1/** 2 * @file libavcodec/vorbis.c 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 "bitstream.h" 29 30#include "vorbis.h" 31 32 33/* Helper functions */ 34 35unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n) { // x^(1/n) 36 unsigned int ret=0, i, j; 37 38 do { 39 ++ret; 40 for(i=0,j=ret;i<n-1;i++) j*=ret; 41 } while (j<=x); 42 43 return ret - 1; 44} 45 46// Generate vlc codes from vorbis huffman code lengths 47 48// the two bits[p] > 32 checks should be redundant, all calling code should 49// already ensure that, but since it allows overwriting the stack it seems 50// reasonable to check redundantly. 51int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, uint_fast32_t num) { 52 uint_fast32_t exit_at_level[33]={404,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 53 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; 54 55 uint_fast8_t i,j; 56 uint_fast32_t code,p; 57 58#ifdef V_DEBUG 59 GetBitContext gb; 60#endif 61 62 for(p=0;(bits[p]==0) && (p<num);++p); 63 if (p==num) { 64// av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n"); 65 return 0; 66 } 67 68 codes[p]=0; 69 if (bits[p] > 32) return 1; 70 for(i=0;i<bits[p];++i) { 71 exit_at_level[i+1]=1<<i; 72 } 73 74#ifdef V_DEBUG 75 av_log(NULL, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]); 76 init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]); 77 for(i=0;i<bits[p];++i) { 78 av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0"); 79 } 80 av_log(NULL, AV_LOG_INFO, "\n"); 81#endif 82 83 ++p; 84 85 for(;p<num;++p) { 86 if (bits[p] > 32) return 1; 87 if (bits[p]==0) continue; 88 // find corresponding exit(node which the tree can grow further from) 89 for(i=bits[p];i>0;--i) { 90 if (exit_at_level[i]) break; 91 } 92 if (!i) return 1; // overspecified tree 93 code=exit_at_level[i]; 94 exit_at_level[i]=0; 95 // construct code (append 0s to end) and introduce new exits 96 for(j=i+1;j<=bits[p];++j) { 97 exit_at_level[j]=code+(1<<(j-1)); 98 } 99 codes[p]=code; 100 101#ifdef V_DEBUG 102 av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]); 103 init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]); 104 for(i=0;i<bits[p];++i) { 105 av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0"); 106 } 107 av_log(NULL, AV_LOG_INFO, "\n"); 108#endif 109 110 } 111 112 //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC) 113 for (p=1; p<33; p++) 114 if (exit_at_level[p]) return 1; 115 116 return 0; 117} 118 119void ff_vorbis_ready_floor1_list(vorbis_floor1_entry * list, int values) { 120 int i; 121 list[0].sort = 0; 122 list[1].sort = 1; 123 for (i = 2; i < values; i++) { 124 int j; 125 list[i].low = 0; 126 list[i].high = 1; 127 list[i].sort = i; 128 for (j = 2; j < i; j++) { 129 int tmp = list[j].x; 130 if (tmp < list[i].x) { 131 if (tmp > list[list[i].low].x) list[i].low = j; 132 } else { 133 if (tmp < list[list[i].high].x) list[i].high = j; 134 } 135 } 136 } 137 for (i = 0; i < values - 1; i++) { 138 int j; 139 for (j = i + 1; j < values; j++) { 140 if (list[list[i].sort].x > list[list[j].sort].x) { 141 int tmp = list[i].sort; 142 list[i].sort = list[j].sort; 143 list[j].sort = tmp; 144 } 145 } 146 } 147} 148 149static void render_line(int x0, int y0, int x1, int y1, float * buf) { 150 int dy = y1 - y0; 151 int adx = x1 - x0; 152 int base = dy / adx; 153 int ady = FFABS(dy) - FFABS(base) * adx; 154 int x = x0; 155 int y = y0; 156 int err = 0; 157 int sy = dy<0 ? -1 : 1; 158 buf[x] = ff_vorbis_floor1_inverse_db_table[y]; 159 while (++x < x1) { 160 err += ady; 161 if (err >= adx) { 162 err -= adx; 163 y += sy; 164 } 165 y += base; 166 buf[x] = ff_vorbis_floor1_inverse_db_table[y]; 167 } 168} 169 170void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values, uint_fast16_t * y_list, int * flag, int multiplier, float * out, int samples) { 171 int lx, ly, i; 172 lx = 0; 173 ly = y_list[0] * multiplier; 174 for (i = 1; i < values; i++) { 175 int pos = list[i].sort; 176 if (flag[pos]) { 177 int x1 = list[pos].x; 178 int y1 = y_list[pos] * multiplier; 179 if (lx < samples) 180 render_line(lx, ly, FFMIN(x1,samples), y1, out); 181 lx = x1; 182 ly = y1; 183 } 184 if (lx >= samples) break; 185 } 186 if (lx < samples) render_line(lx, ly, samples, ly, out); 187} 188