• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 // Copyright 2010 Google Inc. All Rights Reserved.
2 //
3 // This code is licensed under the same terms as WebM:
4 //  Software License Agreement:  http://www.webmproject.org/license/software/
5 //  Additional IP Rights Grant:  http://www.webmproject.org/license/additional/
6 // -----------------------------------------------------------------------------
7 //
8 // VP8 decoder: internal header.
9 //
10 // Author: Skal (pascal.massimino@gmail.com)
11 
12 #ifndef WEBP_DEC_VP8I_H_
13 #define WEBP_DEC_VP8I_H_
14 
15 #include <string.h>     // for memcpy()
16 #include "./vp8li.h"
17 #include "../utils/bit_reader.h"
18 #include "../utils/thread.h"
19 #include "../dsp/dsp.h"
20 
21 #if defined(__cplusplus) || defined(c_plusplus)
22 extern "C" {
23 #endif
24 
25 //------------------------------------------------------------------------------
26 // Various defines and enums
27 
28 // version numbers
29 #define DEC_MAJ_VERSION 0
30 #define DEC_MIN_VERSION 2
31 #define DEC_REV_VERSION 0
32 
33 #define ONLY_KEYFRAME_CODE      // to remove any code related to P-Frames
34 
35 // intra prediction modes
36 enum { B_DC_PRED = 0,   // 4x4 modes
37        B_TM_PRED,
38        B_VE_PRED,
39        B_HE_PRED,
40        B_RD_PRED,
41        B_VR_PRED,
42        B_LD_PRED,
43        B_VL_PRED,
44        B_HD_PRED,
45        B_HU_PRED,
46        NUM_BMODES = B_HU_PRED + 1 - B_DC_PRED,  // = 10
47 
48        // Luma16 or UV modes
49        DC_PRED = B_DC_PRED, V_PRED = B_VE_PRED,
50        H_PRED = B_HE_PRED, TM_PRED = B_TM_PRED,
51        B_PRED = NUM_BMODES,   // refined I4x4 mode
52 
53        // special modes
54        B_DC_PRED_NOTOP = 4,
55        B_DC_PRED_NOLEFT = 5,
56        B_DC_PRED_NOTOPLEFT = 6,
57        NUM_B_DC_MODES = 7 };
58 
59 enum { MB_FEATURE_TREE_PROBS = 3,
60        NUM_MB_SEGMENTS = 4,
61        NUM_REF_LF_DELTAS = 4,
62        NUM_MODE_LF_DELTAS = 4,    // I4x4, ZERO, *, SPLIT
63        MAX_NUM_PARTITIONS = 8,
64        // Probabilities
65        NUM_TYPES = 4,
66        NUM_BANDS = 8,
67        NUM_CTX = 3,
68        NUM_PROBAS = 11,
69        NUM_MV_PROBAS = 19 };
70 
71 // YUV-cache parameters.
72 // Constraints are: We need to store one 16x16 block of luma samples (y),
73 // and two 8x8 chroma blocks (u/v). These are better be 16-bytes aligned,
74 // in order to be SIMD-friendly. We also need to store the top, left and
75 // top-left samples (from previously decoded blocks), along with four
76 // extra top-right samples for luma (intra4x4 prediction only).
77 // One possible layout is, using 32 * (17 + 9) bytes:
78 //
79 //   .+------   <- only 1 pixel high
80 //   .|yyyyt.
81 //   .|yyyyt.
82 //   .|yyyyt.
83 //   .|yyyy..
84 //   .+--.+--   <- only 1 pixel high
85 //   .|uu.|vv
86 //   .|uu.|vv
87 //
88 // Every character is a 4x4 block, with legend:
89 //  '.' = unused
90 //  'y' = y-samples   'u' = u-samples     'v' = u-samples
91 //  '|' = left sample,   '-' = top sample,    '+' = top-left sample
92 //  't' = extra top-right sample for 4x4 modes
93 // With this layout, BPS (=Bytes Per Scan-line) is one cacheline size.
94 #define BPS       32    // this is the common stride used by yuv[]
95 #define YUV_SIZE (BPS * 17 + BPS * 9)
96 #define Y_SIZE   (BPS * 17)
97 #define Y_OFF    (BPS * 1 + 8)
98 #define U_OFF    (Y_OFF + BPS * 16 + BPS)
99 #define V_OFF    (U_OFF + 16)
100 
101 //------------------------------------------------------------------------------
102 // Headers
103 
104 typedef struct {
105   uint8_t key_frame_;
106   uint8_t profile_;
107   uint8_t show_;
108   uint32_t partition_length_;
109 } VP8FrameHeader;
110 
111 typedef struct {
112   uint16_t width_;
113   uint16_t height_;
114   uint8_t xscale_;
115   uint8_t yscale_;
116   uint8_t colorspace_;   // 0 = YCbCr
117   uint8_t clamp_type_;
118 } VP8PictureHeader;
119 
120 // segment features
121 typedef struct {
122   int use_segment_;
123   int update_map_;        // whether to update the segment map or not
124   int absolute_delta_;    // absolute or delta values for quantizer and filter
125   int8_t quantizer_[NUM_MB_SEGMENTS];        // quantization changes
126   int8_t filter_strength_[NUM_MB_SEGMENTS];  // filter strength for segments
127 } VP8SegmentHeader;
128 
129 // Struct collecting all frame-persistent probabilities.
130 typedef struct {
131   uint8_t segments_[MB_FEATURE_TREE_PROBS];
132   // Type: 0:Intra16-AC  1:Intra16-DC   2:Chroma   3:Intra4
133   uint8_t coeffs_[NUM_TYPES][NUM_BANDS][NUM_CTX][NUM_PROBAS];
134 #ifndef ONLY_KEYFRAME_CODE
135   uint8_t ymode_[4], uvmode_[3];
136   uint8_t mv_[2][NUM_MV_PROBAS];
137 #endif
138 } VP8Proba;
139 
140 // Filter parameters
141 typedef struct {
142   int simple_;                  // 0=complex, 1=simple
143   int level_;                   // [0..63]
144   int sharpness_;               // [0..7]
145   int use_lf_delta_;
146   int ref_lf_delta_[NUM_REF_LF_DELTAS];
147   int mode_lf_delta_[NUM_MODE_LF_DELTAS];
148 } VP8FilterHeader;
149 
150 //------------------------------------------------------------------------------
151 // Informations about the macroblocks.
152 
153 typedef struct {  // filter specs
154   unsigned int f_level_:6;      // filter strength: 0..63
155   unsigned int f_ilevel_:6;     // inner limit: 1..63
156   unsigned int f_inner_:1;      // do inner filtering?
157 } VP8FInfo;
158 
159 typedef struct {  // used for syntax-parsing
160   unsigned int nz_;          // non-zero AC/DC coeffs
161   unsigned int dc_nz_:1;     // non-zero DC coeffs
162   unsigned int skip_:1;      // block type
163 } VP8MB;
164 
165 // Dequantization matrices
166 typedef int quant_t[2];      // [DC / AC].  Can be 'uint16_t[2]' too (~slower).
167 typedef struct {
168   quant_t y1_mat_, y2_mat_, uv_mat_;
169 } VP8QuantMatrix;
170 
171 // Persistent information needed by the parallel processing
172 typedef struct {
173   int id_;            // cache row to process (in [0..2])
174   int mb_y_;          // macroblock position of the row
175   int filter_row_;    // true if row-filtering is needed
176   VP8FInfo* f_info_;  // filter strengths
177   VP8Io io_;          // copy of the VP8Io to pass to put()
178 } VP8ThreadContext;
179 
180 //------------------------------------------------------------------------------
181 // VP8Decoder: the main opaque structure handed over to user
182 
183 struct 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 use_threads_;    // use multi-thread
200   int cache_id_;       // current cache row
201   int num_caches_;     // number of cached rows of 16 pixels (1, 2 or 3)
202   VP8ThreadContext thread_ctx_;  // Thread context
203 
204   // dimension, in macroblock units.
205   int mb_w_, mb_h_;
206 
207   // Macroblock to process/filter, depending on cropping and filter_type.
208   int tl_mb_x_, tl_mb_y_;  // top-left MB that must be in-loop filtered
209   int br_mb_x_, br_mb_y_;  // last bottom-right MB that must be decoded
210 
211   // number of partitions.
212   int num_parts_;
213   // per-partition boolean decoders.
214   VP8BitReader parts_[MAX_NUM_PARTITIONS];
215 
216   // buffer refresh flags
217   //   bit 0: refresh Gold, bit 1: refresh Alt
218   //   bit 2-3: copy to Gold, bit 4-5: copy to Alt
219   //   bit 6: Gold sign bias, bit 7: Alt sign bias
220   //   bit 8: refresh last frame
221   uint32_t buffer_flags_;
222 
223   // dequantization (one set of DC/AC dequant factor per segment)
224   VP8QuantMatrix dqm_[NUM_MB_SEGMENTS];
225 
226   // probabilities
227   VP8Proba proba_;
228   int use_skip_proba_;
229   uint8_t skip_p_;
230 #ifndef ONLY_KEYFRAME_CODE
231   uint8_t intra_p_, last_p_, golden_p_;
232   VP8Proba proba_saved_;
233   int update_proba_;
234 #endif
235 
236   // Boundary data cache and persistent buffers.
237   uint8_t* intra_t_;     // top intra modes values: 4 * mb_w_
238   uint8_t  intra_l_[4];  // left intra modes values
239   uint8_t* y_t_;         // top luma samples: 16 * mb_w_
240   uint8_t* u_t_, *v_t_;  // top u/v samples: 8 * mb_w_ each
241 
242   VP8MB* mb_info_;       // contextual macroblock info (mb_w_ + 1)
243   VP8FInfo* f_info_;     // filter strength info
244   uint8_t* yuv_b_;       // main block for Y/U/V (size = YUV_SIZE)
245   int16_t* coeffs_;      // 384 coeffs = (16+8+8) * 4*4
246 
247   uint8_t* cache_y_;     // macroblock row for storing unfiltered samples
248   uint8_t* cache_u_;
249   uint8_t* cache_v_;
250   int cache_y_stride_;
251   int cache_uv_stride_;
252 
253   // main memory chunk for the above data. Persistent.
254   void* mem_;
255   size_t mem_size_;
256 
257   // Per macroblock non-persistent infos.
258   int mb_x_, mb_y_;       // current position, in macroblock units
259   uint8_t is_i4x4_;       // true if intra4x4
260   uint8_t imodes_[16];    // one 16x16 mode (#0) or sixteen 4x4 modes
261   uint8_t uvmode_;        // chroma prediction mode
262   uint8_t segment_;       // block's segment
263 
264   // bit-wise info about the content of each sub-4x4 blocks: there are 16 bits
265   // for luma (bits #0->#15), then 4 bits for chroma-u (#16->#19) and 4 bits for
266   // chroma-v (#20->#23), each corresponding to one 4x4 block in decoding order.
267   // If the bit is set, the 4x4 block contains some non-zero coefficients.
268   uint32_t non_zero_;
269   uint32_t non_zero_ac_;
270 
271   // Filtering side-info
272   int filter_type_;                         // 0=off, 1=simple, 2=complex
273   int filter_row_;                          // per-row flag
274   uint8_t filter_levels_[NUM_MB_SEGMENTS];  // precalculated per-segment
275 
276   // extensions
277   const uint8_t* alpha_data_;   // compressed alpha data (if present)
278   size_t alpha_data_size_;
279   uint8_t* alpha_plane_;        // output. Persistent, contains the whole data.
280 
281   int layer_colorspace_;
282   const uint8_t* layer_data_;   // compressed layer data (if present)
283   size_t layer_data_size_;
284 };
285 
286 //------------------------------------------------------------------------------
287 // internal functions. Not public.
288 
289 // in vp8.c
290 int VP8SetError(VP8Decoder* const dec,
291                 VP8StatusCode error, const char* const msg);
292 
293 // in tree.c
294 void VP8ResetProba(VP8Proba* const proba);
295 void VP8ParseProba(VP8BitReader* const br, VP8Decoder* const dec);
296 void VP8ParseIntraMode(VP8BitReader* const br,  VP8Decoder* const dec);
297 
298 // in quant.c
299 void VP8ParseQuant(VP8Decoder* const dec);
300 
301 // in frame.c
302 int VP8InitFrame(VP8Decoder* const dec, VP8Io* io);
303 // Predict a block and add residual
304 void VP8ReconstructBlock(VP8Decoder* const dec);
305 // Call io->setup() and finish setting up scan parameters.
306 // After this call returns, one must always call VP8ExitCritical() with the
307 // same parameters. Both functions should be used in pair. Returns VP8_STATUS_OK
308 // if ok, otherwise sets and returns the error status on *dec.
309 VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io);
310 // Must always be called in pair with VP8EnterCritical().
311 // Returns false in case of error.
312 int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io);
313 // Process the last decoded row (filtering + output)
314 int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io);
315 // Store a block, along with filtering params
316 void VP8StoreBlock(VP8Decoder* const dec);
317 // To be called at the start of a new scanline, to initialize predictors.
318 void VP8InitScanline(VP8Decoder* const dec);
319 // Decode one macroblock. Returns false if there is not enough data.
320 int VP8DecodeMB(VP8Decoder* const dec, VP8BitReader* const token_br);
321 
322 // in alpha.c
323 const uint8_t* VP8DecompressAlphaRows(VP8Decoder* const dec,
324                                       int row, int num_rows);
325 
326 // in layer.c
327 int VP8DecodeLayer(VP8Decoder* const dec);
328 
329 //------------------------------------------------------------------------------
330 
331 #if defined(__cplusplus) || defined(c_plusplus)
332 }    // extern "C"
333 #endif
334 
335 #endif  /* WEBP_DEC_VP8I_H_ */
336