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libavcodec/wmadec.c

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00001 /*
00002  * WMA compatible decoder
00003  * Copyright (c) 2002 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 
00036 #include "avcodec.h"
00037 #include "wma.h"
00038 
00039 #undef NDEBUG
00040 #include <assert.h>
00041 
00042 #define EXPVLCBITS 8
00043 #define EXPMAX ((19+EXPVLCBITS-1)/EXPVLCBITS)
00044 
00045 #define HGAINVLCBITS 9
00046 #define HGAINMAX ((13+HGAINVLCBITS-1)/HGAINVLCBITS)
00047 
00048 static void wma_lsp_to_curve_init(WMACodecContext *s, int frame_len);
00049 
00050 #ifdef TRACE
00051 static void dump_shorts(WMACodecContext *s, const char *name, const short *tab, int n)
00052 {
00053     int i;
00054 
00055     tprintf(s->avctx, "%s[%d]:\n", name, n);
00056     for(i=0;i<n;i++) {
00057         if ((i & 7) == 0)
00058             tprintf(s->avctx, "%4d: ", i);
00059         tprintf(s->avctx, " %5d.0", tab[i]);
00060         if ((i & 7) == 7)
00061             tprintf(s->avctx, "\n");
00062     }
00063 }
00064 
00065 static void dump_floats(WMACodecContext *s, const char *name, int prec, const float *tab, int n)
00066 {
00067     int i;
00068 
00069     tprintf(s->avctx, "%s[%d]:\n", name, n);
00070     for(i=0;i<n;i++) {
00071         if ((i & 7) == 0)
00072             tprintf(s->avctx, "%4d: ", i);
00073         tprintf(s->avctx, " %8.*f", prec, tab[i]);
00074         if ((i & 7) == 7)
00075             tprintf(s->avctx, "\n");
00076     }
00077     if ((i & 7) != 0)
00078         tprintf(s->avctx, "\n");
00079 }
00080 #endif
00081 
00082 static int wma_decode_init(AVCodecContext * avctx)
00083 {
00084     WMACodecContext *s = avctx->priv_data;
00085     int i, flags2;
00086     uint8_t *extradata;
00087 
00088     s->avctx = avctx;
00089 
00090     /* extract flag infos */
00091     flags2 = 0;
00092     extradata = avctx->extradata;
00093     if (avctx->codec->id == CODEC_ID_WMAV1 && avctx->extradata_size >= 4) {
00094         flags2 = AV_RL16(extradata+2);
00095     } else if (avctx->codec->id == CODEC_ID_WMAV2 && avctx->extradata_size >= 6) {
00096         flags2 = AV_RL16(extradata+4);
00097     }
00098 // for(i=0; i<avctx->extradata_size; i++)
00099 //     av_log(NULL, AV_LOG_ERROR, "%02X ", extradata[i]);
00100 
00101     s->use_exp_vlc = flags2 & 0x0001;
00102     s->use_bit_reservoir = flags2 & 0x0002;
00103     s->use_variable_block_len = flags2 & 0x0004;
00104 
00105     if(ff_wma_init(avctx, flags2)<0)
00106         return -1;
00107 
00108     /* init MDCT */
00109     for(i = 0; i < s->nb_block_sizes; i++)
00110         ff_mdct_init(&s->mdct_ctx[i], s->frame_len_bits - i + 1, 1, 1.0);
00111 
00112     if (s->use_noise_coding) {
00113         init_vlc(&s->hgain_vlc, HGAINVLCBITS, sizeof(ff_wma_hgain_huffbits),
00114                  ff_wma_hgain_huffbits, 1, 1,
00115                  ff_wma_hgain_huffcodes, 2, 2, 0);
00116     }
00117 
00118     if (s->use_exp_vlc) {
00119         init_vlc(&s->exp_vlc, EXPVLCBITS, sizeof(ff_aac_scalefactor_bits), //FIXME move out of context
00120                  ff_aac_scalefactor_bits, 1, 1,
00121                  ff_aac_scalefactor_code, 4, 4, 0);
00122     } else {
00123         wma_lsp_to_curve_init(s, s->frame_len);
00124     }
00125 
00126     avctx->sample_fmt = SAMPLE_FMT_S16;
00127     return 0;
00128 }
00129 
00136 static inline float pow_m1_4(WMACodecContext *s, float x)
00137 {
00138     union {
00139         float f;
00140         unsigned int v;
00141     } u, t;
00142     unsigned int e, m;
00143     float a, b;
00144 
00145     u.f = x;
00146     e = u.v >> 23;
00147     m = (u.v >> (23 - LSP_POW_BITS)) & ((1 << LSP_POW_BITS) - 1);
00148     /* build interpolation scale: 1 <= t < 2. */
00149     t.v = ((u.v << LSP_POW_BITS) & ((1 << 23) - 1)) | (127 << 23);
00150     a = s->lsp_pow_m_table1[m];
00151     b = s->lsp_pow_m_table2[m];
00152     return s->lsp_pow_e_table[e] * (a + b * t.f);
00153 }
00154 
00155 static void wma_lsp_to_curve_init(WMACodecContext *s, int frame_len)
00156 {
00157     float wdel, a, b;
00158     int i, e, m;
00159 
00160     wdel = M_PI / frame_len;
00161     for(i=0;i<frame_len;i++)
00162         s->lsp_cos_table[i] = 2.0f * cos(wdel * i);
00163 
00164     /* tables for x^-0.25 computation */
00165     for(i=0;i<256;i++) {
00166         e = i - 126;
00167         s->lsp_pow_e_table[i] = pow(2.0, e * -0.25);
00168     }
00169 
00170     /* NOTE: these two tables are needed to avoid two operations in
00171        pow_m1_4 */
00172     b = 1.0;
00173     for(i=(1 << LSP_POW_BITS) - 1;i>=0;i--) {
00174         m = (1 << LSP_POW_BITS) + i;
00175         a = (float)m * (0.5 / (1 << LSP_POW_BITS));
00176         a = pow(a, -0.25);
00177         s->lsp_pow_m_table1[i] = 2 * a - b;
00178         s->lsp_pow_m_table2[i] = b - a;
00179         b = a;
00180     }
00181 #if 0
00182     for(i=1;i<20;i++) {
00183         float v, r1, r2;
00184         v = 5.0 / i;
00185         r1 = pow_m1_4(s, v);
00186         r2 = pow(v,-0.25);
00187         printf("%f^-0.25=%f e=%f\n", v, r1, r2 - r1);
00188     }
00189 #endif
00190 }
00191 
00196 static void wma_lsp_to_curve(WMACodecContext *s,
00197                              float *out, float *val_max_ptr,
00198                              int n, float *lsp)
00199 {
00200     int i, j;
00201     float p, q, w, v, val_max;
00202 
00203     val_max = 0;
00204     for(i=0;i<n;i++) {
00205         p = 0.5f;
00206         q = 0.5f;
00207         w = s->lsp_cos_table[i];
00208         for(j=1;j<NB_LSP_COEFS;j+=2){
00209             q *= w - lsp[j - 1];
00210             p *= w - lsp[j];
00211         }
00212         p *= p * (2.0f - w);
00213         q *= q * (2.0f + w);
00214         v = p + q;
00215         v = pow_m1_4(s, v);
00216         if (v > val_max)
00217             val_max = v;
00218         out[i] = v;
00219     }
00220     *val_max_ptr = val_max;
00221 }
00222 
00226 static void decode_exp_lsp(WMACodecContext *s, int ch)
00227 {
00228     float lsp_coefs[NB_LSP_COEFS];
00229     int val, i;
00230 
00231     for(i = 0; i < NB_LSP_COEFS; i++) {
00232         if (i == 0 || i >= 8)
00233             val = get_bits(&s->gb, 3);
00234         else
00235             val = get_bits(&s->gb, 4);
00236         lsp_coefs[i] = ff_wma_lsp_codebook[i][val];
00237     }
00238 
00239     wma_lsp_to_curve(s, s->exponents[ch], &s->max_exponent[ch],
00240                      s->block_len, lsp_coefs);
00241 }
00242 
00244 static const float pow_tab[] = {
00245     1.7782794100389e-04, 2.0535250264571e-04,
00246     2.3713737056617e-04, 2.7384196342644e-04,
00247     3.1622776601684e-04, 3.6517412725484e-04,
00248     4.2169650342858e-04, 4.8696752516586e-04,
00249     5.6234132519035e-04, 6.4938163157621e-04,
00250     7.4989420933246e-04, 8.6596432336006e-04,
00251     1.0000000000000e-03, 1.1547819846895e-03,
00252     1.3335214321633e-03, 1.5399265260595e-03,
00253     1.7782794100389e-03, 2.0535250264571e-03,
00254     2.3713737056617e-03, 2.7384196342644e-03,
00255     3.1622776601684e-03, 3.6517412725484e-03,
00256     4.2169650342858e-03, 4.8696752516586e-03,
00257     5.6234132519035e-03, 6.4938163157621e-03,
00258     7.4989420933246e-03, 8.6596432336006e-03,
00259     1.0000000000000e-02, 1.1547819846895e-02,
00260     1.3335214321633e-02, 1.5399265260595e-02,
00261     1.7782794100389e-02, 2.0535250264571e-02,
00262     2.3713737056617e-02, 2.7384196342644e-02,
00263     3.1622776601684e-02, 3.6517412725484e-02,
00264     4.2169650342858e-02, 4.8696752516586e-02,
00265     5.6234132519035e-02, 6.4938163157621e-02,
00266     7.4989420933246e-02, 8.6596432336007e-02,
00267     1.0000000000000e-01, 1.1547819846895e-01,
00268     1.3335214321633e-01, 1.5399265260595e-01,
00269     1.7782794100389e-01, 2.0535250264571e-01,
00270     2.3713737056617e-01, 2.7384196342644e-01,
00271     3.1622776601684e-01, 3.6517412725484e-01,
00272     4.2169650342858e-01, 4.8696752516586e-01,
00273     5.6234132519035e-01, 6.4938163157621e-01,
00274     7.4989420933246e-01, 8.6596432336007e-01,
00275     1.0000000000000e+00, 1.1547819846895e+00,
00276     1.3335214321633e+00, 1.5399265260595e+00,
00277     1.7782794100389e+00, 2.0535250264571e+00,
00278     2.3713737056617e+00, 2.7384196342644e+00,
00279     3.1622776601684e+00, 3.6517412725484e+00,
00280     4.2169650342858e+00, 4.8696752516586e+00,
00281     5.6234132519035e+00, 6.4938163157621e+00,
00282     7.4989420933246e+00, 8.6596432336007e+00,
00283     1.0000000000000e+01, 1.1547819846895e+01,
00284     1.3335214321633e+01, 1.5399265260595e+01,
00285     1.7782794100389e+01, 2.0535250264571e+01,
00286     2.3713737056617e+01, 2.7384196342644e+01,
00287     3.1622776601684e+01, 3.6517412725484e+01,
00288     4.2169650342858e+01, 4.8696752516586e+01,
00289     5.6234132519035e+01, 6.4938163157621e+01,
00290     7.4989420933246e+01, 8.6596432336007e+01,
00291     1.0000000000000e+02, 1.1547819846895e+02,
00292     1.3335214321633e+02, 1.5399265260595e+02,
00293     1.7782794100389e+02, 2.0535250264571e+02,
00294     2.3713737056617e+02, 2.7384196342644e+02,
00295     3.1622776601684e+02, 3.6517412725484e+02,
00296     4.2169650342858e+02, 4.8696752516586e+02,
00297     5.6234132519035e+02, 6.4938163157621e+02,
00298     7.4989420933246e+02, 8.6596432336007e+02,
00299     1.0000000000000e+03, 1.1547819846895e+03,
00300     1.3335214321633e+03, 1.5399265260595e+03,
00301     1.7782794100389e+03, 2.0535250264571e+03,
00302     2.3713737056617e+03, 2.7384196342644e+03,
00303     3.1622776601684e+03, 3.6517412725484e+03,
00304     4.2169650342858e+03, 4.8696752516586e+03,
00305     5.6234132519035e+03, 6.4938163157621e+03,
00306     7.4989420933246e+03, 8.6596432336007e+03,
00307     1.0000000000000e+04, 1.1547819846895e+04,
00308     1.3335214321633e+04, 1.5399265260595e+04,
00309     1.7782794100389e+04, 2.0535250264571e+04,
00310     2.3713737056617e+04, 2.7384196342644e+04,
00311     3.1622776601684e+04, 3.6517412725484e+04,
00312     4.2169650342858e+04, 4.8696752516586e+04,
00313     5.6234132519035e+04, 6.4938163157621e+04,
00314     7.4989420933246e+04, 8.6596432336007e+04,
00315     1.0000000000000e+05, 1.1547819846895e+05,
00316     1.3335214321633e+05, 1.5399265260595e+05,
00317     1.7782794100389e+05, 2.0535250264571e+05,
00318     2.3713737056617e+05, 2.7384196342644e+05,
00319     3.1622776601684e+05, 3.6517412725484e+05,
00320     4.2169650342858e+05, 4.8696752516586e+05,
00321     5.6234132519035e+05, 6.4938163157621e+05,
00322     7.4989420933246e+05, 8.6596432336007e+05,
00323 };
00324 
00328 static int decode_exp_vlc(WMACodecContext *s, int ch)
00329 {
00330     int last_exp, n, code;
00331     const uint16_t *ptr;
00332     float v, max_scale;
00333     uint32_t *q, *q_end, iv;
00334     const float *ptab = pow_tab + 60;
00335     const uint32_t *iptab = (const uint32_t*)ptab;
00336 
00337     ptr = s->exponent_bands[s->frame_len_bits - s->block_len_bits];
00338     q = (uint32_t *)s->exponents[ch];
00339     q_end = q + s->block_len;
00340     max_scale = 0;
00341     if (s->version == 1) {
00342         last_exp = get_bits(&s->gb, 5) + 10;
00343         v = ptab[last_exp];
00344         iv = iptab[last_exp];
00345         max_scale = v;
00346         n = *ptr++;
00347         switch (n & 3) do {
00348         case 0: *q++ = iv;
00349         case 3: *q++ = iv;
00350         case 2: *q++ = iv;
00351         case 1: *q++ = iv;
00352         } while ((n -= 4) > 0);
00353     }else
00354         last_exp = 36;
00355 
00356     while (q < q_end) {
00357         code = get_vlc2(&s->gb, s->exp_vlc.table, EXPVLCBITS, EXPMAX);
00358         if (code < 0){
00359             av_log(s->avctx, AV_LOG_ERROR, "Exponent vlc invalid\n");
00360             return -1;
00361         }
00362         /* NOTE: this offset is the same as MPEG4 AAC ! */
00363         last_exp += code - 60;
00364         if ((unsigned)last_exp + 60 > FF_ARRAY_ELEMS(pow_tab)) {
00365             av_log(s->avctx, AV_LOG_ERROR, "Exponent out of range: %d\n",
00366                    last_exp);
00367             return -1;
00368         }
00369         v = ptab[last_exp];
00370         iv = iptab[last_exp];
00371         if (v > max_scale)
00372             max_scale = v;
00373         n = *ptr++;
00374         switch (n & 3) do {
00375         case 0: *q++ = iv;
00376         case 3: *q++ = iv;
00377         case 2: *q++ = iv;
00378         case 1: *q++ = iv;
00379         } while ((n -= 4) > 0);
00380     }
00381     s->max_exponent[ch] = max_scale;
00382     return 0;
00383 }
00384 
00385 
00392 static void wma_window(WMACodecContext *s, float *out)
00393 {
00394     float *in = s->output;
00395     int block_len, bsize, n;
00396 
00397     /* left part */
00398     if (s->block_len_bits <= s->prev_block_len_bits) {
00399         block_len = s->block_len;
00400         bsize = s->frame_len_bits - s->block_len_bits;
00401 
00402         s->dsp.vector_fmul_add(out, in, s->windows[bsize],
00403                                out, block_len);
00404 
00405     } else {
00406         block_len = 1 << s->prev_block_len_bits;
00407         n = (s->block_len - block_len) / 2;
00408         bsize = s->frame_len_bits - s->prev_block_len_bits;
00409 
00410         s->dsp.vector_fmul_add(out+n, in+n, s->windows[bsize],
00411                                out+n, block_len);
00412 
00413         memcpy(out+n+block_len, in+n+block_len, n*sizeof(float));
00414     }
00415 
00416     out += s->block_len;
00417     in += s->block_len;
00418 
00419     /* right part */
00420     if (s->block_len_bits <= s->next_block_len_bits) {
00421         block_len = s->block_len;
00422         bsize = s->frame_len_bits - s->block_len_bits;
00423 
00424         s->dsp.vector_fmul_reverse(out, in, s->windows[bsize], block_len);
00425 
00426     } else {
00427         block_len = 1 << s->next_block_len_bits;
00428         n = (s->block_len - block_len) / 2;
00429         bsize = s->frame_len_bits - s->next_block_len_bits;
00430 
00431         memcpy(out, in, n*sizeof(float));
00432 
00433         s->dsp.vector_fmul_reverse(out+n, in+n, s->windows[bsize], block_len);
00434 
00435         memset(out+n+block_len, 0, n*sizeof(float));
00436     }
00437 }
00438 
00439 
00444 static int wma_decode_block(WMACodecContext *s)
00445 {
00446     int n, v, a, ch, bsize;
00447     int coef_nb_bits, total_gain;
00448     int nb_coefs[MAX_CHANNELS];
00449     float mdct_norm;
00450 
00451 #ifdef TRACE
00452     tprintf(s->avctx, "***decode_block: %d:%d\n", s->frame_count - 1, s->block_num);
00453 #endif
00454 
00455     /* compute current block length */
00456     if (s->use_variable_block_len) {
00457         n = av_log2(s->nb_block_sizes - 1) + 1;
00458 
00459         if (s->reset_block_lengths) {
00460             s->reset_block_lengths = 0;
00461             v = get_bits(&s->gb, n);
00462             if (v >= s->nb_block_sizes){
00463                 av_log(s->avctx, AV_LOG_ERROR, "prev_block_len_bits %d out of range\n", s->frame_len_bits - v);
00464                 return -1;
00465             }
00466             s->prev_block_len_bits = s->frame_len_bits - v;
00467             v = get_bits(&s->gb, n);
00468             if (v >= s->nb_block_sizes){
00469                 av_log(s->avctx, AV_LOG_ERROR, "block_len_bits %d out of range\n", s->frame_len_bits - v);
00470                 return -1;
00471             }
00472             s->block_len_bits = s->frame_len_bits - v;
00473         } else {
00474             /* update block lengths */
00475             s->prev_block_len_bits = s->block_len_bits;
00476             s->block_len_bits = s->next_block_len_bits;
00477         }
00478         v = get_bits(&s->gb, n);
00479         if (v >= s->nb_block_sizes){
00480             av_log(s->avctx, AV_LOG_ERROR, "next_block_len_bits %d out of range\n", s->frame_len_bits - v);
00481             return -1;
00482         }
00483         s->next_block_len_bits = s->frame_len_bits - v;
00484     } else {
00485         /* fixed block len */
00486         s->next_block_len_bits = s->frame_len_bits;
00487         s->prev_block_len_bits = s->frame_len_bits;
00488         s->block_len_bits = s->frame_len_bits;
00489     }
00490 
00491     /* now check if the block length is coherent with the frame length */
00492     s->block_len = 1 << s->block_len_bits;
00493     if ((s->block_pos + s->block_len) > s->frame_len){
00494         av_log(s->avctx, AV_LOG_ERROR, "frame_len overflow\n");
00495         return -1;
00496     }
00497 
00498     if (s->nb_channels == 2) {
00499         s->ms_stereo = get_bits1(&s->gb);
00500     }
00501     v = 0;
00502     for(ch = 0; ch < s->nb_channels; ch++) {
00503         a = get_bits1(&s->gb);
00504         s->channel_coded[ch] = a;
00505         v |= a;
00506     }
00507 
00508     bsize = s->frame_len_bits - s->block_len_bits;
00509 
00510     /* if no channel coded, no need to go further */
00511     /* XXX: fix potential framing problems */
00512     if (!v)
00513         goto next;
00514 
00515     /* read total gain and extract corresponding number of bits for
00516        coef escape coding */
00517     total_gain = 1;
00518     for(;;) {
00519         a = get_bits(&s->gb, 7);
00520         total_gain += a;
00521         if (a != 127)
00522             break;
00523     }
00524 
00525     coef_nb_bits= ff_wma_total_gain_to_bits(total_gain);
00526 
00527     /* compute number of coefficients */
00528     n = s->coefs_end[bsize] - s->coefs_start;
00529     for(ch = 0; ch < s->nb_channels; ch++)
00530         nb_coefs[ch] = n;
00531 
00532     /* complex coding */
00533     if (s->use_noise_coding) {
00534 
00535         for(ch = 0; ch < s->nb_channels; ch++) {
00536             if (s->channel_coded[ch]) {
00537                 int i, n, a;
00538                 n = s->exponent_high_sizes[bsize];
00539                 for(i=0;i<n;i++) {
00540                     a = get_bits1(&s->gb);
00541                     s->high_band_coded[ch][i] = a;
00542                     /* if noise coding, the coefficients are not transmitted */
00543                     if (a)
00544                         nb_coefs[ch] -= s->exponent_high_bands[bsize][i];
00545                 }
00546             }
00547         }
00548         for(ch = 0; ch < s->nb_channels; ch++) {
00549             if (s->channel_coded[ch]) {
00550                 int i, n, val, code;
00551 
00552                 n = s->exponent_high_sizes[bsize];
00553                 val = (int)0x80000000;
00554                 for(i=0;i<n;i++) {
00555                     if (s->high_band_coded[ch][i]) {
00556                         if (val == (int)0x80000000) {
00557                             val = get_bits(&s->gb, 7) - 19;
00558                         } else {
00559                             code = get_vlc2(&s->gb, s->hgain_vlc.table, HGAINVLCBITS, HGAINMAX);
00560                             if (code < 0){
00561                                 av_log(s->avctx, AV_LOG_ERROR, "hgain vlc invalid\n");
00562                                 return -1;
00563                             }
00564                             val += code - 18;
00565                         }
00566                         s->high_band_values[ch][i] = val;
00567                     }
00568                 }
00569             }
00570         }
00571     }
00572 
00573     /* exponents can be reused in short blocks. */
00574     if ((s->block_len_bits == s->frame_len_bits) ||
00575         get_bits1(&s->gb)) {
00576         for(ch = 0; ch < s->nb_channels; ch++) {
00577             if (s->channel_coded[ch]) {
00578                 if (s->use_exp_vlc) {
00579                     if (decode_exp_vlc(s, ch) < 0)
00580                         return -1;
00581                 } else {
00582                     decode_exp_lsp(s, ch);
00583                 }
00584                 s->exponents_bsize[ch] = bsize;
00585             }
00586         }
00587     }
00588 
00589     /* parse spectral coefficients : just RLE encoding */
00590     for(ch = 0; ch < s->nb_channels; ch++) {
00591         if (s->channel_coded[ch]) {
00592             int tindex;
00593             WMACoef* ptr = &s->coefs1[ch][0];
00594 
00595             /* special VLC tables are used for ms stereo because
00596                there is potentially less energy there */
00597             tindex = (ch == 1 && s->ms_stereo);
00598             memset(ptr, 0, s->block_len * sizeof(WMACoef));
00599             ff_wma_run_level_decode(s->avctx, &s->gb, &s->coef_vlc[tindex],
00600                   s->level_table[tindex], s->run_table[tindex],
00601                   0, ptr, 0, nb_coefs[ch],
00602                   s->block_len, s->frame_len_bits, coef_nb_bits);
00603         }
00604         if (s->version == 1 && s->nb_channels >= 2) {
00605             align_get_bits(&s->gb);
00606         }
00607     }
00608 
00609     /* normalize */
00610     {
00611         int n4 = s->block_len / 2;
00612         mdct_norm = 1.0 / (float)n4;
00613         if (s->version == 1) {
00614             mdct_norm *= sqrt(n4);
00615         }
00616     }
00617 
00618     /* finally compute the MDCT coefficients */
00619     for(ch = 0; ch < s->nb_channels; ch++) {
00620         if (s->channel_coded[ch]) {
00621             WMACoef *coefs1;
00622             float *coefs, *exponents, mult, mult1, noise;
00623             int i, j, n, n1, last_high_band, esize;
00624             float exp_power[HIGH_BAND_MAX_SIZE];
00625 
00626             coefs1 = s->coefs1[ch];
00627             exponents = s->exponents[ch];
00628             esize = s->exponents_bsize[ch];
00629             mult = pow(10, total_gain * 0.05) / s->max_exponent[ch];
00630             mult *= mdct_norm;
00631             coefs = s->coefs[ch];
00632             if (s->use_noise_coding) {
00633                 mult1 = mult;
00634                 /* very low freqs : noise */
00635                 for(i = 0;i < s->coefs_start; i++) {
00636                     *coefs++ = s->noise_table[s->noise_index] *
00637                       exponents[i<<bsize>>esize] * mult1;
00638                     s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
00639                 }
00640 
00641                 n1 = s->exponent_high_sizes[bsize];
00642 
00643                 /* compute power of high bands */
00644                 exponents = s->exponents[ch] +
00645                     (s->high_band_start[bsize]<<bsize>>esize);
00646                 last_high_band = 0; /* avoid warning */
00647                 for(j=0;j<n1;j++) {
00648                     n = s->exponent_high_bands[s->frame_len_bits -
00649                                               s->block_len_bits][j];
00650                     if (s->high_band_coded[ch][j]) {
00651                         float e2, v;
00652                         e2 = 0;
00653                         for(i = 0;i < n; i++) {
00654                             v = exponents[i<<bsize>>esize];
00655                             e2 += v * v;
00656                         }
00657                         exp_power[j] = e2 / n;
00658                         last_high_band = j;
00659                         tprintf(s->avctx, "%d: power=%f (%d)\n", j, exp_power[j], n);
00660                     }
00661                     exponents += n<<bsize>>esize;
00662                 }
00663 
00664                 /* main freqs and high freqs */
00665                 exponents = s->exponents[ch] + (s->coefs_start<<bsize>>esize);
00666                 for(j=-1;j<n1;j++) {
00667                     if (j < 0) {
00668                         n = s->high_band_start[bsize] -
00669                             s->coefs_start;
00670                     } else {
00671                         n = s->exponent_high_bands[s->frame_len_bits -
00672                                                   s->block_len_bits][j];
00673                     }
00674                     if (j >= 0 && s->high_band_coded[ch][j]) {
00675                         /* use noise with specified power */
00676                         mult1 = sqrt(exp_power[j] / exp_power[last_high_band]);
00677                         /* XXX: use a table */
00678                         mult1 = mult1 * pow(10, s->high_band_values[ch][j] * 0.05);
00679                         mult1 = mult1 / (s->max_exponent[ch] * s->noise_mult);
00680                         mult1 *= mdct_norm;
00681                         for(i = 0;i < n; i++) {
00682                             noise = s->noise_table[s->noise_index];
00683                             s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
00684                             *coefs++ =  noise *
00685                                 exponents[i<<bsize>>esize] * mult1;
00686                         }
00687                         exponents += n<<bsize>>esize;
00688                     } else {
00689                         /* coded values + small noise */
00690                         for(i = 0;i < n; i++) {
00691                             noise = s->noise_table[s->noise_index];
00692                             s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
00693                             *coefs++ = ((*coefs1++) + noise) *
00694                                 exponents[i<<bsize>>esize] * mult;
00695                         }
00696                         exponents += n<<bsize>>esize;
00697                     }
00698                 }
00699 
00700                 /* very high freqs : noise */
00701                 n = s->block_len - s->coefs_end[bsize];
00702                 mult1 = mult * exponents[((-1<<bsize))>>esize];
00703                 for(i = 0; i < n; i++) {
00704                     *coefs++ = s->noise_table[s->noise_index] * mult1;
00705                     s->noise_index = (s->noise_index + 1) & (NOISE_TAB_SIZE - 1);
00706                 }
00707             } else {
00708                 /* XXX: optimize more */
00709                 for(i = 0;i < s->coefs_start; i++)
00710                     *coefs++ = 0.0;
00711                 n = nb_coefs[ch];
00712                 for(i = 0;i < n; i++) {
00713                     *coefs++ = coefs1[i] * exponents[i<<bsize>>esize] * mult;
00714                 }
00715                 n = s->block_len - s->coefs_end[bsize];
00716                 for(i = 0;i < n; i++)
00717                     *coefs++ = 0.0;
00718             }
00719         }
00720     }
00721 
00722 #ifdef TRACE
00723     for(ch = 0; ch < s->nb_channels; ch++) {
00724         if (s->channel_coded[ch]) {
00725             dump_floats(s, "exponents", 3, s->exponents[ch], s->block_len);
00726             dump_floats(s, "coefs", 1, s->coefs[ch], s->block_len);
00727         }
00728     }
00729 #endif
00730 
00731     if (s->ms_stereo && s->channel_coded[1]) {
00732         /* nominal case for ms stereo: we do it before mdct */
00733         /* no need to optimize this case because it should almost
00734            never happen */
00735         if (!s->channel_coded[0]) {
00736             tprintf(s->avctx, "rare ms-stereo case happened\n");
00737             memset(s->coefs[0], 0, sizeof(float) * s->block_len);
00738             s->channel_coded[0] = 1;
00739         }
00740 
00741         s->dsp.butterflies_float(s->coefs[0], s->coefs[1], s->block_len);
00742     }
00743 
00744 next:
00745     for(ch = 0; ch < s->nb_channels; ch++) {
00746         int n4, index;
00747 
00748         n4 = s->block_len / 2;
00749         if(s->channel_coded[ch]){
00750             ff_imdct_calc(&s->mdct_ctx[bsize], s->output, s->coefs[ch]);
00751         }else if(!(s->ms_stereo && ch==1))
00752             memset(s->output, 0, sizeof(s->output));
00753 
00754         /* multiply by the window and add in the frame */
00755         index = (s->frame_len / 2) + s->block_pos - n4;
00756         wma_window(s, &s->frame_out[ch][index]);
00757     }
00758 
00759     /* update block number */
00760     s->block_num++;
00761     s->block_pos += s->block_len;
00762     if (s->block_pos >= s->frame_len)
00763         return 1;
00764     else
00765         return 0;
00766 }
00767 
00768 /* decode a frame of frame_len samples */
00769 static int wma_decode_frame(WMACodecContext *s, int16_t *samples)
00770 {
00771     int ret, i, n, ch, incr;
00772     int16_t *ptr;
00773     float *iptr;
00774 
00775 #ifdef TRACE
00776     tprintf(s->avctx, "***decode_frame: %d size=%d\n", s->frame_count++, s->frame_len);
00777 #endif
00778 
00779     /* read each block */
00780     s->block_num = 0;
00781     s->block_pos = 0;
00782     for(;;) {
00783         ret = wma_decode_block(s);
00784         if (ret < 0)
00785             return -1;
00786         if (ret)
00787             break;
00788     }
00789 
00790     /* convert frame to integer */
00791     n = s->frame_len;
00792     incr = s->nb_channels;
00793     if (s->dsp.float_to_int16_interleave == ff_float_to_int16_interleave_c) {
00794         for(ch = 0; ch < s->nb_channels; ch++) {
00795             ptr = samples + ch;
00796             iptr = s->frame_out[ch];
00797 
00798             for(i=0;i<n;i++) {
00799                 *ptr = av_clip_int16(lrintf(*iptr++));
00800                 ptr += incr;
00801             }
00802             /* prepare for next block */
00803             memmove(&s->frame_out[ch][0], &s->frame_out[ch][s->frame_len],
00804                     s->frame_len * sizeof(float));
00805         }
00806     } else {
00807         float *output[MAX_CHANNELS];
00808         for (ch = 0; ch < MAX_CHANNELS; ch++)
00809             output[ch] = s->frame_out[ch];
00810         s->dsp.float_to_int16_interleave(samples, (const float **)output, n, incr);
00811         for(ch = 0; ch < incr; ch++) {
00812             /* prepare for next block */
00813             memmove(&s->frame_out[ch][0], &s->frame_out[ch][n], n * sizeof(float));
00814         }
00815     }
00816 
00817 #ifdef TRACE
00818     dump_shorts(s, "samples", samples, n * s->nb_channels);
00819 #endif
00820     return 0;
00821 }
00822 
00823 static int wma_decode_superframe(AVCodecContext *avctx,
00824                                  void *data, int *data_size,
00825                                  AVPacket *avpkt)
00826 {
00827     const uint8_t *buf = avpkt->data;
00828     int buf_size = avpkt->size;
00829     WMACodecContext *s = avctx->priv_data;
00830     int nb_frames, bit_offset, i, pos, len;
00831     uint8_t *q;
00832     int16_t *samples;
00833 
00834     tprintf(avctx, "***decode_superframe:\n");
00835 
00836     if(buf_size==0){
00837         s->last_superframe_len = 0;
00838         return 0;
00839     }
00840     if (buf_size < s->block_align)
00841         return 0;
00842     buf_size = s->block_align;
00843 
00844     samples = data;
00845 
00846     init_get_bits(&s->gb, buf, buf_size*8);
00847 
00848     if (s->use_bit_reservoir) {
00849         /* read super frame header */
00850         skip_bits(&s->gb, 4); /* super frame index */
00851         nb_frames = get_bits(&s->gb, 4) - 1;
00852 
00853         if((nb_frames+1) * s->nb_channels * s->frame_len * sizeof(int16_t) > *data_size){
00854             av_log(s->avctx, AV_LOG_ERROR, "Insufficient output space\n");
00855             goto fail;
00856         }
00857 
00858         bit_offset = get_bits(&s->gb, s->byte_offset_bits + 3);
00859 
00860         if (s->last_superframe_len > 0) {
00861             //        printf("skip=%d\n", s->last_bitoffset);
00862             /* add bit_offset bits to last frame */
00863             if ((s->last_superframe_len + ((bit_offset + 7) >> 3)) >
00864                 MAX_CODED_SUPERFRAME_SIZE)
00865                 goto fail;
00866             q = s->last_superframe + s->last_superframe_len;
00867             len = bit_offset;
00868             while (len > 7) {
00869                 *q++ = (get_bits)(&s->gb, 8);
00870                 len -= 8;
00871             }
00872             if (len > 0) {
00873                 *q++ = (get_bits)(&s->gb, len) << (8 - len);
00874             }
00875 
00876             /* XXX: bit_offset bits into last frame */
00877             init_get_bits(&s->gb, s->last_superframe, MAX_CODED_SUPERFRAME_SIZE*8);
00878             /* skip unused bits */
00879             if (s->last_bitoffset > 0)
00880                 skip_bits(&s->gb, s->last_bitoffset);
00881             /* this frame is stored in the last superframe and in the
00882                current one */
00883             if (wma_decode_frame(s, samples) < 0)
00884                 goto fail;
00885             samples += s->nb_channels * s->frame_len;
00886         }
00887 
00888         /* read each frame starting from bit_offset */
00889         pos = bit_offset + 4 + 4 + s->byte_offset_bits + 3;
00890         init_get_bits(&s->gb, buf + (pos >> 3), (MAX_CODED_SUPERFRAME_SIZE - (pos >> 3))*8);
00891         len = pos & 7;
00892         if (len > 0)
00893             skip_bits(&s->gb, len);
00894 
00895         s->reset_block_lengths = 1;
00896         for(i=0;i<nb_frames;i++) {
00897             if (wma_decode_frame(s, samples) < 0)
00898                 goto fail;
00899             samples += s->nb_channels * s->frame_len;
00900         }
00901 
00902         /* we copy the end of the frame in the last frame buffer */
00903         pos = get_bits_count(&s->gb) + ((bit_offset + 4 + 4 + s->byte_offset_bits + 3) & ~7);
00904         s->last_bitoffset = pos & 7;
00905         pos >>= 3;
00906         len = buf_size - pos;
00907         if (len > MAX_CODED_SUPERFRAME_SIZE || len < 0) {
00908             av_log(s->avctx, AV_LOG_ERROR, "len %d invalid\n", len);
00909             goto fail;
00910         }
00911         s->last_superframe_len = len;
00912         memcpy(s->last_superframe, buf + pos, len);
00913     } else {
00914         if(s->nb_channels * s->frame_len * sizeof(int16_t) > *data_size){
00915             av_log(s->avctx, AV_LOG_ERROR, "Insufficient output space\n");
00916             goto fail;
00917         }
00918         /* single frame decode */
00919         if (wma_decode_frame(s, samples) < 0)
00920             goto fail;
00921         samples += s->nb_channels * s->frame_len;
00922     }
00923 
00924 //av_log(NULL, AV_LOG_ERROR, "%d %d %d %d outbytes:%d eaten:%d\n", s->frame_len_bits, s->block_len_bits, s->frame_len, s->block_len,        (int8_t *)samples - (int8_t *)data, s->block_align);
00925 
00926     *data_size = (int8_t *)samples - (int8_t *)data;
00927     return s->block_align;
00928  fail:
00929     /* when error, we reset the bit reservoir */
00930     s->last_superframe_len = 0;
00931     return -1;
00932 }
00933 
00934 static av_cold void flush(AVCodecContext *avctx)
00935 {
00936     WMACodecContext *s = avctx->priv_data;
00937 
00938     s->last_bitoffset=
00939     s->last_superframe_len= 0;
00940 }
00941 
00942 AVCodec wmav1_decoder =
00943 {
00944     "wmav1",
00945     AVMEDIA_TYPE_AUDIO,
00946     CODEC_ID_WMAV1,
00947     sizeof(WMACodecContext),
00948     wma_decode_init,
00949     NULL,
00950     ff_wma_end,
00951     wma_decode_superframe,
00952     .flush=flush,
00953     .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 1"),
00954 };
00955 
00956 AVCodec wmav2_decoder =
00957 {
00958     "wmav2",
00959     AVMEDIA_TYPE_AUDIO,
00960     CODEC_ID_WMAV2,
00961     sizeof(WMACodecContext),
00962     wma_decode_init,
00963     NULL,
00964     ff_wma_end,
00965     wma_decode_superframe,
00966     .flush=flush,
00967     .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 2"),
00968 };

Generated on Fri Sep 16 2011 17:17:46 for FFmpeg by  doxygen 1.7.1