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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, uint16_t **prun_table,
00032                           float **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     float *flevel_table;
00041     int i, l, j, k, level;
00042 
00043     init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
00044 
00045     run_table   = av_malloc(n * sizeof(uint16_t));
00046     level_table = av_malloc(n * sizeof(uint16_t));
00047     flevel_table= av_malloc(n * sizeof(*flevel_table));
00048     int_table   = av_malloc(n * sizeof(uint16_t));
00049     i = 2;
00050     level = 1;
00051     k = 0;
00052     while (i < n) {
00053         int_table[k] = i;
00054         l = levels_table[k++];
00055         for (j = 0; j < l; j++) {
00056             run_table[i]   = j;
00057             level_table[i] = level;
00058             flevel_table[i]= level;
00059             i++;
00060         }
00061         level++;
00062     }
00063     *prun_table   = run_table;
00064     *plevel_table = flevel_table;
00065     *pint_table   = int_table;
00066     av_free(level_table);
00067 }
00068 
00076 int av_cold ff_wma_get_frame_len_bits(int sample_rate, int version,
00077                                       unsigned int decode_flags)
00078 {
00079 
00080     int frame_len_bits;
00081 
00082     if (sample_rate <= 16000) {
00083         frame_len_bits = 9;
00084     } else if (sample_rate <= 22050 ||
00085              (sample_rate <= 32000 && version == 1)) {
00086         frame_len_bits = 10;
00087     } else if (sample_rate <= 48000) {
00088         frame_len_bits = 11;
00089     } else if (sample_rate <= 96000) {
00090         frame_len_bits = 12;
00091     } else {
00092         frame_len_bits = 13;
00093     }
00094 
00095     if (version == 3) {
00096         int tmp = decode_flags & 0x6;
00097         if (tmp == 0x2) {
00098             ++frame_len_bits;
00099         } else if (tmp == 0x4) {
00100             --frame_len_bits;
00101         } else if (tmp == 0x6) {
00102             frame_len_bits -= 2;
00103         }
00104     }
00105 
00106     return frame_len_bits;
00107 }
00108 
00109 int ff_wma_init(AVCodecContext *avctx, int flags2)
00110 {
00111     WMACodecContext *s = avctx->priv_data;
00112     int i;
00113     float bps1, high_freq;
00114     volatile float bps;
00115     int sample_rate1;
00116     int coef_vlc_table;
00117 
00118     if (   avctx->sample_rate <= 0 || avctx->sample_rate > 50000
00119         || avctx->channels    <= 0 || avctx->channels    > 8
00120         || avctx->bit_rate    <= 0)
00121         return -1;
00122 
00123     s->sample_rate = avctx->sample_rate;
00124     s->nb_channels = avctx->channels;
00125     s->bit_rate    = avctx->bit_rate;
00126     s->block_align = avctx->block_align;
00127 
00128     dsputil_init(&s->dsp, avctx);
00129 
00130     if (avctx->codec->id == CODEC_ID_WMAV1) {
00131         s->version = 1;
00132     } else {
00133         s->version = 2;
00134     }
00135 
00136     /* compute MDCT block size */
00137     s->frame_len_bits = ff_wma_get_frame_len_bits(s->sample_rate, s->version, 0);
00138 
00139     s->frame_len = 1 << s->frame_len_bits;
00140     if (s->use_variable_block_len) {
00141         int nb_max, nb;
00142         nb = ((flags2 >> 3) & 3) + 1;
00143         if ((s->bit_rate / s->nb_channels) >= 32000)
00144             nb += 2;
00145         nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
00146         if (nb > nb_max)
00147             nb = nb_max;
00148         s->nb_block_sizes = nb + 1;
00149     } else {
00150         s->nb_block_sizes = 1;
00151     }
00152 
00153     /* init rate dependent parameters */
00154     s->use_noise_coding = 1;
00155     high_freq = s->sample_rate * 0.5;
00156 
00157     /* if version 2, then the rates are normalized */
00158     sample_rate1 = s->sample_rate;
00159     if (s->version == 2) {
00160         if (sample_rate1 >= 44100) {
00161             sample_rate1 = 44100;
00162         } else if (sample_rate1 >= 22050) {
00163             sample_rate1 = 22050;
00164         } else if (sample_rate1 >= 16000) {
00165             sample_rate1 = 16000;
00166         } else if (sample_rate1 >= 11025) {
00167             sample_rate1 = 11025;
00168         } else if (sample_rate1 >= 8000) {
00169             sample_rate1 = 8000;
00170         }
00171     }
00172 
00173     bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
00174     s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
00175 
00176     /* compute high frequency value and choose if noise coding should
00177        be activated */
00178     bps1 = bps;
00179     if (s->nb_channels == 2)
00180         bps1 = bps * 1.6;
00181     if (sample_rate1 == 44100) {
00182         if (bps1 >= 0.61) {
00183             s->use_noise_coding = 0;
00184         } else {
00185             high_freq = high_freq * 0.4;
00186         }
00187     } else if (sample_rate1 == 22050) {
00188         if (bps1 >= 1.16) {
00189             s->use_noise_coding = 0;
00190         } else if (bps1 >= 0.72) {
00191             high_freq = high_freq * 0.7;
00192         } else {
00193             high_freq = high_freq * 0.6;
00194         }
00195     } else if (sample_rate1 == 16000) {
00196         if (bps > 0.5) {
00197             high_freq = high_freq * 0.5;
00198         } else {
00199             high_freq = high_freq * 0.3;
00200         }
00201     } else if (sample_rate1 == 11025) {
00202         high_freq = high_freq * 0.7;
00203     } else if (sample_rate1 == 8000) {
00204         if (bps <= 0.625) {
00205             high_freq = high_freq * 0.5;
00206         } else if (bps > 0.75) {
00207             s->use_noise_coding = 0;
00208         } else {
00209             high_freq = high_freq * 0.65;
00210         }
00211     } else {
00212         if (bps >= 0.8) {
00213             high_freq = high_freq * 0.75;
00214         } else if (bps >= 0.6) {
00215             high_freq = high_freq * 0.6;
00216         } else {
00217             high_freq = high_freq * 0.5;
00218         }
00219     }
00220     dprintf(s->avctx, "flags2=0x%x\n", flags2);
00221     dprintf(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
00222             s->version, s->nb_channels, s->sample_rate, s->bit_rate,
00223             s->block_align);
00224     dprintf(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
00225             bps, bps1, high_freq, s->byte_offset_bits);
00226     dprintf(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
00227             s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
00228 
00229     /* compute the scale factor band sizes for each MDCT block size */
00230     {
00231         int a, b, pos, lpos, k, block_len, i, j, n;
00232         const uint8_t *table;
00233 
00234         if (s->version == 1) {
00235             s->coefs_start = 3;
00236         } else {
00237             s->coefs_start = 0;
00238         }
00239         for (k = 0; k < s->nb_block_sizes; k++) {
00240             block_len = s->frame_len >> k;
00241 
00242             if (s->version == 1) {
00243                 lpos = 0;
00244                 for (i = 0; i < 25; i++) {
00245                     a = ff_wma_critical_freqs[i];
00246                     b = s->sample_rate;
00247                     pos = ((block_len * 2 * a) + (b >> 1)) / b;
00248                     if (pos > block_len)
00249                         pos = block_len;
00250                     s->exponent_bands[0][i] = pos - lpos;
00251                     if (pos >= block_len) {
00252                         i++;
00253                         break;
00254                     }
00255                     lpos = pos;
00256                 }
00257                 s->exponent_sizes[0] = i;
00258             } else {
00259                 /* hardcoded tables */
00260                 table = NULL;
00261                 a = s->frame_len_bits - BLOCK_MIN_BITS - k;
00262                 if (a < 3) {
00263                     if (s->sample_rate >= 44100) {
00264                         table = exponent_band_44100[a];
00265                     } else if (s->sample_rate >= 32000) {
00266                         table = exponent_band_32000[a];
00267                     } else if (s->sample_rate >= 22050) {
00268                         table = exponent_band_22050[a];
00269                     }
00270                 }
00271                 if (table) {
00272                     n = *table++;
00273                     for (i = 0; i < n; i++)
00274                         s->exponent_bands[k][i] = table[i];
00275                     s->exponent_sizes[k] = n;
00276                 } else {
00277                     j = 0;
00278                     lpos = 0;
00279                     for (i = 0; i < 25; i++) {
00280                         a = ff_wma_critical_freqs[i];
00281                         b = s->sample_rate;
00282                         pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
00283                         pos <<= 2;
00284                         if (pos > block_len)
00285                             pos = block_len;
00286                         if (pos > lpos)
00287                             s->exponent_bands[k][j++] = pos - lpos;
00288                         if (pos >= block_len)
00289                             break;
00290                         lpos = pos;
00291                     }
00292                     s->exponent_sizes[k] = j;
00293                 }
00294             }
00295 
00296             /* max number of coefs */
00297             s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
00298             /* high freq computation */
00299             s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
00300                                           s->sample_rate + 0.5);
00301             n = s->exponent_sizes[k];
00302             j = 0;
00303             pos = 0;
00304             for (i = 0; i < n; i++) {
00305                 int start, end;
00306                 start = pos;
00307                 pos += s->exponent_bands[k][i];
00308                 end = pos;
00309                 if (start < s->high_band_start[k])
00310                     start = s->high_band_start[k];
00311                 if (end > s->coefs_end[k])
00312                     end = s->coefs_end[k];
00313                 if (end > start)
00314                     s->exponent_high_bands[k][j++] = end - start;
00315             }
00316             s->exponent_high_sizes[k] = j;
00317 #if 0
00318             tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
00319                     s->frame_len >> k,
00320                     s->coefs_end[k],
00321                     s->high_band_start[k],
00322                     s->exponent_high_sizes[k]);
00323             for (j = 0; j < s->exponent_high_sizes[k]; j++)
00324                 tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
00325             tprintf(s->avctx, "\n");
00326 #endif
00327         }
00328     }
00329 
00330 #ifdef TRACE
00331     {
00332         int i, j;
00333         for (i = 0; i < s->nb_block_sizes; i++) {
00334             tprintf(s->avctx, "%5d: n=%2d:",
00335                     s->frame_len >> i,
00336                     s->exponent_sizes[i]);
00337             for (j = 0; j < s->exponent_sizes[i]; j++)
00338                 tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
00339             tprintf(s->avctx, "\n");
00340         }
00341     }
00342 #endif
00343 
00344     /* init MDCT windows : simple sinus window */
00345     for (i = 0; i < s->nb_block_sizes; i++) {
00346         ff_init_ff_sine_windows(s->frame_len_bits - i);
00347         s->windows[i] = ff_sine_windows[s->frame_len_bits - i];
00348     }
00349 
00350     s->reset_block_lengths = 1;
00351 
00352     if (s->use_noise_coding) {
00353 
00354         /* init the noise generator */
00355         if (s->use_exp_vlc) {
00356             s->noise_mult = 0.02;
00357         } else {
00358             s->noise_mult = 0.04;
00359         }
00360 
00361 #ifdef TRACE
00362         for (i = 0; i < NOISE_TAB_SIZE; i++)
00363             s->noise_table[i] = 1.0 * s->noise_mult;
00364 #else
00365         {
00366             unsigned int seed;
00367             float norm;
00368             seed = 1;
00369             norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
00370             for (i = 0; i < NOISE_TAB_SIZE; i++) {
00371                 seed = seed * 314159 + 1;
00372                 s->noise_table[i] = (float)((int)seed) * norm;
00373             }
00374         }
00375 #endif
00376     }
00377 
00378     /* choose the VLC tables for the coefficients */
00379     coef_vlc_table = 2;
00380     if (s->sample_rate >= 32000) {
00381         if (bps1 < 0.72) {
00382             coef_vlc_table = 0;
00383         } else if (bps1 < 1.16) {
00384             coef_vlc_table = 1;
00385         }
00386     }
00387     s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2    ];
00388     s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
00389     init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
00390                   s->coef_vlcs[0]);
00391     init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
00392                   s->coef_vlcs[1]);
00393 
00394     return 0;
00395 }
00396 
00397 int ff_wma_total_gain_to_bits(int total_gain)
00398 {
00399          if (total_gain < 15) return 13;
00400     else if (total_gain < 32) return 12;
00401     else if (total_gain < 40) return 11;
00402     else if (total_gain < 45) return 10;
00403     else                      return  9;
00404 }
00405 
00406 int ff_wma_end(AVCodecContext *avctx)
00407 {
00408     WMACodecContext *s = avctx->priv_data;
00409     int i;
00410 
00411     for (i = 0; i < s->nb_block_sizes; i++)
00412         ff_mdct_end(&s->mdct_ctx[i]);
00413 
00414     if (s->use_exp_vlc) {
00415         free_vlc(&s->exp_vlc);
00416     }
00417     if (s->use_noise_coding) {
00418         free_vlc(&s->hgain_vlc);
00419     }
00420     for (i = 0; i < 2; i++) {
00421         free_vlc(&s->coef_vlc[i]);
00422         av_free(s->run_table[i]);
00423         av_free(s->level_table[i]);
00424         av_free(s->int_table[i]);
00425     }
00426 
00427     return 0;
00428 }
00429 
00435 unsigned int ff_wma_get_large_val(GetBitContext* gb)
00436 {
00438     int n_bits = 8;
00440     if (get_bits1(gb)) {
00441         n_bits += 8;
00442         if (get_bits1(gb)) {
00443             n_bits += 8;
00444             if (get_bits1(gb)) {
00445                 n_bits += 7;
00446             }
00447         }
00448     }
00449     return get_bits_long(gb, n_bits);
00450 }
00451 
00468 int ff_wma_run_level_decode(AVCodecContext* avctx, GetBitContext* gb,
00469                             VLC *vlc,
00470                             const float *level_table, const uint16_t *run_table,
00471                             int version, WMACoef *ptr, int offset,
00472                             int num_coefs, int block_len, int frame_len_bits,
00473                             int coef_nb_bits)
00474 {
00475     int code, level, sign;
00476     const uint32_t *ilvl = (const uint32_t*)level_table;
00477     uint32_t *iptr = (uint32_t*)ptr;
00478     const unsigned int coef_mask = block_len - 1;
00479     for (; offset < num_coefs; offset++) {
00480         code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
00481         if (code > 1) {
00483             offset += run_table[code];
00484             sign = get_bits1(gb) - 1;
00485             iptr[offset & coef_mask] = ilvl[code] ^ sign<<31;
00486         } else if (code == 1) {
00488             break;
00489         } else {
00491             if (!version) {
00492                 level = get_bits(gb, coef_nb_bits);
00495                 offset += get_bits(gb, frame_len_bits);
00496             } else {
00497                 level = ff_wma_get_large_val(gb);
00499                 if (get_bits1(gb)) {
00500                     if (get_bits1(gb)) {
00501                         if (get_bits1(gb)) {
00502                             av_log(avctx,AV_LOG_ERROR,
00503                                 "broken escape sequence\n");
00504                             return -1;
00505                         } else
00506                             offset += get_bits(gb, frame_len_bits) + 4;
00507                     } else
00508                         offset += get_bits(gb, 2) + 1;
00509                 }
00510             }
00511             sign = get_bits1(gb) - 1;
00512             ptr[offset & coef_mask] = (level^sign) - sign;
00513         }
00514     }
00516     if (offset > num_coefs) {
00517         av_log(avctx, AV_LOG_ERROR, "overflow in spectral RLE, ignoring\n");
00518         return -1;
00519     }
00520 
00521     return 0;
00522 }
00523 

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