1// Copyright 2010 Google Inc. All Rights Reserved.
2//
3// Use of this source code is governed by a BSD-style license
4// that can be found in the COPYING file in the root of the source
5// tree. An additional intellectual property rights grant can be found
6// in the file PATENTS. All contributing project authors may
7// be found in the AUTHORS file in the root of the source tree.
8// -----------------------------------------------------------------------------
9//
10// VP8 decoder: internal header.
11//
12// Author: Skal (pascal.massimino@gmail.com)
13
14#ifndef WEBP_DEC_VP8I_H_
15#define WEBP_DEC_VP8I_H_
16
17#include <string.h> // for memcpy()
18#include "./common_dec.h"
19#include "./vp8li_dec.h"
20#include "../utils/bit_reader_utils.h"
21#include "../utils/random_utils.h"
22#include "../utils/thread_utils.h"
23#include "../dsp/dsp.h"
24
25#ifdef __cplusplus
26extern "C" {
27#endif
28
29//------------------------------------------------------------------------------
30// Various defines and enums
31
32// version numbers
33#define DEC_MAJ_VERSION 0
34#define DEC_MIN_VERSION 6
35#define DEC_REV_VERSION 0
36
37// YUV-cache parameters. Cache is 32-bytes wide (= one cacheline).
38// Constraints are: We need to store one 16x16 block of luma samples (y),
39// and two 8x8 chroma blocks (u/v). These are better be 16-bytes aligned,
40// in order to be SIMD-friendly. We also need to store the top, left and
41// top-left samples (from previously decoded blocks), along with four
42// extra top-right samples for luma (intra4x4 prediction only).
43// One possible layout is, using 32 * (17 + 9) bytes:
44//
45// .+------ <- only 1 pixel high
46// .|yyyyt.
47// .|yyyyt.
48// .|yyyyt.
49// .|yyyy..
50// .+--.+-- <- only 1 pixel high
51// .|uu.|vv
52// .|uu.|vv
53//
54// Every character is a 4x4 block, with legend:
55// '.' = unused
56// 'y' = y-samples 'u' = u-samples 'v' = u-samples
57// '|' = left sample, '-' = top sample, '+' = top-left sample
58// 't' = extra top-right sample for 4x4 modes
59#define YUV_SIZE (BPS * 17 + BPS * 9)
60#define Y_SIZE (BPS * 17)
61#define Y_OFF (BPS * 1 + 8)
62#define U_OFF (Y_OFF + BPS * 16 + BPS)
63#define V_OFF (U_OFF + 16)
64
65// minimal width under which lossy multi-threading is always disabled
66#define MIN_WIDTH_FOR_THREADS 512
67
68//------------------------------------------------------------------------------
69// Headers
70
71typedef struct {
72 uint8_t key_frame_;
73 uint8_t profile_;
74 uint8_t show_;
75 uint32_t partition_length_;
76} VP8FrameHeader;
77
78typedef struct {
79 uint16_t width_;
80 uint16_t height_;
81 uint8_t xscale_;
82 uint8_t yscale_;
83 uint8_t colorspace_; // 0 = YCbCr
84 uint8_t clamp_type_;
85} VP8PictureHeader;
86
87// segment features
88typedef struct {
89 int use_segment_;
90 int update_map_; // whether to update the segment map or not
91 int absolute_delta_; // absolute or delta values for quantizer and filter
92 int8_t quantizer_[NUM_MB_SEGMENTS]; // quantization changes
93 int8_t filter_strength_[NUM_MB_SEGMENTS]; // filter strength for segments
94} VP8SegmentHeader;
95
96// probas associated to one of the contexts
97typedef uint8_t VP8ProbaArray[NUM_PROBAS];
98
99typedef struct { // all the probas associated to one band
100 VP8ProbaArray probas_[NUM_CTX];
101} VP8BandProbas;
102
103// Struct collecting all frame-persistent probabilities.
104typedef struct {
105 uint8_t segments_[MB_FEATURE_TREE_PROBS];
106 // Type: 0:Intra16-AC 1:Intra16-DC 2:Chroma 3:Intra4
107 VP8BandProbas bands_[NUM_TYPES][NUM_BANDS];
108 const VP8BandProbas* bands_ptr_[NUM_TYPES][16 + 1];
109} VP8Proba;
110
111// Filter parameters
112typedef struct {
113 int simple_; // 0=complex, 1=simple
114 int level_; // [0..63]
115 int sharpness_; // [0..7]
116 int use_lf_delta_;
117 int ref_lf_delta_[NUM_REF_LF_DELTAS];
118 int mode_lf_delta_[NUM_MODE_LF_DELTAS];
119} VP8FilterHeader;
120
121//------------------------------------------------------------------------------
122// Informations about the macroblocks.
123
124typedef struct { // filter specs
125 uint8_t f_limit_; // filter limit in [3..189], or 0 if no filtering
126 uint8_t f_ilevel_; // inner limit in [1..63]
127 uint8_t f_inner_; // do inner filtering?
128 uint8_t hev_thresh_; // high edge variance threshold in [0..2]
129} VP8FInfo;
130
131typedef struct { // Top/Left Contexts used for syntax-parsing
132 uint8_t nz_; // non-zero AC/DC coeffs (4bit for luma + 4bit for chroma)
133 uint8_t nz_dc_; // non-zero DC coeff (1bit)
134} VP8MB;
135
136// Dequantization matrices
137typedef int quant_t[2]; // [DC / AC]. Can be 'uint16_t[2]' too (~slower).
138typedef struct {
139 quant_t y1_mat_, y2_mat_, uv_mat_;
140
141 int uv_quant_; // U/V quantizer value
142 int dither_; // dithering amplitude (0 = off, max=255)
143} VP8QuantMatrix;
144
145// Data needed to reconstruct a macroblock
146typedef struct {
147 int16_t coeffs_[384]; // 384 coeffs = (16+4+4) * 4*4
148 uint8_t is_i4x4_; // true if intra4x4
149 uint8_t imodes_[16]; // one 16x16 mode (#0) or sixteen 4x4 modes
150 uint8_t uvmode_; // chroma prediction mode
151 // bit-wise info about the content of each sub-4x4 blocks (in decoding order).
152 // Each of the 4x4 blocks for y/u/v is associated with a 2b code according to:
153 // code=0 -> no coefficient
154 // code=1 -> only DC
155 // code=2 -> first three coefficients are non-zero
156 // code=3 -> more than three coefficients are non-zero
157 // This allows to call specialized transform functions.
158 uint32_t non_zero_y_;
159 uint32_t non_zero_uv_;
160 uint8_t dither_; // local dithering strength (deduced from non_zero_*)
161 uint8_t skip_;
162 uint8_t segment_;
163} VP8MBData;
164
165// Persistent information needed by the parallel processing
166typedef struct {
167 int id_; // cache row to process (in [0..2])
168 int mb_y_; // macroblock position of the row
169 int filter_row_; // true if row-filtering is needed
170 VP8FInfo* f_info_; // filter strengths (swapped with dec->f_info_)
171 VP8MBData* mb_data_; // reconstruction data (swapped with dec->mb_data_)
172 VP8Io io_; // copy of the VP8Io to pass to put()
173} VP8ThreadContext;
174
175// Saved top samples, per macroblock. Fits into a cache-line.
176typedef struct {
177 uint8_t y[16], u[8], v[8];
178} VP8TopSamples;
179
180//------------------------------------------------------------------------------
181// VP8Decoder: the main opaque structure handed over to user
182
183struct VP8Decoder {
184 VP8StatusCode status_;
185 int ready_; // true if ready to decode a picture with VP8Decode()
186 const char* error_msg_; // set when status_ is not OK.
187
188 // Main data source
189 VP8BitReader br_;
190
191 // headers
192 VP8FrameHeader frm_hdr_;
193 VP8PictureHeader pic_hdr_;
194 VP8FilterHeader filter_hdr_;
195 VP8SegmentHeader segment_hdr_;
196
197 // Worker
198 WebPWorker worker_;
199 int mt_method_; // multi-thread method: 0=off, 1=[parse+recon][filter]
200 // 2=[parse][recon+filter]
201 int cache_id_; // current cache row
202 int num_caches_; // number of cached rows of 16 pixels (1, 2 or 3)
203 VP8ThreadContext thread_ctx_; // Thread context
204
205 // dimension, in macroblock units.
206 int mb_w_, mb_h_;
207
208 // Macroblock to process/filter, depending on cropping and filter_type.
209 int tl_mb_x_, tl_mb_y_; // top-left MB that must be in-loop filtered
210 int br_mb_x_, br_mb_y_; // last bottom-right MB that must be decoded
211
212 // number of partitions minus one.
213 uint32_t num_parts_minus_one_;
214 // per-partition boolean decoders.
215 VP8BitReader parts_[MAX_NUM_PARTITIONS];
216
217 // Dithering strength, deduced from decoding options
218 int dither_; // whether to use dithering or not
219 VP8Random dithering_rg_; // random generator for dithering
220
221 // dequantization (one set of DC/AC dequant factor per segment)
222 VP8QuantMatrix dqm_[NUM_MB_SEGMENTS];
223
224 // probabilities
225 VP8Proba proba_;
226 int use_skip_proba_;
227 uint8_t skip_p_;
228
229 // Boundary data cache and persistent buffers.
230 uint8_t* intra_t_; // top intra modes values: 4 * mb_w_
231 uint8_t intra_l_[4]; // left intra modes values
232
233 VP8TopSamples* yuv_t_; // top y/u/v samples
234
235 VP8MB* mb_info_; // contextual macroblock info (mb_w_ + 1)
236 VP8FInfo* f_info_; // filter strength info
237 uint8_t* yuv_b_; // main block for Y/U/V (size = YUV_SIZE)
238
239 uint8_t* cache_y_; // macroblock row for storing unfiltered samples
240 uint8_t* cache_u_;
241 uint8_t* cache_v_;
242 int cache_y_stride_;
243 int cache_uv_stride_;
244
245 // main memory chunk for the above data. Persistent.
246 void* mem_;
247 size_t mem_size_;
248
249 // Per macroblock non-persistent infos.
250 int mb_x_, mb_y_; // current position, in macroblock units
251 VP8MBData* mb_data_; // parsed reconstruction data
252
253 // Filtering side-info
254 int filter_type_; // 0=off, 1=simple, 2=complex
255 VP8FInfo fstrengths_[NUM_MB_SEGMENTS][2]; // precalculated per-segment/type
256
257 // Alpha
258 struct ALPHDecoder* alph_dec_; // alpha-plane decoder object
259 const uint8_t* alpha_data_; // compressed alpha data (if present)
260 size_t alpha_data_size_;
261 int is_alpha_decoded_; // true if alpha_data_ is decoded in alpha_plane_
262 uint8_t* alpha_plane_mem_; // memory allocated for alpha_plane_
263 uint8_t* alpha_plane_; // output. Persistent, contains the whole data.
264 const uint8_t* alpha_prev_line_; // last decoded alpha row (or NULL)
265 int alpha_dithering_; // derived from decoding options (0=off, 100=full)
266};
267
268//------------------------------------------------------------------------------
269// internal functions. Not public.
270
271// in vp8.c
272int VP8SetError(VP8Decoder* const dec,
273 VP8StatusCode error, const char* const msg);
274
275// in tree.c
276void VP8ResetProba(VP8Proba* const proba);
277void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec);
278// parses one row of intra mode data in partition 0, returns !eof
279int VP8ParseIntraModeRow(VP8BitReader* const br, VP8Decoder* const dec);
280
281// in quant.c
282void VP8ParseQuant(VP8Decoder* const dec);
283
284// in frame.c
285int VP8InitFrame(VP8Decoder* const dec, VP8Io* const io);
286// Call io->setup() and finish setting up scan parameters.
287// After this call returns, one must always call VP8ExitCritical() with the
288// same parameters. Both functions should be used in pair. Returns VP8_STATUS_OK
289// if ok, otherwise sets and returns the error status on *dec.
290VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io);
291// Must always be called in pair with VP8EnterCritical().
292// Returns false in case of error.
293int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io);
294// Return the multi-threading method to use (0=off), depending
295// on options and bitstream size. Only for lossy decoding.
296int VP8GetThreadMethod(const WebPDecoderOptions* const options,
297 const WebPHeaderStructure* const headers,
298 int width, int height);
299// Initialize dithering post-process if needed.
300void VP8InitDithering(const WebPDecoderOptions* const options,
301 VP8Decoder* const dec);
302// Process the last decoded row (filtering + output).
303int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io);
304// To be called at the start of a new scanline, to initialize predictors.
305void VP8InitScanline(VP8Decoder* const dec);
306// Decode one macroblock. Returns false if there is not enough data.
307int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br);
308
309// in alpha.c
310const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
311 const VP8Io* const io,
312 int row, int num_rows);
313
314//------------------------------------------------------------------------------
315
316#ifdef __cplusplus
317} // extern "C"
318#endif
319
320#endif /* WEBP_DEC_VP8I_H_ */
321