Libav 0.7.1
libavcodec/wma.c
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00001 /*
00002  * WMA compatible codec
00003  * Copyright (c) 2002-2007 The Libav Project
00004  *
00005  * This file is part of Libav.
00006  *
00007  * Libav 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  * Libav 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 Libav; 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 "sinewin.h"
00024 #include "wma.h"
00025 #include "wmadata.h"
00026 
00027 #undef NDEBUG
00028 #include <assert.h>
00029 
00030 /* XXX: use same run/length optimization as mpeg decoders */
00031 //FIXME maybe split decode / encode or pass flag
00032 static void init_coef_vlc(VLC *vlc, uint16_t **prun_table,
00033                           float **plevel_table, uint16_t **pint_table,
00034                           const CoefVLCTable *vlc_table)
00035 {
00036     int n = vlc_table->n;
00037     const uint8_t  *table_bits   = vlc_table->huffbits;
00038     const uint32_t *table_codes  = vlc_table->huffcodes;
00039     const uint16_t *levels_table = vlc_table->levels;
00040     uint16_t *run_table, *level_table, *int_table;
00041     float *flevel_table;
00042     int i, l, j, k, level;
00043 
00044     init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
00045 
00046     run_table   = av_malloc(n * sizeof(uint16_t));
00047     level_table = av_malloc(n * sizeof(uint16_t));
00048     flevel_table= av_malloc(n * sizeof(*flevel_table));
00049     int_table   = av_malloc(n * sizeof(uint16_t));
00050     i = 2;
00051     level = 1;
00052     k = 0;
00053     while (i < n) {
00054         int_table[k] = i;
00055         l = levels_table[k++];
00056         for (j = 0; j < l; j++) {
00057             run_table[i]   = j;
00058             level_table[i] = level;
00059             flevel_table[i]= level;
00060             i++;
00061         }
00062         level++;
00063     }
00064     *prun_table   = run_table;
00065     *plevel_table = flevel_table;
00066     *pint_table   = int_table;
00067     av_free(level_table);
00068 }
00069 
00077 int av_cold ff_wma_get_frame_len_bits(int sample_rate, int version,
00078                                       unsigned int decode_flags)
00079 {
00080 
00081     int frame_len_bits;
00082 
00083     if (sample_rate <= 16000) {
00084         frame_len_bits = 9;
00085     } else if (sample_rate <= 22050 ||
00086              (sample_rate <= 32000 && version == 1)) {
00087         frame_len_bits = 10;
00088     } else if (sample_rate <= 48000) {
00089         frame_len_bits = 11;
00090     } else if (sample_rate <= 96000) {
00091         frame_len_bits = 12;
00092     } else {
00093         frame_len_bits = 13;
00094     }
00095 
00096     if (version == 3) {
00097         int tmp = decode_flags & 0x6;
00098         if (tmp == 0x2) {
00099             ++frame_len_bits;
00100         } else if (tmp == 0x4) {
00101             --frame_len_bits;
00102         } else if (tmp == 0x6) {
00103             frame_len_bits -= 2;
00104         }
00105     }
00106 
00107     return frame_len_bits;
00108 }
00109 
00110 int ff_wma_init(AVCodecContext *avctx, int flags2)
00111 {
00112     WMACodecContext *s = avctx->priv_data;
00113     int i;
00114     float bps1, high_freq;
00115     volatile float bps;
00116     int sample_rate1;
00117     int coef_vlc_table;
00118 
00119     if (   avctx->sample_rate <= 0 || avctx->sample_rate > 50000
00120         || avctx->channels    <= 0 || avctx->channels    > 8
00121         || avctx->bit_rate    <= 0)
00122         return -1;
00123 
00124     s->sample_rate = avctx->sample_rate;
00125     s->nb_channels = avctx->channels;
00126     s->bit_rate    = avctx->bit_rate;
00127     s->block_align = avctx->block_align;
00128 
00129     dsputil_init(&s->dsp, avctx);
00130     ff_fmt_convert_init(&s->fmt_conv, avctx);
00131 
00132     if (avctx->codec->id == CODEC_ID_WMAV1) {
00133         s->version = 1;
00134     } else {
00135         s->version = 2;
00136     }
00137 
00138     /* compute MDCT block size */
00139     s->frame_len_bits = ff_wma_get_frame_len_bits(s->sample_rate, s->version, 0);
00140 
00141     s->frame_len = 1 << s->frame_len_bits;
00142     if (s->use_variable_block_len) {
00143         int nb_max, nb;
00144         nb = ((flags2 >> 3) & 3) + 1;
00145         if ((s->bit_rate / s->nb_channels) >= 32000)
00146             nb += 2;
00147         nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
00148         if (nb > nb_max)
00149             nb = nb_max;
00150         s->nb_block_sizes = nb + 1;
00151     } else {
00152         s->nb_block_sizes = 1;
00153     }
00154 
00155     /* init rate dependent parameters */
00156     s->use_noise_coding = 1;
00157     high_freq = s->sample_rate * 0.5;
00158 
00159     /* if version 2, then the rates are normalized */
00160     sample_rate1 = s->sample_rate;
00161     if (s->version == 2) {
00162         if (sample_rate1 >= 44100) {
00163             sample_rate1 = 44100;
00164         } else if (sample_rate1 >= 22050) {
00165             sample_rate1 = 22050;
00166         } else if (sample_rate1 >= 16000) {
00167             sample_rate1 = 16000;
00168         } else if (sample_rate1 >= 11025) {
00169             sample_rate1 = 11025;
00170         } else if (sample_rate1 >= 8000) {
00171             sample_rate1 = 8000;
00172         }
00173     }
00174 
00175     bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
00176     s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
00177 
00178     /* compute high frequency value and choose if noise coding should
00179        be activated */
00180     bps1 = bps;
00181     if (s->nb_channels == 2)
00182         bps1 = bps * 1.6;
00183     if (sample_rate1 == 44100) {
00184         if (bps1 >= 0.61) {
00185             s->use_noise_coding = 0;
00186         } else {
00187             high_freq = high_freq * 0.4;
00188         }
00189     } else if (sample_rate1 == 22050) {
00190         if (bps1 >= 1.16) {
00191             s->use_noise_coding = 0;
00192         } else if (bps1 >= 0.72) {
00193             high_freq = high_freq * 0.7;
00194         } else {
00195             high_freq = high_freq * 0.6;
00196         }
00197     } else if (sample_rate1 == 16000) {
00198         if (bps > 0.5) {
00199             high_freq = high_freq * 0.5;
00200         } else {
00201             high_freq = high_freq * 0.3;
00202         }
00203     } else if (sample_rate1 == 11025) {
00204         high_freq = high_freq * 0.7;
00205     } else if (sample_rate1 == 8000) {
00206         if (bps <= 0.625) {
00207             high_freq = high_freq * 0.5;
00208         } else if (bps > 0.75) {
00209             s->use_noise_coding = 0;
00210         } else {
00211             high_freq = high_freq * 0.65;
00212         }
00213     } else {
00214         if (bps >= 0.8) {
00215             high_freq = high_freq * 0.75;
00216         } else if (bps >= 0.6) {
00217             high_freq = high_freq * 0.6;
00218         } else {
00219             high_freq = high_freq * 0.5;
00220         }
00221     }
00222     av_dlog(s->avctx, "flags2=0x%x\n", flags2);
00223     av_dlog(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
00224             s->version, s->nb_channels, s->sample_rate, s->bit_rate,
00225             s->block_align);
00226     av_dlog(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
00227             bps, bps1, high_freq, s->byte_offset_bits);
00228     av_dlog(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
00229             s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
00230 
00231     /* compute the scale factor band sizes for each MDCT block size */
00232     {
00233         int a, b, pos, lpos, k, block_len, i, j, n;
00234         const uint8_t *table;
00235 
00236         if (s->version == 1) {
00237             s->coefs_start = 3;
00238         } else {
00239             s->coefs_start = 0;
00240         }
00241         for (k = 0; k < s->nb_block_sizes; k++) {
00242             block_len = s->frame_len >> k;
00243 
00244             if (s->version == 1) {
00245                 lpos = 0;
00246                 for (i = 0; i < 25; i++) {
00247                     a = ff_wma_critical_freqs[i];
00248                     b = s->sample_rate;
00249                     pos = ((block_len * 2 * a) + (b >> 1)) / b;
00250                     if (pos > block_len)
00251                         pos = block_len;
00252                     s->exponent_bands[0][i] = pos - lpos;
00253                     if (pos >= block_len) {
00254                         i++;
00255                         break;
00256                     }
00257                     lpos = pos;
00258                 }
00259                 s->exponent_sizes[0] = i;
00260             } else {
00261                 /* hardcoded tables */
00262                 table = NULL;
00263                 a = s->frame_len_bits - BLOCK_MIN_BITS - k;
00264                 if (a < 3) {
00265                     if (s->sample_rate >= 44100) {
00266                         table = exponent_band_44100[a];
00267                     } else if (s->sample_rate >= 32000) {
00268                         table = exponent_band_32000[a];
00269                     } else if (s->sample_rate >= 22050) {
00270                         table = exponent_band_22050[a];
00271                     }
00272                 }
00273                 if (table) {
00274                     n = *table++;
00275                     for (i = 0; i < n; i++)
00276                         s->exponent_bands[k][i] = table[i];
00277                     s->exponent_sizes[k] = n;
00278                 } else {
00279                     j = 0;
00280                     lpos = 0;
00281                     for (i = 0; i < 25; i++) {
00282                         a = ff_wma_critical_freqs[i];
00283                         b = s->sample_rate;
00284                         pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
00285                         pos <<= 2;
00286                         if (pos > block_len)
00287                             pos = block_len;
00288                         if (pos > lpos)
00289                             s->exponent_bands[k][j++] = pos - lpos;
00290                         if (pos >= block_len)
00291                             break;
00292                         lpos = pos;
00293                     }
00294                     s->exponent_sizes[k] = j;
00295                 }
00296             }
00297 
00298             /* max number of coefs */
00299             s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
00300             /* high freq computation */
00301             s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
00302                                           s->sample_rate + 0.5);
00303             n = s->exponent_sizes[k];
00304             j = 0;
00305             pos = 0;
00306             for (i = 0; i < n; i++) {
00307                 int start, end;
00308                 start = pos;
00309                 pos += s->exponent_bands[k][i];
00310                 end = pos;
00311                 if (start < s->high_band_start[k])
00312                     start = s->high_band_start[k];
00313                 if (end > s->coefs_end[k])
00314                     end = s->coefs_end[k];
00315                 if (end > start)
00316                     s->exponent_high_bands[k][j++] = end - start;
00317             }
00318             s->exponent_high_sizes[k] = j;
00319 #if 0
00320             tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
00321                     s->frame_len >> k,
00322                     s->coefs_end[k],
00323                     s->high_band_start[k],
00324                     s->exponent_high_sizes[k]);
00325             for (j = 0; j < s->exponent_high_sizes[k]; j++)
00326                 tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
00327             tprintf(s->avctx, "\n");
00328 #endif
00329         }
00330     }
00331 
00332 #ifdef TRACE
00333     {
00334         int i, j;
00335         for (i = 0; i < s->nb_block_sizes; i++) {
00336             tprintf(s->avctx, "%5d: n=%2d:",
00337                     s->frame_len >> i,
00338                     s->exponent_sizes[i]);
00339             for (j = 0; j < s->exponent_sizes[i]; j++)
00340                 tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
00341             tprintf(s->avctx, "\n");
00342         }
00343     }
00344 #endif
00345 
00346     /* init MDCT windows : simple sinus window */
00347     for (i = 0; i < s->nb_block_sizes; i++) {
00348         ff_init_ff_sine_windows(s->frame_len_bits - i);
00349         s->windows[i] = ff_sine_windows[s->frame_len_bits - i];
00350     }
00351 
00352     s->reset_block_lengths = 1;
00353 
00354     if (s->use_noise_coding) {
00355 
00356         /* init the noise generator */
00357         if (s->use_exp_vlc) {
00358             s->noise_mult = 0.02;
00359         } else {
00360             s->noise_mult = 0.04;
00361         }
00362 
00363 #ifdef TRACE
00364         for (i = 0; i < NOISE_TAB_SIZE; i++)
00365             s->noise_table[i] = 1.0 * s->noise_mult;
00366 #else
00367         {
00368             unsigned int seed;
00369             float norm;
00370             seed = 1;
00371             norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
00372             for (i = 0; i < NOISE_TAB_SIZE; i++) {
00373                 seed = seed * 314159 + 1;
00374                 s->noise_table[i] = (float)((int)seed) * norm;
00375             }
00376         }
00377 #endif
00378     }
00379 
00380     /* choose the VLC tables for the coefficients */
00381     coef_vlc_table = 2;
00382     if (s->sample_rate >= 32000) {
00383         if (bps1 < 0.72) {
00384             coef_vlc_table = 0;
00385         } else if (bps1 < 1.16) {
00386             coef_vlc_table = 1;
00387         }
00388     }
00389     s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2    ];
00390     s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
00391     init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
00392                   s->coef_vlcs[0]);
00393     init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
00394                   s->coef_vlcs[1]);
00395 
00396     return 0;
00397 }
00398 
00399 int ff_wma_total_gain_to_bits(int total_gain)
00400 {
00401          if (total_gain < 15) return 13;
00402     else if (total_gain < 32) return 12;
00403     else if (total_gain < 40) return 11;
00404     else if (total_gain < 45) return 10;
00405     else                      return  9;
00406 }
00407 
00408 int ff_wma_end(AVCodecContext *avctx)
00409 {
00410     WMACodecContext *s = avctx->priv_data;
00411     int i;
00412 
00413     for (i = 0; i < s->nb_block_sizes; i++)
00414         ff_mdct_end(&s->mdct_ctx[i]);
00415 
00416     if (s->use_exp_vlc) {
00417         free_vlc(&s->exp_vlc);
00418     }
00419     if (s->use_noise_coding) {
00420         free_vlc(&s->hgain_vlc);
00421     }
00422     for (i = 0; i < 2; i++) {
00423         free_vlc(&s->coef_vlc[i]);
00424         av_free(s->run_table[i]);
00425         av_free(s->level_table[i]);
00426         av_free(s->int_table[i]);
00427     }
00428 
00429     return 0;
00430 }
00431 
00437 unsigned int ff_wma_get_large_val(GetBitContext* gb)
00438 {
00440     int n_bits = 8;
00442     if (get_bits1(gb)) {
00443         n_bits += 8;
00444         if (get_bits1(gb)) {
00445             n_bits += 8;
00446             if (get_bits1(gb)) {
00447                 n_bits += 7;
00448             }
00449         }
00450     }
00451     return get_bits_long(gb, n_bits);
00452 }
00453 
00470 int ff_wma_run_level_decode(AVCodecContext* avctx, GetBitContext* gb,
00471                             VLC *vlc,
00472                             const float *level_table, const uint16_t *run_table,
00473                             int version, WMACoef *ptr, int offset,
00474                             int num_coefs, int block_len, int frame_len_bits,
00475                             int coef_nb_bits)
00476 {
00477     int code, level, sign;
00478     const uint32_t *ilvl = (const uint32_t*)level_table;
00479     uint32_t *iptr = (uint32_t*)ptr;
00480     const unsigned int coef_mask = block_len - 1;
00481     for (; offset < num_coefs; offset++) {
00482         code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
00483         if (code > 1) {
00485             offset += run_table[code];
00486             sign = get_bits1(gb) - 1;
00487             iptr[offset & coef_mask] = ilvl[code] ^ sign<<31;
00488         } else if (code == 1) {
00490             break;
00491         } else {
00493             if (!version) {
00494                 level = get_bits(gb, coef_nb_bits);
00497                 offset += get_bits(gb, frame_len_bits);
00498             } else {
00499                 level = ff_wma_get_large_val(gb);
00501                 if (get_bits1(gb)) {
00502                     if (get_bits1(gb)) {
00503                         if (get_bits1(gb)) {
00504                             av_log(avctx,AV_LOG_ERROR,
00505                                 "broken escape sequence\n");
00506                             return -1;
00507                         } else
00508                             offset += get_bits(gb, frame_len_bits) + 4;
00509                     } else
00510                         offset += get_bits(gb, 2) + 1;
00511                 }
00512             }
00513             sign = get_bits1(gb) - 1;
00514             ptr[offset & coef_mask] = (level^sign) - sign;
00515         }
00516     }
00518     if (offset > num_coefs) {
00519         av_log(avctx, AV_LOG_ERROR, "overflow in spectral RLE, ignoring\n");
00520         return -1;
00521     }
00522 
00523     return 0;
00524 }
00525