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Diffstat (limited to 'media/libwebp/src/dec/vp8i_dec.h')
| -rw-r--r-- | media/libwebp/src/dec/vp8i_dec.h | 319 |
1 files changed, 319 insertions, 0 deletions
diff --git a/media/libwebp/src/dec/vp8i_dec.h b/media/libwebp/src/dec/vp8i_dec.h new file mode 100644 index 0000000000..30c1bd3ef9 --- /dev/null +++ b/media/libwebp/src/dec/vp8i_dec.h @@ -0,0 +1,319 @@ +// Copyright 2010 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. +// ----------------------------------------------------------------------------- +// +// VP8 decoder: internal header. +// +// Author: Skal (pascal.massimino@gmail.com) + +#ifndef WEBP_DEC_VP8I_DEC_H_ +#define WEBP_DEC_VP8I_DEC_H_ + +#include <string.h> // for memcpy() +#include "src/dec/common_dec.h" +#include "src/dec/vp8li_dec.h" +#include "src/utils/bit_reader_utils.h" +#include "src/utils/random_utils.h" +#include "src/utils/thread_utils.h" +#include "src/dsp/dsp.h" + +#ifdef __cplusplus +extern "C" { +#endif + +//------------------------------------------------------------------------------ +// Various defines and enums + +// version numbers +#define DEC_MAJ_VERSION 1 +#define DEC_MIN_VERSION 2 +#define DEC_REV_VERSION 4 + +// YUV-cache parameters. Cache is 32-bytes wide (= one cacheline). +// Constraints are: We need to store one 16x16 block of luma samples (y), +// and two 8x8 chroma blocks (u/v). These are better be 16-bytes aligned, +// in order to be SIMD-friendly. We also need to store the top, left and +// top-left samples (from previously decoded blocks), along with four +// extra top-right samples for luma (intra4x4 prediction only). +// One possible layout is, using 32 * (17 + 9) bytes: +// +// .+------ <- only 1 pixel high +// .|yyyyt. +// .|yyyyt. +// .|yyyyt. +// .|yyyy.. +// .+--.+-- <- only 1 pixel high +// .|uu.|vv +// .|uu.|vv +// +// Every character is a 4x4 block, with legend: +// '.' = unused +// 'y' = y-samples 'u' = u-samples 'v' = u-samples +// '|' = left sample, '-' = top sample, '+' = top-left sample +// 't' = extra top-right sample for 4x4 modes +#define YUV_SIZE (BPS * 17 + BPS * 9) +#define Y_OFF (BPS * 1 + 8) +#define U_OFF (Y_OFF + BPS * 16 + BPS) +#define V_OFF (U_OFF + 16) + +// minimal width under which lossy multi-threading is always disabled +#define MIN_WIDTH_FOR_THREADS 512 + +//------------------------------------------------------------------------------ +// Headers + +typedef struct { + uint8_t key_frame_; + uint8_t profile_; + uint8_t show_; + uint32_t partition_length_; +} VP8FrameHeader; + +typedef struct { + uint16_t width_; + uint16_t height_; + uint8_t xscale_; + uint8_t yscale_; + uint8_t colorspace_; // 0 = YCbCr + uint8_t clamp_type_; +} VP8PictureHeader; + +// segment features +typedef struct { + int use_segment_; + int update_map_; // whether to update the segment map or not + int absolute_delta_; // absolute or delta values for quantizer and filter + int8_t quantizer_[NUM_MB_SEGMENTS]; // quantization changes + int8_t filter_strength_[NUM_MB_SEGMENTS]; // filter strength for segments +} VP8SegmentHeader; + +// probas associated to one of the contexts +typedef uint8_t VP8ProbaArray[NUM_PROBAS]; + +typedef struct { // all the probas associated to one band + VP8ProbaArray probas_[NUM_CTX]; +} VP8BandProbas; + +// Struct collecting all frame-persistent probabilities. +typedef struct { + uint8_t segments_[MB_FEATURE_TREE_PROBS]; + // Type: 0:Intra16-AC 1:Intra16-DC 2:Chroma 3:Intra4 + VP8BandProbas bands_[NUM_TYPES][NUM_BANDS]; + const VP8BandProbas* bands_ptr_[NUM_TYPES][16 + 1]; +} VP8Proba; + +// Filter parameters +typedef struct { + int simple_; // 0=complex, 1=simple + int level_; // [0..63] + int sharpness_; // [0..7] + int use_lf_delta_; + int ref_lf_delta_[NUM_REF_LF_DELTAS]; + int mode_lf_delta_[NUM_MODE_LF_DELTAS]; +} VP8FilterHeader; + +//------------------------------------------------------------------------------ +// Informations about the macroblocks. + +typedef struct { // filter specs + uint8_t f_limit_; // filter limit in [3..189], or 0 if no filtering + uint8_t f_ilevel_; // inner limit in [1..63] + uint8_t f_inner_; // do inner filtering? + uint8_t hev_thresh_; // high edge variance threshold in [0..2] +} VP8FInfo; + +typedef struct { // Top/Left Contexts used for syntax-parsing + uint8_t nz_; // non-zero AC/DC coeffs (4bit for luma + 4bit for chroma) + uint8_t nz_dc_; // non-zero DC coeff (1bit) +} VP8MB; + +// Dequantization matrices +typedef int quant_t[2]; // [DC / AC]. Can be 'uint16_t[2]' too (~slower). +typedef struct { + quant_t y1_mat_, y2_mat_, uv_mat_; + + int uv_quant_; // U/V quantizer value + int dither_; // dithering amplitude (0 = off, max=255) +} VP8QuantMatrix; + +// Data needed to reconstruct a macroblock +typedef struct { + int16_t coeffs_[384]; // 384 coeffs = (16+4+4) * 4*4 + uint8_t is_i4x4_; // true if intra4x4 + uint8_t imodes_[16]; // one 16x16 mode (#0) or sixteen 4x4 modes + uint8_t uvmode_; // chroma prediction mode + // bit-wise info about the content of each sub-4x4 blocks (in decoding order). + // Each of the 4x4 blocks for y/u/v is associated with a 2b code according to: + // code=0 -> no coefficient + // code=1 -> only DC + // code=2 -> first three coefficients are non-zero + // code=3 -> more than three coefficients are non-zero + // This allows to call specialized transform functions. + uint32_t non_zero_y_; + uint32_t non_zero_uv_; + uint8_t dither_; // local dithering strength (deduced from non_zero_*) + uint8_t skip_; + uint8_t segment_; +} VP8MBData; + +// Persistent information needed by the parallel processing +typedef struct { + int id_; // cache row to process (in [0..2]) + int mb_y_; // macroblock position of the row + int filter_row_; // true if row-filtering is needed + VP8FInfo* f_info_; // filter strengths (swapped with dec->f_info_) + VP8MBData* mb_data_; // reconstruction data (swapped with dec->mb_data_) + VP8Io io_; // copy of the VP8Io to pass to put() +} VP8ThreadContext; + +// Saved top samples, per macroblock. Fits into a cache-line. +typedef struct { + uint8_t y[16], u[8], v[8]; +} VP8TopSamples; + +//------------------------------------------------------------------------------ +// VP8Decoder: the main opaque structure handed over to user + +struct VP8Decoder { + VP8StatusCode status_; + int ready_; // true if ready to decode a picture with VP8Decode() + const char* error_msg_; // set when status_ is not OK. + + // Main data source + VP8BitReader br_; + + // headers + VP8FrameHeader frm_hdr_; + VP8PictureHeader pic_hdr_; + VP8FilterHeader filter_hdr_; + VP8SegmentHeader segment_hdr_; + + // Worker + WebPWorker worker_; + int mt_method_; // multi-thread method: 0=off, 1=[parse+recon][filter] + // 2=[parse][recon+filter] + int cache_id_; // current cache row + int num_caches_; // number of cached rows of 16 pixels (1, 2 or 3) + VP8ThreadContext thread_ctx_; // Thread context + + // dimension, in macroblock units. + int mb_w_, mb_h_; + + // Macroblock to process/filter, depending on cropping and filter_type. + int tl_mb_x_, tl_mb_y_; // top-left MB that must be in-loop filtered + int br_mb_x_, br_mb_y_; // last bottom-right MB that must be decoded + + // number of partitions minus one. + uint32_t num_parts_minus_one_; + // per-partition boolean decoders. + VP8BitReader parts_[MAX_NUM_PARTITIONS]; + + // Dithering strength, deduced from decoding options + int dither_; // whether to use dithering or not + VP8Random dithering_rg_; // random generator for dithering + + // dequantization (one set of DC/AC dequant factor per segment) + VP8QuantMatrix dqm_[NUM_MB_SEGMENTS]; + + // probabilities + VP8Proba proba_; + int use_skip_proba_; + uint8_t skip_p_; + + // Boundary data cache and persistent buffers. + uint8_t* intra_t_; // top intra modes values: 4 * mb_w_ + uint8_t intra_l_[4]; // left intra modes values + + VP8TopSamples* yuv_t_; // top y/u/v samples + + VP8MB* mb_info_; // contextual macroblock info (mb_w_ + 1) + VP8FInfo* f_info_; // filter strength info + uint8_t* yuv_b_; // main block for Y/U/V (size = YUV_SIZE) + + uint8_t* cache_y_; // macroblock row for storing unfiltered samples + uint8_t* cache_u_; + uint8_t* cache_v_; + int cache_y_stride_; + int cache_uv_stride_; + + // main memory chunk for the above data. Persistent. + void* mem_; + size_t mem_size_; + + // Per macroblock non-persistent infos. + int mb_x_, mb_y_; // current position, in macroblock units + VP8MBData* mb_data_; // parsed reconstruction data + + // Filtering side-info + int filter_type_; // 0=off, 1=simple, 2=complex + VP8FInfo fstrengths_[NUM_MB_SEGMENTS][2]; // precalculated per-segment/type + + // Alpha + struct ALPHDecoder* alph_dec_; // alpha-plane decoder object + const uint8_t* alpha_data_; // compressed alpha data (if present) + size_t alpha_data_size_; + int is_alpha_decoded_; // true if alpha_data_ is decoded in alpha_plane_ + uint8_t* alpha_plane_mem_; // memory allocated for alpha_plane_ + uint8_t* alpha_plane_; // output. Persistent, contains the whole data. + const uint8_t* alpha_prev_line_; // last decoded alpha row (or NULL) + int alpha_dithering_; // derived from decoding options (0=off, 100=full) +}; + +//------------------------------------------------------------------------------ +// internal functions. Not public. + +// in vp8.c +int VP8SetError(VP8Decoder* const dec, + VP8StatusCode error, const char* const msg); + +// in tree.c +void VP8ResetProba(VP8Proba* const proba); +void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec); +// parses one row of intra mode data in partition 0, returns !eof +int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec); + +// in quant.c +void VP8ParseQuant(VP8Decoder* const dec); + +// in frame.c +int VP8InitFrame(VP8Decoder* const dec, VP8Io* const io); +// Call io->setup() and finish setting up scan parameters. +// After this call returns, one must always call VP8ExitCritical() with the +// same parameters. Both functions should be used in pair. Returns VP8_STATUS_OK +// if ok, otherwise sets and returns the error status on *dec. +VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io); +// Must always be called in pair with VP8EnterCritical(). +// Returns false in case of error. +int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io); +// Return the multi-threading method to use (0=off), depending +// on options and bitstream size. Only for lossy decoding. +int VP8GetThreadMethod(const WebPDecoderOptions* const options, + const WebPHeaderStructure* const headers, + int width, int height); +// Initialize dithering post-process if needed. +void VP8InitDithering(const WebPDecoderOptions* const options, + VP8Decoder* const dec); +// Process the last decoded row (filtering + output). +int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io); +// To be called at the start of a new scanline, to initialize predictors. +void VP8InitScanline(VP8Decoder* const dec); +// Decode one macroblock. Returns false if there is not enough data. +int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br); + +// in alpha.c +const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec, + const VP8Io* const io, + int row, int num_rows); + +//------------------------------------------------------------------------------ + +#ifdef __cplusplus +} // extern "C" +#endif + +#endif // WEBP_DEC_VP8I_DEC_H_ |