Libav

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     s->next_block_len_bits = s->frame_len_bits;
00139     s->prev_block_len_bits = s->frame_len_bits;
00140     s->block_len_bits      = s->frame_len_bits;
00141 
00142     s->frame_len = 1 << s->frame_len_bits;
00143     if (s->use_variable_block_len) {
00144         int nb_max, nb;
00145         nb = ((flags2 >> 3) & 3) + 1;
00146         if ((s->bit_rate / s->nb_channels) >= 32000)
00147             nb += 2;
00148         nb_max = s->frame_len_bits - BLOCK_MIN_BITS;
00149         if (nb > nb_max)
00150             nb = nb_max;
00151         s->nb_block_sizes = nb + 1;
00152     } else {
00153         s->nb_block_sizes = 1;
00154     }
00155 
00156     /* init rate dependent parameters */
00157     s->use_noise_coding = 1;
00158     high_freq = s->sample_rate * 0.5;
00159 
00160     /* if version 2, then the rates are normalized */
00161     sample_rate1 = s->sample_rate;
00162     if (s->version == 2) {
00163         if (sample_rate1 >= 44100) {
00164             sample_rate1 = 44100;
00165         } else if (sample_rate1 >= 22050) {
00166             sample_rate1 = 22050;
00167         } else if (sample_rate1 >= 16000) {
00168             sample_rate1 = 16000;
00169         } else if (sample_rate1 >= 11025) {
00170             sample_rate1 = 11025;
00171         } else if (sample_rate1 >= 8000) {
00172             sample_rate1 = 8000;
00173         }
00174     }
00175 
00176     bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
00177     s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0 + 0.5)) + 2;
00178 
00179     /* compute high frequency value and choose if noise coding should
00180        be activated */
00181     bps1 = bps;
00182     if (s->nb_channels == 2)
00183         bps1 = bps * 1.6;
00184     if (sample_rate1 == 44100) {
00185         if (bps1 >= 0.61) {
00186             s->use_noise_coding = 0;
00187         } else {
00188             high_freq = high_freq * 0.4;
00189         }
00190     } else if (sample_rate1 == 22050) {
00191         if (bps1 >= 1.16) {
00192             s->use_noise_coding = 0;
00193         } else if (bps1 >= 0.72) {
00194             high_freq = high_freq * 0.7;
00195         } else {
00196             high_freq = high_freq * 0.6;
00197         }
00198     } else if (sample_rate1 == 16000) {
00199         if (bps > 0.5) {
00200             high_freq = high_freq * 0.5;
00201         } else {
00202             high_freq = high_freq * 0.3;
00203         }
00204     } else if (sample_rate1 == 11025) {
00205         high_freq = high_freq * 0.7;
00206     } else if (sample_rate1 == 8000) {
00207         if (bps <= 0.625) {
00208             high_freq = high_freq * 0.5;
00209         } else if (bps > 0.75) {
00210             s->use_noise_coding = 0;
00211         } else {
00212             high_freq = high_freq * 0.65;
00213         }
00214     } else {
00215         if (bps >= 0.8) {
00216             high_freq = high_freq * 0.75;
00217         } else if (bps >= 0.6) {
00218             high_freq = high_freq * 0.6;
00219         } else {
00220             high_freq = high_freq * 0.5;
00221         }
00222     }
00223     dprintf(s->avctx, "flags2=0x%x\n", flags2);
00224     dprintf(s->avctx, "version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
00225             s->version, s->nb_channels, s->sample_rate, s->bit_rate,
00226             s->block_align);
00227     dprintf(s->avctx, "bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
00228             bps, bps1, high_freq, s->byte_offset_bits);
00229     dprintf(s->avctx, "use_noise_coding=%d use_exp_vlc=%d nb_block_sizes=%d\n",
00230             s->use_noise_coding, s->use_exp_vlc, s->nb_block_sizes);
00231 
00232     /* compute the scale factor band sizes for each MDCT block size */
00233     {
00234         int a, b, pos, lpos, k, block_len, i, j, n;
00235         const uint8_t *table;
00236 
00237         if (s->version == 1) {
00238             s->coefs_start = 3;
00239         } else {
00240             s->coefs_start = 0;
00241         }
00242         for (k = 0; k < s->nb_block_sizes; k++) {
00243             block_len = s->frame_len >> k;
00244 
00245             if (s->version == 1) {
00246                 lpos = 0;
00247                 for (i = 0; i < 25; i++) {
00248                     a = ff_wma_critical_freqs[i];
00249                     b = s->sample_rate;
00250                     pos = ((block_len * 2 * a) + (b >> 1)) / b;
00251                     if (pos > block_len)
00252                         pos = block_len;
00253                     s->exponent_bands[0][i] = pos - lpos;
00254                     if (pos >= block_len) {
00255                         i++;
00256                         break;
00257                     }
00258                     lpos = pos;
00259                 }
00260                 s->exponent_sizes[0] = i;
00261             } else {
00262                 /* hardcoded tables */
00263                 table = NULL;
00264                 a = s->frame_len_bits - BLOCK_MIN_BITS - k;
00265                 if (a < 3) {
00266                     if (s->sample_rate >= 44100) {
00267                         table = exponent_band_44100[a];
00268                     } else if (s->sample_rate >= 32000) {
00269                         table = exponent_band_32000[a];
00270                     } else if (s->sample_rate >= 22050) {
00271                         table = exponent_band_22050[a];
00272                     }
00273                 }
00274                 if (table) {
00275                     n = *table++;
00276                     for (i = 0; i < n; i++)
00277                         s->exponent_bands[k][i] = table[i];
00278                     s->exponent_sizes[k] = n;
00279                 } else {
00280                     j = 0;
00281                     lpos = 0;
00282                     for (i = 0; i < 25; i++) {
00283                         a = ff_wma_critical_freqs[i];
00284                         b = s->sample_rate;
00285                         pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
00286                         pos <<= 2;
00287                         if (pos > block_len)
00288                             pos = block_len;
00289                         if (pos > lpos)
00290                             s->exponent_bands[k][j++] = pos - lpos;
00291                         if (pos >= block_len)
00292                             break;
00293                         lpos = pos;
00294                     }
00295                     s->exponent_sizes[k] = j;
00296                 }
00297             }
00298 
00299             /* max number of coefs */
00300             s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
00301             /* high freq computation */
00302             s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
00303                                           s->sample_rate + 0.5);
00304             n = s->exponent_sizes[k];
00305             j = 0;
00306             pos = 0;
00307             for (i = 0; i < n; i++) {
00308                 int start, end;
00309                 start = pos;
00310                 pos += s->exponent_bands[k][i];
00311                 end = pos;
00312                 if (start < s->high_band_start[k])
00313                     start = s->high_band_start[k];
00314                 if (end > s->coefs_end[k])
00315                     end = s->coefs_end[k];
00316                 if (end > start)
00317                     s->exponent_high_bands[k][j++] = end - start;
00318             }
00319             s->exponent_high_sizes[k] = j;
00320 #if 0
00321             tprintf(s->avctx, "%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
00322                     s->frame_len >> k,
00323                     s->coefs_end[k],
00324                     s->high_band_start[k],
00325                     s->exponent_high_sizes[k]);
00326             for (j = 0; j < s->exponent_high_sizes[k]; j++)
00327                 tprintf(s->avctx, " %d", s->exponent_high_bands[k][j]);
00328             tprintf(s->avctx, "\n");
00329 #endif
00330         }
00331     }
00332 
00333 #ifdef TRACE
00334     {
00335         int i, j;
00336         for (i = 0; i < s->nb_block_sizes; i++) {
00337             tprintf(s->avctx, "%5d: n=%2d:",
00338                     s->frame_len >> i,
00339                     s->exponent_sizes[i]);
00340             for (j = 0; j < s->exponent_sizes[i]; j++)
00341                 tprintf(s->avctx, " %d", s->exponent_bands[i][j]);
00342             tprintf(s->avctx, "\n");
00343         }
00344     }
00345 #endif
00346 
00347     /* init MDCT windows : simple sinus window */
00348     for (i = 0; i < s->nb_block_sizes; i++) {
00349         ff_init_ff_sine_windows(s->frame_len_bits - i);
00350         s->windows[i] = ff_sine_windows[s->frame_len_bits - i];
00351     }
00352 
00353     s->reset_block_lengths = 1;
00354 
00355     if (s->use_noise_coding) {
00356 
00357         /* init the noise generator */
00358         if (s->use_exp_vlc) {
00359             s->noise_mult = 0.02;
00360         } else {
00361             s->noise_mult = 0.04;
00362         }
00363 
00364 #ifdef TRACE
00365         for (i = 0; i < NOISE_TAB_SIZE; i++)
00366             s->noise_table[i] = 1.0 * s->noise_mult;
00367 #else
00368         {
00369             unsigned int seed;
00370             float norm;
00371             seed = 1;
00372             norm = (1.0 / (float)(1LL << 31)) * sqrt(3) * s->noise_mult;
00373             for (i = 0; i < NOISE_TAB_SIZE; i++) {
00374                 seed = seed * 314159 + 1;
00375                 s->noise_table[i] = (float)((int)seed) * norm;
00376             }
00377         }
00378 #endif
00379     }
00380 
00381     /* choose the VLC tables for the coefficients */
00382     coef_vlc_table = 2;
00383     if (s->sample_rate >= 32000) {
00384         if (bps1 < 0.72) {
00385             coef_vlc_table = 0;
00386         } else if (bps1 < 1.16) {
00387             coef_vlc_table = 1;
00388         }
00389     }
00390     s->coef_vlcs[0]= &coef_vlcs[coef_vlc_table * 2    ];
00391     s->coef_vlcs[1]= &coef_vlcs[coef_vlc_table * 2 + 1];
00392     init_coef_vlc(&s->coef_vlc[0], &s->run_table[0], &s->level_table[0], &s->int_table[0],
00393                   s->coef_vlcs[0]);
00394     init_coef_vlc(&s->coef_vlc[1], &s->run_table[1], &s->level_table[1], &s->int_table[1],
00395                   s->coef_vlcs[1]);
00396 
00397     return 0;
00398 }
00399 
00400 int ff_wma_total_gain_to_bits(int total_gain)
00401 {
00402          if (total_gain < 15) return 13;
00403     else if (total_gain < 32) return 12;
00404     else if (total_gain < 40) return 11;
00405     else if (total_gain < 45) return 10;
00406     else                      return  9;
00407 }
00408 
00409 int ff_wma_end(AVCodecContext *avctx)
00410 {
00411     WMACodecContext *s = avctx->priv_data;
00412     int i;
00413 
00414     for (i = 0; i < s->nb_block_sizes; i++)
00415         ff_mdct_end(&s->mdct_ctx[i]);
00416 
00417     if (s->use_exp_vlc) {
00418         free_vlc(&s->exp_vlc);
00419     }
00420     if (s->use_noise_coding) {
00421         free_vlc(&s->hgain_vlc);
00422     }
00423     for (i = 0; i < 2; i++) {
00424         free_vlc(&s->coef_vlc[i]);
00425         av_free(s->run_table[i]);
00426         av_free(s->level_table[i]);
00427         av_free(s->int_table[i]);
00428     }
00429 
00430     return 0;
00431 }
00432 
00438 unsigned int ff_wma_get_large_val(GetBitContext* gb)
00439 {
00441     int n_bits = 8;
00443     if (get_bits1(gb)) {
00444         n_bits += 8;
00445         if (get_bits1(gb)) {
00446             n_bits += 8;
00447             if (get_bits1(gb)) {
00448                 n_bits += 7;
00449             }
00450         }
00451     }
00452     return get_bits_long(gb, n_bits);
00453 }
00454 
00471 int ff_wma_run_level_decode(AVCodecContext* avctx, GetBitContext* gb,
00472                             VLC *vlc,
00473                             const float *level_table, const uint16_t *run_table,
00474                             int version, WMACoef *ptr, int offset,
00475                             int num_coefs, int block_len, int frame_len_bits,
00476                             int coef_nb_bits)
00477 {
00478     int code, level, sign;
00479     const uint32_t *ilvl = (const uint32_t*)level_table;
00480     uint32_t *iptr = (uint32_t*)ptr;
00481     const unsigned int coef_mask = block_len - 1;
00482     for (; offset < num_coefs; offset++) {
00483         code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
00484         if (code > 1) {
00486             offset += run_table[code];
00487             sign = get_bits1(gb) - 1;
00488             iptr[offset & coef_mask] = ilvl[code] ^ sign<<31;
00489         } else if (code == 1) {
00491             break;
00492         } else {
00494             if (!version) {
00495                 level = get_bits(gb, coef_nb_bits);
00498                 offset += get_bits(gb, frame_len_bits);
00499             } else {
00500                 level = ff_wma_get_large_val(gb);
00502                 if (get_bits1(gb)) {
00503                     if (get_bits1(gb)) {
00504                         if (get_bits1(gb)) {
00505                             av_log(avctx,AV_LOG_ERROR,
00506                                 "broken escape sequence\n");
00507                             return -1;
00508                         } else
00509                             offset += get_bits(gb, frame_len_bits) + 4;
00510                     } else
00511                         offset += get_bits(gb, 2) + 1;
00512                 }
00513             }
00514             sign = get_bits1(gb) - 1;
00515             ptr[offset & coef_mask] = (level^sign) - sign;
00516         }
00517     }
00519     if (offset > num_coefs) {
00520         av_log(avctx, AV_LOG_ERROR, "overflow in spectral RLE, ignoring\n");
00521         return -1;
00522     }
00523 
00524     return 0;
00525 }
00526