libavcodec/vorbis.c

   1 /*
   2  * This file is part of Libav.
   3  *
   4  * Libav is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * Libav is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with Libav; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 /**
  20  * @file
  21  * Common code for Vorbis I encoder and decoder
  22  * @author Denes Balatoni  ( dbalatoni programozo hu )
  23  */
  24
  25 #define BITSTREAM_READER_LE
  26 #include "avcodec.h"
  27 #include "get_bits.h"
  28
  29 #include "vorbis.h"
  30
  31
  32 /* Helper functions */
  33
  34 // x^(1/n)
  35 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
  36 {
  37     unsigned int ret = 0, i, j;
  38
  39     do {
  40         ++ret;
  41         for (i = 0, j = ret; i < n - 1; i++)
  42             j *= ret;
  43     } while (j <= x);
  44
  45     return ret - 1;
  46 }
  47
  48 // Generate vlc codes from vorbis huffman code lengths
  49
  50 // the two bits[p] > 32 checks should be redundant, all calling code should
  51 // already ensure that, but since it allows overwriting the stack it seems
  52 // reasonable to check redundantly.
  53 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
  54 {
  55     uint32_t exit_at_level[33] = { 404 };
  56
  57     unsigned i, j, p, code;
  58
  59 #ifdef DEBUG
  60     GetBitContext gb;
  61 #endif
  62
  63     for (p = 0; (bits[p] == 0) && (p < num); ++p)
  64         ;
  65     if (p == num)
  66         return 0;
  67
  68     codes[p] = 0;
  69     if (bits[p] > 32)
  70         return 1;
  71     for (i = 0; i < bits[p]; ++i)
  72         exit_at_level[i+1] = 1 << i;
  73
  74 #ifdef DEBUG
  75     av_log(NULL, AV_LOG_INFO, " %u. of %u code len %d code %d - ", p, num, bits[p], codes[p]);
  76     init_get_bits(&gb, (uint8_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     av_log(NULL, AV_LOG_INFO, "\n");
  80 #endif
  81
  82     ++p;
  83
  84     for (; p < num; ++p) {
  85         if (bits[p] > 32)
  86              return 1;
  87         if (bits[p] == 0)
  88              continue;
  89         // find corresponding exit(node which the tree can grow further from)
  90         for (i = bits[p]; i > 0; --i)
  91             if (exit_at_level[i])
  92                 break;
  93         if (!i) // overspecified tree
  94              return 1;
  95         code = exit_at_level[i];
  96         exit_at_level[i] = 0;
  97         // construct code (append 0s to end) and introduce new exits
  98         for (j = i + 1 ;j <= bits[p]; ++j)
  99             exit_at_level[j] = code + (1 << (j - 1));
 100         codes[p] = code;
 101
 102 #ifdef DEBUG
 103         av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
 104         init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
 105         for (i = 0; i < bits[p]; ++i)
 106             av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
 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])
 115             return 1;
 116
 117     return 0;
 118 }
 119
 120 int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,
 121                                 vorbis_floor1_entry *list, int values)
 122 {
 123     int i;
 124     list[0].sort = 0;
 125     list[1].sort = 1;
 126     for (i = 2; i < values; i++) {
 127         int j;
 128         list[i].low  = 0;
 129         list[i].high = 1;
 130         list[i].sort = i;
 131         for (j = 2; j < i; j++) {
 132             int tmp = list[j].x;
 133             if (tmp < list[i].x) {
 134                 if (tmp > list[list[i].low].x)
 135                     list[i].low  =  j;
 136             } else {
 137                 if (tmp < list[list[i].high].x)
 138                     list[i].high = j;
 139             }
 140         }
 141     }
 142     for (i = 0; i < values - 1; i++) {
 143         int j;
 144         for (j = i + 1; j < values; j++) {
 145             if (list[i].x == list[j].x) {
 146                 av_log(avctx, AV_LOG_ERROR,
 147                        "Duplicate value found in floor 1 X coordinates\n");
 148                 return AVERROR_INVALIDDATA;
 149             }
 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     return 0;
 158 }
 159
 160 static inline void render_line_unrolled(intptr_t x, int y, int x1,
 161                                         intptr_t sy, int ady, int adx,
 162                                         float *buf)
 163 {
 164     int err = -adx;
 165     x -= x1 - 1;
 166     buf += x1 - 1;
 167     while (++x < 0) {
 168         err += ady;
 169         if (err >= 0) {
 170             err += ady - adx;
 171             y   += sy;
 172             buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 173         }
 174         buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 175     }
 176     if (x <= 0) {
 177         if (err + ady >= 0)
 178             y += sy;
 179         buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 180     }
 181 }
 182
 183 static void render_line(int x0, int y0, int x1, int y1, float *buf)
 184 {
 185     int dy  = y1 - y0;
 186     int adx = x1 - x0;
 187     int ady = FFABS(dy);
 188     int sy  = dy < 0 ? -1 : 1;
 189     buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
 190     if (ady*2 <= adx) { // optimized common case
 191         render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
 192     } else {
 193         int base  = dy / adx;
 194         int x     = x0;
 195         int y     = y0;
 196         int err   = -adx;
 197         ady -= FFABS(base) * adx;
 198         while (++x < x1) {
 199             y += base;
 200             err += ady;
 201             if (err >= 0) {
 202                 err -= adx;
 203                 y   += sy;
 204             }
 205             buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 206         }
 207     }
 208 }
 209
 210 void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
 211                                   uint16_t *y_list, int *flag,
 212                                   int multiplier, float *out, int samples)
 213 {
 214     int lx, ly, i;
 215     lx = 0;
 216     ly = y_list[0] * multiplier;
 217     for (i = 1; i < values; i++) {
 218         int pos = list[i].sort;
 219         if (flag[pos]) {
 220             int x1 = list[pos].x;
 221             int y1 = y_list[pos] * multiplier;
 222             if (lx < samples)
 223                 render_line(lx, ly, FFMIN(x1,samples), y1, out);
 224             lx = x1;
 225             ly = y1;
 226         }
 227         if (lx >= samples)
 228             break;
 229     }
 230     if (lx < samples)
 231         render_line(lx, ly, samples, ly, out);
 232 }