From 6bf0a5cb5034a7e684dcc3500e841785237ce2dd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 19:32:43 +0200 Subject: Adding upstream version 1:115.7.0. Signed-off-by: Daniel Baumann --- media/libwebp/src/enc/alpha_enc.c | 445 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 445 insertions(+) create mode 100644 media/libwebp/src/enc/alpha_enc.c (limited to 'media/libwebp/src/enc/alpha_enc.c') diff --git a/media/libwebp/src/enc/alpha_enc.c b/media/libwebp/src/enc/alpha_enc.c new file mode 100644 index 0000000000..7d205586fe --- /dev/null +++ b/media/libwebp/src/enc/alpha_enc.c @@ -0,0 +1,445 @@ +// Copyright 2011 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. +// ----------------------------------------------------------------------------- +// +// Alpha-plane compression. +// +// Author: Skal (pascal.massimino@gmail.com) + +#include +#include +#include + +#include "src/enc/vp8i_enc.h" +#include "src/dsp/dsp.h" +#include "src/utils/filters_utils.h" +#include "src/utils/quant_levels_utils.h" +#include "src/utils/utils.h" +#include "src/webp/format_constants.h" + +// ----------------------------------------------------------------------------- +// Encodes the given alpha data via specified compression method 'method'. +// The pre-processing (quantization) is performed if 'quality' is less than 100. +// For such cases, the encoding is lossy. The valid range is [0, 100] for +// 'quality' and [0, 1] for 'method': +// 'method = 0' - No compression; +// 'method = 1' - Use lossless coder on the alpha plane only +// 'filter' values [0, 4] correspond to prediction modes none, horizontal, +// vertical & gradient filters. The prediction mode 4 will try all the +// prediction modes 0 to 3 and pick the best one. +// 'effort_level': specifies how much effort must be spent to try and reduce +// the compressed output size. In range 0 (quick) to 6 (slow). +// +// 'output' corresponds to the buffer containing compressed alpha data. +// This buffer is allocated by this method and caller should call +// WebPSafeFree(*output) when done. +// 'output_size' corresponds to size of this compressed alpha buffer. +// +// Returns 1 on successfully encoding the alpha and +// 0 if either: +// invalid quality or method, or +// memory allocation for the compressed data fails. + +#include "src/enc/vp8li_enc.h" + +static int EncodeLossless(const uint8_t* const data, int width, int height, + int effort_level, // in [0..6] range + int use_quality_100, VP8LBitWriter* const bw, + WebPAuxStats* const stats) { + int ok = 0; + WebPConfig config; + WebPPicture picture; + + WebPPictureInit(&picture); + picture.width = width; + picture.height = height; + picture.use_argb = 1; + picture.stats = stats; + if (!WebPPictureAlloc(&picture)) return 0; + + // Transfer the alpha values to the green channel. + WebPDispatchAlphaToGreen(data, width, picture.width, picture.height, + picture.argb, picture.argb_stride); + + WebPConfigInit(&config); + config.lossless = 1; + // Enable exact, or it would alter RGB values of transparent alpha, which is + // normally OK but not here since we are not encoding the input image but an + // internal encoding-related image containing necessary exact information in + // RGB channels. + config.exact = 1; + config.method = effort_level; // impact is very small + // Set a low default quality for encoding alpha. Ensure that Alpha quality at + // lower methods (3 and below) is less than the threshold for triggering + // costly 'BackwardReferencesTraceBackwards'. + // If the alpha quality is set to 100 and the method to 6, allow for a high + // lossless quality to trigger the cruncher. + config.quality = + (use_quality_100 && effort_level == 6) ? 100 : 8.f * effort_level; + assert(config.quality >= 0 && config.quality <= 100.f); + + // TODO(urvang): Temporary fix to avoid generating images that trigger + // a decoder bug related to alpha with color cache. + // See: https://code.google.com/p/webp/issues/detail?id=239 + // Need to re-enable this later. + ok = VP8LEncodeStream(&config, &picture, bw, /*use_cache=*/0); + WebPPictureFree(&picture); + ok = ok && !bw->error_; + if (!ok) { + VP8LBitWriterWipeOut(bw); + return 0; + } + return 1; +} + +// ----------------------------------------------------------------------------- + +// Small struct to hold the result of a filter mode compression attempt. +typedef struct { + size_t score; + VP8BitWriter bw; + WebPAuxStats stats; +} FilterTrial; + +// This function always returns an initialized 'bw' object, even upon error. +static int EncodeAlphaInternal(const uint8_t* const data, int width, int height, + int method, int filter, int reduce_levels, + int effort_level, // in [0..6] range + uint8_t* const tmp_alpha, + FilterTrial* result) { + int ok = 0; + const uint8_t* alpha_src; + WebPFilterFunc filter_func; + uint8_t header; + const size_t data_size = width * height; + const uint8_t* output = NULL; + size_t output_size = 0; + VP8LBitWriter tmp_bw; + + assert((uint64_t)data_size == (uint64_t)width * height); // as per spec + assert(filter >= 0 && filter < WEBP_FILTER_LAST); + assert(method >= ALPHA_NO_COMPRESSION); + assert(method <= ALPHA_LOSSLESS_COMPRESSION); + assert(sizeof(header) == ALPHA_HEADER_LEN); + + filter_func = WebPFilters[filter]; + if (filter_func != NULL) { + filter_func(data, width, height, width, tmp_alpha); + alpha_src = tmp_alpha; + } else { + alpha_src = data; + } + + if (method != ALPHA_NO_COMPRESSION) { + ok = VP8LBitWriterInit(&tmp_bw, data_size >> 3); + ok = ok && EncodeLossless(alpha_src, width, height, effort_level, + !reduce_levels, &tmp_bw, &result->stats); + if (ok) { + output = VP8LBitWriterFinish(&tmp_bw); + output_size = VP8LBitWriterNumBytes(&tmp_bw); + if (output_size > data_size) { + // compressed size is larger than source! Revert to uncompressed mode. + method = ALPHA_NO_COMPRESSION; + VP8LBitWriterWipeOut(&tmp_bw); + } + } else { + VP8LBitWriterWipeOut(&tmp_bw); + memset(&result->bw, 0, sizeof(result->bw)); + return 0; + } + } + + if (method == ALPHA_NO_COMPRESSION) { + output = alpha_src; + output_size = data_size; + ok = 1; + } + + // Emit final result. + header = method | (filter << 2); + if (reduce_levels) header |= ALPHA_PREPROCESSED_LEVELS << 4; + + if (!VP8BitWriterInit(&result->bw, ALPHA_HEADER_LEN + output_size)) ok = 0; + ok = ok && VP8BitWriterAppend(&result->bw, &header, ALPHA_HEADER_LEN); + ok = ok && VP8BitWriterAppend(&result->bw, output, output_size); + + if (method != ALPHA_NO_COMPRESSION) { + VP8LBitWriterWipeOut(&tmp_bw); + } + ok = ok && !result->bw.error_; + result->score = VP8BitWriterSize(&result->bw); + return ok; +} + +// ----------------------------------------------------------------------------- + +static int GetNumColors(const uint8_t* data, int width, int height, + int stride) { + int j; + int colors = 0; + uint8_t color[256] = { 0 }; + + for (j = 0; j < height; ++j) { + int i; + const uint8_t* const p = data + j * stride; + for (i = 0; i < width; ++i) { + color[p[i]] = 1; + } + } + for (j = 0; j < 256; ++j) { + if (color[j] > 0) ++colors; + } + return colors; +} + +#define FILTER_TRY_NONE (1 << WEBP_FILTER_NONE) +#define FILTER_TRY_ALL ((1 << WEBP_FILTER_LAST) - 1) + +// Given the input 'filter' option, return an OR'd bit-set of filters to try. +static uint32_t GetFilterMap(const uint8_t* alpha, int width, int height, + int filter, int effort_level) { + uint32_t bit_map = 0U; + if (filter == WEBP_FILTER_FAST) { + // Quick estimate of the best candidate. + int try_filter_none = (effort_level > 3); + const int kMinColorsForFilterNone = 16; + const int kMaxColorsForFilterNone = 192; + const int num_colors = GetNumColors(alpha, width, height, width); + // For low number of colors, NONE yields better compression. + filter = (num_colors <= kMinColorsForFilterNone) + ? WEBP_FILTER_NONE + : WebPEstimateBestFilter(alpha, width, height, width); + bit_map |= 1 << filter; + // For large number of colors, try FILTER_NONE in addition to the best + // filter as well. + if (try_filter_none || num_colors > kMaxColorsForFilterNone) { + bit_map |= FILTER_TRY_NONE; + } + } else if (filter == WEBP_FILTER_NONE) { + bit_map = FILTER_TRY_NONE; + } else { // WEBP_FILTER_BEST -> try all + bit_map = FILTER_TRY_ALL; + } + return bit_map; +} + +static void InitFilterTrial(FilterTrial* const score) { + score->score = (size_t)~0U; + VP8BitWriterInit(&score->bw, 0); +} + +static int ApplyFiltersAndEncode(const uint8_t* alpha, int width, int height, + size_t data_size, int method, int filter, + int reduce_levels, int effort_level, + uint8_t** const output, + size_t* const output_size, + WebPAuxStats* const stats) { + int ok = 1; + FilterTrial best; + uint32_t try_map = + GetFilterMap(alpha, width, height, filter, effort_level); + InitFilterTrial(&best); + + if (try_map != FILTER_TRY_NONE) { + uint8_t* filtered_alpha = (uint8_t*)WebPSafeMalloc(1ULL, data_size); + if (filtered_alpha == NULL) return 0; + + for (filter = WEBP_FILTER_NONE; ok && try_map; ++filter, try_map >>= 1) { + if (try_map & 1) { + FilterTrial trial; + ok = EncodeAlphaInternal(alpha, width, height, method, filter, + reduce_levels, effort_level, filtered_alpha, + &trial); + if (ok && trial.score < best.score) { + VP8BitWriterWipeOut(&best.bw); + best = trial; + } else { + VP8BitWriterWipeOut(&trial.bw); + } + } + } + WebPSafeFree(filtered_alpha); + } else { + ok = EncodeAlphaInternal(alpha, width, height, method, WEBP_FILTER_NONE, + reduce_levels, effort_level, NULL, &best); + } + if (ok) { +#if !defined(WEBP_DISABLE_STATS) + if (stats != NULL) { + stats->lossless_features = best.stats.lossless_features; + stats->histogram_bits = best.stats.histogram_bits; + stats->transform_bits = best.stats.transform_bits; + stats->cache_bits = best.stats.cache_bits; + stats->palette_size = best.stats.palette_size; + stats->lossless_size = best.stats.lossless_size; + stats->lossless_hdr_size = best.stats.lossless_hdr_size; + stats->lossless_data_size = best.stats.lossless_data_size; + } +#else + (void)stats; +#endif + *output_size = VP8BitWriterSize(&best.bw); + *output = VP8BitWriterBuf(&best.bw); + } else { + VP8BitWriterWipeOut(&best.bw); + } + return ok; +} + +static int EncodeAlpha(VP8Encoder* const enc, + int quality, int method, int filter, + int effort_level, + uint8_t** const output, size_t* const output_size) { + const WebPPicture* const pic = enc->pic_; + const int width = pic->width; + const int height = pic->height; + + uint8_t* quant_alpha = NULL; + const size_t data_size = width * height; + uint64_t sse = 0; + int ok = 1; + const int reduce_levels = (quality < 100); + + // quick correctness checks + assert((uint64_t)data_size == (uint64_t)width * height); // as per spec + assert(enc != NULL && pic != NULL && pic->a != NULL); + assert(output != NULL && output_size != NULL); + assert(width > 0 && height > 0); + assert(pic->a_stride >= width); + assert(filter >= WEBP_FILTER_NONE && filter <= WEBP_FILTER_FAST); + + if (quality < 0 || quality > 100) { + return 0; + } + + if (method < ALPHA_NO_COMPRESSION || method > ALPHA_LOSSLESS_COMPRESSION) { + return 0; + } + + if (method == ALPHA_NO_COMPRESSION) { + // Don't filter, as filtering will make no impact on compressed size. + filter = WEBP_FILTER_NONE; + } + + quant_alpha = (uint8_t*)WebPSafeMalloc(1ULL, data_size); + if (quant_alpha == NULL) { + return 0; + } + + // Extract alpha data (width x height) from raw_data (stride x height). + WebPCopyPlane(pic->a, pic->a_stride, quant_alpha, width, width, height); + + if (reduce_levels) { // No Quantization required for 'quality = 100'. + // 16 alpha levels gives quite a low MSE w.r.t original alpha plane hence + // mapped to moderate quality 70. Hence Quality:[0, 70] -> Levels:[2, 16] + // and Quality:]70, 100] -> Levels:]16, 256]. + const int alpha_levels = (quality <= 70) ? (2 + quality / 5) + : (16 + (quality - 70) * 8); + ok = QuantizeLevels(quant_alpha, width, height, alpha_levels, &sse); + } + + if (ok) { + VP8FiltersInit(); + ok = ApplyFiltersAndEncode(quant_alpha, width, height, data_size, method, + filter, reduce_levels, effort_level, output, + output_size, pic->stats); +#if !defined(WEBP_DISABLE_STATS) + if (pic->stats != NULL) { // need stats? + pic->stats->coded_size += (int)(*output_size); + enc->sse_[3] = sse; + } +#endif + } + + WebPSafeFree(quant_alpha); + return ok; +} + +//------------------------------------------------------------------------------ +// Main calls + +static int CompressAlphaJob(void* arg1, void* unused) { + VP8Encoder* const enc = (VP8Encoder*)arg1; + const WebPConfig* config = enc->config_; + uint8_t* alpha_data = NULL; + size_t alpha_size = 0; + const int effort_level = config->method; // maps to [0..6] + const WEBP_FILTER_TYPE filter = + (config->alpha_filtering == 0) ? WEBP_FILTER_NONE : + (config->alpha_filtering == 1) ? WEBP_FILTER_FAST : + WEBP_FILTER_BEST; + if (!EncodeAlpha(enc, config->alpha_quality, config->alpha_compression, + filter, effort_level, &alpha_data, &alpha_size)) { + return 0; + } + if (alpha_size != (uint32_t)alpha_size) { // Soundness check. + WebPSafeFree(alpha_data); + return 0; + } + enc->alpha_data_size_ = (uint32_t)alpha_size; + enc->alpha_data_ = alpha_data; + (void)unused; + return 1; +} + +void VP8EncInitAlpha(VP8Encoder* const enc) { + WebPInitAlphaProcessing(); + enc->has_alpha_ = WebPPictureHasTransparency(enc->pic_); + enc->alpha_data_ = NULL; + enc->alpha_data_size_ = 0; + if (enc->thread_level_ > 0) { + WebPWorker* const worker = &enc->alpha_worker_; + WebPGetWorkerInterface()->Init(worker); + worker->data1 = enc; + worker->data2 = NULL; + worker->hook = CompressAlphaJob; + } +} + +int VP8EncStartAlpha(VP8Encoder* const enc) { + if (enc->has_alpha_) { + if (enc->thread_level_ > 0) { + WebPWorker* const worker = &enc->alpha_worker_; + // Makes sure worker is good to go. + if (!WebPGetWorkerInterface()->Reset(worker)) { + return 0; + } + WebPGetWorkerInterface()->Launch(worker); + return 1; + } else { + return CompressAlphaJob(enc, NULL); // just do the job right away + } + } + return 1; +} + +int VP8EncFinishAlpha(VP8Encoder* const enc) { + if (enc->has_alpha_) { + if (enc->thread_level_ > 0) { + WebPWorker* const worker = &enc->alpha_worker_; + if (!WebPGetWorkerInterface()->Sync(worker)) return 0; // error + } + } + return WebPReportProgress(enc->pic_, enc->percent_ + 20, &enc->percent_); +} + +int VP8EncDeleteAlpha(VP8Encoder* const enc) { + int ok = 1; + if (enc->thread_level_ > 0) { + WebPWorker* const worker = &enc->alpha_worker_; + // finish anything left in flight + ok = WebPGetWorkerInterface()->Sync(worker); + // still need to end the worker, even if !ok + WebPGetWorkerInterface()->End(worker); + } + WebPSafeFree(enc->alpha_data_); + enc->alpha_data_ = NULL; + enc->alpha_data_size_ = 0; + enc->has_alpha_ = 0; + return ok; +} -- cgit v1.2.3