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#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) 36unsigned 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. 54int 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 126void 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 159static 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 182static 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 209void 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} 232