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+// 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_H_
+#define WEBP_DEC_VP8I_H_
+
+#include <string.h> // for memcpy()
+#include "./common_dec.h"
+#include "./vp8li_dec.h"
+#include "../utils/bit_reader_utils.h"
+#include "../utils/random_utils.h"
+#include "../utils/thread_utils.h"
+#include "../dsp/dsp.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+//------------------------------------------------------------------------------
+// Various defines and enums
+
+// version numbers
+#define DEC_MAJ_VERSION 0
+#define DEC_MIN_VERSION 6
+#define DEC_REV_VERSION 0
+
+// 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_SIZE (BPS * 17)
+#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_H_ */