libavcodec/nellymoserenc.c

   1 /*
   2  * Nellymoser encoder
   3  * This code is developed as part of Google Summer of Code 2008 Program.
   4  *
   5  * Copyright (c) 2008 Bartlomiej Wolowiec
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 /**
  25  * @file libavcodec/nellymoserenc.c
  26  * Nellymoser encoder
  27  * by Bartlomiej Wolowiec
  28  *
  29  * Generic codec information: libavcodec/nellymoserdec.c
  30  *
  31  * Some information also from: http://samples.mplayerhq.hu/A-codecs/Nelly_Moser/ASAO/ASAO.zip
  32  *                             (Copyright Joseph Artsimovich and UAB "DKD")
  33  *
  34  * for more information about nellymoser format, visit:
  35  * http://wiki.multimedia.cx/index.php?title=Nellymoser
  36  */
  37
  38 #include "nellymoser.h"
  39 #include "avcodec.h"
  40 #include "dsputil.h"
  41
  42 #define BITSTREAM_WRITER_LE
  43 #include "put_bits.h"
  44
  45 #define POW_TABLE_SIZE (1<<11)
  46 #define POW_TABLE_OFFSET 3
  47 #define OPT_SIZE ((1<<15) + 3000)
  48
  49 typedef struct NellyMoserEncodeContext {
  50     AVCodecContext  *avctx;
  51     int             last_frame;
  52     int             bufsel;
  53     int             have_saved;
  54     DSPContext      dsp;
  55     MDCTContext     mdct_ctx;
  56     DECLARE_ALIGNED_16(float, mdct_out[NELLY_SAMPLES]);
  57     DECLARE_ALIGNED_16(float, in_buff[NELLY_SAMPLES]);
  58     DECLARE_ALIGNED_16(float, buf[2][3 * NELLY_BUF_LEN]);     ///< sample buffer
  59     float           (*opt )[NELLY_BANDS];
  60     uint8_t         (*path)[NELLY_BANDS];
  61 } NellyMoserEncodeContext;
  62
  63 static float pow_table[POW_TABLE_SIZE];     ///< -pow(2, -i / 2048.0 - 3.0);
  64
  65 static const uint8_t sf_lut[96] = {
  66      0,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  4,  4,
  67      5,  5,  5,  6,  7,  7,  8,  8,  9, 10, 11, 11, 12, 13, 13, 14,
  68     15, 15, 16, 17, 17, 18, 19, 19, 20, 21, 22, 22, 23, 24, 25, 26,
  69     27, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40,
  70     41, 41, 42, 43, 44, 45, 45, 46, 47, 48, 49, 50, 51, 52, 52, 53,
  71     54, 55, 55, 56, 57, 57, 58, 59, 59, 60, 60, 60, 61, 61, 61, 62,
  72 };
  73
  74 static const uint8_t sf_delta_lut[78] = {
  75      0,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  4,  4,
  76      4,  5,  5,  5,  6,  6,  7,  7,  8,  8,  9, 10, 10, 11, 11, 12,
  77     13, 13, 14, 15, 16, 17, 17, 18, 19, 19, 20, 21, 21, 22, 22, 23,
  78     23, 24, 24, 25, 25, 25, 26, 26, 26, 26, 27, 27, 27, 27, 27, 28,
  79     28, 28, 28, 28, 28, 29, 29, 29, 29, 29, 29, 29, 29, 30,
  80 };
  81
  82 static const uint8_t quant_lut[230] = {
  83      0,
  84
  85      0,  1,  2,
  86
  87      0,  1,  2,  3,  4,  5,  6,
  88
  89      0,  1,  1,  2,  2,  3,  3,  4,  5,  6,  7,  8,  9, 10, 11, 11,
  90     12, 13, 13, 13, 14,
  91
  92      0,  1,  1,  2,  2,  2,  3,  3,  4,  4,  5,  5,  6,  6,  7,  8,
  93      8,  9, 10, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
  94     22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 29,
  95     30,
  96
  97      0,  1,  1,  1,  1,  1,  1,  2,  2,  2,  2,  2,  3,  3,  3,  3,
  98      4,  4,  4,  5,  5,  5,  6,  6,  7,  7,  7,  8,  8,  9,  9,  9,
  99     10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15,
 100     15, 15, 16, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 20, 20, 20,
 101     21, 21, 22, 22, 23, 23, 24, 25, 26, 26, 27, 28, 29, 30, 31, 32,
 102     33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 42, 43, 44, 44, 45, 45,
 103     46, 47, 47, 48, 48, 49, 49, 50, 50, 50, 51, 51, 51, 52, 52, 52,
 104     53, 53, 53, 54, 54, 54, 55, 55, 55, 56, 56, 56, 57, 57, 57, 57,
 105     58, 58, 58, 58, 59, 59, 59, 59, 60, 60, 60, 60, 60, 61, 61, 61,
 106     61, 61, 61, 61, 62,
 107 };
 108
 109 static const float quant_lut_mul[7] = { 0.0,  0.0,  2.0,  2.0,  5.0, 12.0,  36.6 };
 110 static const float quant_lut_add[7] = { 0.0,  0.0,  2.0,  7.0, 21.0, 56.0, 157.0 };
 111 static const uint8_t quant_lut_offset[8] = { 0, 0, 1, 4, 11, 32, 81, 230 };
 112
 113 void apply_mdct(NellyMoserEncodeContext *s)
 114 {
 115     memcpy(s->in_buff, s->buf[s->bufsel], NELLY_BUF_LEN * sizeof(float));
 116     s->dsp.vector_fmul(s->in_buff, ff_sine_128, NELLY_BUF_LEN);
 117     s->dsp.vector_fmul_reverse(s->in_buff + NELLY_BUF_LEN, s->buf[s->bufsel] + NELLY_BUF_LEN, ff_sine_128,
 118                                NELLY_BUF_LEN);
 119     ff_mdct_calc(&s->mdct_ctx, s->mdct_out, s->in_buff);
 120
 121     s->dsp.vector_fmul(s->buf[s->bufsel] + NELLY_BUF_LEN, ff_sine_128, NELLY_BUF_LEN);
 122     s->dsp.vector_fmul_reverse(s->buf[s->bufsel] + 2 * NELLY_BUF_LEN, s->buf[1 - s->bufsel], ff_sine_128,
 123                                NELLY_BUF_LEN);
 124     ff_mdct_calc(&s->mdct_ctx, s->mdct_out + NELLY_BUF_LEN, s->buf[s->bufsel] + NELLY_BUF_LEN);
 125 }
 126
 127 static av_cold int encode_init(AVCodecContext *avctx)
 128 {
 129     NellyMoserEncodeContext *s = avctx->priv_data;
 130     int i;
 131
 132     if (avctx->channels != 1) {
 133         av_log(avctx, AV_LOG_ERROR, "Nellymoser supports only 1 channel\n");
 134         return -1;
 135     }
 136
 137     if (avctx->sample_rate != 8000 && avctx->sample_rate != 16000 &&
 138         avctx->sample_rate != 11025 &&
 139         avctx->sample_rate != 22050 && avctx->sample_rate != 44100 &&
 140         avctx->strict_std_compliance >= FF_COMPLIANCE_NORMAL) {
 141         av_log(avctx, AV_LOG_ERROR, "Nellymoser works only with 8000, 16000, 11025, 22050 and 44100 sample rate\n");
 142         return -1;
 143     }
 144
 145     avctx->frame_size = NELLY_SAMPLES;
 146     s->avctx = avctx;
 147     ff_mdct_init(&s->mdct_ctx, 8, 0, 1.0);
 148     dsputil_init(&s->dsp, avctx);
 149
 150     /* Generate overlap window */
 151     ff_sine_window_init(ff_sine_128, 128);
 152     for (i = 0; i < POW_TABLE_SIZE; i++)
 153         pow_table[i] = -pow(2, -i / 2048.0 - 3.0 + POW_TABLE_OFFSET);
 154
 155     if (s->avctx->trellis) {
 156         s->opt  = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(float  ));
 157         s->path = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(uint8_t));
 158     }
 159
 160     return 0;
 161 }
 162
 163 static av_cold int encode_end(AVCodecContext *avctx)
 164 {
 165     NellyMoserEncodeContext *s = avctx->priv_data;
 166
 167     ff_mdct_end(&s->mdct_ctx);
 168
 169     if (s->avctx->trellis) {
 170         av_free(s->opt);
 171         av_free(s->path);
 172     }
 173
 174     return 0;
 175 }
 176
 177 #define find_best(val, table, LUT, LUT_add, LUT_size) \
 178     best_idx = \
 179         LUT[av_clip ((lrintf(val) >> 8) + LUT_add, 0, LUT_size - 1)]; \
 180     if (fabs(val - table[best_idx]) > fabs(val - table[best_idx + 1])) \
 181         best_idx++;
 182
 183 static void get_exponent_greedy(NellyMoserEncodeContext *s, float *cand, int *idx_table)
 184 {
 185     int band, best_idx, power_idx = 0;
 186     float power_candidate;
 187
 188     //base exponent
 189     find_best(cand[0], ff_nelly_init_table, sf_lut, -20, 96);
 190     idx_table[0] = best_idx;
 191     power_idx = ff_nelly_init_table[best_idx];
 192
 193     for (band = 1; band < NELLY_BANDS; band++) {
 194         power_candidate = cand[band] - power_idx;
 195         find_best(power_candidate, ff_nelly_delta_table, sf_delta_lut, 37, 78);
 196         idx_table[band] = best_idx;
 197         power_idx += ff_nelly_delta_table[best_idx];
 198     }
 199 }
 200
 201 static inline float distance(float x, float y, int band)
 202 {
 203     //return pow(fabs(x-y), 2.0);
 204     float tmp = x - y;
 205     return tmp * tmp;
 206 }
 207
 208 static void get_exponent_dynamic(NellyMoserEncodeContext *s, float *cand, int *idx_table)
 209 {
 210     int i, j, band, best_idx;
 211     float power_candidate, best_val;
 212
 213     float  (*opt )[NELLY_BANDS] = s->opt ;
 214     uint8_t(*path)[NELLY_BANDS] = s->path;
 215
 216     for (i = 0; i < NELLY_BANDS * OPT_SIZE; i++) {
 217         opt[0][i] = INFINITY;
 218     }
 219
 220     for (i = 0; i < 64; i++) {
 221         opt[0][ff_nelly_init_table[i]] = distance(cand[0], ff_nelly_init_table[i], 0);
 222         path[0][ff_nelly_init_table[i]] = i;
 223     }
 224
 225     for (band = 1; band < NELLY_BANDS; band++) {
 226         int q, c = 0;
 227         float tmp;
 228         int idx_min, idx_max, idx;
 229         power_candidate = cand[band];
 230         for (q = 1000; !c && q < OPT_SIZE; q <<= 2) {
 231             idx_min = FFMAX(0, cand[band] - q);
 232             idx_max = FFMIN(OPT_SIZE, cand[band - 1] + q);
 233             for (i = FFMAX(0, cand[band - 1] - q); i < FFMIN(OPT_SIZE, cand[band - 1] + q); i++) {
 234                 if ( isinf(opt[band - 1][i]) )
 235                     continue;
 236                 for (j = 0; j < 32; j++) {
 237                     idx = i + ff_nelly_delta_table[j];
 238                     if (idx > idx_max)
 239                         break;
 240                     if (idx >= idx_min) {
 241                         tmp = opt[band - 1][i] + distance(idx, power_candidate, band);
 242                         if (opt[band][idx] > tmp) {
 243                             opt[band][idx] = tmp;
 244                             path[band][idx] = j;
 245                             c = 1;
 246                         }
 247                     }
 248                 }
 249             }
 250         }
 251         assert(c); //FIXME
 252     }
 253
 254     best_val = INFINITY;
 255     best_idx = -1;
 256     band = NELLY_BANDS - 1;
 257     for (i = 0; i < OPT_SIZE; i++) {
 258         if (best_val > opt[band][i]) {
 259             best_val = opt[band][i];
 260             best_idx = i;
 261         }
 262     }
 263     for (band = NELLY_BANDS - 1; band >= 0; band--) {
 264         idx_table[band] = path[band][best_idx];
 265         if (band) {
 266             best_idx -= ff_nelly_delta_table[path[band][best_idx]];
 267         }
 268     }
 269 }
 270
 271 /**
 272  * Encodes NELLY_SAMPLES samples. It assumes, that samples contains 3 * NELLY_BUF_LEN values
 273  *  @param s               encoder context
 274  *  @param output          output buffer
 275  *  @param output_size     size of output buffer
 276  */
 277 static void encode_block(NellyMoserEncodeContext *s, unsigned char *output, int output_size)
 278 {
 279     PutBitContext pb;
 280     int i, j, band, block, best_idx, power_idx = 0;
 281     float power_val, coeff, coeff_sum;
 282     float pows[NELLY_FILL_LEN];
 283     int bits[NELLY_BUF_LEN], idx_table[NELLY_BANDS];
 284     float cand[NELLY_BANDS];
 285
 286     apply_mdct(s);
 287
 288     init_put_bits(&pb, output, output_size * 8);
 289
 290     i = 0;
 291     for (band = 0; band < NELLY_BANDS; band++) {
 292         coeff_sum = 0;
 293         for (j = 0; j < ff_nelly_band_sizes_table[band]; i++, j++) {
 294             coeff_sum += s->mdct_out[i                ] * s->mdct_out[i                ]
 295                        + s->mdct_out[i + NELLY_BUF_LEN] * s->mdct_out[i + NELLY_BUF_LEN];
 296         }
 297         cand[band] =
 298             log(FFMAX(1.0, coeff_sum / (ff_nelly_band_sizes_table[band] << 7))) * 1024.0 / M_LN2;
 299     }
 300
 301     if (s->avctx->trellis) {
 302         get_exponent_dynamic(s, cand, idx_table);
 303     } else {
 304         get_exponent_greedy(s, cand, idx_table);
 305     }
 306
 307     i = 0;
 308     for (band = 0; band < NELLY_BANDS; band++) {
 309         if (band) {
 310             power_idx += ff_nelly_delta_table[idx_table[band]];
 311             put_bits(&pb, 5, idx_table[band]);
 312         } else {
 313             power_idx = ff_nelly_init_table[idx_table[0]];
 314             put_bits(&pb, 6, idx_table[0]);
 315         }
 316         power_val = pow_table[power_idx & 0x7FF] / (1 << ((power_idx >> 11) + POW_TABLE_OFFSET));
 317         for (j = 0; j < ff_nelly_band_sizes_table[band]; i++, j++) {
 318             s->mdct_out[i] *= power_val;
 319             s->mdct_out[i + NELLY_BUF_LEN] *= power_val;
 320             pows[i] = power_idx;
 321         }
 322     }
 323
 324     ff_nelly_get_sample_bits(pows, bits);
 325
 326     for (block = 0; block < 2; block++) {
 327         for (i = 0; i < NELLY_FILL_LEN; i++) {
 328             if (bits[i] > 0) {
 329                 const float *table = ff_nelly_dequantization_table + (1 << bits[i]) - 1;
 330                 coeff = s->mdct_out[block * NELLY_BUF_LEN + i];
 331                 best_idx =
 332                     quant_lut[av_clip (
 333                             coeff * quant_lut_mul[bits[i]] + quant_lut_add[bits[i]],
 334                             quant_lut_offset[bits[i]],
 335                             quant_lut_offset[bits[i]+1] - 1
 336                             )];
 337                 if (fabs(coeff - table[best_idx]) > fabs(coeff - table[best_idx + 1]))
 338                     best_idx++;
 339
 340                 put_bits(&pb, bits[i], best_idx);
 341             }
 342         }
 343         if (!block)
 344             put_bits(&pb, NELLY_HEADER_BITS + NELLY_DETAIL_BITS - put_bits_count(&pb), 0);
 345     }
 346
 347     flush_put_bits(&pb);
 348 }
 349
 350 static int encode_frame(AVCodecContext *avctx, uint8_t *frame, int buf_size, void *data)
 351 {
 352     NellyMoserEncodeContext *s = avctx->priv_data;
 353     int16_t *samples = data;
 354     int i;
 355
 356     if (s->last_frame)
 357         return 0;
 358
 359     if (data) {
 360         for (i = 0; i < avctx->frame_size; i++) {
 361             s->buf[s->bufsel][i] = samples[i];
 362         }
 363         for (; i < NELLY_SAMPLES; i++) {
 364             s->buf[s->bufsel][i] = 0;
 365         }
 366         s->bufsel = 1 - s->bufsel;
 367         if (!s->have_saved) {
 368             s->have_saved = 1;
 369             return 0;
 370         }
 371     } else {
 372         memset(s->buf[s->bufsel], 0, sizeof(s->buf[0][0]) * NELLY_BUF_LEN);
 373         s->bufsel = 1 - s->bufsel;
 374         s->last_frame = 1;
 375     }
 376
 377     if (s->have_saved) {
 378         encode_block(s, frame, buf_size);
 379         return NELLY_BLOCK_LEN;
 380     }
 381     return 0;
 382 }
 383
 384 AVCodec nellymoser_encoder = {
 385     .name = "nellymoser",
 386     .type = CODEC_TYPE_AUDIO,
 387     .id = CODEC_ID_NELLYMOSER,
 388     .priv_data_size = sizeof(NellyMoserEncodeContext),
 389     .init = encode_init,
 390     .encode = encode_frame,
 391     .close = encode_end,
 392     .capabilities = CODEC_CAP_SMALL_LAST_FRAME | CODEC_CAP_DELAY,
 393     .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
 394 };