quality = quality;
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config->target_size = 0;
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config->target_PSNR = 0.;
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config->method = 4;
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config->sns_strength = 50;
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config->filter_strength = 20; // default: light filtering
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config->filter_sharpness = 0;
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config->filter_type = 0; // default: simple
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config->partitions = 0;
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config->segments = 4;
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config->pass = 1;
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config->show_compressed = 0;
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config->preprocessing = 0;
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config->autofilter = 0;
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config->partition_limit = 0;
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config->alpha_compression = 1;
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config->alpha_filtering = 1;
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config->alpha_quality = 100;
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config->lossless = 0;
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config->image_hint = WEBP_HINT_DEFAULT;
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// TODO(skal): tune.
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switch (preset) {
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case WEBP_PRESET_PICTURE:
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config->sns_strength = 80;
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config->filter_sharpness = 4;
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config->filter_strength = 35;
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break;
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case WEBP_PRESET_PHOTO:
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config->sns_strength = 80;
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config->filter_sharpness = 3;
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config->filter_strength = 30;
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break;
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case WEBP_PRESET_DRAWING:
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config->sns_strength = 25;
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config->filter_sharpness = 6;
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config->filter_strength = 10;
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break;
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case WEBP_PRESET_ICON:
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config->sns_strength = 0;
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config->filter_strength = 0; // disable filtering to retain sharpness
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break;
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case WEBP_PRESET_TEXT:
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config->sns_strength = 0;
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config->filter_strength = 0; // disable filtering to retain sharpness
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config->segments = 2;
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break;
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case WEBP_PRESET_DEFAULT:
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default:
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break;
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}
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return WebPValidateConfig(config);
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}
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int WebPValidateConfig(const WebPConfig* config) {
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if (config == NULL) return 0;
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if (config->quality < 0 || config->quality > 100)
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return 0;
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if (config->target_size < 0)
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return 0;
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if (config->target_PSNR < 0)
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return 0;
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if (config->method < 0 || config->method > 6)
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return 0;
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if (config->segments < 1 || config->segments > 4)
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return 0;
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if (config->sns_strength < 0 || config->sns_strength > 100)
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return 0;
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if (config->filter_strength < 0 || config->filter_strength > 100)
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return 0;
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if (config->filter_sharpness < 0 || config->filter_sharpness > 7)
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return 0;
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if (config->filter_type < 0 || config->filter_type > 1)
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return 0;
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if (config->autofilter < 0 || config->autofilter > 1)
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return 0;
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if (config->pass < 1 || config->pass > 10)
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return 0;
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if (config->show_compressed < 0 || config->show_compressed > 1)
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return 0;
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if (config->preprocessing < 0 || config->preprocessing > 1)
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return 0;
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if (config->partitions < 0 || config->partitions > 3)
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return 0;
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if (config->partition_limit < 0 || config->partition_limit > 100)
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return 0;
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if (config->alpha_compression < 0)
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return 0;
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if (config->alpha_filtering < 0)
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return 0;
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if (config->alpha_quality < 0 || config->alpha_quality > 100)
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return 0;
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if (config->lossless < 0 || config->lossless > 1)
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return 0;
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if (config->image_hint >= WEBP_HINT_LAST)
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return 0;
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return 1;
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}
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//------------------------------------------------------------------------------
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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