// 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 "./vp8li.h" #include "../utils/bit_reader.h" #include "../utils/random.h" #include "../utils/thread.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 4 #define DEC_REV_VERSION 3 // intra prediction modes enum { B_DC_PRED = 0, // 4x4 modes B_TM_PRED, B_VE_PRED, B_HE_PRED, B_RD_PRED, B_VR_PRED, B_LD_PRED, B_VL_PRED, B_HD_PRED, B_HU_PRED, NUM_BMODES = B_HU_PRED + 1 - B_DC_PRED, // = 10 // Luma16 or UV modes DC_PRED = B_DC_PRED, V_PRED = B_VE_PRED, H_PRED = B_HE_PRED, TM_PRED = B_TM_PRED, B_PRED = NUM_BMODES, // refined I4x4 mode // special modes B_DC_PRED_NOTOP = 4, B_DC_PRED_NOLEFT = 5, B_DC_PRED_NOTOPLEFT = 6, NUM_B_DC_MODES = 7 }; enum { MB_FEATURE_TREE_PROBS = 3, NUM_MB_SEGMENTS = 4, NUM_REF_LF_DELTAS = 4, NUM_MODE_LF_DELTAS = 4, // I4x4, ZERO, *, SPLIT MAX_NUM_PARTITIONS = 8, // Probabilities NUM_TYPES = 4, NUM_BANDS = 8, NUM_CTX = 3, NUM_PROBAS = 11, NUM_MV_PROBAS = 19 }; // YUV-cache parameters. // 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 // With this layout, BPS (=Bytes Per Scan-line) is one cacheline size. #define BPS 32 // this is the common stride used by yuv[] #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]; } 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. int num_parts_; // 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_; // output. Persistent, contains the whole data. 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* 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, int row, int num_rows); //------------------------------------------------------------------------------ #ifdef __cplusplus } // extern "C" #endif #endif /* WEBP_DEC_VP8I_H_ */