d576a2035b896d53eb0d40f16ce5e4a78a418ecd
[libav.git] / libavcodec / vorbis.c
1 /**
2 * @file
3 * Common code for Vorbis I encoder and decoder
4 * @author Denes Balatoni ( dbalatoni programozo hu )
5 *
6 * This file is part of Libav.
7 *
8 * Libav is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * Libav is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #undef V_DEBUG
24 //#define V_DEBUG
25
26 #define ALT_BITSTREAM_READER_LE
27 #include "avcodec.h"
28 #include "get_bits.h"
29
30 #include "vorbis.h"
31
32
33 /* Helper functions */
34
35 // x^(1/n)
36 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
37 {
38 unsigned int ret = 0, i, j;
39
40 do {
41 ++ret;
42 for (i = 0, j = ret; i < n - 1; i++)
43 j *= ret;
44 } while (j <= x);
45
46 return ret - 1;
47 }
48
49 // Generate vlc codes from vorbis huffman code lengths
50
51 // the two bits[p] > 32 checks should be redundant, all calling code should
52 // already ensure that, but since it allows overwriting the stack it seems
53 // reasonable to check redundantly.
54 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, uint_fast32_t num)
55 {
56 uint_fast32_t exit_at_level[33] = {
57 404, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
58 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
59
60 uint_fast8_t i, j;
61 uint_fast32_t code, p;
62
63 #ifdef V_DEBUG
64 GetBitContext gb;
65 #endif
66
67 for (p = 0; (bits[p] == 0) && (p < num); ++p)
68 ;
69 if (p == num) {
70 // av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n");
71 return 0;
72 }
73
74 codes[p] = 0;
75 if (bits[p] > 32)
76 return 1;
77 for (i = 0; i < bits[p]; ++i)
78 exit_at_level[i+1] = 1 << i;
79
80 #ifdef V_DEBUG
81 av_log(NULL, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]);
82 init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
83 for (i = 0; i < bits[p]; ++i)
84 av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
85 av_log(NULL, AV_LOG_INFO, "\n");
86 #endif
87
88 ++p;
89
90 for (; p < num; ++p) {
91 if (bits[p] > 32)
92 return 1;
93 if (bits[p] == 0)
94 continue;
95 // find corresponding exit(node which the tree can grow further from)
96 for (i = bits[p]; i > 0; --i)
97 if (exit_at_level[i])
98 break;
99 if (!i) // overspecified tree
100 return 1;
101 code = exit_at_level[i];
102 exit_at_level[i] = 0;
103 // construct code (append 0s to end) and introduce new exits
104 for (j = i + 1 ;j <= bits[p]; ++j)
105 exit_at_level[j] = code + (1 << (j - 1));
106 codes[p] = code;
107
108 #ifdef V_DEBUG
109 av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
110 init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
111 for (i = 0; i < bits[p]; ++i)
112 av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
113 av_log(NULL, AV_LOG_INFO, "\n");
114 #endif
115
116 }
117
118 //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
119 for (p = 1; p < 33; p++)
120 if (exit_at_level[p])
121 return 1;
122
123 return 0;
124 }
125
126 void ff_vorbis_ready_floor1_list(vorbis_floor1_entry * list, int values)
127 {
128 int i;
129 list[0].sort = 0;
130 list[1].sort = 1;
131 for (i = 2; i < values; i++) {
132 int j;
133 list[i].low = 0;
134 list[i].high = 1;
135 list[i].sort = i;
136 for (j = 2; j < i; j++) {
137 int tmp = list[j].x;
138 if (tmp < list[i].x) {
139 if (tmp > list[list[i].low].x)
140 list[i].low = j;
141 } else {
142 if (tmp < list[list[i].high].x)
143 list[i].high = j;
144 }
145 }
146 }
147 for (i = 0; i < values - 1; i++) {
148 int j;
149 for (j = i + 1; j < values; j++) {
150 if (list[list[i].sort].x > list[list[j].sort].x) {
151 int tmp = list[i].sort;
152 list[i].sort = list[j].sort;
153 list[j].sort = tmp;
154 }
155 }
156 }
157 }
158
159 static inline void render_line_unrolled(intptr_t x, intptr_t y, int x1,
160 intptr_t sy, int ady, int adx,
161 float *buf)
162 {
163 int err = -adx;
164 x -= x1 - 1;
165 buf += x1 - 1;
166 while (++x < 0) {
167 err += ady;
168 if (err >= 0) {
169 err += ady - adx;
170 y += sy;
171 buf[x++] = ff_vorbis_floor1_inverse_db_table[y];
172 }
173 buf[x] = ff_vorbis_floor1_inverse_db_table[y];
174 }
175 if (x <= 0) {
176 if (err + ady >= 0)
177 y += sy;
178 buf[x] = ff_vorbis_floor1_inverse_db_table[y];
179 }
180 }
181
182 static void render_line(int x0, int y0, int x1, int y1, float *buf)
183 {
184 int dy = y1 - y0;
185 int adx = x1 - x0;
186 int ady = FFABS(dy);
187 int sy = dy < 0 ? -1 : 1;
188 buf[x0] = ff_vorbis_floor1_inverse_db_table[y0];
189 if (ady*2 <= adx) { // optimized common case
190 render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
191 } else {
192 int base = dy / adx;
193 int x = x0;
194 int y = y0;
195 int err = -adx;
196 ady -= FFABS(base) * adx;
197 while (++x < x1) {
198 y += base;
199 err += ady;
200 if (err >= 0) {
201 err -= adx;
202 y += sy;
203 }
204 buf[x] = ff_vorbis_floor1_inverse_db_table[y];
205 }
206 }
207 }
208
209 void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
210 uint_fast16_t *y_list, int *flag,
211 int multiplier, float *out, int samples)
212 {
213 int lx, ly, i;
214 lx = 0;
215 ly = y_list[0] * multiplier;
216 for (i = 1; i < values; i++) {
217 int pos = list[i].sort;
218 if (flag[pos]) {
219 int x1 = list[pos].x;
220 int y1 = y_list[pos] * multiplier;
221 if (lx < samples)
222 render_line(lx, ly, FFMIN(x1,samples), y1, out);
223 lx = x1;
224 ly = y1;
225 }
226 if (lx >= samples)
227 break;
228 }
229 if (lx < samples)
230 render_line(lx, ly, samples, ly, out);
231 }