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 FFmpeg.
7 *
8 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * Common code for Vorbis I encoder and decoder
26 * @author Denes Balatoni ( dbalatoni programozo hu )
27 */
28
29 #include "libavutil/common.h"
30
31 #include "avcodec.h"
32 #include "vorbis.h"
33
34
35 /* Helper functions */
36
37 // x^(1/n)
ff_vorbis_nth_root(unsigned int x,unsigned int n)38 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
39 {
40 unsigned int ret = 0, i, j;
41
42 do {
43 ++ret;
44 for (i = 0, j = ret; i < n - 1; i++)
45 j *= ret;
46 } while (j <= x);
47
48 return ret - 1;
49 }
50
51 // Generate vlc codes from vorbis huffman code lengths
52
53 // the two bits[p] > 32 checks should be redundant, all calling code should
54 // already ensure that, but since it allows overwriting the stack it seems
55 // reasonable to check redundantly.
ff_vorbis_len2vlc(uint8_t * bits,uint32_t * codes,unsigned num)56 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
57 {
58 uint32_t exit_at_level[33] = { 404 };
59 unsigned i, j, p, code;
60
61 for (p = 0; (p < num) && (bits[p] == 0); ++p)
62 ;
63 if (p == num)
64 return 0;
65
66 codes[p] = 0;
67 if (bits[p] > 32)
68 return AVERROR_INVALIDDATA;
69 for (i = 0; i < bits[p]; ++i)
70 exit_at_level[i+1] = 1u << i;
71
72 ++p;
73
74 for (i = p; (i < num) && (bits[i] == 0); ++i)
75 ;
76 if (i == num)
77 return 0;
78
79 for (; p < num; ++p) {
80 if (bits[p] > 32)
81 return AVERROR_INVALIDDATA;
82 if (bits[p] == 0)
83 continue;
84 // find corresponding exit(node which the tree can grow further from)
85 for (i = bits[p]; i > 0; --i)
86 if (exit_at_level[i])
87 break;
88 if (!i) // overspecified tree
89 return AVERROR_INVALIDDATA;
90 code = exit_at_level[i];
91 exit_at_level[i] = 0;
92 // construct code (append 0s to end) and introduce new exits
93 for (j = i + 1 ;j <= bits[p]; ++j)
94 exit_at_level[j] = code + (1u << (j - 1));
95 codes[p] = code;
96 }
97
98 //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
99 for (p = 1; p < 33; p++)
100 if (exit_at_level[p])
101 return AVERROR_INVALIDDATA;
102
103 return 0;
104 }
105
ff_vorbis_ready_floor1_list(AVCodecContext * avctx,vorbis_floor1_entry * list,int values)106 int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,
107 vorbis_floor1_entry *list, int values)
108 {
109 int i;
110 list[0].sort = 0;
111 list[1].sort = 1;
112 for (i = 2; i < values; i++) {
113 int j;
114 list[i].low = 0;
115 list[i].high = 1;
116 list[i].sort = i;
117 for (j = 2; j < i; j++) {
118 int tmp = list[j].x;
119 if (tmp < list[i].x) {
120 if (tmp > list[list[i].low].x)
121 list[i].low = j;
122 } else {
123 if (tmp < list[list[i].high].x)
124 list[i].high = j;
125 }
126 }
127 }
128 for (i = 0; i < values - 1; i++) {
129 int j;
130 for (j = i + 1; j < values; j++) {
131 if (list[i].x == list[j].x) {
132 av_log(avctx, AV_LOG_ERROR,
133 "Duplicate value found in floor 1 X coordinates\n");
134 return AVERROR_INVALIDDATA;
135 }
136 if (list[list[i].sort].x > list[list[j].sort].x) {
137 int tmp = list[i].sort;
138 list[i].sort = list[j].sort;
139 list[j].sort = tmp;
140 }
141 }
142 }
143 return 0;
144 }
145
render_line_unrolled(intptr_t x,int y,int x1,intptr_t sy,int ady,int adx,float * buf)146 static inline void render_line_unrolled(intptr_t x, int y, int x1,
147 intptr_t sy, int ady, int adx,
148 float *buf)
149 {
150 int err = -adx;
151 x -= x1 - 1;
152 buf += x1 - 1;
153 while (++x < 0) {
154 err += ady;
155 if (err >= 0) {
156 err += ady - adx;
157 y += sy;
158 buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
159 }
160 buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
161 }
162 if (x <= 0) {
163 if (err + ady >= 0)
164 y += sy;
165 buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
166 }
167 }
168
render_line(int x0,int y0,int x1,int y1,float * buf)169 static void render_line(int x0, int y0, int x1, int y1, float *buf)
170 {
171 int dy = y1 - y0;
172 int adx = x1 - x0;
173 int ady = FFABS(dy);
174 int sy = dy < 0 ? -1 : 1;
175 buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
176 if (ady*2 <= adx) { // optimized common case
177 render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
178 } else {
179 int base = dy / adx;
180 int x = x0;
181 int y = y0;
182 int err = -adx;
183 ady -= FFABS(base) * adx;
184 while (++x < x1) {
185 y += base;
186 err += ady;
187 if (err >= 0) {
188 err -= adx;
189 y += sy;
190 }
191 buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
192 }
193 }
194 }
195
ff_vorbis_floor1_render_list(vorbis_floor1_entry * list,int values,uint16_t * y_list,int * flag,int multiplier,float * out,int samples)196 void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
197 uint16_t *y_list, int *flag,
198 int multiplier, float *out, int samples)
199 {
200 int lx, ly, i;
201 lx = 0;
202 ly = y_list[0] * multiplier;
203 for (i = 1; i < values; i++) {
204 int pos = list[i].sort;
205 if (flag[pos]) {
206 int x1 = list[pos].x;
207 int y1 = y_list[pos] * multiplier;
208 if (lx < samples)
209 render_line(lx, ly, FFMIN(x1,samples), y1, out);
210 lx = x1;
211 ly = y1;
212 }
213 if (lx >= samples)
214 break;
215 }
216 if (lx < samples)
217 render_line(lx, ly, samples, ly, out);
218 }
219