libavcodec/nellymoserdec.c

   1 /*
   2  * NellyMoser audio decoder
   3  * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5,
   4  *                    539459aeb7d425140b62a3ec7dbf6dc8e408a306, and
   5  *                    520e17cd55896441042b14df2566a6eb610ed444
   6  * Copyright (c) 2007 Loic Minier <lool at dooz.org>
   7  *                    Benjamin Larsson
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining a
  10  * copy of this software and associated documentation files (the "Software"),
  11  * to deal in the Software without restriction, including without limitation
  12  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  13  * and/or sell copies of the Software, and to permit persons to whom the
  14  * Software is furnished to do so, subject to the following conditions:
  15  *
  16  * The above copyright notice and this permission notice shall be included in
  17  * all copies or substantial portions of the Software.
  18  *
  19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  24  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  25  * DEALINGS IN THE SOFTWARE.
  26  */
  27
  28 /**
  29  * @file nellymoserdec.c
  30  * The 3 alphanumeric copyright notices are md5summed they are from the original
  31  * implementors. The original code is available from http://code.google.com/p/nelly2pcm/
  32  */
  33 #include "avcodec.h"
  34 #include "random.h"
  35 #include "dsputil.h"
  36
  37 #define ALT_BITSTREAM_READER_LE
  38 #include "bitstream.h"
  39
  40 #define NELLY_BANDS       23
  41 #define NELLY_BLOCK_LEN   64
  42 #define NELLY_HEADER_BITS 116
  43 #define NELLY_DETAIL_BITS 198
  44 #define NELLY_BUF_LEN     128
  45 #define NELLY_FILL_LEN    124
  46 #define NELLY_BIT_CAP     6
  47 #define NELLY_BASE_OFF    4228
  48 #define NELLY_BASE_SHIFT  19
  49 #define NELLY_SAMPLES     (2 * NELLY_BUF_LEN)
  50
  51 static const float dequantization_table[127] = {
  52 0.0000000000,-0.8472560048, 0.7224709988, -1.5247479677, -0.4531480074, 0.3753609955, 1.4717899561,
  53 -1.9822579622, -1.1929379702, -0.5829370022, -0.0693780035, 0.3909569979,0.9069200158, 1.4862740040,
  54  2.2215409279, -2.3887870312, -1.8067539930, -1.4105420113, -1.0773609877, -0.7995010018,-0.5558109879,
  55 -0.3334020078, -0.1324490011, 0.0568020009, 0.2548770010, 0.4773550034, 0.7386850119, 1.0443060398,
  56 1.3954459429, 1.8098750114, 2.3918759823,-2.3893830776, -1.9884680510, -1.7514040470, -1.5643119812,
  57 -1.3922129869,-1.2164649963, -1.0469499826, -0.8905100226, -0.7645580173, -0.6454579830, -0.5259280205,
  58 -0.4059549868, -0.3029719889, -0.2096900046, -0.1239869967, -0.0479229987, 0.0257730000, 0.1001340002,
  59 0.1737180054, 0.2585540116, 0.3522900045, 0.4569880068, 0.5767750144, 0.7003160119, 0.8425520062,
  60 1.0093879700, 1.1821349859, 1.3534560204, 1.5320819616, 1.7332619429, 1.9722349644, 2.3978140354,
  61 -2.5756309032, -2.0573320389, -1.8984919786, -1.7727810144, -1.6662600040, -1.5742180347, -1.4993319511,
  62 -1.4316639900, -1.3652280569, -1.3000990152, -1.2280930281, -1.1588579416, -1.0921250582, -1.0135740042,
  63 -0.9202849865, -0.8287050128, -0.7374889851, -0.6447759867, -0.5590940118, -0.4857139885, -0.4110319912,
  64 -0.3459700048, -0.2851159871, -0.2341620028, -0.1870580018, -0.1442500055, -0.1107169986, -0.0739680007,
  65 -0.0365610011, -0.0073290002, 0.0203610007, 0.0479039997, 0.0751969963, 0.0980999991, 0.1220389977,
  66 0.1458999962, 0.1694349945, 0.1970459968, 0.2252430022, 0.2556869984, 0.2870100141, 0.3197099864,
  67 0.3525829911, 0.3889069855, 0.4334920049, 0.4769459963, 0.5204820037, 0.5644530058, 0.6122040153,
  68 0.6685929894, 0.7341650128, 0.8032159805, 0.8784040213, 0.9566209912, 1.0397069454, 1.1293770075,
  69 1.2211159468, 1.3080279827, 1.4024800062, 1.5056819916, 1.6227730513, 1.7724959850, 1.9430880547,
  70  2.2903931141
  71 };
  72
  73 static const uint8_t nelly_band_sizes_table[NELLY_BANDS] = {
  74 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 4, 4, 5, 6, 6, 7, 8, 9, 10, 12, 14, 15
  75 };
  76
  77 static const uint16_t nelly_init_table[64] = {
  78 3134, 5342, 6870, 7792, 8569, 9185, 9744, 10191, 10631, 11061, 11434, 11770,
  79 12116, 12513, 12925, 13300, 13674, 14027, 14352, 14716, 15117, 15477, 15824,
  80 16157, 16513, 16804, 17090, 17401, 17679, 17948, 18238, 18520, 18764, 19078,
  81 19381, 19640, 19921, 20205, 20500, 20813, 21162, 21465, 21794, 22137, 22453,
  82 22756, 23067, 23350, 23636, 23926, 24227, 24521, 24819, 25107, 25414, 25730,
  83 26120, 26497, 26895, 27344, 27877, 28463, 29426, 31355
  84 };
  85
  86 static const int16_t nelly_delta_table[32] = {
  87 -11725, -9420, -7910, -6801, -5948, -5233, -4599, -4039, -3507, -3030, -2596,
  88 -2170, -1774, -1383, -1016, -660, -329, -1, 337, 696, 1085, 1512, 1962, 2433,
  89 2968, 3569, 4314, 5279, 6622, 8154, 10076, 12975
  90 };
  91
  92 typedef struct NellyMoserDecodeContext {
  93     AVCodecContext* avctx;
  94     DECLARE_ALIGNED_16(float,float_buf[NELLY_SAMPLES]);
  95     float           state[64];
  96     AVRandomState   random_state;
  97     GetBitContext   gb;
  98     int             add_bias;
  99     int             scale_bias;
 100     DSPContext      dsp;
 101     MDCTContext     imdct_ctx;
 102     DECLARE_ALIGNED_16(float,imdct_tmp[NELLY_BUF_LEN]);
 103     DECLARE_ALIGNED_16(float,imdct_out[NELLY_BUF_LEN * 2]);
 104 } NellyMoserDecodeContext;
 105
 106 static DECLARE_ALIGNED_16(float,sine_window[128]);
 107
 108 static inline int signed_shift(int i, int shift) {
 109     if (shift > 0)
 110         return i << shift;
 111     return i >> -shift;
 112 }
 113
 114 static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio)
 115 {
 116     int bot, mid_up, mid_down, top;
 117     float s_bot, s_top;
 118
 119     bot = 0;
 120     top = NELLY_BUF_LEN-1;
 121     mid_up = NELLY_BUF_LEN/2;
 122     mid_down = (NELLY_BUF_LEN/2)-1;
 123
 124     while (bot < NELLY_BUF_LEN/4) {
 125         s_bot = audio[bot];
 126         s_top = -audio[top];
 127         audio[bot] =  (-audio[mid_up]*sine_window[bot]-state[bot   ]*sine_window[top])/s->scale_bias + s->add_bias;
 128         audio[top] = (-state[bot   ]*sine_window[bot]+audio[mid_up]*sine_window[top])/s->scale_bias + s->add_bias;
 129         state[bot] =  audio[mid_down];
 130
 131         audio[mid_down] =  (s_top          *sine_window[mid_down]-state[mid_down]*sine_window[mid_up])/s->scale_bias + s->add_bias;
 132         audio[mid_up  ] = (-state[mid_down]*sine_window[mid_down]-s_top          *sine_window[mid_up])/s->scale_bias + s->add_bias;
 133         state[mid_down] =  s_bot;
 134
 135         bot++;
 136         mid_up++;
 137         mid_down--;
 138         top--;
 139     }
 140 }
 141
 142 static int sum_bits(short *buf, short shift, short off)
 143 {
 144     int b, i = 0, ret = 0;
 145
 146     for (i = 0; i < NELLY_FILL_LEN; i++) {
 147         b = buf[i]-off;
 148         b = ((b>>(shift-1))+1)>>1;
 149         ret += av_clip(b, 0, NELLY_BIT_CAP);
 150     }
 151
 152     return ret;
 153 }
 154
 155 static int headroom(int *la)
 156 {
 157     int l;
 158     if (*la == 0) {
 159         return 31;
 160     }
 161     l = 30 - av_log2(FFABS(*la));
 162     *la <<= l;
 163     return l;
 164 }
 165
 166
 167 static void get_sample_bits(const float *buf, int *bits)
 168 {
 169     int i, j;
 170     short sbuf[128];
 171     int bitsum = 0, last_bitsum, small_bitsum, big_bitsum;
 172     short shift, shift_saved;
 173     int max, sum, last_off, tmp;
 174     int big_off, small_off;
 175     int off;
 176
 177     max = 0;
 178     for (i = 0; i < NELLY_FILL_LEN; i++) {
 179         max = FFMAX(max, buf[i]);
 180     }
 181     shift = -16;
 182     shift += headroom(&max);
 183
 184     sum = 0;
 185     for (i = 0; i < NELLY_FILL_LEN; i++) {
 186         sbuf[i] = signed_shift(buf[i], shift);
 187         sbuf[i] = (3*sbuf[i])>>2;
 188         sum += sbuf[i];
 189     }
 190
 191     shift += 11;
 192     shift_saved = shift;
 193     sum -= NELLY_DETAIL_BITS << shift;
 194     shift += headroom(&sum);
 195     small_off = (NELLY_BASE_OFF * (sum>>16)) >> 15;
 196     shift = shift_saved - (NELLY_BASE_SHIFT+shift-31);
 197
 198     small_off = signed_shift(small_off, shift);
 199
 200     bitsum = sum_bits(sbuf, shift_saved, small_off);
 201
 202     if (bitsum != NELLY_DETAIL_BITS) {
 203         shift = 0;
 204         off = bitsum - NELLY_DETAIL_BITS;
 205
 206         for(shift=0; FFABS(off) <= 16383; shift++)
 207             off *= 2;
 208
 209         off = (off * NELLY_BASE_OFF) >> 15;
 210         shift = shift_saved-(NELLY_BASE_SHIFT+shift-15);
 211
 212         off = signed_shift(off, shift);
 213
 214         for (j = 1; j < 20; j++) {
 215             last_off = small_off;
 216             small_off += off;
 217             last_bitsum = bitsum;
 218
 219             bitsum = sum_bits(sbuf, shift_saved, small_off);
 220
 221             if ((bitsum-NELLY_DETAIL_BITS) * (last_bitsum-NELLY_DETAIL_BITS) <= 0)
 222                 break;
 223         }
 224
 225         if (bitsum > NELLY_DETAIL_BITS) {
 226             big_off = small_off;
 227             small_off = last_off;
 228             big_bitsum=bitsum;
 229             small_bitsum=last_bitsum;
 230         } else {
 231             big_off = last_off;
 232             big_bitsum=last_bitsum;
 233             small_bitsum=bitsum;
 234         }
 235
 236         while (bitsum != NELLY_DETAIL_BITS && j <= 19) {
 237             off = (big_off+small_off)>>1;
 238             bitsum = sum_bits(sbuf, shift_saved, off);
 239             if (bitsum > NELLY_DETAIL_BITS) {
 240                 big_off=off;
 241                 big_bitsum=bitsum;
 242             } else {
 243                 small_off = off;
 244                 small_bitsum=bitsum;
 245             }
 246             j++;
 247         }
 248
 249         if (abs(big_bitsum-NELLY_DETAIL_BITS) >=
 250             abs(small_bitsum-NELLY_DETAIL_BITS)) {
 251             bitsum = small_bitsum;
 252         } else {
 253             small_off = big_off;
 254             bitsum = big_bitsum;
 255         }
 256     }
 257
 258     for (i = 0; i < NELLY_FILL_LEN; i++) {
 259         tmp = sbuf[i]-small_off;
 260         tmp = ((tmp>>(shift_saved-1))+1)>>1;
 261         bits[i] = av_clip(tmp, 0, NELLY_BIT_CAP);
 262     }
 263
 264     if (bitsum > NELLY_DETAIL_BITS) {
 265         tmp = i = 0;
 266         while (tmp < NELLY_DETAIL_BITS) {
 267             tmp += bits[i];
 268             i++;
 269         }
 270
 271         bits[i-1] -= tmp - NELLY_DETAIL_BITS;
 272         for(; i < NELLY_FILL_LEN; i++)
 273             bits[i] = 0;
 274     }
 275 }
 276
 277 void nelly_decode_block(NellyMoserDecodeContext *s, const unsigned char block[NELLY_BLOCK_LEN], float audio[NELLY_SAMPLES])
 278 {
 279     int i,j;
 280     float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
 281     float *aptr, *bptr, *pptr, val, pval;
 282     int bits[NELLY_BUF_LEN];
 283     unsigned char v;
 284
 285     init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
 286
 287     bptr = buf;
 288     pptr = pows;
 289     val = nelly_init_table[get_bits(&s->gb, 6)];
 290     for (i=0 ; i<NELLY_BANDS ; i++) {
 291         if (i > 0)
 292             val += nelly_delta_table[get_bits(&s->gb, 5)];
 293         pval = pow(2, val/2048);
 294         for (j = 0; j < nelly_band_sizes_table[i]; j++) {
 295             *bptr++ = val;
 296             *pptr++ = pval;
 297         }
 298
 299     }
 300
 301     get_sample_bits(buf, bits);
 302
 303     for (i = 0; i < 2; i++) {
 304         aptr = audio + i * NELLY_BUF_LEN;
 305
 306         init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
 307         skip_bits(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
 308
 309         for (j = 0; j < NELLY_FILL_LEN; j++) {
 310             if (bits[j] <= 0) {
 311                 aptr[j] = M_SQRT1_2*pows[j];
 312                 if (av_random(&s->random_state) & 1)
 313                     aptr[j] *= -1.0;
 314             } else {
 315                 v = get_bits(&s->gb, bits[j]);
 316                 aptr[j] = dequantization_table[(1<<bits[j])-1+v]*pows[j];
 317             }
 318         }
 319         memset(&aptr[NELLY_FILL_LEN], 0,
 320                (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
 321
 322         s->imdct_ctx.fft.imdct_calc(&s->imdct_ctx, s->imdct_out,
 323                                     aptr, s->imdct_tmp);
 324         /* XXX: overlapping and windowing should be part of a more
 325            generic imdct function */
 326         memcpy(&aptr[0],&s->imdct_out[NELLY_BUF_LEN+NELLY_BUF_LEN/2], (NELLY_BUF_LEN/2)*sizeof(float));
 327         memcpy(&aptr[NELLY_BUF_LEN / 2],&s->imdct_out[0],(NELLY_BUF_LEN/2)*sizeof(float));
 328         overlap_and_window(s, s->state, aptr);
 329     }
 330 }
 331
 332 static int decode_init(AVCodecContext * avctx) {
 333     NellyMoserDecodeContext *s = avctx->priv_data;
 334     int i;
 335
 336     s->avctx = avctx;
 337     av_init_random(0, &s->random_state);
 338     ff_mdct_init(&s->imdct_ctx, 8, 1);
 339
 340     dsputil_init(&s->dsp, avctx);
 341
 342     if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
 343         s->add_bias = 385;
 344         s->scale_bias = 8*32768;
 345     } else {
 346         s->add_bias = 0;
 347         s->scale_bias = 1*8;
 348     }
 349
 350     /* Generate overlap window */
 351     if (!sine_window[0])
 352         for (i=0 ; i<128; i++) {
 353             sine_window[i] = sin((i + 0.5) / 256.0 * M_PI);
 354         }
 355
 356     return 0;
 357 }
 358
 359 static int decode_tag(AVCodecContext * avctx,
 360                       void *data, int *data_size,
 361                       const uint8_t * buf, int buf_size) {
 362     NellyMoserDecodeContext *s = avctx->priv_data;
 363     int blocks, i;
 364     int16_t* samples;
 365     *data_size = 0;
 366     samples = (int16_t*)data;
 367
 368     if (buf_size < avctx->block_align)
 369         return buf_size;
 370
 371     switch (buf_size) {
 372         case 64:    // 8000Hz
 373             blocks = 1; break;
 374         case 128:   // 11025Hz
 375             blocks = 2; break;
 376         case 256:   // 22050Hz
 377             blocks = 4; break;
 378         case 512:   // 44100Hz
 379             blocks = 8; break;
 380         default:
 381             av_log(avctx, AV_LOG_ERROR, "Tag size %d unknown, report sample!\n", buf_size);
 382             return buf_size;
 383     }
 384
 385     for (i=0 ; i<blocks ; i++) {
 386         nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);
 387         s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);
 388         *data_size += NELLY_SAMPLES*sizeof(int16_t);
 389     }
 390
 391     return buf_size;
 392 }
 393
 394 static int decode_end(AVCodecContext * avctx) {
 395     NellyMoserDecodeContext *s = avctx->priv_data;
 396
 397     ff_mdct_end(&s->imdct_ctx);
 398     return 0;
 399 }
 400
 401 AVCodec nellymoser_decoder = {
 402     "nellymoser",
 403     CODEC_TYPE_AUDIO,
 404     CODEC_ID_NELLYMOSER,
 405     sizeof(NellyMoserDecodeContext),
 406     decode_init,
 407     NULL,
 408     decode_end,
 409     decode_tag,
 410 };
 411