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// 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.
// -----------------------------------------------------------------------------
// WebP encoder: internal header.
// Author: Skal (
#ifndef WEBP_ENC_VP8I_ENC_H_
#define WEBP_ENC_VP8I_ENC_H_
#if !defined(STARBOARD)
#include <string.h> // for memcpy()
#include "src/dec/common_dec.h"
#include "src/dsp/dsp.h"
#include "src/utils/bit_writer_utils.h"
#include "src/utils/thread_utils.h"
#include "src/utils/utils.h"
#include "src/webp/encode.h"
#ifdef __cplusplus
extern "C" {
// Various defines and enums
// version numbers
enum { MAX_LF_LEVELS = 64, // Maximum loop filter level
MAX_VARIABLE_LEVEL = 67, // last (inclusive) level with variable cost
MAX_LEVEL = 2047 // max level (note: max codable is 2047 + 67)
typedef enum { // Rate-distortion optimization levels
RD_OPT_NONE = 0, // no rd-opt
RD_OPT_BASIC = 1, // basic scoring (no trellis)
RD_OPT_TRELLIS = 2, // perform trellis-quant on the final decision only
RD_OPT_TRELLIS_ALL = 3 // trellis-quant for every scoring (much slower)
} VP8RDLevel;
// YUV-cache parameters. Cache is 32-bytes wide (= one cacheline).
// The original or reconstructed samples can be accessed using VP8Scan[].
// The predicted blocks can be accessed using offsets to yuv_p_ and
// the arrays VP8*ModeOffsets[].
// * YUV Samples area (yuv_in_/yuv_out_/yuv_out2_)
// (see VP8Scan[] for accessing the blocks, along with
// +----+----+
// V_OFF_ENC |YYYY|....| <- 25% wasted U/V area
// |YYYY|....|
// +----+----+
// * Prediction area ('yuv_p_', size = PRED_SIZE_ENC)
// Intra16 predictions (16x16 block each, two per row):
// |I16DC16|I16TM16|
// |I16VE16|I16HE16|
// Chroma U/V predictions (16x8 block each, two per row):
// |C8DC8|C8TM8|
// |C8VE8|C8HE8|
// Intra 4x4 predictions (4x4 block each)
// |I4DC4 I4TM4 I4VE4 I4HE4|I4RD4 I4VR4 I4LD4 I4VL4|
// |I4HD4 I4HU4 I4TMP .....|.......................| <- ~31% wasted
#define YUV_SIZE_ENC (BPS * 16)
#define PRED_SIZE_ENC (32 * BPS + 16 * BPS + 8 * BPS) // I16+Chroma+I4 preds
#define Y_OFF_ENC (0)
#define U_OFF_ENC (16)
#define V_OFF_ENC (16 + 8)
extern const uint16_t VP8Scan[16];
extern const uint16_t VP8UVModeOffsets[4];
extern const uint16_t VP8I16ModeOffsets[4];
extern const uint16_t VP8I4ModeOffsets[NUM_BMODES];
// Layout of prediction blocks
// intra 16x16
#define I16DC16 (0 * 16 * BPS)
#define I16TM16 (I16DC16 + 16)
#define I16VE16 (1 * 16 * BPS)
#define I16HE16 (I16VE16 + 16)
// chroma 8x8, two U/V blocks side by side (hence: 16x8 each)
#define C8DC8 (2 * 16 * BPS)
#define C8TM8 (C8DC8 + 1 * 16)
#define C8VE8 (2 * 16 * BPS + 8 * BPS)
#define C8HE8 (C8VE8 + 1 * 16)
// intra 4x4
#define I4DC4 (3 * 16 * BPS + 0)
#define I4TM4 (I4DC4 + 4)
#define I4VE4 (I4DC4 + 8)
#define I4HE4 (I4DC4 + 12)
#define I4RD4 (I4DC4 + 16)
#define I4VR4 (I4DC4 + 20)
#define I4LD4 (I4DC4 + 24)
#define I4VL4 (I4DC4 + 28)
#define I4HD4 (3 * 16 * BPS + 4 * BPS)
#define I4HU4 (I4HD4 + 4)
#define I4TMP (I4HD4 + 8)
typedef int64_t score_t; // type used for scores, rate, distortion
// Note that MAX_COST is not the maximum allowed by sizeof(score_t),
// in order to allow overflowing computations.
#define MAX_COST ((score_t)0x7fffffffffffffLL)
#define QFIX 17
#define BIAS(b) ((b) << (QFIX - 8))
// Fun fact: this is the _only_ line where we're actually being lossy and
// discarding bits.
static WEBP_INLINE int QUANTDIV(uint32_t n, uint32_t iQ, uint32_t B) {
return (int)((n * iQ + B) >> QFIX);
// Uncomment the following to remove token-buffer code:
// quality below which error-diffusion is enabled
// Headers
typedef uint32_t proba_t; // 16b + 16b
typedef uint8_t ProbaArray[NUM_CTX][NUM_PROBAS];
typedef proba_t StatsArray[NUM_CTX][NUM_PROBAS];
typedef uint16_t CostArray[NUM_CTX][MAX_VARIABLE_LEVEL + 1];
typedef const uint16_t* (*CostArrayPtr)[NUM_CTX]; // for easy casting
typedef const uint16_t* CostArrayMap[16][NUM_CTX];
typedef double LFStats[NUM_MB_SEGMENTS][MAX_LF_LEVELS]; // filter stats
typedef struct VP8Encoder VP8Encoder;
// segment features
typedef struct {
int num_segments_; // Actual number of segments. 1 segment only = unused.
int update_map_; // whether to update the segment map or not.
// must be 0 if there's only 1 segment.
int size_; // bit-cost for transmitting the segment map
} VP8EncSegmentHeader;
// Struct collecting all frame-persistent probabilities.
typedef struct {
uint8_t segments_[3]; // probabilities for segment tree
uint8_t skip_proba_; // final probability of being skipped.
ProbaArray coeffs_[NUM_TYPES][NUM_BANDS]; // 1056 bytes
StatsArray stats_[NUM_TYPES][NUM_BANDS]; // 4224 bytes
CostArray level_cost_[NUM_TYPES][NUM_BANDS]; // 13056 bytes
CostArrayMap remapped_costs_[NUM_TYPES]; // 1536 bytes
int dirty_; // if true, need to call VP8CalculateLevelCosts()
int use_skip_proba_; // Note: we always use skip_proba for now.
int nb_skip_; // number of skipped blocks
} VP8EncProba;
// Filter parameters. Not actually used in the code (we don't perform
// the in-loop filtering), but filled from user's config
typedef struct {
int simple_; // filtering type: 0=complex, 1=simple
int level_; // base filter level [0..63]
int sharpness_; // [0..7]
int i4x4_lf_delta_; // delta filter level for i4x4 relative to i16x16
} VP8EncFilterHeader;
// Informations about the macroblocks.
typedef struct {
// block type
unsigned int type_:2; // 0=i4x4, 1=i16x16
unsigned int uv_mode_:2;
unsigned int skip_:1;
unsigned int segment_:2;
uint8_t alpha_; // quantization-susceptibility
} VP8MBInfo;
typedef struct VP8Matrix {
uint16_t q_[16]; // quantizer steps
uint16_t iq_[16]; // reciprocals, fixed point.
uint32_t bias_[16]; // rounding bias
uint32_t zthresh_[16]; // value below which a coefficient is zeroed
uint16_t sharpen_[16]; // frequency boosters for slight sharpening
} VP8Matrix;
typedef struct {
VP8Matrix y1_, y2_, uv_; // quantization matrices
int alpha_; // quant-susceptibility, range [-127,127]. Zero is neutral.
// Lower values indicate a lower risk of blurriness.
int beta_; // filter-susceptibility, range [0,255].
int quant_; // final segment quantizer.
int fstrength_; // final in-loop filtering strength
int max_edge_; // max edge delta (for filtering strength)
int min_disto_; // minimum distortion required to trigger filtering record
// reactivities
int lambda_i16_, lambda_i4_, lambda_uv_;
int lambda_mode_, lambda_trellis_, tlambda_;
int lambda_trellis_i16_, lambda_trellis_i4_, lambda_trellis_uv_;
// lambda values for distortion-based evaluation
score_t i4_penalty_; // penalty for using Intra4
} VP8SegmentInfo;
typedef int8_t DError[2 /* u/v */][2 /* top or left */];
// Handy transient struct to accumulate score and info during RD-optimization
// and mode evaluation.
typedef struct {
score_t D, SD; // Distortion, spectral distortion
score_t H, R, score; // header bits, rate, score.
int16_t y_dc_levels[16]; // Quantized levels for luma-DC, luma-AC, chroma.
int16_t y_ac_levels[16][16];
int16_t uv_levels[4 + 4][16];
int mode_i16; // mode number for intra16 prediction
uint8_t modes_i4[16]; // mode numbers for intra4 predictions
int mode_uv; // mode number of chroma prediction
uint32_t nz; // non-zero blocks
int8_t derr[2][3]; // DC diffusion errors for U/V for blocks #1/2/3
} VP8ModeScore;
// Iterator structure to iterate through macroblocks, pointing to the
// right neighbouring data (samples, predictions, contexts, ...)
typedef struct {
int x_, y_; // current macroblock
uint8_t* yuv_in_; // input samples
uint8_t* yuv_out_; // output samples
uint8_t* yuv_out2_; // secondary buffer swapped with yuv_out_.
uint8_t* yuv_p_; // scratch buffer for prediction
VP8Encoder* enc_; // back-pointer
VP8MBInfo* mb_; // current macroblock
VP8BitWriter* bw_; // current bit-writer
uint8_t* preds_; // intra mode predictors (4x4 blocks)
uint32_t* nz_; // non-zero pattern
uint8_t i4_boundary_[37]; // 32+5 boundary samples needed by intra4x4
uint8_t* i4_top_; // pointer to the current top boundary sample
int i4_; // current intra4x4 mode being tested
int top_nz_[9]; // top-non-zero context.
int left_nz_[9]; // left-non-zero. left_nz[8] is independent.
uint64_t bit_count_[4][3]; // bit counters for coded levels.
uint64_t luma_bits_; // macroblock bit-cost for luma
uint64_t uv_bits_; // macroblock bit-cost for chroma
LFStats* lf_stats_; // filter stats (borrowed from enc_)
int do_trellis_; // if true, perform extra level optimisation
int count_down_; // number of mb still to be processed
int count_down0_; // starting counter value (for progress)
int percent0_; // saved initial progress percent
DError left_derr_; // left error diffusion (u/v)
DError *top_derr_; // top diffusion error - NULL if disabled
uint8_t* y_left_; // left luma samples (addressable from index -1 to 15).
uint8_t* u_left_; // left u samples (addressable from index -1 to 7)
uint8_t* v_left_; // left v samples (addressable from index -1 to 7)
uint8_t* y_top_; // top luma samples at position 'x_'
uint8_t* uv_top_; // top u/v samples at position 'x_', packed as 16 bytes
// memory for storing y/u/v_left_
uint8_t yuv_left_mem_[17 + 16 + 16 + 8 + WEBP_ALIGN_CST];
// memory for yuv_*
uint8_t yuv_mem_[3 * YUV_SIZE_ENC + PRED_SIZE_ENC + WEBP_ALIGN_CST];
} VP8EncIterator;
// in iterator.c
// must be called first
void VP8IteratorInit(VP8Encoder* const enc, VP8EncIterator* const it);
// restart a scan
void VP8IteratorReset(VP8EncIterator* const it);
// reset iterator position to row 'y'
void VP8IteratorSetRow(VP8EncIterator* const it, int y);
// set count down (=number of iterations to go)
void VP8IteratorSetCountDown(VP8EncIterator* const it, int count_down);
// return true if iteration is finished
int VP8IteratorIsDone(const VP8EncIterator* const it);
// Import uncompressed samples from source.
// If tmp_32 is not NULL, import boundary samples too.
// tmp_32 is a 32-bytes scratch buffer that must be aligned in memory.
void VP8IteratorImport(VP8EncIterator* const it, uint8_t* tmp_32);
// export decimated samples
void VP8IteratorExport(const VP8EncIterator* const it);
// go to next macroblock. Returns false if not finished.
int VP8IteratorNext(VP8EncIterator* const it);
// save the yuv_out_ boundary values to top_/left_ arrays for next iterations.
void VP8IteratorSaveBoundary(VP8EncIterator* const it);
// Report progression based on macroblock rows. Return 0 for user-abort request.
int VP8IteratorProgress(const VP8EncIterator* const it,
int final_delta_percent);
// Intra4x4 iterations
void VP8IteratorStartI4(VP8EncIterator* const it);
// returns true if not done.
int VP8IteratorRotateI4(VP8EncIterator* const it,
const uint8_t* const yuv_out);
// Non-zero context setup/teardown
void VP8IteratorNzToBytes(VP8EncIterator* const it);
void VP8IteratorBytesToNz(VP8EncIterator* const it);
// Helper functions to set mode properties
void VP8SetIntra16Mode(const VP8EncIterator* const it, int mode);
void VP8SetIntra4Mode(const VP8EncIterator* const it, const uint8_t* modes);
void VP8SetIntraUVMode(const VP8EncIterator* const it, int mode);
void VP8SetSkip(const VP8EncIterator* const it, int skip);
void VP8SetSegment(const VP8EncIterator* const it, int segment);
// Paginated token buffer
typedef struct VP8Tokens VP8Tokens; // struct details in token.c
typedef struct {
VP8Tokens* pages_; // first page
VP8Tokens** last_page_; // last page
uint16_t* tokens_; // set to (*last_page_)->tokens_
int left_; // how many free tokens left before the page is full
int page_size_; // number of tokens per page
int error_; // true in case of malloc error
} VP8TBuffer;
// initialize an empty buffer
void VP8TBufferInit(VP8TBuffer* const b, int page_size);
void VP8TBufferClear(VP8TBuffer* const b); // de-allocate pages memory
// Finalizes bitstream when probabilities are known.
// Deletes the allocated token memory if final_pass is true.
int VP8EmitTokens(VP8TBuffer* const b, VP8BitWriter* const bw,
const uint8_t* const probas, int final_pass);
// record the coding of coefficients without knowing the probabilities yet
int VP8RecordCoeffTokens(int ctx, const struct VP8Residual* const res,
VP8TBuffer* const tokens);
// Estimate the final coded size given a set of 'probas'.
size_t VP8EstimateTokenSize(VP8TBuffer* const b, const uint8_t* const probas);
// VP8Encoder
struct VP8Encoder {
const WebPConfig* config_; // user configuration and parameters
WebPPicture* pic_; // input / output picture
// headers
VP8EncFilterHeader filter_hdr_; // filtering information
VP8EncSegmentHeader segment_hdr_; // segment information
int profile_; // VP8's profile, deduced from Config.
// dimension, in macroblock units.
int mb_w_, mb_h_;
int preds_w_; // stride of the *preds_ prediction plane (=4*mb_w + 1)
// number of partitions (1, 2, 4 or 8 = MAX_NUM_PARTITIONS)
int num_parts_;
// per-partition boolean decoders.
VP8BitWriter bw_; // part0
VP8BitWriter parts_[MAX_NUM_PARTITIONS]; // token partitions
VP8TBuffer tokens_; // token buffer
int percent_; // for progress
// transparency blob
int has_alpha_;
uint8_t* alpha_data_; // non-NULL if transparency is present
uint32_t alpha_data_size_;
WebPWorker alpha_worker_;
// quantization info (one set of DC/AC dequant factor per segment)
VP8SegmentInfo dqm_[NUM_MB_SEGMENTS];
int base_quant_; // nominal quantizer value. Only used
// for relative coding of segments' quant.
int alpha_; // global susceptibility (<=> complexity)
int uv_alpha_; // U/V quantization susceptibility
// global offset of quantizers, shared by all segments
int dq_y1_dc_;
int dq_y2_dc_, dq_y2_ac_;
int dq_uv_dc_, dq_uv_ac_;
// probabilities and statistics
VP8EncProba proba_;
uint64_t sse_[4]; // sum of Y/U/V/A squared errors for all macroblocks
uint64_t sse_count_; // pixel count for the sse_[] stats
int coded_size_;
int residual_bytes_[3][4];
int block_count_[3];
// quality/speed settings
int method_; // 0=fastest, 6=best/slowest.
VP8RDLevel rd_opt_level_; // Deduced from method_.
int max_i4_header_bits_; // partition #0 safeness factor
int mb_header_limit_; // rough limit for header bits per MB
int thread_level_; // derived from config->thread_level
int do_search_; // derived from config->target_XXX
int use_tokens_; // if true, use token buffer
// Memory
VP8MBInfo* mb_info_; // contextual macroblock infos (mb_w_ + 1)
uint8_t* preds_; // predictions modes: (4*mb_w+1) * (4*mb_h+1)
uint32_t* nz_; // non-zero bit context: mb_w+1
uint8_t* y_top_; // top luma samples.
uint8_t* uv_top_; // top u/v samples.
// U and V are packed into 16 bytes (8 U + 8 V)
LFStats* lf_stats_; // autofilter stats (if NULL, autofilter is off)
DError* top_derr_; // diffusion error (NULL if disabled)
// internal functions. Not public.
// in tree.c
extern const uint8_t VP8CoeffsProba0[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];
extern const uint8_t
// Reset the token probabilities to their initial (default) values
void VP8DefaultProbas(VP8Encoder* const enc);
// Write the token probabilities
void VP8WriteProbas(VP8BitWriter* const bw, const VP8EncProba* const probas);
// Writes the partition #0 modes (that is: all intra modes)
void VP8CodeIntraModes(VP8Encoder* const enc);
// in syntax.c
// Generates the final bitstream by coding the partition0 and headers,
// and appending an assembly of all the pre-coded token partitions.
// Return true if everything is ok.
int VP8EncWrite(VP8Encoder* const enc);
// Release memory allocated for bit-writing in VP8EncLoop & seq.
void VP8EncFreeBitWriters(VP8Encoder* const enc);
// in frame.c
extern const uint8_t VP8Cat3[];
extern const uint8_t VP8Cat4[];
extern const uint8_t VP8Cat5[];
extern const uint8_t VP8Cat6[];
// Form all the four Intra16x16 predictions in the yuv_p_ cache
void VP8MakeLuma16Preds(const VP8EncIterator* const it);
// Form all the four Chroma8x8 predictions in the yuv_p_ cache
void VP8MakeChroma8Preds(const VP8EncIterator* const it);
// Form all the ten Intra4x4 predictions in the yuv_p_ cache
// for the 4x4 block it->i4_
void VP8MakeIntra4Preds(const VP8EncIterator* const it);
// Rate calculation
int VP8GetCostLuma16(VP8EncIterator* const it, const VP8ModeScore* const rd);
int VP8GetCostLuma4(VP8EncIterator* const it, const int16_t levels[16]);
int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd);
// Main coding calls
int VP8EncLoop(VP8Encoder* const enc);
int VP8EncTokenLoop(VP8Encoder* const enc);
// in webpenc.c
// Assign an error code to a picture. Return false for convenience.
int WebPEncodingSetError(const WebPPicture* const pic, WebPEncodingError error);
int WebPReportProgress(const WebPPicture* const pic,
int percent, int* const percent_store);
// in analysis.c
// Main analysis loop. Decides the segmentations and complexity.
// Assigns a first guess for Intra16 and uvmode_ prediction modes.
int VP8EncAnalyze(VP8Encoder* const enc);
// in quant.c
// Sets up segment's quantization values, base_quant_ and filter strengths.
void VP8SetSegmentParams(VP8Encoder* const enc, float quality);
// Pick best modes and fills the levels. Returns true if skipped.
int VP8Decimate(VP8EncIterator* const it, VP8ModeScore* const rd,
VP8RDLevel rd_opt);
// in alpha.c
void VP8EncInitAlpha(VP8Encoder* const enc); // initialize alpha compression
int VP8EncStartAlpha(VP8Encoder* const enc); // start alpha coding process
int VP8EncFinishAlpha(VP8Encoder* const enc); // finalize compressed data
int VP8EncDeleteAlpha(VP8Encoder* const enc); // delete compressed data
// autofilter
void VP8InitFilter(VP8EncIterator* const it);
void VP8StoreFilterStats(VP8EncIterator* const it);
void VP8AdjustFilterStrength(VP8EncIterator* const it);
// returns the approximate filtering strength needed to smooth a edge
// step of 'delta', given a sharpness parameter 'sharpness'.
int VP8FilterStrengthFromDelta(int sharpness, int delta);
// misc utils for picture_*.c:
// Remove reference to the ARGB/YUVA buffer (doesn't free anything).
void WebPPictureResetBuffers(WebPPicture* const picture);
// Allocates ARGB buffer of given dimension (previous one is always free'd).
// Preserves the YUV(A) buffer. Returns false in case of error (invalid param,
// out-of-memory).
int WebPPictureAllocARGB(WebPPicture* const picture, int width, int height);
// Allocates YUVA buffer of given dimension (previous one is always free'd).
// Uses picture->csp to determine whether an alpha buffer is needed.
// Preserves the ARGB buffer.
// Returns false in case of error (invalid param, out-of-memory).
int WebPPictureAllocYUVA(WebPPicture* const picture, int width, int height);
// Clean-up the RGB samples under fully transparent area, to help lossless
// compressibility (no guarantee, though). Assumes that pic->use_argb is true.
void WebPCleanupTransparentAreaLossless(WebPPicture* const pic);
#ifdef __cplusplus
} // extern "C"
#endif /* WEBP_ENC_VP8I_ENC_H_ */