more #ifdef CONFIG_ENCODERS by (Wolfgang Hesseler <qv at multimediaware dot com>)
[libav.git] / libavcodec / common.c
1 /*
2 * Common bit i/o utils
3 * Copyright (c) 2000, 2001 Fabrice Bellard.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * alternative bitstream reader & writer by Michael Niedermayer <michaelni@gmx.at>
20 */
21
22 /**
23 * @file common.c
24 * common internal api.
25 */
26
27 #include "avcodec.h"
28
29 const uint8_t ff_sqrt_tab[128]={
30 0, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5,
31 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
32 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
33 9, 9, 9, 9,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,10,11,11,11,11,11,11,11
34 };
35
36 const uint8_t ff_log2_tab[256]={
37 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
38 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
39 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
40 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
41 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
42 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
43 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
44 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
45 };
46
47 void init_put_bits(PutBitContext *s,
48 uint8_t *buffer, int buffer_size,
49 void *opaque,
50 void (*write_data)(void *, uint8_t *, int))
51 {
52 s->buf = buffer;
53 s->buf_end = s->buf + buffer_size;
54 s->data_out_size = 0;
55 if(write_data!=NULL)
56 {
57 fprintf(stderr, "write Data callback is not supported\n");
58 }
59 #ifdef ALT_BITSTREAM_WRITER
60 s->index=0;
61 ((uint32_t*)(s->buf))[0]=0;
62 // memset(buffer, 0, buffer_size);
63 #else
64 s->buf_ptr = s->buf;
65 s->bit_left=32;
66 s->bit_buf=0;
67 #endif
68 }
69
70 #ifdef CONFIG_ENCODERS
71
72 /* return the number of bits output */
73 int64_t get_bit_count(PutBitContext *s)
74 {
75 #ifdef ALT_BITSTREAM_WRITER
76 return s->data_out_size * 8 + s->index;
77 #else
78 return (s->buf_ptr - s->buf + s->data_out_size) * 8 + 32 - (int64_t)s->bit_left;
79 #endif
80 }
81
82 void align_put_bits(PutBitContext *s)
83 {
84 #ifdef ALT_BITSTREAM_WRITER
85 put_bits(s,( - s->index) & 7,0);
86 #else
87 put_bits(s,s->bit_left & 7,0);
88 #endif
89 }
90
91 #endif //CONFIG_ENCODERS
92
93 /* pad the end of the output stream with zeros */
94 void flush_put_bits(PutBitContext *s)
95 {
96 #ifdef ALT_BITSTREAM_WRITER
97 align_put_bits(s);
98 #else
99 s->bit_buf<<= s->bit_left;
100 while (s->bit_left < 32) {
101 /* XXX: should test end of buffer */
102 *s->buf_ptr++=s->bit_buf >> 24;
103 s->bit_buf<<=8;
104 s->bit_left+=8;
105 }
106 s->bit_left=32;
107 s->bit_buf=0;
108 #endif
109 }
110
111 #ifdef CONFIG_ENCODERS
112
113 void put_string(PutBitContext * pbc, char *s)
114 {
115 while(*s){
116 put_bits(pbc, 8, *s);
117 s++;
118 }
119 put_bits(pbc, 8, 0);
120 }
121
122 /* bit input functions */
123
124 #endif //CONFIG_ENCODERS
125
126 void init_get_bits(GetBitContext *s,
127 const uint8_t *buffer, int bit_size)
128 {
129 const int buffer_size= (bit_size+7)>>3;
130
131 s->buffer= buffer;
132 s->size_in_bits= bit_size;
133 s->buffer_end= buffer + buffer_size;
134 #ifdef ALT_BITSTREAM_READER
135 s->index=0;
136 #elif defined LIBMPEG2_BITSTREAM_READER
137 s->buffer_ptr = buffer;
138 s->bit_count = 16;
139 s->cache = 0;
140 #elif defined A32_BITSTREAM_READER
141 s->buffer_ptr = (uint32_t*)buffer;
142 s->bit_count = 32;
143 s->cache0 = 0;
144 s->cache1 = 0;
145 #endif
146 {
147 OPEN_READER(re, s)
148 UPDATE_CACHE(re, s)
149 // UPDATE_CACHE(re, s)
150 CLOSE_READER(re, s)
151 }
152 #ifdef A32_BITSTREAM_READER
153 s->cache1 = 0;
154 #endif
155 }
156
157 void align_get_bits(GetBitContext *s)
158 {
159 int n= (-get_bits_count(s)) & 7;
160 if(n) skip_bits(s, n);
161 }
162
163 int check_marker(GetBitContext *s, const char *msg)
164 {
165 int bit= get_bits1(s);
166 if(!bit) printf("Marker bit missing %s\n", msg);
167
168 return bit;
169 }
170
171 /* VLC decoding */
172
173 //#define DEBUG_VLC
174
175 #define GET_DATA(v, table, i, wrap, size) \
176 {\
177 const uint8_t *ptr = (const uint8_t *)table + i * wrap;\
178 switch(size) {\
179 case 1:\
180 v = *(const uint8_t *)ptr;\
181 break;\
182 case 2:\
183 v = *(const uint16_t *)ptr;\
184 break;\
185 default:\
186 v = *(const uint32_t *)ptr;\
187 break;\
188 }\
189 }
190
191
192 static int alloc_table(VLC *vlc, int size)
193 {
194 int index;
195 index = vlc->table_size;
196 vlc->table_size += size;
197 if (vlc->table_size > vlc->table_allocated) {
198 vlc->table_allocated += (1 << vlc->bits);
199 vlc->table = av_realloc(vlc->table,
200 sizeof(VLC_TYPE) * 2 * vlc->table_allocated);
201 if (!vlc->table)
202 return -1;
203 }
204 return index;
205 }
206
207 static int build_table(VLC *vlc, int table_nb_bits,
208 int nb_codes,
209 const void *bits, int bits_wrap, int bits_size,
210 const void *codes, int codes_wrap, int codes_size,
211 uint32_t code_prefix, int n_prefix)
212 {
213 int i, j, k, n, table_size, table_index, nb, n1, index;
214 uint32_t code;
215 VLC_TYPE (*table)[2];
216
217 table_size = 1 << table_nb_bits;
218 table_index = alloc_table(vlc, table_size);
219 #ifdef DEBUG_VLC
220 printf("new table index=%d size=%d code_prefix=%x n=%d\n",
221 table_index, table_size, code_prefix, n_prefix);
222 #endif
223 if (table_index < 0)
224 return -1;
225 table = &vlc->table[table_index];
226
227 for(i=0;i<table_size;i++) {
228 table[i][1] = 0; //bits
229 table[i][0] = -1; //codes
230 }
231
232 /* first pass: map codes and compute auxillary table sizes */
233 for(i=0;i<nb_codes;i++) {
234 GET_DATA(n, bits, i, bits_wrap, bits_size);
235 GET_DATA(code, codes, i, codes_wrap, codes_size);
236 /* we accept tables with holes */
237 if (n <= 0)
238 continue;
239 #if defined(DEBUG_VLC) && 0
240 printf("i=%d n=%d code=0x%x\n", i, n, code);
241 #endif
242 /* if code matches the prefix, it is in the table */
243 n -= n_prefix;
244 if (n > 0 && (code >> n) == code_prefix) {
245 if (n <= table_nb_bits) {
246 /* no need to add another table */
247 j = (code << (table_nb_bits - n)) & (table_size - 1);
248 nb = 1 << (table_nb_bits - n);
249 for(k=0;k<nb;k++) {
250 #ifdef DEBUG_VLC
251 printf("%4x: code=%d n=%d\n",
252 j, i, n);
253 #endif
254 if (table[j][1] /*bits*/ != 0) {
255 fprintf(stderr, "incorrect codes\n");
256 exit(1);
257 }
258 table[j][1] = n; //bits
259 table[j][0] = i; //code
260 j++;
261 }
262 } else {
263 n -= table_nb_bits;
264 j = (code >> n) & ((1 << table_nb_bits) - 1);
265 #ifdef DEBUG_VLC
266 printf("%4x: n=%d (subtable)\n",
267 j, n);
268 #endif
269 /* compute table size */
270 n1 = -table[j][1]; //bits
271 if (n > n1)
272 n1 = n;
273 table[j][1] = -n1; //bits
274 }
275 }
276 }
277
278 /* second pass : fill auxillary tables recursively */
279 for(i=0;i<table_size;i++) {
280 n = table[i][1]; //bits
281 if (n < 0) {
282 n = -n;
283 if (n > table_nb_bits) {
284 n = table_nb_bits;
285 table[i][1] = -n; //bits
286 }
287 index = build_table(vlc, n, nb_codes,
288 bits, bits_wrap, bits_size,
289 codes, codes_wrap, codes_size,
290 (code_prefix << table_nb_bits) | i,
291 n_prefix + table_nb_bits);
292 if (index < 0)
293 return -1;
294 /* note: realloc has been done, so reload tables */
295 table = &vlc->table[table_index];
296 table[i][0] = index; //code
297 }
298 }
299 return table_index;
300 }
301
302
303 /* Build VLC decoding tables suitable for use with get_vlc().
304
305 'nb_bits' set thee decoding table size (2^nb_bits) entries. The
306 bigger it is, the faster is the decoding. But it should not be too
307 big to save memory and L1 cache. '9' is a good compromise.
308
309 'nb_codes' : number of vlcs codes
310
311 'bits' : table which gives the size (in bits) of each vlc code.
312
313 'codes' : table which gives the bit pattern of of each vlc code.
314
315 'xxx_wrap' : give the number of bytes between each entry of the
316 'bits' or 'codes' tables.
317
318 'xxx_size' : gives the number of bytes of each entry of the 'bits'
319 or 'codes' tables.
320
321 'wrap' and 'size' allows to use any memory configuration and types
322 (byte/word/long) to store the 'bits' and 'codes' tables.
323 */
324 int init_vlc(VLC *vlc, int nb_bits, int nb_codes,
325 const void *bits, int bits_wrap, int bits_size,
326 const void *codes, int codes_wrap, int codes_size)
327 {
328 vlc->bits = nb_bits;
329 vlc->table = NULL;
330 vlc->table_allocated = 0;
331 vlc->table_size = 0;
332 #ifdef DEBUG_VLC
333 printf("build table nb_codes=%d\n", nb_codes);
334 #endif
335
336 if (build_table(vlc, nb_bits, nb_codes,
337 bits, bits_wrap, bits_size,
338 codes, codes_wrap, codes_size,
339 0, 0) < 0) {
340 av_free(vlc->table);
341 return -1;
342 }
343 return 0;
344 }
345
346
347 void free_vlc(VLC *vlc)
348 {
349 av_free(vlc->table);
350 }
351
352 int64_t ff_gcd(int64_t a, int64_t b){
353 if(b) return ff_gcd(b, a%b);
354 else return a;
355 }
356
357 void ff_float2fraction(int *nom_arg, int *denom_arg, double f, int max){
358 double best_diff=1E10, diff;
359 int best_denom=1, best_nom=1;
360 int nom, denom, gcd;
361
362 //brute force here, perhaps we should try continued fractions if we need large max ...
363 for(denom=1; denom<=max; denom++){
364 nom= (int)(f*denom + 0.5);
365 if(nom<=0 || nom>max) continue;
366
367 diff= ABS( f - (double)nom / (double)denom );
368 if(diff < best_diff){
369 best_diff= diff;
370 best_nom= nom;
371 best_denom= denom;
372 }
373 }
374
375 gcd= ff_gcd(best_nom, best_denom);
376 best_nom /= gcd;
377 best_denom /= gcd;
378
379 *nom_arg= best_nom;
380 *denom_arg= best_denom;
381 }