ffmpeg/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 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 #define BITSTREAM_READER_LE
  30 #include "avcodec.h"
  31 #include "get_bits.h"
  32
  33 #include "vorbis.h"
  34
  35
  36 /* Helper functions */
  37
  38 // x^(1/n)
  39 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
  40 {
  41     unsigned int ret = 0, i, j;
  42
  43     do {
  44         ++ret;
  45         for (i = 0, j = ret; i < n - 1; i++)
  46             j *= ret;
  47     } while (j <= x);
  48
  49     return ret - 1;
  50 }
  51
  52 // Generate vlc codes from vorbis huffman code lengths
  53
  54 // the two bits[p] > 32 checks should be redundant, all calling code should
  55 // already ensure that, but since it allows overwriting the stack it seems
  56 // reasonable to check redundantly.
  57 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)
  58 {
  59     uint32_t exit_at_level[33] = { 404 };
  60
  61     unsigned i, j, p, code;
  62
  63 #ifdef DEBUG
  64     GetBitContext gb;
  65 #endif
  66
  67     for (p = 0; (bits[p] == 0) && (p < num); ++p)
  68         ;
  69     if (p == num)
  70         return 0;
  71
  72     codes[p] = 0;
  73     if (bits[p] > 32)
  74         return AVERROR_INVALIDDATA;
  75     for (i = 0; i < bits[p]; ++i)
  76         exit_at_level[i+1] = 1 << i;
  77
  78 #ifdef DEBUG
  79     av_log(NULL, AV_LOG_INFO, " %u. of %u code len %d code %d - ", p, num, bits[p], codes[p]);
  80     init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
  81     for (i = 0; i < bits[p]; ++i)
  82         av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
  83     av_log(NULL, AV_LOG_INFO, "\n");
  84 #endif
  85
  86     ++p;
  87
  88     for (i = p; (bits[i] == 0) && (i < num); ++i)
  89         ;
  90     if (i == num)
  91         return 0;
  92
  93     for (; p < num; ++p) {
  94         if (bits[p] > 32)
  95              return AVERROR_INVALIDDATA;
  96         if (bits[p] == 0)
  97              continue;
  98         // find corresponding exit(node which the tree can grow further from)
  99         for (i = bits[p]; i > 0; --i)
 100             if (exit_at_level[i])
 101                 break;
 102         if (!i) // overspecified tree
 103              return AVERROR_INVALIDDATA;
 104         code = exit_at_level[i];
 105         exit_at_level[i] = 0;
 106         // construct code (append 0s to end) and introduce new exits
 107         for (j = i + 1 ;j <= bits[p]; ++j)
 108             exit_at_level[j] = code + (1 << (j - 1));
 109         codes[p] = code;
 110
 111 #ifdef DEBUG
 112         av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
 113         init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);
 114         for (i = 0; i < bits[p]; ++i)
 115             av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
 116         av_log(NULL, AV_LOG_INFO, "\n");
 117 #endif
 118
 119     }
 120
 121     //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
 122     for (p = 1; p < 33; p++)
 123         if (exit_at_level[p])
 124             return AVERROR_INVALIDDATA;
 125
 126     return 0;
 127 }
 128
 129 int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,
 130                                 vorbis_floor1_entry *list, int values)
 131 {
 132     int i;
 133     list[0].sort = 0;
 134     list[1].sort = 1;
 135     for (i = 2; i < values; i++) {
 136         int j;
 137         list[i].low  = 0;
 138         list[i].high = 1;
 139         list[i].sort = i;
 140         for (j = 2; j < i; j++) {
 141             int tmp = list[j].x;
 142             if (tmp < list[i].x) {
 143                 if (tmp > list[list[i].low].x)
 144                     list[i].low  =  j;
 145             } else {
 146                 if (tmp < list[list[i].high].x)
 147                     list[i].high = j;
 148             }
 149         }
 150     }
 151     for (i = 0; i < values - 1; i++) {
 152         int j;
 153         for (j = i + 1; j < values; j++) {
 154             if (list[i].x == list[j].x) {
 155                 av_log(avctx, AV_LOG_ERROR,
 156                        "Duplicate value found in floor 1 X coordinates\n");
 157                 return AVERROR_INVALIDDATA;
 158             }
 159             if (list[list[i].sort].x > list[list[j].sort].x) {
 160                 int tmp = list[i].sort;
 161                 list[i].sort = list[j].sort;
 162                 list[j].sort = tmp;
 163             }
 164         }
 165     }
 166     return 0;
 167 }
 168
 169 static inline void render_line_unrolled(intptr_t x, int y, int x1,
 170                                         intptr_t sy, int ady, int adx,
 171                                         float *buf)
 172 {
 173     int err = -adx;
 174     x -= x1 - 1;
 175     buf += x1 - 1;
 176     while (++x < 0) {
 177         err += ady;
 178         if (err >= 0) {
 179             err += ady - adx;
 180             y   += sy;
 181             buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 182         }
 183         buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 184     }
 185     if (x <= 0) {
 186         if (err + ady >= 0)
 187             y += sy;
 188         buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 189     }
 190 }
 191
 192 static void render_line(int x0, int y0, int x1, int y1, float *buf)
 193 {
 194     int dy  = y1 - y0;
 195     int adx = x1 - x0;
 196     int ady = FFABS(dy);
 197     int sy  = dy < 0 ? -1 : 1;
 198     buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];
 199     if (ady*2 <= adx) { // optimized common case
 200         render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
 201     } else {
 202         int base  = dy / adx;
 203         int x     = x0;
 204         int y     = y0;
 205         int err   = -adx;
 206         ady -= FFABS(base) * adx;
 207         while (++x < x1) {
 208             y += base;
 209             err += ady;
 210             if (err >= 0) {
 211                 err -= adx;
 212                 y   += sy;
 213             }
 214             buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];
 215         }
 216     }
 217 }
 218
 219 void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,
 220                                   uint16_t *y_list, int *flag,
 221                                   int multiplier, float *out, int samples)
 222 {
 223     int lx, ly, i;
 224     lx = 0;
 225     ly = y_list[0] * multiplier;
 226     for (i = 1; i < values; i++) {
 227         int pos = list[i].sort;
 228         if (flag[pos]) {
 229             int x1 = list[pos].x;
 230             int y1 = y_list[pos] * multiplier;
 231             if (lx < samples)
 232                 render_line(lx, ly, FFMIN(x1,samples), y1, out);
 233             lx = x1;
 234             ly = y1;
 235         }
 236         if (lx >= samples)
 237             break;
 238     }
 239     if (lx < samples)
 240         render_line(lx, ly, samples, ly, out);
 241 }