ih264e_cabac.h revision 3749f6f435e79624f72841e866245d84195551cd 
1/******************************************************************************
2 *
3 * Copyright (C) 2015 The Android Open Source Project
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 *****************************************************************************
18 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
19*/
20
21/**
22 *******************************************************************************
23 * @file
24 *  ih264e_cabac_structs.h
25 *
26 * @brief
27 *  This file contains cabac related macros, enums, tables and function declarations.
28 *
29 * @author
30 *  Doney Alex
31 *
32 * @remarks
33 *  none
34 *
35 *******************************************************************************
36 */
37
38#ifndef IH264E_CABAC_H_
39#define IH264E_CABAC_H_
40
41
42
43/*******************************************************************************
44@brief Bit precision of cabac engine;
45*******************************************************************************
46*/
47#define CABAC_BITS  9
48
49
50
51
52/**
53******************************************************************************
54 *  @macro Count number of bits set
55******************************************************************************
56*/
57#define REV_NBITS(word, size, rev_word)               \
58{                                                     \
59    WORD32 i;                                         \
60    rev_word = 0;                                     \
61    for (i = 0; i < (size); i++)                      \
62    {                                                 \
63        UWORD32 bit = ((word) >> i) & 1;              \
64        rev_word += (1 << ((size) - i - 1)) * bit;    \
65    }                                                 \
66}                                                     \
67
68/**
69******************************************************************************
70 *  @macro Reverse bits in an unsigned integer
71******************************************************************************
72*/
73#define REV(u4_input, u4_output)                 \
74{                                                \
75    UWORD32 u4_temp = (u4_input);                \
76    WORD8 i;                                     \
77    u4_output = 0;                               \
78    for (i = 0; i < 32; i++)                     \
79    {                                            \
80        u4_output = (u4_output << 1) +           \
81                        ((u4_temp >> i) & 0x01); \
82    }                                            \
83}
84
85/**
86******************************************************************************
87*! Bit manipulation macros
88******************************************************************************
89*/
90#define SETBIT(a, i)   ((a) |= (1 << (i)))
91#define CLEARBIT(a, i) ((a) &= ~(1 << (i)))
92
93
94/**
95******************************************************************************
96*! Cabac module expect atlesat MIN_STREAM_SIZE_MB bytes left in stream buffer
97*! for encoding an MB
98******************************************************************************
99*/
100#define MIN_STREAM_SIZE_MB   1024
101
102
103
104/*****************************************************************************/
105/* Function Declarations                                                 */
106/*****************************************************************************/
107
108
109/**
110 *******************************************************************************
111 *
112 * @brief
113 * Initialize default context values and pointers.
114 *
115 * @param[in] ps_ent_ctxt
116 *  Pointer to entropy context structure
117 *
118 * @returns
119 *
120 * @remarks
121 *  None
122 *
123 *******************************************************************************
124 */
125void ih264e_init_cabac_table(entropy_ctxt_t *ps_ent_ctxt);
126
127
128/**
129 *******************************************************************************
130 *
131 * @brief
132 * Initialize cabac context: Intitalize all contest with init values given in the spec.
133 * Called at the beginning of entropy coding of each slice for CABAC encoding.
134 *
135 * @param[in] ps_ent_ctxt
136 *  Pointer to entropy context structure
137 *
138 * @returns
139 *
140 * @remarks
141 *  None
142 *
143 *******************************************************************************
144 */
145void ih264e_init_cabac_ctxt(entropy_ctxt_t *ps_ent_ctxt);
146
147
148
149/**
150 *******************************************************************************
151 *
152 * @brief
153 *  k-th order Exp-Golomb (UEGk) binarization process: Implements concatenated
154 *   unary/ k-th order Exp-Golomb  (UEGk) binarization process,
155 *   where k = 0 as defined in 9.3.2.3 of  ITU_T_H264-201402
156 *
157 * @param[in] i2_sufs
158 *  Suffix bit string
159 *
160 * @param[in] pi1_bins_len
161 *  Pointer to length of the string
162 *
163 * @returns Binarized value
164 *
165 * @remarks
166 *  None
167 *
168 *******************************************************************************
169 */
170UWORD32 ih264e_cabac_UEGk0_binarization(WORD16 i2_sufs, WORD8 *pi1_bins_len);
171
172
173/**
174 *******************************************************************************
175 *
176 * @brief
177 *  Get cabac context for the MB :calculates the pointers to Top and   left
178 *          cabac neighbor context depending upon neighbor  availability.
179 *
180 * @param[in] ps_ent_ctxt
181 *  Pointer to entropy context structure
182 *
183 * @param[in] u4_mb_type
184 *  Type of MB
185 *
186 * @returns
187 *
188 * @remarks
189 *  None
190 *
191 *******************************************************************************
192 */
193void ih264e_get_cabac_context(entropy_ctxt_t *ps_ent_ctxt, WORD32 u4_mb_type);
194
195
196/**
197 *******************************************************************************
198 * @brief
199 *  flushing at termination: Explained in flowchart 9-12(ITU_T_H264-201402).
200 *
201 *  @param[in]   ps_cabac_ctxt
202 *  pointer to cabac context (handle)
203 *
204 * @returns  success or failure error code
205 *
206 * @remarks
207 *  None
208 *
209 *******************************************************************************
210 */
211WORD32 ih264e_cabac_flush(cabac_ctxt_t *ps_cabac_ctxt);
212
213
214/**
215 ******************************************************************************
216 *
217 *  @brief Puts new byte (and outstanding bytes) into bitstream after cabac
218 *         renormalization
219 *
220 *  @par   Description
221 *  1. Extract the leading byte of low(L)
222 *  2. If leading byte=0xff increment outstanding bytes and return
223 *     (as the actual bits depend on carry propogation later)
224 *  3. If leading byte is not 0xff check for any carry propogation
225 *  4. Insert the carry (propogated in previous byte) along with outstanding
226 *     bytes (if any) and leading byte
227 *
228 *
229 *  @param[inout]   ps_cabac_ctxt
230 *  pointer to cabac context (handle)
231 *
232 *  @return
233 *
234 ******************************************************************************
235 */
236void ih264e_cabac_put_byte(cabac_ctxt_t *ps_cabac_ctxt);
237
238
239/**
240 ******************************************************************************
241 *
242 *  @brief Codes a bin based on probablilty and mps packed context model
243 *
244 *  @par   Description
245 *  1. Apart from encoding bin, context model is updated as per state transition
246 *  2. Range and Low renormalization is done based on bin and original state
247 *  3. After renorm bistream is updated (if required)
248 *
249 *  @param[inout]   ps_cabac
250 *  pointer to cabac context (handle)
251 *
252 *  @param[in]   bin
253 *  bin(boolean) to be encoded
254 *
255 *  @param[in]  pu1_bin_ctxts
256 *  index of cabac context model containing pState[bits 5-0] | MPS[bit6]
257 *
258 *  @return
259 *
260 ******************************************************************************
261 */
262void ih264e_cabac_encode_bin(cabac_ctxt_t *ps_cabac, WORD32 bin,
263                             bin_ctxt_model *pu1_bin_ctxts);
264
265
266
267/**
268 *******************************************************************************
269 *
270 * @brief
271 *  Encoding process for a binary decision :implements encoding process of a decision
272 *  as defined in 9.3.4.2 . This function encodes multiple bins, of a symbol. Implements
273 *  flowchart Figure 9-7( ITU_T_H264-201402)
274 *
275 * @param[in] u4_bins
276 * array of bin values
277 *
278 * @param[in] i1_bins_len
279 *  Length of bins, maximum 32
280 *
281 * @param[in] u4_ctx_inc
282 *  CtxInc, byte0- bin0, byte1-bin1 ..
283 *
284 * @param[in] i1_valid_len
285 *  valid length of bins, after that CtxInc is constant
286 *
287 * @param[in] pu1_bin_ctxt_type
288 *  Pointer to binary contexts
289
290 * @param[in] ps_cabac
291 *  Pointer to cabac_context_structure
292 *
293 * @returns
294 *
295 * @remarks
296 *  None
297 *
298 *******************************************************************************
299 */
300void ih264e_encode_decision_bins(UWORD32 u4_bins, WORD8 i1_bins_len,
301                                 UWORD32 u4_ctx_inc, WORD8 i1_valid_len,
302                                 bin_ctxt_model *pu1_bin_ctxt_type,
303                                 cabac_ctxt_t *ps_cabac);
304
305/**
306 *******************************************************************************
307 * @brief
308 *  Encoding process for a binary decision before termination:Encoding process
309 *  of a termination(9.3.4.5 :ITU_T_H264-201402) . Explained in flowchart 9-11.
310 *
311 * @param[in] ps_cabac
312 *  Pointer to cabac structure
313 *
314 * @param[in] term_bin
315 *  Symbol value, end of slice or not, term_bin is binary
316 *
317 * @returns
318 *
319 * @remarks
320 *  None
321 *
322 *******************************************************************************
323 */
324void ih264e_cabac_encode_terminate(cabac_ctxt_t *ps_cabac, WORD32 term_bin);
325
326
327/**
328 *******************************************************************************
329 * @brief
330 * Bypass encoding process for binary decisions:  Explained (9.3.4.4 :ITU_T_H264-201402)
331 * , flowchart 9-10.
332 *
333 *  @param[in]  ps_cabac : pointer to cabac context (handle)
334 *
335 *  @param[in]   bin :  bypass bin(0/1) to be encoded
336 *
337 *  @returns
338 *
339 *  @remarks
340 *  None
341 *
342 *******************************************************************************
343 */
344
345void ih264e_cabac_encode_bypass_bin(cabac_ctxt_t *ps_cabac, WORD32 bin);
346
347
348
349/**
350 ******************************************************************************
351 *
352 *  @brief Encodes a series of bypass bins (FLC bypass bins)
353 *
354 *  @par   Description
355 *  This function is more optimal than calling ih264e_cabac_encode_bypass_bin()
356 *  in a loop as cabac low, renorm and generating the stream (8bins at a time)
357 *  can be done in one operation
358 *
359 *  @param[inout]ps_cabac
360 *   pointer to cabac context (handle)
361 *
362 *  @param[in]   u4_bins
363 *   syntax element to be coded (as FLC bins)
364 *
365 *  @param[in]   num_bins
366 *   This is the FLC length for u4_sym
367 *
368 *  @return
369 *
370 ******************************************************************************
371 */
372
373void ih264e_cabac_encode_bypass_bins(cabac_ctxt_t *ps_cabac, UWORD32 u4_bins,
374                                     WORD32 num_bins);
375
376
377
378
379
380/**
381 *******************************************************************************
382 *
383 * @brief
384 *  This function generates CABAC coded bit stream for an Intra Slice.
385 *
386 * @description
387 *  The mb syntax layer for intra slices constitutes luma mb mode, luma sub modes
388 *  (if present), mb qp delta, coded block pattern, chroma mb mode and
389 *  luma/chroma residue. These syntax elements are written as directed by table
390 *  7.3.5 of h264 specification.
391 *
392 * @param[in] ps_ent_ctxt
393 *  pointer to entropy context
394 *
395 * @returns error code
396 *
397 * @remarks none
398 *
399 *******************************************************************************
400 */
401IH264E_ERROR_T ih264e_write_islice_mb_cabac(entropy_ctxt_t *ps_ent_ctxt);
402
403
404/**
405 *******************************************************************************
406 *
407 * @brief
408 *  This function generates CABAC coded bit stream for Inter slices
409 *
410 * @description
411 *  The mb syntax layer for inter slices constitutes luma mb mode, luma sub modes
412 *  (if present), mb qp delta, coded block pattern, chroma mb mode and
413 *  luma/chroma residue. These syntax elements are written as directed by table
414 *  7.3.5 of h264 specification
415 *
416 * @param[in] ps_ent_ctxt
417 *  pointer to entropy context
418 *
419 * @returns error code
420 *
421 * @remarks none
422 *
423 *******************************************************************************
424 */
425IH264E_ERROR_T ih264e_write_pslice_mb_cabac(entropy_ctxt_t *ps_ent_ctxt);
426
427
428/**
429 *******************************************************************************
430 *
431 * @brief
432 *  This function generates CABAC coded bit stream for B slices
433 *
434 * @description
435 *  The mb syntax layer for inter slices constitutes luma mb mode,
436 *  mb qp delta, coded block pattern, chroma mb mode and
437 *  luma/chroma residue. These syntax elements are written as directed by table
438 *  7.3.5 of h264 specification
439 *
440 * @param[in] ps_ent_ctxt
441 *  pointer to entropy context
442 *
443 * @returns error code
444 *
445 * @remarks none
446 *
447 *******************************************************************************
448 */
449IH264E_ERROR_T ih264e_write_bslice_mb_cabac(entropy_ctxt_t *ps_ent_ctxt);
450
451
452#endif /* IH264E_CABAC_H_ */
453