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libavcodec/imc.c

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00001 /*
00002  * IMC compatible decoder
00003  * Copyright (c) 2002-2004 Maxim Poliakovski
00004  * Copyright (c) 2006 Benjamin Larsson
00005  * Copyright (c) 2006 Konstantin Shishkov
00006  *
00007  * This file is part of FFmpeg.
00008  *
00009  * FFmpeg is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  * FFmpeg is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00017  * Lesser General Public License for more details.
00018  *
00019  * You should have received a copy of the GNU Lesser General Public
00020  * License along with FFmpeg; if not, write to the Free Software
00021  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00022  */
00023 
00034 #include <math.h>
00035 #include <stddef.h>
00036 #include <stdio.h>
00037 
00038 #define ALT_BITSTREAM_READER
00039 #include "avcodec.h"
00040 #include "get_bits.h"
00041 #include "dsputil.h"
00042 #include "fft.h"
00043 
00044 #include "imcdata.h"
00045 
00046 #define IMC_BLOCK_SIZE 64
00047 #define IMC_FRAME_ID 0x21
00048 #define BANDS 32
00049 #define COEFFS 256
00050 
00051 typedef struct {
00052     float old_floor[BANDS];
00053     float flcoeffs1[BANDS];
00054     float flcoeffs2[BANDS];
00055     float flcoeffs3[BANDS];
00056     float flcoeffs4[BANDS];
00057     float flcoeffs5[BANDS];
00058     float flcoeffs6[BANDS];
00059     float CWdecoded[COEFFS];
00060 
00063     float mdct_sine_window[COEFFS];
00064     float post_cos[COEFFS];
00065     float post_sin[COEFFS];
00066     float pre_coef1[COEFFS];
00067     float pre_coef2[COEFFS];
00068     float last_fft_im[COEFFS];
00070 
00071     int bandWidthT[BANDS];     
00072     int bitsBandT[BANDS];      
00073     int CWlengthT[COEFFS];     
00074     int levlCoeffBuf[BANDS];
00075     int bandFlagsBuf[BANDS];   
00076     int sumLenArr[BANDS];      
00077     int skipFlagRaw[BANDS];    
00078     int skipFlagBits[BANDS];   
00079     int skipFlagCount[BANDS];  
00080     int skipFlags[COEFFS];     
00081     int codewords[COEFFS];     
00082     float sqrt_tab[30];
00083     GetBitContext gb;
00084     int decoder_reset;
00085     float one_div_log2;
00086 
00087     DSPContext dsp;
00088     FFTContext fft;
00089     DECLARE_ALIGNED(16, FFTComplex, samples)[COEFFS/2];
00090     DECLARE_ALIGNED(16, float, out_samples)[COEFFS];
00091 } IMCContext;
00092 
00093 static VLC huffman_vlc[4][4];
00094 
00095 #define VLC_TABLES_SIZE 9512
00096 
00097 static const int vlc_offsets[17] = {
00098     0,     640, 1156, 1732, 2308, 2852, 3396, 3924,
00099     4452, 5220, 5860, 6628, 7268, 7908, 8424, 8936, VLC_TABLES_SIZE};
00100 
00101 static VLC_TYPE vlc_tables[VLC_TABLES_SIZE][2];
00102 
00103 static av_cold int imc_decode_init(AVCodecContext * avctx)
00104 {
00105     int i, j;
00106     IMCContext *q = avctx->priv_data;
00107     double r1, r2;
00108 
00109     q->decoder_reset = 1;
00110 
00111     for(i = 0; i < BANDS; i++)
00112         q->old_floor[i] = 1.0;
00113 
00114     /* Build mdct window, a simple sine window normalized with sqrt(2) */
00115     ff_sine_window_init(q->mdct_sine_window, COEFFS);
00116     for(i = 0; i < COEFFS; i++)
00117         q->mdct_sine_window[i] *= sqrt(2.0);
00118     for(i = 0; i < COEFFS/2; i++){
00119         q->post_cos[i] = cos(i / 256.0 * M_PI);
00120         q->post_sin[i] = sin(i / 256.0 * M_PI);
00121 
00122         r1 = sin((i * 4.0 + 1.0) / 1024.0 * M_PI);
00123         r2 = cos((i * 4.0 + 1.0) / 1024.0 * M_PI);
00124 
00125         if (i & 0x1)
00126         {
00127             q->pre_coef1[i] =  (r1 + r2) * sqrt(2.0);
00128             q->pre_coef2[i] = -(r1 - r2) * sqrt(2.0);
00129         }
00130         else
00131         {
00132             q->pre_coef1[i] = -(r1 + r2) * sqrt(2.0);
00133             q->pre_coef2[i] =  (r1 - r2) * sqrt(2.0);
00134         }
00135 
00136         q->last_fft_im[i] = 0;
00137     }
00138 
00139     /* Generate a square root table */
00140 
00141     for(i = 0; i < 30; i++) {
00142         q->sqrt_tab[i] = sqrt(i);
00143     }
00144 
00145     /* initialize the VLC tables */
00146     for(i = 0; i < 4 ; i++) {
00147         for(j = 0; j < 4; j++) {
00148             huffman_vlc[i][j].table = &vlc_tables[vlc_offsets[i * 4 + j]];
00149             huffman_vlc[i][j].table_allocated = vlc_offsets[i * 4 + j + 1] - vlc_offsets[i * 4 + j];
00150             init_vlc(&huffman_vlc[i][j], 9, imc_huffman_sizes[i],
00151                      imc_huffman_lens[i][j], 1, 1,
00152                      imc_huffman_bits[i][j], 2, 2, INIT_VLC_USE_NEW_STATIC);
00153         }
00154     }
00155     q->one_div_log2 = 1/log(2);
00156 
00157     ff_fft_init(&q->fft, 7, 1);
00158     dsputil_init(&q->dsp, avctx);
00159     avctx->sample_fmt = SAMPLE_FMT_S16;
00160     avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;
00161     return 0;
00162 }
00163 
00164 static void imc_calculate_coeffs(IMCContext* q, float* flcoeffs1, float* flcoeffs2, int* bandWidthT,
00165                                 float* flcoeffs3, float* flcoeffs5)
00166 {
00167     float   workT1[BANDS];
00168     float   workT2[BANDS];
00169     float   workT3[BANDS];
00170     float   snr_limit = 1.e-30;
00171     float   accum = 0.0;
00172     int i, cnt2;
00173 
00174     for(i = 0; i < BANDS; i++) {
00175         flcoeffs5[i] = workT2[i] = 0.0;
00176         if (bandWidthT[i]){
00177             workT1[i] = flcoeffs1[i] * flcoeffs1[i];
00178             flcoeffs3[i] = 2.0 * flcoeffs2[i];
00179         } else {
00180             workT1[i] = 0.0;
00181             flcoeffs3[i] = -30000.0;
00182         }
00183         workT3[i] = bandWidthT[i] * workT1[i] * 0.01;
00184         if (workT3[i] <= snr_limit)
00185             workT3[i] = 0.0;
00186     }
00187 
00188     for(i = 0; i < BANDS; i++) {
00189         for(cnt2 = i; cnt2 < cyclTab[i]; cnt2++)
00190             flcoeffs5[cnt2] = flcoeffs5[cnt2] + workT3[i];
00191         workT2[cnt2-1] = workT2[cnt2-1] + workT3[i];
00192     }
00193 
00194     for(i = 1; i < BANDS; i++) {
00195         accum = (workT2[i-1] + accum) * imc_weights1[i-1];
00196         flcoeffs5[i] += accum;
00197     }
00198 
00199     for(i = 0; i < BANDS; i++)
00200         workT2[i] = 0.0;
00201 
00202     for(i = 0; i < BANDS; i++) {
00203         for(cnt2 = i-1; cnt2 > cyclTab2[i]; cnt2--)
00204             flcoeffs5[cnt2] += workT3[i];
00205         workT2[cnt2+1] += workT3[i];
00206     }
00207 
00208     accum = 0.0;
00209 
00210     for(i = BANDS-2; i >= 0; i--) {
00211         accum = (workT2[i+1] + accum) * imc_weights2[i];
00212         flcoeffs5[i] += accum;
00213         //there is missing code here, but it seems to never be triggered
00214     }
00215 }
00216 
00217 
00218 static void imc_read_level_coeffs(IMCContext* q, int stream_format_code, int* levlCoeffs)
00219 {
00220     int i;
00221     VLC *hufftab[4];
00222     int start = 0;
00223     const uint8_t *cb_sel;
00224     int s;
00225 
00226     s = stream_format_code >> 1;
00227     hufftab[0] = &huffman_vlc[s][0];
00228     hufftab[1] = &huffman_vlc[s][1];
00229     hufftab[2] = &huffman_vlc[s][2];
00230     hufftab[3] = &huffman_vlc[s][3];
00231     cb_sel = imc_cb_select[s];
00232 
00233     if(stream_format_code & 4)
00234         start = 1;
00235     if(start)
00236         levlCoeffs[0] = get_bits(&q->gb, 7);
00237     for(i = start; i < BANDS; i++){
00238         levlCoeffs[i] = get_vlc2(&q->gb, hufftab[cb_sel[i]]->table, hufftab[cb_sel[i]]->bits, 2);
00239         if(levlCoeffs[i] == 17)
00240             levlCoeffs[i] += get_bits(&q->gb, 4);
00241     }
00242 }
00243 
00244 static void imc_decode_level_coefficients(IMCContext* q, int* levlCoeffBuf, float* flcoeffs1,
00245                                          float* flcoeffs2)
00246 {
00247     int i, level;
00248     float tmp, tmp2;
00249     //maybe some frequency division thingy
00250 
00251     flcoeffs1[0] = 20000.0 / pow (2, levlCoeffBuf[0] * 0.18945); // 0.18945 = log2(10) * 0.05703125
00252     flcoeffs2[0] = log(flcoeffs1[0])/log(2);
00253     tmp = flcoeffs1[0];
00254     tmp2 = flcoeffs2[0];
00255 
00256     for(i = 1; i < BANDS; i++) {
00257         level = levlCoeffBuf[i];
00258         if (level == 16) {
00259             flcoeffs1[i] = 1.0;
00260             flcoeffs2[i] = 0.0;
00261         } else {
00262             if (level < 17)
00263                 level -=7;
00264             else if (level <= 24)
00265                 level -=32;
00266             else
00267                 level -=16;
00268 
00269             tmp  *= imc_exp_tab[15 + level];
00270             tmp2 += 0.83048 * level;  // 0.83048 = log2(10) * 0.25
00271             flcoeffs1[i] = tmp;
00272             flcoeffs2[i] = tmp2;
00273         }
00274     }
00275 }
00276 
00277 
00278 static void imc_decode_level_coefficients2(IMCContext* q, int* levlCoeffBuf, float* old_floor, float* flcoeffs1,
00279                                           float* flcoeffs2) {
00280     int i;
00281         //FIXME maybe flag_buf = noise coding and flcoeffs1 = new scale factors
00282         //      and flcoeffs2 old scale factors
00283         //      might be incomplete due to a missing table that is in the binary code
00284     for(i = 0; i < BANDS; i++) {
00285         flcoeffs1[i] = 0;
00286         if(levlCoeffBuf[i] < 16) {
00287             flcoeffs1[i] = imc_exp_tab2[levlCoeffBuf[i]] * old_floor[i];
00288             flcoeffs2[i] = (levlCoeffBuf[i]-7) * 0.83048 + flcoeffs2[i]; // 0.83048 = log2(10) * 0.25
00289         } else {
00290             flcoeffs1[i] = old_floor[i];
00291         }
00292     }
00293 }
00294 
00298 static int bit_allocation (IMCContext* q, int stream_format_code, int freebits, int flag) {
00299     int i, j;
00300     const float limit = -1.e20;
00301     float highest = 0.0;
00302     int indx;
00303     int t1 = 0;
00304     int t2 = 1;
00305     float summa = 0.0;
00306     int iacc = 0;
00307     int summer = 0;
00308     int rres, cwlen;
00309     float lowest = 1.e10;
00310     int low_indx = 0;
00311     float workT[32];
00312     int flg;
00313     int found_indx = 0;
00314 
00315     for(i = 0; i < BANDS; i++)
00316         highest = FFMAX(highest, q->flcoeffs1[i]);
00317 
00318     for(i = 0; i < BANDS-1; i++) {
00319         q->flcoeffs4[i] = q->flcoeffs3[i] - log(q->flcoeffs5[i])/log(2);
00320     }
00321     q->flcoeffs4[BANDS - 1] = limit;
00322 
00323     highest = highest * 0.25;
00324 
00325     for(i = 0; i < BANDS; i++) {
00326         indx = -1;
00327         if ((band_tab[i+1] - band_tab[i]) == q->bandWidthT[i])
00328             indx = 0;
00329 
00330         if ((band_tab[i+1] - band_tab[i]) > q->bandWidthT[i])
00331             indx = 1;
00332 
00333         if (((band_tab[i+1] - band_tab[i])/2) >= q->bandWidthT[i])
00334             indx = 2;
00335 
00336         if (indx == -1)
00337             return -1;
00338 
00339         q->flcoeffs4[i] = q->flcoeffs4[i] + xTab[(indx*2 + (q->flcoeffs1[i] < highest)) * 2 + flag];
00340     }
00341 
00342     if (stream_format_code & 0x2) {
00343         q->flcoeffs4[0] = limit;
00344         q->flcoeffs4[1] = limit;
00345         q->flcoeffs4[2] = limit;
00346         q->flcoeffs4[3] = limit;
00347     }
00348 
00349     for(i = (stream_format_code & 0x2)?4:0; i < BANDS-1; i++) {
00350         iacc += q->bandWidthT[i];
00351         summa += q->bandWidthT[i] * q->flcoeffs4[i];
00352     }
00353     q->bandWidthT[BANDS-1] = 0;
00354     summa = (summa * 0.5 - freebits) / iacc;
00355 
00356 
00357     for(i = 0; i < BANDS/2; i++) {
00358         rres = summer - freebits;
00359         if((rres >= -8) && (rres <= 8)) break;
00360 
00361         summer = 0;
00362         iacc = 0;
00363 
00364         for(j = (stream_format_code & 0x2)?4:0; j < BANDS; j++) {
00365             cwlen = av_clip((int)((q->flcoeffs4[j] * 0.5) - summa + 0.5), 0, 6);
00366 
00367             q->bitsBandT[j] = cwlen;
00368             summer += q->bandWidthT[j] * cwlen;
00369 
00370             if (cwlen > 0)
00371                 iacc += q->bandWidthT[j];
00372         }
00373 
00374         flg = t2;
00375         t2 = 1;
00376         if (freebits < summer)
00377             t2 = -1;
00378         if (i == 0)
00379             flg = t2;
00380         if(flg != t2)
00381             t1++;
00382 
00383         summa = (float)(summer - freebits) / ((t1 + 1) * iacc) + summa;
00384     }
00385 
00386     for(i = (stream_format_code & 0x2)?4:0; i < BANDS; i++) {
00387         for(j = band_tab[i]; j < band_tab[i+1]; j++)
00388             q->CWlengthT[j] = q->bitsBandT[i];
00389     }
00390 
00391     if (freebits > summer) {
00392         for(i = 0; i < BANDS; i++) {
00393             workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
00394         }
00395 
00396         highest = 0.0;
00397 
00398         do{
00399             if (highest <= -1.e20)
00400                 break;
00401 
00402             found_indx = 0;
00403             highest = -1.e20;
00404 
00405             for(i = 0; i < BANDS; i++) {
00406                 if (workT[i] > highest) {
00407                     highest = workT[i];
00408                     found_indx = i;
00409                 }
00410             }
00411 
00412             if (highest > -1.e20) {
00413                 workT[found_indx] -= 2.0;
00414                 if (++(q->bitsBandT[found_indx]) == 6)
00415                     workT[found_indx] = -1.e20;
00416 
00417                 for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (freebits > summer); j++){
00418                     q->CWlengthT[j]++;
00419                     summer++;
00420                 }
00421             }
00422         }while (freebits > summer);
00423     }
00424     if (freebits < summer) {
00425         for(i = 0; i < BANDS; i++) {
00426             workT[i] = q->bitsBandT[i] ? (q->bitsBandT[i] * -2 + q->flcoeffs4[i] + 1.585) : 1.e20;
00427         }
00428         if (stream_format_code & 0x2) {
00429             workT[0] = 1.e20;
00430             workT[1] = 1.e20;
00431             workT[2] = 1.e20;
00432             workT[3] = 1.e20;
00433         }
00434         while (freebits < summer){
00435             lowest = 1.e10;
00436             low_indx = 0;
00437             for(i = 0; i < BANDS; i++) {
00438                 if (workT[i] < lowest) {
00439                     lowest = workT[i];
00440                     low_indx = i;
00441                 }
00442             }
00443             //if(lowest >= 1.e10) break;
00444             workT[low_indx] = lowest + 2.0;
00445 
00446             if (!(--q->bitsBandT[low_indx]))
00447                 workT[low_indx] = 1.e20;
00448 
00449             for(j = band_tab[low_indx]; j < band_tab[low_indx+1] && (freebits < summer); j++){
00450                 if(q->CWlengthT[j] > 0){
00451                     q->CWlengthT[j]--;
00452                     summer--;
00453                 }
00454             }
00455         }
00456     }
00457     return 0;
00458 }
00459 
00460 static void imc_get_skip_coeff(IMCContext* q) {
00461     int i, j;
00462 
00463     memset(q->skipFlagBits, 0, sizeof(q->skipFlagBits));
00464     memset(q->skipFlagCount, 0, sizeof(q->skipFlagCount));
00465     for(i = 0; i < BANDS; i++) {
00466         if (!q->bandFlagsBuf[i] || !q->bandWidthT[i])
00467             continue;
00468 
00469         if (!q->skipFlagRaw[i]) {
00470             q->skipFlagBits[i] = band_tab[i+1] - band_tab[i];
00471 
00472             for(j = band_tab[i]; j < band_tab[i+1]; j++) {
00473                 if ((q->skipFlags[j] = get_bits1(&q->gb)))
00474                     q->skipFlagCount[i]++;
00475             }
00476         } else {
00477             for(j = band_tab[i]; j < (band_tab[i+1]-1); j += 2) {
00478                 if(!get_bits1(&q->gb)){//0
00479                     q->skipFlagBits[i]++;
00480                     q->skipFlags[j]=1;
00481                     q->skipFlags[j+1]=1;
00482                     q->skipFlagCount[i] += 2;
00483                 }else{
00484                     if(get_bits1(&q->gb)){//11
00485                         q->skipFlagBits[i] +=2;
00486                         q->skipFlags[j]=0;
00487                         q->skipFlags[j+1]=1;
00488                         q->skipFlagCount[i]++;
00489                     }else{
00490                         q->skipFlagBits[i] +=3;
00491                         q->skipFlags[j+1]=0;
00492                         if(!get_bits1(&q->gb)){//100
00493                             q->skipFlags[j]=1;
00494                             q->skipFlagCount[i]++;
00495                         }else{//101
00496                             q->skipFlags[j]=0;
00497                         }
00498                     }
00499                 }
00500             }
00501 
00502             if (j < band_tab[i+1]) {
00503                 q->skipFlagBits[i]++;
00504                 if ((q->skipFlags[j] = get_bits1(&q->gb)))
00505                     q->skipFlagCount[i]++;
00506             }
00507         }
00508     }
00509 }
00510 
00514 static void imc_adjust_bit_allocation (IMCContext* q, int summer) {
00515     float workT[32];
00516     int corrected = 0;
00517     int i, j;
00518     float highest = 0;
00519     int found_indx=0;
00520 
00521     for(i = 0; i < BANDS; i++) {
00522         workT[i] = (q->bitsBandT[i] == 6) ? -1.e20 : (q->bitsBandT[i] * -2 + q->flcoeffs4[i] - 0.415);
00523     }
00524 
00525     while (corrected < summer) {
00526         if(highest <= -1.e20)
00527             break;
00528 
00529         highest = -1.e20;
00530 
00531         for(i = 0; i < BANDS; i++) {
00532             if (workT[i] > highest) {
00533                 highest = workT[i];
00534                 found_indx = i;
00535             }
00536         }
00537 
00538         if (highest > -1.e20) {
00539             workT[found_indx] -= 2.0;
00540             if (++(q->bitsBandT[found_indx]) == 6)
00541                 workT[found_indx] = -1.e20;
00542 
00543             for(j = band_tab[found_indx]; j < band_tab[found_indx+1] && (corrected < summer); j++) {
00544                 if (!q->skipFlags[j] && (q->CWlengthT[j] < 6)) {
00545                     q->CWlengthT[j]++;
00546                     corrected++;
00547                 }
00548             }
00549         }
00550     }
00551 }
00552 
00553 static void imc_imdct256(IMCContext *q) {
00554     int i;
00555     float re, im;
00556 
00557     /* prerotation */
00558     for(i=0; i < COEFFS/2; i++){
00559         q->samples[i].re = -(q->pre_coef1[i] * q->CWdecoded[COEFFS-1-i*2]) -
00560                            (q->pre_coef2[i] * q->CWdecoded[i*2]);
00561         q->samples[i].im = (q->pre_coef2[i] * q->CWdecoded[COEFFS-1-i*2]) -
00562                            (q->pre_coef1[i] * q->CWdecoded[i*2]);
00563     }
00564 
00565     /* FFT */
00566     ff_fft_permute(&q->fft, q->samples);
00567     ff_fft_calc (&q->fft, q->samples);
00568 
00569     /* postrotation, window and reorder */
00570     for(i = 0; i < COEFFS/2; i++){
00571         re = (q->samples[i].re * q->post_cos[i]) + (-q->samples[i].im * q->post_sin[i]);
00572         im = (-q->samples[i].im * q->post_cos[i]) - (q->samples[i].re * q->post_sin[i]);
00573         q->out_samples[i*2] = (q->mdct_sine_window[COEFFS-1-i*2] * q->last_fft_im[i]) + (q->mdct_sine_window[i*2] * re);
00574         q->out_samples[COEFFS-1-i*2] = (q->mdct_sine_window[i*2] * q->last_fft_im[i]) - (q->mdct_sine_window[COEFFS-1-i*2] * re);
00575         q->last_fft_im[i] = im;
00576     }
00577 }
00578 
00579 static int inverse_quant_coeff (IMCContext* q, int stream_format_code) {
00580     int i, j;
00581     int middle_value, cw_len, max_size;
00582     const float* quantizer;
00583 
00584     for(i = 0; i < BANDS; i++) {
00585         for(j = band_tab[i]; j < band_tab[i+1]; j++) {
00586             q->CWdecoded[j] = 0;
00587             cw_len = q->CWlengthT[j];
00588 
00589             if (cw_len <= 0 || q->skipFlags[j])
00590                 continue;
00591 
00592             max_size = 1 << cw_len;
00593             middle_value = max_size >> 1;
00594 
00595             if (q->codewords[j] >= max_size || q->codewords[j] < 0)
00596                 return -1;
00597 
00598             if (cw_len >= 4){
00599                 quantizer = imc_quantizer2[(stream_format_code & 2) >> 1];
00600                 if (q->codewords[j] >= middle_value)
00601                     q->CWdecoded[j] = quantizer[q->codewords[j] - 8] * q->flcoeffs6[i];
00602                 else
00603                     q->CWdecoded[j] = -quantizer[max_size - q->codewords[j] - 8 - 1] * q->flcoeffs6[i];
00604             }else{
00605                 quantizer = imc_quantizer1[((stream_format_code & 2) >> 1) | (q->bandFlagsBuf[i] << 1)];
00606                 if (q->codewords[j] >= middle_value)
00607                     q->CWdecoded[j] = quantizer[q->codewords[j] - 1] * q->flcoeffs6[i];
00608                 else
00609                     q->CWdecoded[j] = -quantizer[max_size - 2 - q->codewords[j]] * q->flcoeffs6[i];
00610             }
00611         }
00612     }
00613     return 0;
00614 }
00615 
00616 
00617 static int imc_get_coeffs (IMCContext* q) {
00618     int i, j, cw_len, cw;
00619 
00620     for(i = 0; i < BANDS; i++) {
00621         if(!q->sumLenArr[i]) continue;
00622         if (q->bandFlagsBuf[i] || q->bandWidthT[i]) {
00623             for(j = band_tab[i]; j < band_tab[i+1]; j++) {
00624                 cw_len = q->CWlengthT[j];
00625                 cw = 0;
00626 
00627                 if (get_bits_count(&q->gb) + cw_len > 512){
00628 //av_log(NULL,0,"Band %i coeff %i cw_len %i\n",i,j,cw_len);
00629                     return -1;
00630                 }
00631 
00632                 if(cw_len && (!q->bandFlagsBuf[i] || !q->skipFlags[j]))
00633                     cw = get_bits(&q->gb, cw_len);
00634 
00635                 q->codewords[j] = cw;
00636             }
00637         }
00638     }
00639     return 0;
00640 }
00641 
00642 static int imc_decode_frame(AVCodecContext * avctx,
00643                             void *data, int *data_size,
00644                             AVPacket *avpkt)
00645 {
00646     const uint8_t *buf = avpkt->data;
00647     int buf_size = avpkt->size;
00648 
00649     IMCContext *q = avctx->priv_data;
00650 
00651     int stream_format_code;
00652     int imc_hdr, i, j;
00653     int flag;
00654     int bits, summer;
00655     int counter, bitscount;
00656     uint16_t buf16[IMC_BLOCK_SIZE / 2];
00657 
00658     if (buf_size < IMC_BLOCK_SIZE) {
00659         av_log(avctx, AV_LOG_ERROR, "imc frame too small!\n");
00660         return -1;
00661     }
00662     for(i = 0; i < IMC_BLOCK_SIZE / 2; i++)
00663         buf16[i] = bswap_16(((const uint16_t*)buf)[i]);
00664 
00665     init_get_bits(&q->gb, (const uint8_t*)buf16, IMC_BLOCK_SIZE * 8);
00666 
00667     /* Check the frame header */
00668     imc_hdr = get_bits(&q->gb, 9);
00669     if (imc_hdr != IMC_FRAME_ID) {
00670         av_log(avctx, AV_LOG_ERROR, "imc frame header check failed!\n");
00671         av_log(avctx, AV_LOG_ERROR, "got %x instead of 0x21.\n", imc_hdr);
00672         return -1;
00673     }
00674     stream_format_code = get_bits(&q->gb, 3);
00675 
00676     if(stream_format_code & 1){
00677         av_log(avctx, AV_LOG_ERROR, "Stream code format %X is not supported\n", stream_format_code);
00678         return -1;
00679     }
00680 
00681 //    av_log(avctx, AV_LOG_DEBUG, "stream_format_code = %d\n", stream_format_code);
00682 
00683     if (stream_format_code & 0x04)
00684         q->decoder_reset = 1;
00685 
00686     if(q->decoder_reset) {
00687         memset(q->out_samples, 0, sizeof(q->out_samples));
00688         for(i = 0; i < BANDS; i++)q->old_floor[i] = 1.0;
00689         for(i = 0; i < COEFFS; i++)q->CWdecoded[i] = 0;
00690         q->decoder_reset = 0;
00691     }
00692 
00693     flag = get_bits1(&q->gb);
00694     imc_read_level_coeffs(q, stream_format_code, q->levlCoeffBuf);
00695 
00696     if (stream_format_code & 0x4)
00697         imc_decode_level_coefficients(q, q->levlCoeffBuf, q->flcoeffs1, q->flcoeffs2);
00698     else
00699         imc_decode_level_coefficients2(q, q->levlCoeffBuf, q->old_floor, q->flcoeffs1, q->flcoeffs2);
00700 
00701     memcpy(q->old_floor, q->flcoeffs1, 32 * sizeof(float));
00702 
00703     counter = 0;
00704     for (i=0 ; i<BANDS ; i++) {
00705         if (q->levlCoeffBuf[i] == 16) {
00706             q->bandWidthT[i] = 0;
00707             counter++;
00708         } else
00709             q->bandWidthT[i] = band_tab[i+1] - band_tab[i];
00710     }
00711     memset(q->bandFlagsBuf, 0, BANDS * sizeof(int));
00712     for(i = 0; i < BANDS-1; i++) {
00713         if (q->bandWidthT[i])
00714             q->bandFlagsBuf[i] = get_bits1(&q->gb);
00715     }
00716 
00717     imc_calculate_coeffs(q, q->flcoeffs1, q->flcoeffs2, q->bandWidthT, q->flcoeffs3, q->flcoeffs5);
00718 
00719     bitscount = 0;
00720     /* first 4 bands will be assigned 5 bits per coefficient */
00721     if (stream_format_code & 0x2) {
00722         bitscount += 15;
00723 
00724         q->bitsBandT[0] = 5;
00725         q->CWlengthT[0] = 5;
00726         q->CWlengthT[1] = 5;
00727         q->CWlengthT[2] = 5;
00728         for(i = 1; i < 4; i++){
00729             bits = (q->levlCoeffBuf[i] == 16) ? 0 : 5;
00730             q->bitsBandT[i] = bits;
00731             for(j = band_tab[i]; j < band_tab[i+1]; j++) {
00732                 q->CWlengthT[j] = bits;
00733                 bitscount += bits;
00734             }
00735         }
00736     }
00737 
00738     if(bit_allocation (q, stream_format_code, 512 - bitscount - get_bits_count(&q->gb), flag) < 0) {
00739         av_log(avctx, AV_LOG_ERROR, "Bit allocations failed\n");
00740         q->decoder_reset = 1;
00741         return -1;
00742     }
00743 
00744     for(i = 0; i < BANDS; i++) {
00745         q->sumLenArr[i] = 0;
00746         q->skipFlagRaw[i] = 0;
00747         for(j = band_tab[i]; j < band_tab[i+1]; j++)
00748             q->sumLenArr[i] += q->CWlengthT[j];
00749         if (q->bandFlagsBuf[i])
00750             if( (((band_tab[i+1] - band_tab[i]) * 1.5) > q->sumLenArr[i]) && (q->sumLenArr[i] > 0))
00751                 q->skipFlagRaw[i] = 1;
00752     }
00753 
00754     imc_get_skip_coeff(q);
00755 
00756     for(i = 0; i < BANDS; i++) {
00757         q->flcoeffs6[i] = q->flcoeffs1[i];
00758         /* band has flag set and at least one coded coefficient */
00759         if (q->bandFlagsBuf[i] && (band_tab[i+1] - band_tab[i]) != q->skipFlagCount[i]){
00760                 q->flcoeffs6[i] *= q->sqrt_tab[band_tab[i+1] - band_tab[i]] /
00761                                    q->sqrt_tab[(band_tab[i+1] - band_tab[i] - q->skipFlagCount[i])];
00762         }
00763     }
00764 
00765     /* calculate bits left, bits needed and adjust bit allocation */
00766     bits = summer = 0;
00767 
00768     for(i = 0; i < BANDS; i++) {
00769         if (q->bandFlagsBuf[i]) {
00770             for(j = band_tab[i]; j < band_tab[i+1]; j++) {
00771                 if(q->skipFlags[j]) {
00772                     summer += q->CWlengthT[j];
00773                     q->CWlengthT[j] = 0;
00774                 }
00775             }
00776             bits += q->skipFlagBits[i];
00777             summer -= q->skipFlagBits[i];
00778         }
00779     }
00780     imc_adjust_bit_allocation(q, summer);
00781 
00782     for(i = 0; i < BANDS; i++) {
00783         q->sumLenArr[i] = 0;
00784 
00785         for(j = band_tab[i]; j < band_tab[i+1]; j++)
00786             if (!q->skipFlags[j])
00787                 q->sumLenArr[i] += q->CWlengthT[j];
00788     }
00789 
00790     memset(q->codewords, 0, sizeof(q->codewords));
00791 
00792     if(imc_get_coeffs(q) < 0) {
00793         av_log(avctx, AV_LOG_ERROR, "Read coefficients failed\n");
00794         q->decoder_reset = 1;
00795         return 0;
00796     }
00797 
00798     if(inverse_quant_coeff(q, stream_format_code) < 0) {
00799         av_log(avctx, AV_LOG_ERROR, "Inverse quantization of coefficients failed\n");
00800         q->decoder_reset = 1;
00801         return 0;
00802     }
00803 
00804     memset(q->skipFlags, 0, sizeof(q->skipFlags));
00805 
00806     imc_imdct256(q);
00807 
00808     q->dsp.float_to_int16(data, q->out_samples, COEFFS);
00809 
00810     *data_size = COEFFS * sizeof(int16_t);
00811 
00812     return IMC_BLOCK_SIZE;
00813 }
00814 
00815 
00816 static av_cold int imc_decode_close(AVCodecContext * avctx)
00817 {
00818     IMCContext *q = avctx->priv_data;
00819 
00820     ff_fft_end(&q->fft);
00821     return 0;
00822 }
00823 
00824 
00825 AVCodec imc_decoder = {
00826     .name = "imc",
00827     .type = AVMEDIA_TYPE_AUDIO,
00828     .id = CODEC_ID_IMC,
00829     .priv_data_size = sizeof(IMCContext),
00830     .init = imc_decode_init,
00831     .close = imc_decode_close,
00832     .decode = imc_decode_frame,
00833     .long_name = NULL_IF_CONFIG_SMALL("IMC (Intel Music Coder)"),
00834 };

Generated on Fri Sep 16 2011 17:17:37 for FFmpeg by  doxygen 1.7.1