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libavcodec/wma.c

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00001 /*
00002  * WMA compatible codec
00003  * Copyright (c) 2002-2007 The FFmpeg Project
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "avcodec.h"
00023 #include "wma.h"
00024 #include "wmadata.h"
00025 
00026 #undef NDEBUG
00027 #include <assert.h>
00028 
00029 /* XXX: use same run/length optimization as mpeg decoders */
00030 //FIXME maybe split decode / encode or pass flag
00031 static void init_coef_vlc(VLC *vlc,
00032                           uint16_t **prun_table, uint16_t **plevel_table, uint16_t **pint_table,
00033                           const CoefVLCTable *vlc_table)
00034 {
00035     int n = vlc_table->n;
00036     const uint8_t *table_bits = vlc_table->huffbits;
00037     const uint32_t *table_codes = vlc_table->huffcodes;
00038     const uint16_t *levels_table = vlc_table->levels;
00039     uint16_t *run_table, *level_table, *int_table;
00040     int i, l, j, k, level;
00041 
00042     init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
00043 
00044     run_table = av_malloc(n * sizeof(uint16_t));
00045     level_table = av_malloc(n * sizeof(uint16_t));
00046     int_table = av_malloc(n * sizeof(uint16_t));
00047     i = 2;
00048     level = 1;
00049     k = 0;
00050     while (i < n) {
00051         int_table[k]= i;
00052         l = levels_table[k++];
00053         for(j=0;j<l;j++) {
00054             run_table[i] = j;
00055             level_table[i] = level;
00056             i++;
00057         }
00058         level++;
00059     }
00060     *prun_table = run_table;
00061     *plevel_table = level_table;
00062     *pint_table= int_table;
00063 }
00064 
00065 int ff_wma_init(AVCodecContext * avctx, int flags2)
00066 {
00067     WMACodecContext *s = avctx->priv_data;
00068     int i;
00069     float bps1, high_freq;
00070     volatile float bps;
00071     int sample_rate1;
00072     int coef_vlc_table;
00073 
00074     if(   avctx->sample_rate<=0 || avctx->sample_rate>50000
00075        || avctx->channels<=0 || avctx->channels>8
00076        || avctx->bit_rate<=0)
00077         return -1;
00078 
00079     s->sample_rate = avctx->sample_rate;
00080     s->nb_channels = avctx->channels;
00081     s->bit_rate = avctx->bit_rate;
00082     s->block_align = avctx->block_align;
00083 
00084     dsputil_init(&s->dsp, avctx);
00085 
00086     if (avctx->codec->id == CODEC_ID_WMAV1) {
00087         s->version = 1;
00088     } else {
00089         s->version = 2;
00090     }
00091 
00092     /* compute MDCT block size */
00093     if (s->sample_rate <= 16000) {
00094         s->frame_len_bits = 9;
00095     } else if (s->sample_rate <= 22050 ||
00096                (s->sample_rate <= 32000 && s->version == 1)) {
00097         s->frame_len_bits = 10;
00098     } else {
00099         s->frame_len_bits = 11;
00100     }
00101     s->frame_len = 1 << s->frame_len_bits;
00102     if (s->use_variable_block_len) {
00103         int nb_max, nb;
00104         nb = ((flags2 >> 3) & 3) + 1;
00105         if ((s->bit_rate / s->nb_channels) >= 32000)
00106             nb += 2;
00107         nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
00108         if (nb > nb_max)
00109             nb = nb_max;
00110         s->nb_block_sizes = nb + 1;
00111     } else {
00112         s->nb_block_sizes = 1;
00113     }
00114 
00115     /* init rate dependent parameters */
00116     s->use_noise_coding = 1;
00117     high_freq = s->sample_rate * 0.5;
00118 
00119     /* if version 2, then the rates are normalized */
00120     sample_rate1 = s->sample_rate;
00121     if (s->version == 2) {
00122         if (sample_rate1 >= 44100)
00123             sample_rate1 = 44100;
00124         else if (sample_rate1 >= 22050)
00125             sample_rate1 = 22050;
00126         else if (sample_rate1 >= 16000)
00127             sample_rate1 = 16000;
00128         else if (sample_rate1 >= 11025)
00129             sample_rate1 = 11025;
00130         else if (sample_rate1 >= 8000)
00131             sample_rate1 = 8000;
00132     }
00133 
00134     bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
00135     s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
00136 
00137     /* compute high frequency value and choose if noise coding should
00138        be activated */
00139     bps1 = bps;
00140     if (s->nb_channels == 2)
00141         bps1 = bps * 1.6;
00142     if (sample_rate1 == 44100) {
00143         if (bps1 >= 0.61)
00144             s->use_noise_coding = 0;
00145         else
00146             high_freq = high_freq * 0.4;
00147     } else if (sample_rate1 == 22050) {
00148         if (bps1 >= 1.16)
00149             s->use_noise_coding = 0;
00150         else if (bps1 >= 0.72)
00151             high_freq = high_freq * 0.7;
00152         else
00153             high_freq = high_freq * 0.6;
00154     } else if (sample_rate1 == 16000) {
00155         if (bps > 0.5)
00156             high_freq = high_freq * 0.5;
00157         else
00158             high_freq = high_freq * 0.3;
00159     } else if (sample_rate1 == 11025) {
00160         high_freq = high_freq * 0.7;
00161     } else if (sample_rate1 == 8000) {
00162         if (bps <= 0.625) {
00163             high_freq = high_freq * 0.5;
00164         } else if (bps > 0.75) {
00165             s->use_noise_coding = 0;
00166         } else {
00167             high_freq = high_freq * 0.65;
00168         }
00169     } else {
00170         if (bps >= 0.8) {
00171             high_freq = high_freq * 0.75;
00172         } else if (bps >= 0.6) {
00173             high_freq = high_freq * 0.6;
00174         } else {
00175             high_freq = high_freq * 0.5;
00176         }
00177     }
00178     dprintf(s->avctx, "flags2=0x%x\n", flags2);
00179     dprintf(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
00180            s->version, s->nb_channels, s->sample_rate, s->bit_rate,
00181            s->block_align);
00182     dprintf(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
00183            bps, bps1, high_freq, s->byte_offset_bits);
00184     dprintf(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
00185            s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
00186 
00187     /* compute the scale factor band sizes for each MDCT block size */
00188     {
00189         int a, b, pos, lpos, k, block_len, i, j, n;
00190         const uint8_t *table;
00191 
00192         if (s->version == 1) {
00193             s->coefs_start = 3;
00194         } else {
00195             s->coefs_start = 0;
00196         }
00197         for(k = 0; k < s->nb_block_sizes; k++) {
00198             block_len = s->frame_len >> k;
00199 
00200             if (s->version == 1) {
00201                 lpos = 0;
00202                 for(i=0;i<25;i++) {
00203                     a = wma_critical_freqs[i];
00204                     b = s->sample_rate;
00205                     pos = ((block_len * 2 * a)  + (b >> 1)) / b;
00206                     if (pos > block_len)
00207                         pos = block_len;
00208                     s->exponent_bands[0][i] = pos - lpos;
00209                     if (pos >= block_len) {
00210                         i++;
00211                         break;
00212                     }
00213                     lpos = pos;
00214                 }
00215                 s->exponent_sizes[0] = i;
00216             } else {
00217                 /* hardcoded tables */
00218                 table = NULL;
00219                 a = s->frame_len_bits - BLOCK_MIN_BITS - k;
00220                 if (a < 3) {
00221                     if (s->sample_rate >= 44100)
00222                         table = exponent_band_44100[a];
00223                     else if (s->sample_rate >= 32000)
00224                         table = exponent_band_32000[a];
00225                     else if (s->sample_rate >= 22050)
00226                         table = exponent_band_22050[a];
00227                 }
00228                 if (table) {
00229                     n = *table++;
00230                     for(i=0;i<n;i++)
00231                         s->exponent_bands[k][i] = table[i];
00232                     s->exponent_sizes[k] = n;
00233                 } else {
00234                     j = 0;
00235                     lpos = 0;
00236                     for(i=0;i<25;i++) {
00237                         a = wma_critical_freqs[i];
00238                         b = s->sample_rate;
00239                         pos = ((block_len * 2 * a)  + (b << 1)) / (4 * b);
00240                         pos <<= 2;
00241                         if (pos > block_len)
00242                             pos = block_len;
00243                         if (pos > lpos)
00244                             s->exponent_bands[k][j++] = pos - lpos;
00245                         if (pos >= block_len)
00246                             break;
00247                         lpos = pos;
00248                     }
00249                     s->exponent_sizes[k] = j;
00250                 }
00251             }
00252 
00253             /* max number of coefs */
00254             s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
00255             /* high freq computation */
00256             s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
00257                                           s->sample_rate + 0.5);
00258             n = s->exponent_sizes[k];
00259             j = 0;
00260             pos = 0;
00261             for(i=0;i<n;i++) {
00262                 int start, end;
00263                 start = pos;
00264                 pos += s->exponent_bands[k][i];
00265                 end = pos;
00266                 if (start < s->high_band_start[k])
00267                     start = s->high_band_start[k];
00268                 if (end > s->coefs_end[k])
00269                     end = s->coefs_end[k];
00270                 if (end > start)
00271                     s->exponent_high_bands[k][j++] = end - start;
00272             }
00273             s->exponent_high_sizes[k] = j;
00274 #if 0
00275             tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
00276                   s->frame_len >> k,
00277                   s->coefs_end[k],
00278                   s->high_band_start[k],
00279                   s->exponent_high_sizes[k]);
00280             for(j=0;j<s->exponent_high_sizes[k];j++)
00281                 tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
00282             tprintf(s->avctx, "\n");
00283 #endif
00284         }
00285     }
00286 
00287 #ifdef TRACE
00288     {
00289         int i, j;
00290         for(i = 0; i < s->nb_block_sizes; i++) {
00291             tprintf(s->avctx, "%5d: n=%2d:",
00292                    s->frame_len >> i,
00293                    s->exponent_sizes[i]);
00294             for(j=0;j<s->exponent_sizes[i];j++)
00295                 tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
00296             tprintf(s->avctx, "\n");
00297         }
00298     }
00299 #endif
00300 
00301     /* init MDCT windows : simple sinus window */
00302     for(i = 0; i < s->nb_block_sizes; i++) {
00303         int n;
00304         n = 1 << (s->frame_len_bits - i);
00305         ff_sine_window_init(ff_sine_windows[s->frame_len_bits - i - 7], n);
00306         s->windows[i] = ff_sine_windows[s->frame_len_bits - i - 7];
00307     }
00308 
00309     s->reset_block_lengths = 1;
00310 
00311     if (s->use_noise_coding) {
00312 
00313         /* init the noise generator */
00314         if (s->use_exp_vlc)
00315             s->noise_mult = 0.02;
00316         else
00317             s->noise_mult = 0.04;
00318 
00319 #ifdef TRACE
00320         for(i=0;i<NOISE_TAB_SIZE;i++)
00321             s->noise_table[i] = 1.0 * s->noise_mult;
00322 #else
00323         {
00324             unsigned int seed;
00325             float norm;
00326             seed = 1;
00327             norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
00328             for(i=0;i<NOISE_TAB_SIZE;i++) {
00329                 seed = seed * 314159 + 1;
00330                 s->noise_table[i] = (float)((int)seed) * norm;
00331             }
00332         }
00333 #endif
00334     }
00335 
00336     /* choose the VLC tables for the coefficients */
00337     coef_vlc_table = 2;
00338     if (s->sample_rate >= 32000) {
00339         if (bps1 < 0.72)
00340             coef_vlc_table = 0;
00341         else if (bps1 < 1.16)
00342             coef_vlc_table = 1;
00343     }
00344     s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2    ];
00345     s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
00346     init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
00347                   s->coef_vlcs[0]);
00348     init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
00349                   s->coef_vlcs[1]);
00350 
00351     return 0;
00352 }
00353 
00354 int ff_wma_total_gain_to_bits(int total_gain){
00355          if (total_gain < 15) return 13;
00356     else if (total_gain < 32) return 12;
00357     else if (total_gain < 40) return 11;
00358     else if (total_gain < 45) return 10;
00359     else                      return  9;
00360 }
00361 
00362 int ff_wma_end(AVCodecContext *avctx)
00363 {
00364     WMACodecContext *s = avctx->priv_data;
00365     int i;
00366 
00367     for(i = 0; i < s->nb_block_sizes; i++)
00368         ff_mdct_end(&s->mdct_ctx[i]);
00369 
00370     if (s->use_exp_vlc) {
00371         free_vlc(&s->exp_vlc);
00372     }
00373     if (s->use_noise_coding) {
00374         free_vlc(&s->hgain_vlc);
00375     }
00376     for(i = 0;i < 2; i++) {
00377         free_vlc(&s->coef_vlc[i]);
00378         av_free(s->run_table[i]);
00379         av_free(s->level_table[i]);
00380         av_free(s->int_table[i]);
00381     }
00382 
00383     return 0;
00384 }

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