ac3enc.c 85 KB
Newer Older
Fabrice Bellard's avatar
Fabrice Bellard committed
1
/*
2
 * The simplest AC-3 encoder
3
 * Copyright (c) 2000 Fabrice Bellard
4 5
 * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
 * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
Fabrice Bellard's avatar
Fabrice Bellard committed
6
 *
7 8 9
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
10 11
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
12
 * version 2.1 of the License, or (at your option) any later version.
Fabrice Bellard's avatar
Fabrice Bellard committed
13
 *
14
 * FFmpeg is distributed in the hope that it will be useful,
Fabrice Bellard's avatar
Fabrice Bellard committed
15
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 17
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
Fabrice Bellard's avatar
Fabrice Bellard committed
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
Fabrice Bellard's avatar
Fabrice Bellard committed
22
 */
Michael Niedermayer's avatar
Michael Niedermayer committed
23 24

/**
25
 * @file
26
 * The simplest AC-3 encoder.
Michael Niedermayer's avatar
Michael Niedermayer committed
27
 */
28

29
//#define ASSERT_LEVEL 2
30

31 32
#include <stdint.h>

33
#include "libavutil/avassert.h"
34
#include "libavutil/avstring.h"
35
#include "libavutil/channel_layout.h"
36
#include "libavutil/crc.h"
37
#include "libavutil/opt.h"
Fabrice Bellard's avatar
Fabrice Bellard committed
38
#include "avcodec.h"
39
#include "put_bits.h"
40
#include "dsputil.h"
41
#include "ac3dsp.h"
42
#include "ac3.h"
43
#include "fft.h"
44 45
#include "ac3enc.h"
#include "eac3enc.h"
Fabrice Bellard's avatar
Fabrice Bellard committed
46

47
typedef struct AC3Mant {
48
    int16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
49 50
    int mant1_cnt, mant2_cnt, mant4_cnt;    ///< mantissa counts for bap=1,2,4
} AC3Mant;
51

52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68
#define CMIXLEV_NUM_OPTIONS 3
static const float cmixlev_options[CMIXLEV_NUM_OPTIONS] = {
    LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, LEVEL_MINUS_6DB
};

#define SURMIXLEV_NUM_OPTIONS 3
static const float surmixlev_options[SURMIXLEV_NUM_OPTIONS] = {
    LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO
};

#define EXTMIXLEV_NUM_OPTIONS 8
static const float extmixlev_options[EXTMIXLEV_NUM_OPTIONS] = {
    LEVEL_PLUS_3DB,  LEVEL_PLUS_1POINT5DB,  LEVEL_ONE,       LEVEL_MINUS_4POINT5DB,
    LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, LEVEL_MINUS_6DB, LEVEL_ZERO
};


69 70
/**
 * LUT for number of exponent groups.
71
 * exponent_group_tab[coupling][exponent strategy-1][number of coefficients]
72
 */
73
static uint8_t exponent_group_tab[2][3][256];
74

75

76 77 78
/**
 * List of supported channel layouts.
 */
79
const uint64_t ff_ac3_channel_layouts[19] = {
80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101
     AV_CH_LAYOUT_MONO,
     AV_CH_LAYOUT_STEREO,
     AV_CH_LAYOUT_2_1,
     AV_CH_LAYOUT_SURROUND,
     AV_CH_LAYOUT_2_2,
     AV_CH_LAYOUT_QUAD,
     AV_CH_LAYOUT_4POINT0,
     AV_CH_LAYOUT_5POINT0,
     AV_CH_LAYOUT_5POINT0_BACK,
    (AV_CH_LAYOUT_MONO     | AV_CH_LOW_FREQUENCY),
    (AV_CH_LAYOUT_STEREO   | AV_CH_LOW_FREQUENCY),
    (AV_CH_LAYOUT_2_1      | AV_CH_LOW_FREQUENCY),
    (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
    (AV_CH_LAYOUT_2_2      | AV_CH_LOW_FREQUENCY),
    (AV_CH_LAYOUT_QUAD     | AV_CH_LOW_FREQUENCY),
    (AV_CH_LAYOUT_4POINT0  | AV_CH_LOW_FREQUENCY),
     AV_CH_LAYOUT_5POINT1,
     AV_CH_LAYOUT_5POINT1_BACK,
     0
};


102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131
/**
 * LUT to select the bandwidth code based on the bit rate, sample rate, and
 * number of full-bandwidth channels.
 * bandwidth_tab[fbw_channels-1][sample rate code][bit rate code]
 */
static const uint8_t ac3_bandwidth_tab[5][3][19] = {
//      32  40  48  56  64  80  96 112 128 160 192 224 256 320 384 448 512 576 640

    { {  0,  0,  0, 12, 16, 32, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48 },
      {  0,  0,  0, 16, 20, 36, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56 },
      {  0,  0,  0, 32, 40, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60 } },

    { {  0,  0,  0,  0,  0,  0,  0, 20, 24, 32, 48, 48, 48, 48, 48, 48, 48, 48, 48 },
      {  0,  0,  0,  0,  0,  0,  4, 24, 28, 36, 56, 56, 56, 56, 56, 56, 56, 56, 56 },
      {  0,  0,  0,  0,  0,  0, 20, 44, 52, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60 } },

    { {  0,  0,  0,  0,  0,  0,  0,  0,  0, 16, 24, 32, 40, 48, 48, 48, 48, 48, 48 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  4, 20, 28, 36, 44, 56, 56, 56, 56, 56, 56 },
      {  0,  0,  0,  0,  0,  0,  0,  0, 20, 40, 48, 60, 60, 60, 60, 60, 60, 60, 60 } },

    { {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 12, 24, 32, 48, 48, 48, 48, 48, 48 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 16, 28, 36, 56, 56, 56, 56, 56, 56 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 32, 48, 60, 60, 60, 60, 60, 60, 60 } },

    { {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  8, 20, 32, 40, 48, 48, 48, 48 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 12, 24, 36, 44, 56, 56, 56, 56 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, 28, 44, 60, 60, 60, 60, 60, 60 } }
};


132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174
/**
 * LUT to select the coupling start band based on the bit rate, sample rate, and
 * number of full-bandwidth channels. -1 = coupling off
 * ac3_coupling_start_tab[channel_mode-2][sample rate code][bit rate code]
 *
 * TODO: more testing for optimal parameters.
 *       multi-channel tests at 44.1kHz and 32kHz.
 */
static const int8_t ac3_coupling_start_tab[6][3][19] = {
//      32  40  48  56  64  80  96 112 128 160 192 224 256 320 384 448 512 576 640

    // 2/0
    { {  0,  0,  0,  0,  0,  0,  0,  1,  1,  7,  8, 11, 12, -1, -1, -1, -1, -1, -1 },
      {  0,  0,  0,  0,  0,  0,  1,  3,  5,  7, 10, 12, 13, -1, -1, -1, -1, -1, -1 },
      {  0,  0,  0,  0,  1,  2,  2,  9, 13, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },

    // 3/0
    { {  0,  0,  0,  0,  0,  0,  0,  0,  2,  2,  6,  9, 11, 12, 13, -1, -1, -1, -1 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  2,  2,  6,  9, 11, 12, 13, -1, -1, -1, -1 },
      { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },

    // 2/1 - untested
    { {  0,  0,  0,  0,  0,  0,  0,  0,  2,  2,  6,  9, 11, 12, 13, -1, -1, -1, -1 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  2,  2,  6,  9, 11, 12, 13, -1, -1, -1, -1 },
      { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },

    // 3/1
    { {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  3,  2, 10, 11, 11, 12, 12, 14, -1 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  3,  2, 10, 11, 11, 12, 12, 14, -1 },
      { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },

    // 2/2 - untested
    { {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  3,  2, 10, 11, 11, 12, 12, 14, -1 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  3,  2, 10, 11, 11, 12, 12, 14, -1 },
      { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },

    // 3/2
    { {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  6,  8, 11, 12, 12, -1, -1 },
      {  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  1,  6,  8, 11, 12, 12, -1, -1 },
      { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
};


175 176
/**
 * Adjust the frame size to make the average bit rate match the target bit rate.
177
 * This is only needed for 11025, 22050, and 44100 sample rates or any E-AC-3.
Justin Ruggles's avatar
Justin Ruggles committed
178 179
 *
 * @param s  AC-3 encoder private context
180
 */
181
void ff_ac3_adjust_frame_size(AC3EncodeContext *s)
182 183 184 185 186
{
    while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
        s->bits_written    -= s->bit_rate;
        s->samples_written -= s->sample_rate;
    }
187 188
    s->frame_size = s->frame_size_min +
                    2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
189
    s->bits_written    += s->frame_size * 8;
190
    s->samples_written += AC3_BLOCK_SIZE * s->num_blocks;
191 192 193
}


Justin Ruggles's avatar
Justin Ruggles committed
194 195 196 197 198
/**
 * Set the initial coupling strategy parameters prior to coupling analysis.
 *
 * @param s  AC-3 encoder private context
 */
199
void ff_ac3_compute_coupling_strategy(AC3EncodeContext *s)
200 201 202
{
    int blk, ch;
    int got_cpl_snr;
203
    int num_cpl_blocks;
204 205 206

    /* set coupling use flags for each block/channel */
    /* TODO: turn coupling on/off and adjust start band based on bit usage */
207
    for (blk = 0; blk < s->num_blocks; blk++) {
208 209 210 211 212 213 214 215
        AC3Block *block = &s->blocks[blk];
        for (ch = 1; ch <= s->fbw_channels; ch++)
            block->channel_in_cpl[ch] = s->cpl_on;
    }

    /* enable coupling for each block if at least 2 channels have coupling
       enabled for that block */
    got_cpl_snr = 0;
216
    num_cpl_blocks = 0;
217
    for (blk = 0; blk < s->num_blocks; blk++) {
218 219 220 221 222
        AC3Block *block = &s->blocks[blk];
        block->num_cpl_channels = 0;
        for (ch = 1; ch <= s->fbw_channels; ch++)
            block->num_cpl_channels += block->channel_in_cpl[ch];
        block->cpl_in_use = block->num_cpl_channels > 1;
223
        num_cpl_blocks += block->cpl_in_use;
224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248
        if (!block->cpl_in_use) {
            block->num_cpl_channels = 0;
            for (ch = 1; ch <= s->fbw_channels; ch++)
                block->channel_in_cpl[ch] = 0;
        }

        block->new_cpl_strategy = !blk;
        if (blk) {
            for (ch = 1; ch <= s->fbw_channels; ch++) {
                if (block->channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
                    block->new_cpl_strategy = 1;
                    break;
                }
            }
        }
        block->new_cpl_leak = block->new_cpl_strategy;

        if (!blk || (block->cpl_in_use && !got_cpl_snr)) {
            block->new_snr_offsets = 1;
            if (block->cpl_in_use)
                got_cpl_snr = 1;
        } else {
            block->new_snr_offsets = 0;
        }
    }
249 250
    if (!num_cpl_blocks)
        s->cpl_on = 0;
251 252

    /* set bandwidth for each channel */
253
    for (blk = 0; blk < s->num_blocks; blk++) {
254 255 256 257 258 259 260 261 262 263 264
        AC3Block *block = &s->blocks[blk];
        for (ch = 1; ch <= s->fbw_channels; ch++) {
            if (block->channel_in_cpl[ch])
                block->end_freq[ch] = s->start_freq[CPL_CH];
            else
                block->end_freq[ch] = s->bandwidth_code * 3 + 73;
        }
    }
}


265 266
/**
 * Apply stereo rematrixing to coefficients based on rematrixing flags.
Justin Ruggles's avatar
Justin Ruggles committed
267 268
 *
 * @param s  AC-3 encoder private context
269
 */
270
void ff_ac3_apply_rematrixing(AC3EncodeContext *s)
271 272 273 274
{
    int nb_coefs;
    int blk, bnd, i;
    int start, end;
275
    uint8_t *flags = NULL;
276

277
    if (!s->rematrixing_enabled)
278 279
        return;

280
    for (blk = 0; blk < s->num_blocks; blk++) {
281 282 283
        AC3Block *block = &s->blocks[blk];
        if (block->new_rematrixing_strategy)
            flags = block->rematrixing_flags;
284 285
        nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]);
        for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) {
286 287 288 289
            if (flags[bnd]) {
                start = ff_ac3_rematrix_band_tab[bnd];
                end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
                for (i = start; i < end; i++) {
290 291 292 293
                    int32_t lt = block->fixed_coef[1][i];
                    int32_t rt = block->fixed_coef[2][i];
                    block->fixed_coef[1][i] = (lt + rt) >> 1;
                    block->fixed_coef[2][i] = (lt - rt) >> 1;
294 295 296 297 298 299 300
                }
            }
        }
    }
}


Justin Ruggles's avatar
Justin Ruggles committed
301
/*
302 303 304 305
 * Initialize exponent tables.
 */
static av_cold void exponent_init(AC3EncodeContext *s)
{
306 307 308 309
    int expstr, i, grpsize;

    for (expstr = EXP_D15-1; expstr <= EXP_D45-1; expstr++) {
        grpsize = 3 << expstr;
310 311 312
        for (i = 12; i < 256; i++) {
            exponent_group_tab[0][expstr][i] = (i + grpsize - 4) / grpsize;
            exponent_group_tab[1][expstr][i] = (i              ) / grpsize;
313
        }
314
    }
315
    /* LFE */
316
    exponent_group_tab[0][0][7] = 2;
317 318 319

    if (CONFIG_EAC3_ENCODER && s->eac3)
        ff_eac3_exponent_init();
320 321 322
}


Justin Ruggles's avatar
Justin Ruggles committed
323
/*
324 325
 * Extract exponents from the MDCT coefficients.
 */
326
static void extract_exponents(AC3EncodeContext *s)
327
{
328
    int ch        = !s->cpl_on;
329
    int chan_size = AC3_MAX_COEFS * s->num_blocks * (s->channels - ch + 1);
330
    AC3Block *block = &s->blocks[0];
331

332
    s->ac3dsp.extract_exponents(block->exp[ch], block->fixed_coef[ch], chan_size);
333 334 335
}


336 337 338 339
/**
 * Exponent Difference Threshold.
 * New exponents are sent if their SAD exceed this number.
 */
340
#define EXP_DIFF_THRESHOLD 500
341

342 343 344 345 346 347 348 349 350
/**
 * Table used to select exponent strategy based on exponent reuse block interval.
 */
static const uint8_t exp_strategy_reuse_tab[4][6] = {
    { EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
    { EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
    { EXP_D25, EXP_D25, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
    { EXP_D45, EXP_D25, EXP_D25, EXP_D15, EXP_D15, EXP_D15 }
};
351

Justin Ruggles's avatar
Justin Ruggles committed
352
/*
353
 * Calculate exponent strategies for all channels.
354
 * Array arrangement is reversed to simplify the per-channel calculation.
355
 */
356
static void compute_exp_strategy(AC3EncodeContext *s)
357
{
358
    int ch, blk, blk1;
359

360
    for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
361 362 363 364 365 366 367 368
        uint8_t *exp_strategy = s->exp_strategy[ch];
        uint8_t *exp          = s->blocks[0].exp[ch];
        int exp_diff;

        /* estimate if the exponent variation & decide if they should be
           reused in the next frame */
        exp_strategy[0] = EXP_NEW;
        exp += AC3_MAX_COEFS;
369
        for (blk = 1; blk < s->num_blocks; blk++, exp += AC3_MAX_COEFS) {
370 371 372 373 374 375 376 377 378
            if (ch == CPL_CH) {
                if (!s->blocks[blk-1].cpl_in_use) {
                    exp_strategy[blk] = EXP_NEW;
                    continue;
                } else if (!s->blocks[blk].cpl_in_use) {
                    exp_strategy[blk] = EXP_REUSE;
                    continue;
                }
            } else if (s->blocks[blk].channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
379 380 381
                exp_strategy[blk] = EXP_NEW;
                continue;
            }
382
            exp_diff = s->dsp.sad[0](NULL, exp, exp - AC3_MAX_COEFS, 16, 16);
383 384 385 386
            exp_strategy[blk] = EXP_REUSE;
            if (ch == CPL_CH && exp_diff > (EXP_DIFF_THRESHOLD * (s->blocks[blk].end_freq[ch] - s->start_freq[ch]) / AC3_MAX_COEFS))
                exp_strategy[blk] = EXP_NEW;
            else if (ch > CPL_CH && exp_diff > EXP_DIFF_THRESHOLD)
387 388 389 390 391 392
                exp_strategy[blk] = EXP_NEW;
        }

        /* now select the encoding strategy type : if exponents are often
           recoded, we use a coarse encoding */
        blk = 0;
393
        while (blk < s->num_blocks) {
394
            blk1 = blk + 1;
395
            while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE)
396
                blk1++;
397
            exp_strategy[blk] = exp_strategy_reuse_tab[s->num_blks_code][blk1-blk-1];
398 399
            blk = blk1;
        }
400 401 402
    }
    if (s->lfe_on) {
        ch = s->lfe_channel;
403
        s->exp_strategy[ch][0] = EXP_D15;
404
        for (blk = 1; blk < s->num_blocks; blk++)
405
            s->exp_strategy[ch][blk] = EXP_REUSE;
406
    }
407 408 409 410

    /* for E-AC-3, determine frame exponent strategy */
    if (CONFIG_EAC3_ENCODER && s->eac3)
        ff_eac3_get_frame_exp_strategy(s);
411 412 413
}


414 415
/**
 * Update the exponents so that they are the ones the decoder will decode.
Justin Ruggles's avatar
Justin Ruggles committed
416 417 418 419 420
 *
 * @param[in,out] exp   array of exponents for 1 block in 1 channel
 * @param nb_exps       number of exponents in active bandwidth
 * @param exp_strategy  exponent strategy for the block
 * @param cpl           indicates if the block is in the coupling channel
421
 */
422 423
static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy,
                                    int cpl)
Fabrice Bellard's avatar
Fabrice Bellard committed
424
{
425
    int nb_groups, i, k;
Fabrice Bellard's avatar
Fabrice Bellard committed
426

427
    nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_exps] * 3;
Fabrice Bellard's avatar
Fabrice Bellard committed
428 429

    /* for each group, compute the minimum exponent */
430 431
    switch(exp_strategy) {
    case EXP_D25:
432
        for (i = 1, k = 1-cpl; i <= nb_groups; i++) {
433 434 435
            uint8_t exp_min = exp[k];
            if (exp[k+1] < exp_min)
                exp_min = exp[k+1];
436
            exp[i-cpl] = exp_min;
437
            k += 2;
Fabrice Bellard's avatar
Fabrice Bellard committed
438
        }
439 440
        break;
    case EXP_D45:
441
        for (i = 1, k = 1-cpl; i <= nb_groups; i++) {
442 443 444 445 446 447 448
            uint8_t exp_min = exp[k];
            if (exp[k+1] < exp_min)
                exp_min = exp[k+1];
            if (exp[k+2] < exp_min)
                exp_min = exp[k+2];
            if (exp[k+3] < exp_min)
                exp_min = exp[k+3];
449
            exp[i-cpl] = exp_min;
450 451 452
            k += 4;
        }
        break;
453
    }
Fabrice Bellard's avatar
Fabrice Bellard committed
454 455

    /* constraint for DC exponent */
456
    if (!cpl && exp[0] > 15)
457
        exp[0] = 15;
Fabrice Bellard's avatar
Fabrice Bellard committed
458

459 460 461
    /* decrease the delta between each groups to within 2 so that they can be
       differentially encoded */
    for (i = 1; i <= nb_groups; i++)
462
        exp[i] = FFMIN(exp[i], exp[i-1] + 2);
463 464
    i--;
    while (--i >= 0)
465
        exp[i] = FFMIN(exp[i], exp[i+1] + 2);
466

467 468 469
    if (cpl)
        exp[-1] = exp[0] & ~1;

Fabrice Bellard's avatar
Fabrice Bellard committed
470
    /* now we have the exponent values the decoder will see */
471 472
    switch (exp_strategy) {
    case EXP_D25:
473 474
        for (i = nb_groups, k = (nb_groups * 2)-cpl; i > 0; i--) {
            uint8_t exp1 = exp[i-cpl];
475 476 477 478 479
            exp[k--] = exp1;
            exp[k--] = exp1;
        }
        break;
    case EXP_D45:
480 481
        for (i = nb_groups, k = (nb_groups * 4)-cpl; i > 0; i--) {
            exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i-cpl];
482 483 484
            k -= 4;
        }
        break;
Fabrice Bellard's avatar
Fabrice Bellard committed
485 486 487
    }
}

488

Justin Ruggles's avatar
Justin Ruggles committed
489
/*
490 491 492 493 494
 * Encode exponents from original extracted form to what the decoder will see.
 * This copies and groups exponents based on exponent strategy and reduces
 * deltas between adjacent exponent groups so that they can be differentially
 * encoded.
 */
495
static void encode_exponents(AC3EncodeContext *s)
496
{
497
    int blk, blk1, ch, cpl;
498
    uint8_t *exp, *exp_strategy;
499
    int nb_coefs, num_reuse_blocks;
500

501 502
    for (ch = !s->cpl_on; ch <= s->channels; ch++) {
        exp          = s->blocks[0].exp[ch] + s->start_freq[ch];
503 504
        exp_strategy = s->exp_strategy[ch];

505
        cpl = (ch == CPL_CH);
506
        blk = 0;
507
        while (blk < s->num_blocks) {
508 509 510 511 512 513 514
            AC3Block *block = &s->blocks[blk];
            if (cpl && !block->cpl_in_use) {
                exp += AC3_MAX_COEFS;
                blk++;
                continue;
            }
            nb_coefs = block->end_freq[ch] - s->start_freq[ch];
515
            blk1 = blk + 1;
516

517
            /* count the number of EXP_REUSE blocks after the current block
518 519
               and set exponent reference block numbers */
            s->exp_ref_block[ch][blk] = blk;
520
            while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE) {
521
                s->exp_ref_block[ch][blk1] = blk;
522
                blk1++;
523
            }
524 525 526
            num_reuse_blocks = blk1 - blk - 1;

            /* for the EXP_REUSE case we select the min of the exponents */
527 528
            s->ac3dsp.ac3_exponent_min(exp-s->start_freq[ch], num_reuse_blocks,
                                       AC3_MAX_COEFS);
529

530
            encode_exponents_blk_ch(exp, nb_coefs, exp_strategy[blk], cpl);
531

532
            exp += AC3_MAX_COEFS * (num_reuse_blocks + 1);
533 534 535
            blk = blk1;
        }
    }
536 537 538

    /* reference block numbers have been changed, so reset ref_bap_set */
    s->ref_bap_set = 0;
539 540 541
}


Justin Ruggles's avatar
Justin Ruggles committed
542
/*
543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569
 * Count exponent bits based on bandwidth, coupling, and exponent strategies.
 */
static int count_exponent_bits(AC3EncodeContext *s)
{
    int blk, ch;
    int nb_groups, bit_count;

    bit_count = 0;
    for (blk = 0; blk < s->num_blocks; blk++) {
        AC3Block *block = &s->blocks[blk];
        for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
            int exp_strategy = s->exp_strategy[ch][blk];
            int cpl          = (ch == CPL_CH);
            int nb_coefs     = block->end_freq[ch] - s->start_freq[ch];

            if (exp_strategy == EXP_REUSE)
                continue;

            nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_coefs];
            bit_count += 4 + (nb_groups * 7);
        }
    }

    return bit_count;
}


570 571 572 573
/**
 * Group exponents.
 * 3 delta-encoded exponents are in each 7-bit group. The number of groups
 * varies depending on exponent strategy and bandwidth.
Justin Ruggles's avatar
Justin Ruggles committed
574 575
 *
 * @param s  AC-3 encoder private context
576
 */
577
void ff_ac3_group_exponents(AC3EncodeContext *s)
578
{
579
    int blk, ch, i, cpl;
580
    int group_size, nb_groups;
581 582 583 584
    uint8_t *p;
    int delta0, delta1, delta2;
    int exp0, exp1;

585
    for (blk = 0; blk < s->num_blocks; blk++) {
586
        AC3Block *block = &s->blocks[blk];
587
        for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
588 589
            int exp_strategy = s->exp_strategy[ch][blk];
            if (exp_strategy == EXP_REUSE)
590
                continue;
591
            cpl = (ch == CPL_CH);
592
            group_size = exp_strategy + (exp_strategy == EXP_D45);
593 594
            nb_groups = exponent_group_tab[cpl][exp_strategy-1][block->end_freq[ch]-s->start_freq[ch]];
            p = block->exp[ch] + s->start_freq[ch] - cpl;
595 596 597

            /* DC exponent */
            exp1 = *p++;
598
            block->grouped_exp[ch][0] = exp1;
599 600

            /* remaining exponents are delta encoded */
601
            for (i = 1; i <= nb_groups; i++) {
602 603 604 605 606
                /* merge three delta in one code */
                exp0   = exp1;
                exp1   = p[0];
                p     += group_size;
                delta0 = exp1 - exp0 + 2;
607
                av_assert2(delta0 >= 0 && delta0 <= 4);
608 609 610 611 612

                exp0   = exp1;
                exp1   = p[0];
                p     += group_size;
                delta1 = exp1 - exp0 + 2;
613
                av_assert2(delta1 >= 0 && delta1 <= 4);
614 615 616 617 618

                exp0   = exp1;
                exp1   = p[0];
                p     += group_size;
                delta2 = exp1 - exp0 + 2;
619
                av_assert2(delta2 >= 0 && delta2 <= 4);
620

621
                block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
622 623 624
            }
        }
    }
625 626 627 628 629 630 631
}


/**
 * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
 * Extract exponents from MDCT coefficients, calculate exponent strategies,
 * and encode final exponents.
Justin Ruggles's avatar
Justin Ruggles committed
632 633
 *
 * @param s  AC-3 encoder private context
634
 */
635
void ff_ac3_process_exponents(AC3EncodeContext *s)
636
{
637
    extract_exponents(s);
638

639
    compute_exp_strategy(s);
640

641
    encode_exponents(s);
642

643
    emms_c();
644 645 646
}


Justin Ruggles's avatar
Justin Ruggles committed
647
/*
648 649 650 651 652 653 654 655 656 657 658 659 660 661
 * Count frame bits that are based solely on fixed parameters.
 * This only has to be run once when the encoder is initialized.
 */
static void count_frame_bits_fixed(AC3EncodeContext *s)
{
    static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
    int blk;
    int frame_bits;

    /* assumptions:
     *   no dynamic range codes
     *   bit allocation parameters do not change between blocks
     *   no delta bit allocation
     *   no skipped data
Diego Biurrun's avatar
Diego Biurrun committed
662
     *   no auxiliary data
663
     *   no E-AC-3 metadata
664 665
     */

666
    /* header */
667 668 669 670
    frame_bits = 16; /* sync info */
    if (s->eac3) {
        /* bitstream info header */
        frame_bits += 35;
671 672 673 674
        frame_bits += 1 + 1;
        if (s->num_blocks != 0x6)
            frame_bits++;
        frame_bits++;
675
        /* audio frame header */
676 677
        if (s->num_blocks == 6)
            frame_bits += 2;
678 679
        frame_bits += 10;
        /* exponent strategy */
680 681 682
        if (s->use_frame_exp_strategy)
            frame_bits += 5 * s->fbw_channels;
        else
683
            frame_bits += s->num_blocks * 2 * s->fbw_channels;
684
        if (s->lfe_on)
685
            frame_bits += s->num_blocks;
686
        /* converter exponent strategy */
687 688 689 690
        if (s->num_blks_code != 0x3)
            frame_bits++;
        else
            frame_bits += s->fbw_channels * 5;
691 692 693
        /* snr offsets */
        frame_bits += 10;
        /* block start info */
694 695
        if (s->num_blocks != 1)
            frame_bits++;
696 697 698 699
    } else {
        frame_bits += 49;
        frame_bits += frame_bits_inc[s->channel_mode];
    }
700 701

    /* audio blocks */
702
    for (blk = 0; blk < s->num_blocks; blk++) {
703
        if (!s->eac3) {
704 705
            /* block switch flags */
            frame_bits += s->fbw_channels;
706

707 708
            /* dither flags */
            frame_bits += s->fbw_channels;
709
        }
710 711 712 713

        /* dynamic range */
        frame_bits++;

714 715
        /* spectral extension */
        if (s->eac3)
716 717
            frame_bits++;

718
        if (!s->eac3) {
719 720 721 722
            /* exponent strategy */
            frame_bits += 2 * s->fbw_channels;
            if (s->lfe_on)
                frame_bits++;
723

724 725 726 727
            /* bit allocation params */
            frame_bits++;
            if (!blk)
                frame_bits += 2 + 2 + 2 + 2 + 3;
728
        }
729

730 731 732 733 734
        /* converter snr offset */
        if (s->eac3)
            frame_bits++;

        if (!s->eac3) {
735 736
            /* delta bit allocation */
            frame_bits++;
737

738 739
            /* skipped data */
            frame_bits++;
740
        }
741 742
    }

743 744
    /* auxiliary data */
    frame_bits++;
745 746

    /* CRC */
747
    frame_bits += 1 + 16;
748 749 750 751 752

    s->frame_bits_fixed = frame_bits;
}


Justin Ruggles's avatar
Justin Ruggles committed
753
/*
754 755 756 757 758 759 760 761 762 763 764
 * Initialize bit allocation.
 * Set default parameter codes and calculate parameter values.
 */
static void bit_alloc_init(AC3EncodeContext *s)
{
    int ch;

    /* init default parameters */
    s->slow_decay_code = 2;
    s->fast_decay_code = 1;
    s->slow_gain_code  = 1;
765
    s->db_per_bit_code = s->eac3 ? 2 : 3;
766
    s->floor_code      = 7;
767
    for (ch = 0; ch <= s->channels; ch++)
768 769 770 771 772 773 774 775 776 777 778 779 780
        s->fast_gain_code[ch] = 4;

    /* initial snr offset */
    s->coarse_snr_offset = 40;

    /* compute real values */
    /* currently none of these values change during encoding, so we can just
       set them once at initialization */
    s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
    s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
    s->bit_alloc.slow_gain  = ff_ac3_slow_gain_tab[s->slow_gain_code];
    s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
    s->bit_alloc.floor      = ff_ac3_floor_tab[s->floor_code];
781 782
    s->bit_alloc.cpl_fast_leak = 0;
    s->bit_alloc.cpl_slow_leak = 0;
783 784

    count_frame_bits_fixed(s);
785 786 787
}


Justin Ruggles's avatar
Justin Ruggles committed
788
/*
789
 * Count the bits used to encode the frame, minus exponents and mantissas.
790 791
 * Bits based on fixed parameters have already been counted, so now we just
 * have to add the bits based on parameters that change during encoding.
792
 */
793
static void count_frame_bits(AC3EncodeContext *s)
794
{
795
    AC3EncOptions *opt = &s->options;
796
    int blk, ch;
797
    int frame_bits = 0;
798

799
    /* header */
800
    if (s->eac3) {
801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824
        if (opt->eac3_mixing_metadata) {
            if (s->channel_mode > AC3_CHMODE_STEREO)
                frame_bits += 2;
            if (s->has_center)
                frame_bits += 6;
            if (s->has_surround)
                frame_bits += 6;
            frame_bits += s->lfe_on;
            frame_bits += 1 + 1 + 2;
            if (s->channel_mode < AC3_CHMODE_STEREO)
                frame_bits++;
            frame_bits++;
        }
        if (opt->eac3_info_metadata) {
            frame_bits += 3 + 1 + 1;
            if (s->channel_mode == AC3_CHMODE_STEREO)
                frame_bits += 2 + 2;
            if (s->channel_mode >= AC3_CHMODE_2F2R)
                frame_bits += 2;
            frame_bits++;
            if (opt->audio_production_info)
                frame_bits += 5 + 2 + 1;
            frame_bits++;
        }
825 826 827
        /* coupling */
        if (s->channel_mode > AC3_CHMODE_MONO) {
            frame_bits++;
828
            for (blk = 1; blk < s->num_blocks; blk++) {
829 830 831 832 833 834 835
                AC3Block *block = &s->blocks[blk];
                frame_bits++;
                if (block->new_cpl_strategy)
                    frame_bits++;
            }
        }
        /* coupling exponent strategy */
836 837 838 839
        if (s->cpl_on) {
            if (s->use_frame_exp_strategy) {
                frame_bits += 5 * s->cpl_on;
            } else {
840
                for (blk = 0; blk < s->num_blocks; blk++)
841 842 843
                    frame_bits += 2 * s->blocks[blk].cpl_in_use;
            }
        }
844
    } else {
845 846 847 848 849 850 851 852
        if (opt->audio_production_info)
            frame_bits += 7;
        if (s->bitstream_id == 6) {
            if (opt->extended_bsi_1)
                frame_bits += 14;
            if (opt->extended_bsi_2)
                frame_bits += 14;
        }
853 854
    }

855
    /* audio blocks */
856
    for (blk = 0; blk < s->num_blocks; blk++) {
857 858 859
        AC3Block *block = &s->blocks[blk];

        /* coupling strategy */
860
        if (!s->eac3)
861 862
            frame_bits++;
        if (block->new_cpl_strategy) {
863
            if (!s->eac3)
864
                frame_bits++;
865
            if (block->cpl_in_use) {
866 867 868
                if (s->eac3)
                    frame_bits++;
                if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO)
869
                    frame_bits += s->fbw_channels;
870 871 872
                if (s->channel_mode == AC3_CHMODE_STEREO)
                    frame_bits++;
                frame_bits += 4 + 4;
873 874 875
                if (s->eac3)
                    frame_bits++;
                else
876
                    frame_bits += s->num_cpl_subbands - 1;
877 878 879 880 881 882 883
            }
        }

        /* coupling coordinates */
        if (block->cpl_in_use) {
            for (ch = 1; ch <= s->fbw_channels; ch++) {
                if (block->channel_in_cpl[ch]) {
884
                    if (!s->eac3 || block->new_cpl_coords[ch] != 2)
885
                        frame_bits++;
886
                    if (block->new_cpl_coords[ch]) {
887 888 889 890 891 892 893
                        frame_bits += 2;
                        frame_bits += (4 + 4) * s->num_cpl_bands;
                    }
                }
            }
        }

894
        /* stereo rematrixing */
895
        if (s->channel_mode == AC3_CHMODE_STEREO) {
896
            if (!s->eac3 || blk > 0)
897
                frame_bits++;
898
            if (s->blocks[blk].new_rematrixing_strategy)
899
                frame_bits += block->num_rematrixing_bands;
900 901
        }

902
        /* bandwidth codes & gain range */
903 904 905 906 907 908 909 910 911
        for (ch = 1; ch <= s->fbw_channels; ch++) {
            if (s->exp_strategy[ch][blk] != EXP_REUSE) {
                if (!block->channel_in_cpl[ch])
                    frame_bits += 6;
                frame_bits += 2;
            }
        }

        /* coupling exponent strategy */
912
        if (!s->eac3 && block->cpl_in_use)
913 914 915
            frame_bits += 2;

        /* snr offsets and fast gain codes */
916
        if (!s->eac3) {
917 918 919
            frame_bits++;
            if (block->new_snr_offsets)
                frame_bits += 6 + (s->channels + block->cpl_in_use) * (4 + 3);
920
        }
921 922 923

        /* coupling leak info */
        if (block->cpl_in_use) {
924
            if (!s->eac3 || block->new_cpl_leak != 2)
925
                frame_bits++;
926 927
            if (block->new_cpl_leak)
                frame_bits += 3 + 3;
928 929
        }
    }
930

931
    s->frame_bits = s->frame_bits_fixed + frame_bits;
932 933 934
}


Justin Ruggles's avatar
Justin Ruggles committed
935
/*
936 937 938
 * Calculate masking curve based on the final exponents.
 * Also calculate the power spectral densities to use in future calculations.
 */
939
static void bit_alloc_masking(AC3EncodeContext *s)
940 941 942
{
    int blk, ch;

943
    for (blk = 0; blk < s->num_blocks; blk++) {
944
        AC3Block *block = &s->blocks[blk];
945
        for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
946 947 948
            /* We only need psd and mask for calculating bap.
               Since we currently do not calculate bap when exponent
               strategy is EXP_REUSE we do not need to calculate psd or mask. */
949
            if (s->exp_strategy[ch][blk] != EXP_REUSE) {
950 951 952
                ff_ac3_bit_alloc_calc_psd(block->exp[ch], s->start_freq[ch],
                                          block->end_freq[ch], block->psd[ch],
                                          block->band_psd[ch]);
953
                ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
954
                                           s->start_freq[ch], block->end_freq[ch],
955
                                           ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
956
                                           ch == s->lfe_channel,
957
                                           DBA_NONE, 0, NULL, NULL, NULL,
958
                                           block->mask[ch]);
959 960 961 962 963
            }
        }
    }
}

964

Justin Ruggles's avatar
Justin Ruggles committed
965
/*
966 967 968 969 970 971
 * Ensure that bap for each block and channel point to the current bap_buffer.
 * They may have been switched during the bit allocation search.
 */
static void reset_block_bap(AC3EncodeContext *s)
{
    int blk, ch;
972 973 974
    uint8_t *ref_bap;

    if (s->ref_bap[0][0] == s->bap_buffer && s->ref_bap_set)
975
        return;
976 977 978

    ref_bap = s->bap_buffer;
    for (ch = 0; ch <= s->channels; ch++) {
979
        for (blk = 0; blk < s->num_blocks; blk++)
980
            s->ref_bap[ch][blk] = ref_bap + AC3_MAX_COEFS * s->exp_ref_block[ch][blk];
981
        ref_bap += AC3_MAX_COEFS * s->num_blocks;
982
    }
983
    s->ref_bap_set = 1;
984 985 986
}


987 988 989 990
/**
 * Initialize mantissa counts.
 * These are set so that they are padded to the next whole group size when bits
 * are counted in compute_mantissa_size.
Justin Ruggles's avatar
Justin Ruggles committed
991 992
 *
 * @param[in,out] mant_cnt  running counts for each bap value for each block
993 994
 */
static void count_mantissa_bits_init(uint16_t mant_cnt[AC3_MAX_BLOCKS][16])
Fabrice Bellard's avatar
Fabrice Bellard committed
995
{
996 997
    int blk;

998
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
999 1000 1001 1002 1003 1004 1005 1006 1007 1008
        memset(mant_cnt[blk], 0, sizeof(mant_cnt[blk]));
        mant_cnt[blk][1] = mant_cnt[blk][2] = 2;
        mant_cnt[blk][4] = 1;
    }
}


/**
 * Update mantissa bit counts for all blocks in 1 channel in a given bandwidth
 * range.
Justin Ruggles's avatar
Justin Ruggles committed
1009 1010 1011 1012 1013 1014
 *
 * @param s                 AC-3 encoder private context
 * @param ch                channel index
 * @param[in,out] mant_cnt  running counts for each bap value for each block
 * @param start             starting coefficient bin
 * @param end               ending coefficient bin
1015 1016 1017 1018 1019 1020
 */
static void count_mantissa_bits_update_ch(AC3EncodeContext *s, int ch,
                                          uint16_t mant_cnt[AC3_MAX_BLOCKS][16],
                                          int start, int end)
{
    int blk;
Justin Ruggles's avatar
Justin Ruggles committed
1021

1022
    for (blk = 0; blk < s->num_blocks; blk++) {
1023
        AC3Block *block = &s->blocks[blk];
1024 1025 1026 1027 1028
        if (ch == CPL_CH && !block->cpl_in_use)
            continue;
        s->ac3dsp.update_bap_counts(mant_cnt[blk],
                                    s->ref_bap[ch][blk] + start,
                                    FFMIN(end, block->end_freq[ch]) - start);
1029 1030 1031 1032
    }
}


Justin Ruggles's avatar
Justin Ruggles committed
1033
/*
1034 1035 1036 1037 1038
 * Count the number of mantissa bits in the frame based on the bap values.
 */
static int count_mantissa_bits(AC3EncodeContext *s)
{
    int ch, max_end_freq;
1039
    LOCAL_ALIGNED_16(uint16_t, mant_cnt, [AC3_MAX_BLOCKS], [16]);
1040 1041 1042 1043 1044 1045 1046 1047 1048

    count_mantissa_bits_init(mant_cnt);

    max_end_freq = s->bandwidth_code * 3 + 73;
    for (ch = !s->cpl_enabled; ch <= s->channels; ch++)
        count_mantissa_bits_update_ch(s, ch, mant_cnt, s->start_freq[ch],
                                      max_end_freq);

    return s->ac3dsp.compute_mantissa_size(mant_cnt);
1049
}
1050

1051

1052 1053 1054 1055
/**
 * Run the bit allocation with a given SNR offset.
 * This calculates the bit allocation pointers that will be used to determine
 * the quantization of each mantissa.
Justin Ruggles's avatar
Justin Ruggles committed
1056 1057 1058
 *
 * @param s           AC-3 encoder private context
 * @param snr_offset  SNR offset, 0 to 1023
1059 1060
 * @return the number of bits needed for mantissas if the given SNR offset is
 *         is used.
1061
 */
1062
static int bit_alloc(AC3EncodeContext *s, int snr_offset)
Fabrice Bellard's avatar
Fabrice Bellard committed
1063
{
1064
    int blk, ch;
Justin Ruggles's avatar
Justin Ruggles committed
1065

1066
    snr_offset = (snr_offset - 240) << 2;
Fabrice Bellard's avatar
Fabrice Bellard committed
1067

1068
    reset_block_bap(s);
1069
    for (blk = 0; blk < s->num_blocks; blk++) {
1070
        AC3Block *block = &s->blocks[blk];
1071

1072
        for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1073 1074 1075 1076
            /* Currently the only bit allocation parameters which vary across
               blocks within a frame are the exponent values.  We can take
               advantage of that by reusing the bit allocation pointers
               whenever we reuse exponents. */
1077
            if (s->exp_strategy[ch][blk] != EXP_REUSE) {
1078
                s->ac3dsp.bit_alloc_calc_bap(block->mask[ch], block->psd[ch],
1079 1080
                                             s->start_freq[ch], block->end_freq[ch],
                                             snr_offset, s->bit_alloc.floor,
1081
                                             ff_ac3_bap_tab, s->ref_bap[ch][blk]);
1082
            }
Fabrice Bellard's avatar
Fabrice Bellard committed
1083 1084
        }
    }
1085
    return count_mantissa_bits(s);
Fabrice Bellard's avatar
Fabrice Bellard committed
1086 1087
}

1088

Justin Ruggles's avatar
Justin Ruggles committed
1089
/*
1090 1091
 * Constant bitrate bit allocation search.
 * Find the largest SNR offset that will allow data to fit in the frame.
1092
 */
1093
static int cbr_bit_allocation(AC3EncodeContext *s)
Fabrice Bellard's avatar
Fabrice Bellard committed
1094
{
1095
    int ch;
1096
    int bits_left;
1097
    int snr_offset, snr_incr;
Fabrice Bellard's avatar
Fabrice Bellard committed
1098

1099
    bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
1100 1101
    if (bits_left < 0)
        return AVERROR(EINVAL);
1102

1103
    snr_offset = s->coarse_snr_offset << 4;
1104

1105 1106
    /* if previous frame SNR offset was 1023, check if current frame can also
       use SNR offset of 1023. if so, skip the search. */
1107
    if ((snr_offset | s->fine_snr_offset[1]) == 1023) {
1108 1109 1110 1111
        if (bit_alloc(s, 1023) <= bits_left)
            return 0;
    }

1112
    while (snr_offset >= 0 &&
1113
           bit_alloc(s, snr_offset) > bits_left) {
1114
        snr_offset -= 64;
1115
    }
1116
    if (snr_offset < 0)
1117
        return AVERROR(EINVAL);
1118

1119
    FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
1120
    for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
1121
        while (snr_offset + snr_incr <= 1023 &&
1122 1123 1124 1125
               bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
            snr_offset += snr_incr;
            FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
        }
Fabrice Bellard's avatar
Fabrice Bellard committed
1126
    }
1127 1128
    FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
    reset_block_bap(s);
1129

1130
    s->coarse_snr_offset = snr_offset >> 4;
1131
    for (ch = !s->cpl_on; ch <= s->channels; ch++)
1132
        s->fine_snr_offset[ch] = snr_offset & 0xF;
1133

Fabrice Bellard's avatar
Fabrice Bellard committed
1134 1135 1136
    return 0;
}

1137

Justin Ruggles's avatar
Justin Ruggles committed
1138
/*
1139 1140 1141 1142 1143
 * Perform bit allocation search.
 * Finds the SNR offset value that maximizes quality and fits in the specified
 * frame size.  Output is the SNR offset and a set of bit allocation pointers
 * used to quantize the mantissas.
 */
1144
int ff_ac3_compute_bit_allocation(AC3EncodeContext *s)
1145 1146 1147
{
    count_frame_bits(s);

1148 1149
    s->exponent_bits = count_exponent_bits(s);

1150 1151
    bit_alloc_masking(s);

1152
    return cbr_bit_allocation(s);
1153 1154 1155
}


1156 1157
/**
 * Symmetric quantization on 'levels' levels.
Justin Ruggles's avatar
Justin Ruggles committed
1158 1159 1160 1161 1162
 *
 * @param c       unquantized coefficient
 * @param e       exponent
 * @param levels  number of quantization levels
 * @return        quantized coefficient
1163
 */
Fabrice Bellard's avatar
Fabrice Bellard committed
1164 1165
static inline int sym_quant(int c, int e, int levels)
{
1166
    int v = (((levels * c) >> (24 - e)) + levels) >> 1;
1167
    av_assert2(v >= 0 && v < levels);
Fabrice Bellard's avatar
Fabrice Bellard committed
1168 1169 1170
    return v;
}

1171

1172 1173
/**
 * Asymmetric quantization on 2^qbits levels.
Justin Ruggles's avatar
Justin Ruggles committed
1174 1175 1176 1177 1178
 *
 * @param c      unquantized coefficient
 * @param e      exponent
 * @param qbits  number of quantization bits
 * @return       quantized coefficient
1179
 */
Fabrice Bellard's avatar
Fabrice Bellard committed
1180 1181
static inline int asym_quant(int c, int e, int qbits)
{
1182
    int m;
1183

1184
    c = (((c << e) >> (24 - qbits)) + 1) >> 1;
Fabrice Bellard's avatar
Fabrice Bellard committed
1185
    m = (1 << (qbits-1));
1186 1187 1188 1189
    if (c >= m)
        c = m - 1;
    av_assert2(c >= -m);
    return c;
Fabrice Bellard's avatar
Fabrice Bellard committed
1190 1191
}

1192

1193 1194
/**
 * Quantize a set of mantissas for a single channel in a single block.
Justin Ruggles's avatar
Justin Ruggles committed
1195 1196 1197 1198 1199 1200 1201 1202
 *
 * @param s           Mantissa count context
 * @param fixed_coef  unquantized fixed-point coefficients
 * @param exp         exponents
 * @param bap         bit allocation pointer indices
 * @param[out] qmant  quantized coefficients
 * @param start_freq  starting coefficient bin
 * @param end_freq    ending coefficient bin
1203
 */
1204
static void quantize_mantissas_blk_ch(AC3Mant *s, int32_t *fixed_coef,
1205
                                      uint8_t *exp, uint8_t *bap,
1206
                                      int16_t *qmant, int start_freq,
1207
                                      int end_freq)
1208 1209 1210
{
    int i;

1211
    for (i = start_freq; i < end_freq; i++) {
1212
        int c = fixed_coef[i];
1213
        int e = exp[i];
1214 1215 1216
        int v = bap[i];
        if (v)
        switch (v) {
1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284
        case 1:
            v = sym_quant(c, e, 3);
            switch (s->mant1_cnt) {
            case 0:
                s->qmant1_ptr = &qmant[i];
                v = 9 * v;
                s->mant1_cnt = 1;
                break;
            case 1:
                *s->qmant1_ptr += 3 * v;
                s->mant1_cnt = 2;
                v = 128;
                break;
            default:
                *s->qmant1_ptr += v;
                s->mant1_cnt = 0;
                v = 128;
                break;
            }
            break;
        case 2:
            v = sym_quant(c, e, 5);
            switch (s->mant2_cnt) {
            case 0:
                s->qmant2_ptr = &qmant[i];
                v = 25 * v;
                s->mant2_cnt = 1;
                break;
            case 1:
                *s->qmant2_ptr += 5 * v;
                s->mant2_cnt = 2;
                v = 128;
                break;
            default:
                *s->qmant2_ptr += v;
                s->mant2_cnt = 0;
                v = 128;
                break;
            }
            break;
        case 3:
            v = sym_quant(c, e, 7);
            break;
        case 4:
            v = sym_quant(c, e, 11);
            switch (s->mant4_cnt) {
            case 0:
                s->qmant4_ptr = &qmant[i];
                v = 11 * v;
                s->mant4_cnt = 1;
                break;
            default:
                *s->qmant4_ptr += v;
                s->mant4_cnt = 0;
                v = 128;
                break;
            }
            break;
        case 5:
            v = sym_quant(c, e, 15);
            break;
        case 14:
            v = asym_quant(c, e, 14);
            break;
        case 15:
            v = asym_quant(c, e, 16);
            break;
        default:
1285
            v = asym_quant(c, e, v - 1);
1286 1287 1288 1289 1290 1291 1292 1293 1294
            break;
        }
        qmant[i] = v;
    }
}


/**
 * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
Justin Ruggles's avatar
Justin Ruggles committed
1295 1296
 *
 * @param s  AC-3 encoder private context
1297
 */
1298
void ff_ac3_quantize_mantissas(AC3EncodeContext *s)
1299
{
1300
    int blk, ch, ch0=0, got_cpl;
1301

1302
    for (blk = 0; blk < s->num_blocks; blk++) {
1303
        AC3Block *block = &s->blocks[blk];
1304
        AC3Mant m = { 0 };
1305

1306 1307 1308 1309 1310 1311 1312
        got_cpl = !block->cpl_in_use;
        for (ch = 1; ch <= s->channels; ch++) {
            if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
                ch0     = ch - 1;
                ch      = CPL_CH;
                got_cpl = 1;
            }
1313
            quantize_mantissas_blk_ch(&m, block->fixed_coef[ch],
1314 1315
                                      s->blocks[s->exp_ref_block[ch][blk]].exp[ch],
                                      s->ref_bap[ch][blk], block->qmant[ch],
1316 1317 1318
                                      s->start_freq[ch], block->end_freq[ch]);
            if (ch == CPL_CH)
                ch = ch0;
1319 1320 1321 1322 1323
        }
    }
}


Justin Ruggles's avatar
Justin Ruggles committed
1324
/*
1325 1326
 * Write the AC-3 frame header to the output bitstream.
 */
1327
static void ac3_output_frame_header(AC3EncodeContext *s)
1328
{
1329 1330
    AC3EncOptions *opt = &s->options;

1331 1332 1333 1334 1335 1336 1337 1338
    put_bits(&s->pb, 16, 0x0b77);   /* frame header */
    put_bits(&s->pb, 16, 0);        /* crc1: will be filled later */
    put_bits(&s->pb, 2,  s->bit_alloc.sr_code);
    put_bits(&s->pb, 6,  s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
    put_bits(&s->pb, 5,  s->bitstream_id);
    put_bits(&s->pb, 3,  s->bitstream_mode);
    put_bits(&s->pb, 3,  s->channel_mode);
    if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
1339
        put_bits(&s->pb, 2, s->center_mix_level);
1340
    if (s->channel_mode & 0x04)
1341
        put_bits(&s->pb, 2, s->surround_mix_level);
1342
    if (s->channel_mode == AC3_CHMODE_STEREO)
1343
        put_bits(&s->pb, 2, opt->dolby_surround_mode);
1344
    put_bits(&s->pb, 1, s->lfe_on); /* LFE */
1345
    put_bits(&s->pb, 5, -opt->dialogue_level);
1346 1347
    put_bits(&s->pb, 1, 0);         /* no compression control word */
    put_bits(&s->pb, 1, 0);         /* no lang code */
1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372
    put_bits(&s->pb, 1, opt->audio_production_info);
    if (opt->audio_production_info) {
        put_bits(&s->pb, 5, opt->mixing_level - 80);
        put_bits(&s->pb, 2, opt->room_type);
    }
    put_bits(&s->pb, 1, opt->copyright);
    put_bits(&s->pb, 1, opt->original);
    if (s->bitstream_id == 6) {
        /* alternate bit stream syntax */
        put_bits(&s->pb, 1, opt->extended_bsi_1);
        if (opt->extended_bsi_1) {
            put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
            put_bits(&s->pb, 3, s->ltrt_center_mix_level);
            put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
            put_bits(&s->pb, 3, s->loro_center_mix_level);
            put_bits(&s->pb, 3, s->loro_surround_mix_level);
        }
        put_bits(&s->pb, 1, opt->extended_bsi_2);
        if (opt->extended_bsi_2) {
            put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
            put_bits(&s->pb, 2, opt->dolby_headphone_mode);
            put_bits(&s->pb, 1, opt->ad_converter_type);
            put_bits(&s->pb, 9, 0);     /* xbsi2 and encinfo : reserved */
        }
    } else {
1373 1374
    put_bits(&s->pb, 1, 0);         /* no time code 1 */
    put_bits(&s->pb, 1, 0);         /* no time code 2 */
1375
    }
1376 1377 1378 1379
    put_bits(&s->pb, 1, 0);         /* no additional bit stream info */
}


Justin Ruggles's avatar
Justin Ruggles committed
1380
/*
1381 1382
 * Write one audio block to the output bitstream.
 */
1383
static void output_audio_block(AC3EncodeContext *s, int blk)
Fabrice Bellard's avatar
Fabrice Bellard committed
1384
{
1385
    int ch, i, baie, bnd, got_cpl, ch0;
1386
    AC3Block *block = &s->blocks[blk];
Fabrice Bellard's avatar
Fabrice Bellard committed
1387

1388
    /* block switching */
1389
    if (!s->eac3) {
1390 1391
        for (ch = 0; ch < s->fbw_channels; ch++)
            put_bits(&s->pb, 1, 0);
1392
    }
1393 1394

    /* dither flags */
1395
    if (!s->eac3) {
1396 1397
        for (ch = 0; ch < s->fbw_channels; ch++)
            put_bits(&s->pb, 1, 1);
1398
    }
1399 1400 1401 1402

    /* dynamic range codes */
    put_bits(&s->pb, 1, 0);

1403 1404 1405 1406
    /* spectral extension */
    if (s->eac3)
        put_bits(&s->pb, 1, 0);

1407
    /* channel coupling */
1408
    if (!s->eac3)
1409
        put_bits(&s->pb, 1, block->new_cpl_strategy);
1410
    if (block->new_cpl_strategy) {
1411
        if (!s->eac3)
1412
            put_bits(&s->pb, 1, block->cpl_in_use);
1413 1414
        if (block->cpl_in_use) {
            int start_sub, end_sub;
1415 1416 1417
            if (s->eac3)
                put_bits(&s->pb, 1, 0); /* enhanced coupling */
            if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO) {
1418 1419
                for (ch = 1; ch <= s->fbw_channels; ch++)
                    put_bits(&s->pb, 1, block->channel_in_cpl[ch]);
1420
            }
1421 1422 1423 1424 1425 1426
            if (s->channel_mode == AC3_CHMODE_STEREO)
                put_bits(&s->pb, 1, 0); /* phase flags in use */
            start_sub = (s->start_freq[CPL_CH] - 37) / 12;
            end_sub   = (s->cpl_end_freq       - 37) / 12;
            put_bits(&s->pb, 4, start_sub);
            put_bits(&s->pb, 4, end_sub - 3);
1427 1428 1429 1430
            /* coupling band structure */
            if (s->eac3) {
                put_bits(&s->pb, 1, 0); /* use default */
            } else {
1431 1432
                for (bnd = start_sub+1; bnd < end_sub; bnd++)
                    put_bits(&s->pb, 1, ff_eac3_default_cpl_band_struct[bnd]);
1433
            }
1434 1435 1436 1437 1438 1439 1440
        }
    }

    /* coupling coordinates */
    if (block->cpl_in_use) {
        for (ch = 1; ch <= s->fbw_channels; ch++) {
            if (block->channel_in_cpl[ch]) {
1441 1442 1443
                if (!s->eac3 || block->new_cpl_coords[ch] != 2)
                    put_bits(&s->pb, 1, block->new_cpl_coords[ch]);
                if (block->new_cpl_coords[ch]) {
1444 1445 1446 1447 1448 1449 1450 1451
                    put_bits(&s->pb, 2, block->cpl_master_exp[ch]);
                    for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
                        put_bits(&s->pb, 4, block->cpl_coord_exp [ch][bnd]);
                        put_bits(&s->pb, 4, block->cpl_coord_mant[ch][bnd]);
                    }
                }
            }
        }
Fabrice Bellard's avatar
Fabrice Bellard committed
1452 1453
    }

1454
    /* stereo rematrixing */
1455
    if (s->channel_mode == AC3_CHMODE_STEREO) {
1456
        if (!s->eac3 || blk > 0)
1457
            put_bits(&s->pb, 1, block->new_rematrixing_strategy);
1458 1459
        if (block->new_rematrixing_strategy) {
            /* rematrixing flags */
1460 1461
            for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++)
                put_bits(&s->pb, 1, block->rematrixing_flags[bnd]);
1462 1463
        }
    }
Fabrice Bellard's avatar
Fabrice Bellard committed
1464 1465

    /* exponent strategy */
1466
    if (!s->eac3) {
1467 1468 1469 1470
        for (ch = !block->cpl_in_use; ch <= s->fbw_channels; ch++)
            put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
        if (s->lfe_on)
            put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
1471
    }
1472

1473
    /* bandwidth */
1474 1475
    for (ch = 1; ch <= s->fbw_channels; ch++) {
        if (s->exp_strategy[ch][blk] != EXP_REUSE && !block->channel_in_cpl[ch])
1476
            put_bits(&s->pb, 6, s->bandwidth_code);
Fabrice Bellard's avatar
Fabrice Bellard committed
1477
    }
1478

Fabrice Bellard's avatar
Fabrice Bellard committed
1479
    /* exponents */
1480
    for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
1481
        int nb_groups;
1482
        int cpl = (ch == CPL_CH);
1483

1484
        if (s->exp_strategy[ch][blk] == EXP_REUSE)
Fabrice Bellard's avatar
Fabrice Bellard committed
1485 1486
            continue;

1487
        /* DC exponent */
1488
        put_bits(&s->pb, 4, block->grouped_exp[ch][0] >> cpl);
1489

1490
        /* exponent groups */
1491
        nb_groups = exponent_group_tab[cpl][s->exp_strategy[ch][blk]-1][block->end_freq[ch]-s->start_freq[ch]];
1492
        for (i = 1; i <= nb_groups; i++)
1493
            put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
Fabrice Bellard's avatar
Fabrice Bellard committed
1494

1495
        /* gain range info */
1496
        if (ch != s->lfe_channel && !cpl)
1497
            put_bits(&s->pb, 2, 0);
Fabrice Bellard's avatar
Fabrice Bellard committed
1498 1499 1500
    }

    /* bit allocation info */
1501
    if (!s->eac3) {
1502 1503 1504 1505 1506 1507 1508 1509 1510
        baie = (blk == 0);
        put_bits(&s->pb, 1, baie);
        if (baie) {
            put_bits(&s->pb, 2, s->slow_decay_code);
            put_bits(&s->pb, 2, s->fast_decay_code);
            put_bits(&s->pb, 2, s->slow_gain_code);
            put_bits(&s->pb, 2, s->db_per_bit_code);
            put_bits(&s->pb, 3, s->floor_code);
        }
Fabrice Bellard's avatar
Fabrice Bellard committed
1511 1512 1513
    }

    /* snr offset */
1514
    if (!s->eac3) {
1515 1516 1517 1518 1519 1520 1521
        put_bits(&s->pb, 1, block->new_snr_offsets);
        if (block->new_snr_offsets) {
            put_bits(&s->pb, 6, s->coarse_snr_offset);
            for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
                put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
                put_bits(&s->pb, 3, s->fast_gain_code[ch]);
            }
Fabrice Bellard's avatar
Fabrice Bellard committed
1522
        }
1523 1524
    } else {
        put_bits(&s->pb, 1, 0); /* no converter snr offset */
Fabrice Bellard's avatar
Fabrice Bellard committed
1525
    }
1526

1527 1528
    /* coupling leak */
    if (block->cpl_in_use) {
1529
        if (!s->eac3 || block->new_cpl_leak != 2)
1530
            put_bits(&s->pb, 1, block->new_cpl_leak);
1531 1532 1533 1534 1535 1536
        if (block->new_cpl_leak) {
            put_bits(&s->pb, 3, s->bit_alloc.cpl_fast_leak);
            put_bits(&s->pb, 3, s->bit_alloc.cpl_slow_leak);
        }
    }

1537
    if (!s->eac3) {
1538 1539
        put_bits(&s->pb, 1, 0); /* no delta bit allocation */
        put_bits(&s->pb, 1, 0); /* no data to skip */
1540
    }
Fabrice Bellard's avatar
Fabrice Bellard committed
1541

1542
    /* mantissas */
1543 1544
    got_cpl = !block->cpl_in_use;
    for (ch = 1; ch <= s->channels; ch++) {
Fabrice Bellard's avatar
Fabrice Bellard committed
1545
        int b, q;
1546 1547 1548 1549 1550 1551 1552

        if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
            ch0     = ch - 1;
            ch      = CPL_CH;
            got_cpl = 1;
        }
        for (i = s->start_freq[ch]; i < block->end_freq[ch]; i++) {
1553
            q = block->qmant[ch][i];
1554
            b = s->ref_bap[ch][blk][i];
1555
            switch (b) {
1556 1557 1558 1559 1560 1561 1562 1563
            case 0:                                          break;
            case 1: if (q != 128) put_bits (&s->pb,   5, q); break;
            case 2: if (q != 128) put_bits (&s->pb,   7, q); break;
            case 3:               put_sbits(&s->pb,   3, q); break;
            case 4: if (q != 128) put_bits (&s->pb,   7, q); break;
            case 14:              put_sbits(&s->pb,  14, q); break;
            case 15:              put_sbits(&s->pb,  16, q); break;
            default:              put_sbits(&s->pb, b-1, q); break;
Fabrice Bellard's avatar
Fabrice Bellard committed
1564 1565
            }
        }
1566 1567
        if (ch == CPL_CH)
            ch = ch0;
Fabrice Bellard's avatar
Fabrice Bellard committed
1568 1569 1570
    }
}

1571

1572
/** CRC-16 Polynomial */
Fabrice Bellard's avatar
Fabrice Bellard committed
1573 1574
#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))

1575

Fabrice Bellard's avatar
Fabrice Bellard committed
1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
{
    unsigned int c;

    c = 0;
    while (a) {
        if (a & 1)
            c ^= b;
        a = a >> 1;
        b = b << 1;
        if (b & (1 << 16))
            b ^= poly;
    }
    return c;
}

1592

Fabrice Bellard's avatar
Fabrice Bellard committed
1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605
static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
{
    unsigned int r;
    r = 1;
    while (n) {
        if (n & 1)
            r = mul_poly(r, a, poly);
        a = mul_poly(a, a, poly);
        n >>= 1;
    }
    return r;
}

1606

Justin Ruggles's avatar
Justin Ruggles committed
1607
/*
1608 1609
 * Fill the end of the frame with 0's and compute the two CRCs.
 */
1610
static void output_frame_end(AC3EncodeContext *s)
Fabrice Bellard's avatar
Fabrice Bellard committed
1611
{
1612
    const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
1613
    int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
1614
    uint8_t *frame;
Fabrice Bellard's avatar
Fabrice Bellard committed
1615

1616
    frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
1617 1618

    /* pad the remainder of the frame with zeros */
1619
    av_assert2(s->frame_size * 8 - put_bits_count(&s->pb) >= 18);
Fabrice Bellard's avatar
Fabrice Bellard committed
1620 1621
    flush_put_bits(&s->pb);
    frame = s->pb.buf;
1622
    pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
1623
    av_assert2(pad_bytes >= 0);
1624 1625
    if (pad_bytes > 0)
        memset(put_bits_ptr(&s->pb), 0, pad_bytes);
1626

1627 1628 1629 1630
    if (s->eac3) {
        /* compute crc2 */
        crc2_partial = av_crc(crc_ctx, 0, frame + 2, s->frame_size - 5);
    } else {
1631 1632
    /* compute crc1 */
    /* this is not so easy because it is at the beginning of the data... */
1633
    crc1    = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
1634
    crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
1635 1636
    crc1    = mul_poly(crc_inv, crc1, CRC16_POLY);
    AV_WB16(frame + 2, crc1);
1637

1638
    /* compute crc2 */
1639 1640
    crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
                          s->frame_size - frame_size_58 - 3);
1641
    }
1642 1643 1644 1645 1646 1647 1648
    crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
    /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
    if (crc2 == 0x770B) {
        frame[s->frame_size - 3] ^= 0x1;
        crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
    }
    crc2 = av_bswap16(crc2);
1649
    AV_WB16(frame + s->frame_size - 2, crc2);
Fabrice Bellard's avatar
Fabrice Bellard committed
1650 1651
}

1652

1653 1654
/**
 * Write the frame to the output bitstream.
Justin Ruggles's avatar
Justin Ruggles committed
1655 1656 1657
 *
 * @param s      AC-3 encoder private context
 * @param frame  output data buffer
1658
 */
1659
void ff_ac3_output_frame(AC3EncodeContext *s, unsigned char *frame)
1660 1661 1662 1663 1664
{
    int blk;

    init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);

1665
    s->output_frame_header(s);
1666

1667
    for (blk = 0; blk < s->num_blocks; blk++)
1668
        output_audio_block(s, blk);
1669 1670 1671 1672 1673

    output_frame_end(s);
}


1674
static void dprint_options(AC3EncodeContext *s)
1675 1676
{
#ifdef DEBUG
1677
    AVCodecContext *avctx = s->avctx;
1678 1679 1680 1681
    AC3EncOptions *opt = &s->options;
    char strbuf[32];

    switch (s->bitstream_id) {
1682 1683 1684 1685 1686
    case  6:  av_strlcpy(strbuf, "AC-3 (alt syntax)",       32); break;
    case  8:  av_strlcpy(strbuf, "AC-3 (standard)",         32); break;
    case  9:  av_strlcpy(strbuf, "AC-3 (dnet half-rate)",   32); break;
    case 10:  av_strlcpy(strbuf, "AC-3 (dnet quater-rate)", 32); break;
    case 16:  av_strlcpy(strbuf, "E-AC-3 (enhanced)",       32); break;
1687 1688 1689 1690 1691 1692 1693 1694
    default: snprintf(strbuf, 32, "ERROR");
    }
    av_dlog(avctx, "bitstream_id: %s (%d)\n", strbuf, s->bitstream_id);
    av_dlog(avctx, "sample_fmt: %s\n", av_get_sample_fmt_name(avctx->sample_fmt));
    av_get_channel_layout_string(strbuf, 32, s->channels, avctx->channel_layout);
    av_dlog(avctx, "channel_layout: %s\n", strbuf);
    av_dlog(avctx, "sample_rate: %d\n", s->sample_rate);
    av_dlog(avctx, "bit_rate: %d\n", s->bit_rate);
1695
    av_dlog(avctx, "blocks/frame: %d (code=%d)\n", s->num_blocks, s->num_blks_code);
1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713
    if (s->cutoff)
        av_dlog(avctx, "cutoff: %d\n", s->cutoff);

    av_dlog(avctx, "per_frame_metadata: %s\n",
            opt->allow_per_frame_metadata?"on":"off");
    if (s->has_center)
        av_dlog(avctx, "center_mixlev: %0.3f (%d)\n", opt->center_mix_level,
                s->center_mix_level);
    else
        av_dlog(avctx, "center_mixlev: {not written}\n");
    if (s->has_surround)
        av_dlog(avctx, "surround_mixlev: %0.3f (%d)\n", opt->surround_mix_level,
                s->surround_mix_level);
    else
        av_dlog(avctx, "surround_mixlev: {not written}\n");
    if (opt->audio_production_info) {
        av_dlog(avctx, "mixing_level: %ddB\n", opt->mixing_level);
        switch (opt->room_type) {
1714 1715 1716
        case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
        case AC3ENC_OPT_LARGE_ROOM:    av_strlcpy(strbuf, "large", 32);        break;
        case AC3ENC_OPT_SMALL_ROOM:    av_strlcpy(strbuf, "small", 32);        break;
1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727
        default: snprintf(strbuf, 32, "ERROR (%d)", opt->room_type);
        }
        av_dlog(avctx, "room_type: %s\n", strbuf);
    } else {
        av_dlog(avctx, "mixing_level: {not written}\n");
        av_dlog(avctx, "room_type: {not written}\n");
    }
    av_dlog(avctx, "copyright: %s\n", opt->copyright?"on":"off");
    av_dlog(avctx, "dialnorm: %ddB\n", opt->dialogue_level);
    if (s->channel_mode == AC3_CHMODE_STEREO) {
        switch (opt->dolby_surround_mode) {
1728 1729 1730
        case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
        case AC3ENC_OPT_MODE_ON:       av_strlcpy(strbuf, "on", 32);           break;
        case AC3ENC_OPT_MODE_OFF:      av_strlcpy(strbuf, "off", 32);          break;
1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741
        default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_mode);
        }
        av_dlog(avctx, "dsur_mode: %s\n", strbuf);
    } else {
        av_dlog(avctx, "dsur_mode: {not written}\n");
    }
    av_dlog(avctx, "original: %s\n", opt->original?"on":"off");

    if (s->bitstream_id == 6) {
        if (opt->extended_bsi_1) {
            switch (opt->preferred_stereo_downmix) {
1742 1743 1744
            case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
            case AC3ENC_OPT_DOWNMIX_LTRT:  av_strlcpy(strbuf, "ltrt", 32);         break;
            case AC3ENC_OPT_DOWNMIX_LORO:  av_strlcpy(strbuf, "loro", 32);         break;
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760
            default: snprintf(strbuf, 32, "ERROR (%d)", opt->preferred_stereo_downmix);
            }
            av_dlog(avctx, "dmix_mode: %s\n", strbuf);
            av_dlog(avctx, "ltrt_cmixlev: %0.3f (%d)\n",
                    opt->ltrt_center_mix_level, s->ltrt_center_mix_level);
            av_dlog(avctx, "ltrt_surmixlev: %0.3f (%d)\n",
                    opt->ltrt_surround_mix_level, s->ltrt_surround_mix_level);
            av_dlog(avctx, "loro_cmixlev: %0.3f (%d)\n",
                    opt->loro_center_mix_level, s->loro_center_mix_level);
            av_dlog(avctx, "loro_surmixlev: %0.3f (%d)\n",
                    opt->loro_surround_mix_level, s->loro_surround_mix_level);
        } else {
            av_dlog(avctx, "extended bitstream info 1: {not written}\n");
        }
        if (opt->extended_bsi_2) {
            switch (opt->dolby_surround_ex_mode) {
1761 1762 1763
            case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
            case AC3ENC_OPT_MODE_ON:       av_strlcpy(strbuf, "on", 32);           break;
            case AC3ENC_OPT_MODE_OFF:      av_strlcpy(strbuf, "off", 32);          break;
1764 1765 1766 1767
            default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_ex_mode);
            }
            av_dlog(avctx, "dsurex_mode: %s\n", strbuf);
            switch (opt->dolby_headphone_mode) {
1768 1769 1770
            case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break;
            case AC3ENC_OPT_MODE_ON:       av_strlcpy(strbuf, "on", 32);           break;
            case AC3ENC_OPT_MODE_OFF:      av_strlcpy(strbuf, "off", 32);          break;
1771 1772 1773 1774 1775
            default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_headphone_mode);
            }
            av_dlog(avctx, "dheadphone_mode: %s\n", strbuf);

            switch (opt->ad_converter_type) {
1776 1777
            case AC3ENC_OPT_ADCONV_STANDARD: av_strlcpy(strbuf, "standard", 32); break;
            case AC3ENC_OPT_ADCONV_HDCD:     av_strlcpy(strbuf, "hdcd", 32);     break;
1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827
            default: snprintf(strbuf, 32, "ERROR (%d)", opt->ad_converter_type);
            }
            av_dlog(avctx, "ad_conv_type: %s\n", strbuf);
        } else {
            av_dlog(avctx, "extended bitstream info 2: {not written}\n");
        }
    }
#endif
}


#define FLT_OPTION_THRESHOLD 0.01

static int validate_float_option(float v, const float *v_list, int v_list_size)
{
    int i;

    for (i = 0; i < v_list_size; i++) {
        if (v < (v_list[i] + FLT_OPTION_THRESHOLD) &&
            v > (v_list[i] - FLT_OPTION_THRESHOLD))
            break;
    }
    if (i == v_list_size)
        return -1;

    return i;
}


static void validate_mix_level(void *log_ctx, const char *opt_name,
                               float *opt_param, const float *list,
                               int list_size, int default_value, int min_value,
                               int *ctx_param)
{
    int mixlev = validate_float_option(*opt_param, list, list_size);
    if (mixlev < min_value) {
        mixlev = default_value;
        if (*opt_param >= 0.0) {
            av_log(log_ctx, AV_LOG_WARNING, "requested %s is not valid. using "
                   "default value: %0.3f\n", opt_name, list[mixlev]);
        }
    }
    *opt_param = list[mixlev];
    *ctx_param = mixlev;
}


/**
 * Validate metadata options as set by AVOption system.
 * These values can optionally be changed per-frame.
Justin Ruggles's avatar
Justin Ruggles committed
1828 1829
 *
 * @param s  AC-3 encoder private context
1830
 */
1831
int ff_ac3_validate_metadata(AC3EncodeContext *s)
1832
{
1833
    AVCodecContext *avctx = s->avctx;
1834 1835
    AC3EncOptions *opt = &s->options;

1836 1837 1838 1839 1840 1841 1842
    opt->audio_production_info = 0;
    opt->extended_bsi_1        = 0;
    opt->extended_bsi_2        = 0;
    opt->eac3_mixing_metadata  = 0;
    opt->eac3_info_metadata    = 0;

    /* determine mixing metadata / xbsi1 use */
1843
    if (s->channel_mode > AC3_CHMODE_STEREO && opt->preferred_stereo_downmix != AC3ENC_OPT_NONE) {
1844 1845 1846 1847 1848 1849 1850
        opt->extended_bsi_1       = 1;
        opt->eac3_mixing_metadata = 1;
    }
    if (s->has_center &&
        (opt->ltrt_center_mix_level >= 0 || opt->loro_center_mix_level >= 0)) {
        opt->extended_bsi_1       = 1;
        opt->eac3_mixing_metadata = 1;
1851
    }
1852 1853 1854 1855
    if (s->has_surround &&
        (opt->ltrt_surround_mix_level >= 0 || opt->loro_surround_mix_level >= 0)) {
        opt->extended_bsi_1       = 1;
        opt->eac3_mixing_metadata = 1;
1856 1857
    }

1858 1859 1860 1861
    if (s->eac3) {
        /* determine info metadata use */
        if (avctx->audio_service_type != AV_AUDIO_SERVICE_TYPE_MAIN)
            opt->eac3_info_metadata = 1;
1862
        if (opt->copyright != AC3ENC_OPT_NONE || opt->original != AC3ENC_OPT_NONE)
1863 1864
            opt->eac3_info_metadata = 1;
        if (s->channel_mode == AC3_CHMODE_STEREO &&
1865
            (opt->dolby_headphone_mode != AC3ENC_OPT_NONE || opt->dolby_surround_mode != AC3ENC_OPT_NONE))
1866
            opt->eac3_info_metadata = 1;
1867
        if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE)
1868
            opt->eac3_info_metadata = 1;
1869 1870
        if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE ||
            opt->ad_converter_type != AC3ENC_OPT_NONE) {
1871 1872
            opt->audio_production_info = 1;
            opt->eac3_info_metadata    = 1;
1873 1874
        }
    } else {
1875
        /* determine audio production info use */
1876
        if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE)
1877 1878 1879
            opt->audio_production_info = 1;

        /* determine xbsi2 use */
1880
        if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE)
1881
            opt->extended_bsi_2 = 1;
1882
        if (s->channel_mode == AC3_CHMODE_STEREO && opt->dolby_headphone_mode != AC3ENC_OPT_NONE)
1883
            opt->extended_bsi_2 = 1;
1884
        if (opt->ad_converter_type != AC3ENC_OPT_NONE)
1885
            opt->extended_bsi_2 = 1;
1886 1887
    }

1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903
    /* validate AC-3 mixing levels */
    if (!s->eac3) {
        if (s->has_center) {
            validate_mix_level(avctx, "center_mix_level", &opt->center_mix_level,
                            cmixlev_options, CMIXLEV_NUM_OPTIONS, 1, 0,
                            &s->center_mix_level);
        }
        if (s->has_surround) {
            validate_mix_level(avctx, "surround_mix_level", &opt->surround_mix_level,
                            surmixlev_options, SURMIXLEV_NUM_OPTIONS, 1, 0,
                            &s->surround_mix_level);
        }
    }

    /* validate extended bsi 1 / mixing metadata */
    if (opt->extended_bsi_1 || opt->eac3_mixing_metadata) {
1904
        /* default preferred stereo downmix */
1905 1906
        if (opt->preferred_stereo_downmix == AC3ENC_OPT_NONE)
            opt->preferred_stereo_downmix = AC3ENC_OPT_NOT_INDICATED;
1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930
        if (!s->eac3 || s->has_center) {
            /* validate Lt/Rt center mix level */
            validate_mix_level(avctx, "ltrt_center_mix_level",
                               &opt->ltrt_center_mix_level, extmixlev_options,
                               EXTMIXLEV_NUM_OPTIONS, 5, 0,
                               &s->ltrt_center_mix_level);
            /* validate Lo/Ro center mix level */
            validate_mix_level(avctx, "loro_center_mix_level",
                               &opt->loro_center_mix_level, extmixlev_options,
                               EXTMIXLEV_NUM_OPTIONS, 5, 0,
                               &s->loro_center_mix_level);
        }
        if (!s->eac3 || s->has_surround) {
            /* validate Lt/Rt surround mix level */
            validate_mix_level(avctx, "ltrt_surround_mix_level",
                               &opt->ltrt_surround_mix_level, extmixlev_options,
                               EXTMIXLEV_NUM_OPTIONS, 6, 3,
                               &s->ltrt_surround_mix_level);
            /* validate Lo/Ro surround mix level */
            validate_mix_level(avctx, "loro_surround_mix_level",
                               &opt->loro_surround_mix_level, extmixlev_options,
                               EXTMIXLEV_NUM_OPTIONS, 6, 3,
                               &s->loro_surround_mix_level);
        }
1931 1932
    }

1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946
    /* validate audio service type / channels combination */
    if ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_KARAOKE &&
         avctx->channels == 1) ||
        ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_COMMENTARY ||
          avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_EMERGENCY  ||
          avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_VOICE_OVER)
         && avctx->channels > 1)) {
        av_log(avctx, AV_LOG_ERROR, "invalid audio service type for the "
                                    "specified number of channels\n");
        return AVERROR(EINVAL);
    }

    /* validate extended bsi 2 / info metadata */
    if (opt->extended_bsi_2 || opt->eac3_info_metadata) {
1947
        /* default dolby headphone mode */
1948 1949
        if (opt->dolby_headphone_mode == AC3ENC_OPT_NONE)
            opt->dolby_headphone_mode = AC3ENC_OPT_NOT_INDICATED;
1950
        /* default dolby surround ex mode */
1951 1952
        if (opt->dolby_surround_ex_mode == AC3ENC_OPT_NONE)
            opt->dolby_surround_ex_mode = AC3ENC_OPT_NOT_INDICATED;
1953
        /* default A/D converter type */
1954 1955
        if (opt->ad_converter_type == AC3ENC_OPT_NONE)
            opt->ad_converter_type = AC3ENC_OPT_ADCONV_STANDARD;
1956 1957 1958 1959 1960
    }

    /* copyright & original defaults */
    if (!s->eac3 || opt->eac3_info_metadata) {
        /* default copyright */
1961 1962
        if (opt->copyright == AC3ENC_OPT_NONE)
            opt->copyright = AC3ENC_OPT_OFF;
1963
        /* default original */
1964 1965
        if (opt->original == AC3ENC_OPT_NONE)
            opt->original = AC3ENC_OPT_ON;
1966 1967 1968 1969
    }

    /* dolby surround mode default */
    if (!s->eac3 || opt->eac3_info_metadata) {
1970 1971
        if (opt->dolby_surround_mode == AC3ENC_OPT_NONE)
            opt->dolby_surround_mode = AC3ENC_OPT_NOT_INDICATED;
1972 1973 1974 1975
    }

    /* validate audio production info */
    if (opt->audio_production_info) {
1976
        if (opt->mixing_level == AC3ENC_OPT_NONE) {
1977 1978 1979 1980 1981 1982 1983 1984 1985 1986
            av_log(avctx, AV_LOG_ERROR, "mixing_level must be set if "
                   "room_type is set\n");
            return AVERROR(EINVAL);
        }
        if (opt->mixing_level < 80) {
            av_log(avctx, AV_LOG_ERROR, "invalid mixing level. must be between "
                   "80dB and 111dB\n");
            return AVERROR(EINVAL);
        }
        /* default room type */
1987 1988
        if (opt->room_type == AC3ENC_OPT_NONE)
            opt->room_type = AC3ENC_OPT_NOT_INDICATED;
1989 1990 1991
    }

    /* set bitstream id for alternate bitstream syntax */
1992
    if (!s->eac3 && (opt->extended_bsi_1 || opt->extended_bsi_2)) {
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
        if (s->bitstream_id > 8 && s->bitstream_id < 11) {
            static int warn_once = 1;
            if (warn_once) {
                av_log(avctx, AV_LOG_WARNING, "alternate bitstream syntax is "
                       "not compatible with reduced samplerates. writing of "
                       "extended bitstream information will be disabled.\n");
                warn_once = 0;
            }
        } else {
            s->bitstream_id = 6;
        }
    }

    return 0;
}


2010 2011
/**
 * Finalize encoding and free any memory allocated by the encoder.
Justin Ruggles's avatar
Justin Ruggles committed
2012 2013
 *
 * @param avctx  Codec context
2014
 */
2015
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
2016
{
2017
    int blk, ch;
2018 2019
    AC3EncodeContext *s = avctx->priv_data;

2020
    av_freep(&s->windowed_samples);
2021 2022 2023
    for (ch = 0; ch < s->channels; ch++)
        av_freep(&s->planar_samples[ch]);
    av_freep(&s->planar_samples);
2024 2025
    av_freep(&s->bap_buffer);
    av_freep(&s->bap1_buffer);
2026
    av_freep(&s->mdct_coef_buffer);
2027
    av_freep(&s->fixed_coef_buffer);
2028 2029 2030 2031 2032 2033
    av_freep(&s->exp_buffer);
    av_freep(&s->grouped_exp_buffer);
    av_freep(&s->psd_buffer);
    av_freep(&s->band_psd_buffer);
    av_freep(&s->mask_buffer);
    av_freep(&s->qmant_buffer);
Justin Ruggles's avatar
Justin Ruggles committed
2034 2035
    av_freep(&s->cpl_coord_exp_buffer);
    av_freep(&s->cpl_coord_mant_buffer);
2036
    for (blk = 0; blk < s->num_blocks; blk++) {
2037
        AC3Block *block = &s->blocks[blk];
2038
        av_freep(&block->mdct_coef);
2039
        av_freep(&block->fixed_coef);
2040 2041 2042 2043 2044 2045
        av_freep(&block->exp);
        av_freep(&block->grouped_exp);
        av_freep(&block->psd);
        av_freep(&block->band_psd);
        av_freep(&block->mask);
        av_freep(&block->qmant);
Justin Ruggles's avatar
Justin Ruggles committed
2046 2047
        av_freep(&block->cpl_coord_exp);
        av_freep(&block->cpl_coord_mant);
2048 2049
    }

2050
    s->mdct_end(s);
2051

2052
#if FF_API_OLD_ENCODE_AUDIO
2053
    av_freep(&avctx->coded_frame);
2054
#endif
2055
    return 0;
2056 2057
}

2058

Justin Ruggles's avatar
Justin Ruggles committed
2059
/*
2060 2061
 * Set channel information during initialization.
 */
2062
static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
2063
                                    uint64_t *channel_layout)
2064 2065 2066 2067
{
    int ch_layout;

    if (channels < 1 || channels > AC3_MAX_CHANNELS)
2068
        return AVERROR(EINVAL);
2069
    if (*channel_layout > 0x7FF)
2070
        return AVERROR(EINVAL);
2071 2072
    ch_layout = *channel_layout;
    if (!ch_layout)
2073
        ch_layout = av_get_default_channel_layout(channels);
2074 2075 2076 2077

    s->lfe_on       = !!(ch_layout & AV_CH_LOW_FREQUENCY);
    s->channels     = channels;
    s->fbw_channels = channels - s->lfe_on;
2078
    s->lfe_channel  = s->lfe_on ? s->fbw_channels + 1 : -1;
2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092
    if (s->lfe_on)
        ch_layout -= AV_CH_LOW_FREQUENCY;

    switch (ch_layout) {
    case AV_CH_LAYOUT_MONO:           s->channel_mode = AC3_CHMODE_MONO;   break;
    case AV_CH_LAYOUT_STEREO:         s->channel_mode = AC3_CHMODE_STEREO; break;
    case AV_CH_LAYOUT_SURROUND:       s->channel_mode = AC3_CHMODE_3F;     break;
    case AV_CH_LAYOUT_2_1:            s->channel_mode = AC3_CHMODE_2F1R;   break;
    case AV_CH_LAYOUT_4POINT0:        s->channel_mode = AC3_CHMODE_3F1R;   break;
    case AV_CH_LAYOUT_QUAD:
    case AV_CH_LAYOUT_2_2:            s->channel_mode = AC3_CHMODE_2F2R;   break;
    case AV_CH_LAYOUT_5POINT0:
    case AV_CH_LAYOUT_5POINT0_BACK:   s->channel_mode = AC3_CHMODE_3F2R;   break;
    default:
2093
        return AVERROR(EINVAL);
2094
    }
2095 2096
    s->has_center   = (s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO;
    s->has_surround =  s->channel_mode & 0x04;
2097 2098 2099 2100 2101 2102 2103 2104 2105

    s->channel_map  = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
    *channel_layout = ch_layout;
    if (s->lfe_on)
        *channel_layout |= AV_CH_LOW_FREQUENCY;

    return 0;
}

2106

2107
static av_cold int validate_options(AC3EncodeContext *s)
2108
{
2109
    AVCodecContext *avctx = s->avctx;
2110
    int i, ret, max_sr;
2111

2112
    /* validate channel layout */
2113 2114 2115 2116 2117
    if (!avctx->channel_layout) {
        av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
                                      "encoder will guess the layout, but it "
                                      "might be incorrect.\n");
    }
2118 2119
    ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
    if (ret) {
2120
        av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
2121
        return ret;
2122 2123
    }

2124
    /* validate sample rate */
2125 2126 2127 2128 2129 2130
    /* note: max_sr could be changed from 2 to 5 for E-AC-3 once we find a
             decoder that supports half sample rate so we can validate that
             the generated files are correct. */
    max_sr = s->eac3 ? 2 : 8;
    for (i = 0; i <= max_sr; i++) {
        if ((ff_ac3_sample_rate_tab[i % 3] >> (i / 3)) == avctx->sample_rate)
2131
            break;
2132
    }
2133
    if (i > max_sr) {
2134 2135
        av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
        return AVERROR(EINVAL);
2136
    }
2137
    s->sample_rate        = avctx->sample_rate;
2138 2139 2140
    s->bit_alloc.sr_shift = i / 3;
    s->bit_alloc.sr_code  = i % 3;
    s->bitstream_id       = s->eac3 ? 16 : 8 + s->bit_alloc.sr_shift;
2141

2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152
    /* select a default bit rate if not set by the user */
    if (!avctx->bit_rate) {
        switch (s->fbw_channels) {
        case 1: avctx->bit_rate =  96000; break;
        case 2: avctx->bit_rate = 192000; break;
        case 3: avctx->bit_rate = 320000; break;
        case 4: avctx->bit_rate = 384000; break;
        case 5: avctx->bit_rate = 448000; break;
        }
    }

2153
    /* validate bit rate */
2154 2155
    if (s->eac3) {
        int max_br, min_br, wpf, min_br_dist, min_br_code;
2156
        int num_blks_code, num_blocks, frame_samples;
2157 2158

        /* calculate min/max bitrate */
2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169
        /* TODO: More testing with 3 and 2 blocks. All E-AC-3 samples I've
                 found use either 6 blocks or 1 block, even though 2 or 3 blocks
                 would work as far as the bit rate is concerned. */
        for (num_blks_code = 3; num_blks_code >= 0; num_blks_code--) {
            num_blocks = ((int[]){ 1, 2, 3, 6 })[num_blks_code];
            frame_samples  = AC3_BLOCK_SIZE * num_blocks;
            max_br = 2048 * s->sample_rate / frame_samples * 16;
            min_br = ((s->sample_rate + (frame_samples-1)) / frame_samples) * 16;
            if (avctx->bit_rate <= max_br)
                break;
        }
2170 2171 2172 2173 2174
        if (avctx->bit_rate < min_br || avctx->bit_rate > max_br) {
            av_log(avctx, AV_LOG_ERROR, "invalid bit rate. must be %d to %d "
                   "for this sample rate\n", min_br, max_br);
            return AVERROR(EINVAL);
        }
2175 2176
        s->num_blks_code = num_blks_code;
        s->num_blocks    = num_blocks;
2177 2178

        /* calculate words-per-frame for the selected bitrate */
2179
        wpf = (avctx->bit_rate / 16) * frame_samples / s->sample_rate;
2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200
        av_assert1(wpf > 0 && wpf <= 2048);

        /* find the closest AC-3 bitrate code to the selected bitrate.
           this is needed for lookup tables for bandwidth and coupling
           parameter selection */
        min_br_code = -1;
        min_br_dist = INT_MAX;
        for (i = 0; i < 19; i++) {
            int br_dist = abs(ff_ac3_bitrate_tab[i] * 1000 - avctx->bit_rate);
            if (br_dist < min_br_dist) {
                min_br_dist = br_dist;
                min_br_code = i;
            }
        }

        /* make sure the minimum frame size is below the average frame size */
        s->frame_size_code = min_br_code << 1;
        while (wpf > 1 && wpf * s->sample_rate / AC3_FRAME_SIZE * 16 > avctx->bit_rate)
            wpf--;
        s->frame_size_min = 2 * wpf;
    } else {
2201
        int best_br = 0, best_code = 0, best_diff = INT_MAX;
2202
        for (i = 0; i < 19; i++) {
2203 2204 2205 2206 2207 2208 2209 2210
            int br   = (ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift) * 1000;
            int diff = abs(br - avctx->bit_rate);
            if (diff < best_diff) {
                best_br   = br;
                best_code = i;
                best_diff = diff;
            }
            if (!best_diff)
2211 2212
                break;
        }
2213 2214
        avctx->bit_rate    = best_br;
        s->frame_size_code = best_code << 1;
2215
        s->frame_size_min  = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
2216 2217
        s->num_blks_code   = 0x3;
        s->num_blocks      = 6;
2218
    }
2219 2220
    s->bit_rate   = avctx->bit_rate;
    s->frame_size = s->frame_size_min;
2221

2222 2223 2224 2225 2226 2227 2228 2229 2230
    /* validate cutoff */
    if (avctx->cutoff < 0) {
        av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
        return AVERROR(EINVAL);
    }
    s->cutoff = avctx->cutoff;
    if (s->cutoff > (s->sample_rate >> 1))
        s->cutoff = s->sample_rate >> 1;

Justin Ruggles's avatar
Justin Ruggles committed
2231 2232 2233
    ret = ff_ac3_validate_metadata(s);
    if (ret)
        return ret;
2234

2235 2236 2237
    s->rematrixing_enabled = s->options.stereo_rematrixing &&
                             (s->channel_mode == AC3_CHMODE_STEREO);

2238
    s->cpl_enabled = s->options.channel_coupling &&
2239
                     s->channel_mode >= AC3_CHMODE_STEREO;
2240

2241 2242 2243 2244
    return 0;
}


Justin Ruggles's avatar
Justin Ruggles committed
2245
/*
2246 2247 2248 2249
 * Set bandwidth for all channels.
 * The user can optionally supply a cutoff frequency. Otherwise an appropriate
 * default value will be used.
 */
2250
static av_cold void set_bandwidth(AC3EncodeContext *s)
2251
{
2252
    int blk, ch, cpl_start;
2253

2254
    if (s->cutoff) {
2255 2256
        /* calculate bandwidth based on user-specified cutoff frequency */
        int fbw_coeffs;
2257
        fbw_coeffs     = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
2258
        s->bandwidth_code = av_clip((fbw_coeffs - 73) / 3, 0, 60);
2259 2260
    } else {
        /* use default bandwidth setting */
2261
        s->bandwidth_code = ac3_bandwidth_tab[s->fbw_channels-1][s->bit_alloc.sr_code][s->frame_size_code/2];
2262 2263 2264
    }

    /* set number of coefficients for each channel */
2265 2266
    for (ch = 1; ch <= s->fbw_channels; ch++) {
        s->start_freq[ch] = 0;
2267
        for (blk = 0; blk < s->num_blocks; blk++)
2268 2269 2270 2271 2272
            s->blocks[blk].end_freq[ch] = s->bandwidth_code * 3 + 73;
    }
    /* LFE channel always has 7 coefs */
    if (s->lfe_on) {
        s->start_freq[s->lfe_channel] = 0;
2273
        for (blk = 0; blk < s->num_blocks; blk++)
2274 2275 2276 2277 2278
            s->blocks[blk].end_freq[ch] = 7;
    }

    /* initialize coupling strategy */
    if (s->cpl_enabled) {
2279
        if (s->options.cpl_start != AC3ENC_OPT_AUTO) {
2280 2281 2282
            cpl_start = s->options.cpl_start;
        } else {
            cpl_start = ac3_coupling_start_tab[s->channel_mode-2][s->bit_alloc.sr_code][s->frame_size_code/2];
2283
            if (cpl_start < 0) {
2284
                if (s->options.channel_coupling == AC3ENC_OPT_AUTO)
2285 2286 2287 2288
                    s->cpl_enabled = 0;
                else
                    cpl_start = 15;
            }
2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313
        }
    }
    if (s->cpl_enabled) {
        int i, cpl_start_band, cpl_end_band;
        uint8_t *cpl_band_sizes = s->cpl_band_sizes;

        cpl_end_band   = s->bandwidth_code / 4 + 3;
        cpl_start_band = av_clip(cpl_start, 0, FFMIN(cpl_end_band-1, 15));

        s->num_cpl_subbands = cpl_end_band - cpl_start_band;

        s->num_cpl_bands = 1;
        *cpl_band_sizes  = 12;
        for (i = cpl_start_band + 1; i < cpl_end_band; i++) {
            if (ff_eac3_default_cpl_band_struct[i]) {
                *cpl_band_sizes += 12;
            } else {
                s->num_cpl_bands++;
                cpl_band_sizes++;
                *cpl_band_sizes = 12;
            }
        }

        s->start_freq[CPL_CH] = cpl_start_band * 12 + 37;
        s->cpl_end_freq       = cpl_end_band   * 12 + 37;
2314
        for (blk = 0; blk < s->num_blocks; blk++)
2315
            s->blocks[blk].end_freq[CPL_CH] = s->cpl_end_freq;
2316 2317 2318 2319
    }
}


2320
static av_cold int allocate_buffers(AC3EncodeContext *s)
2321
{
2322
    AVCodecContext *avctx = s->avctx;
2323
    int blk, ch;
2324
    int channels = s->channels + 1; /* includes coupling channel */
2325 2326
    int channel_blocks = channels * s->num_blocks;
    int total_coefs    = AC3_MAX_COEFS * channel_blocks;
2327

2328 2329 2330
    if (s->allocate_sample_buffers(s))
        goto alloc_fail;

2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348
    FF_ALLOC_OR_GOTO(avctx, s->bap_buffer, total_coefs *
                     sizeof(*s->bap_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, total_coefs *
                     sizeof(*s->bap1_buffer), alloc_fail);
    FF_ALLOCZ_OR_GOTO(avctx, s->mdct_coef_buffer, total_coefs *
                      sizeof(*s->mdct_coef_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, total_coefs *
                     sizeof(*s->exp_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, channel_blocks * 128 *
                     sizeof(*s->grouped_exp_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, total_coefs *
                     sizeof(*s->psd_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, channel_blocks * 64 *
                     sizeof(*s->band_psd_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, channel_blocks * 64 *
                     sizeof(*s->mask_buffer), alloc_fail);
    FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, total_coefs *
                     sizeof(*s->qmant_buffer), alloc_fail);
2349
    if (s->cpl_enabled) {
2350 2351 2352 2353
        FF_ALLOC_OR_GOTO(avctx, s->cpl_coord_exp_buffer, channel_blocks * 16 *
                         sizeof(*s->cpl_coord_exp_buffer), alloc_fail);
        FF_ALLOC_OR_GOTO(avctx, s->cpl_coord_mant_buffer, channel_blocks * 16 *
                         sizeof(*s->cpl_coord_mant_buffer), alloc_fail);
2354
    }
2355
    for (blk = 0; blk < s->num_blocks; blk++) {
2356
        AC3Block *block = &s->blocks[blk];
2357
        FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, channels * sizeof(*block->mdct_coef),
2358
                          alloc_fail);
2359
        FF_ALLOCZ_OR_GOTO(avctx, block->exp, channels * sizeof(*block->exp),
2360
                          alloc_fail);
2361
        FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, channels * sizeof(*block->grouped_exp),
2362
                          alloc_fail);
2363
        FF_ALLOCZ_OR_GOTO(avctx, block->psd, channels * sizeof(*block->psd),
2364
                          alloc_fail);
2365
        FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, channels * sizeof(*block->band_psd),
2366
                          alloc_fail);
2367
        FF_ALLOCZ_OR_GOTO(avctx, block->mask, channels * sizeof(*block->mask),
2368
                          alloc_fail);
2369
        FF_ALLOCZ_OR_GOTO(avctx, block->qmant, channels * sizeof(*block->qmant),
2370
                          alloc_fail);
2371 2372 2373 2374 2375 2376
        if (s->cpl_enabled) {
            FF_ALLOCZ_OR_GOTO(avctx, block->cpl_coord_exp, channels * sizeof(*block->cpl_coord_exp),
                              alloc_fail);
            FF_ALLOCZ_OR_GOTO(avctx, block->cpl_coord_mant, channels * sizeof(*block->cpl_coord_mant),
                              alloc_fail);
        }
2377

2378
        for (ch = 0; ch < channels; ch++) {
2379
            /* arrangement: block, channel, coeff */
2380 2381 2382 2383 2384 2385 2386 2387 2388
            block->grouped_exp[ch] = &s->grouped_exp_buffer[128           * (blk * channels + ch)];
            block->psd[ch]         = &s->psd_buffer        [AC3_MAX_COEFS * (blk * channels + ch)];
            block->band_psd[ch]    = &s->band_psd_buffer   [64            * (blk * channels + ch)];
            block->mask[ch]        = &s->mask_buffer       [64            * (blk * channels + ch)];
            block->qmant[ch]       = &s->qmant_buffer      [AC3_MAX_COEFS * (blk * channels + ch)];
            if (s->cpl_enabled) {
                block->cpl_coord_exp[ch]  = &s->cpl_coord_exp_buffer [16  * (blk * channels + ch)];
                block->cpl_coord_mant[ch] = &s->cpl_coord_mant_buffer[16  * (blk * channels + ch)];
            }
2389 2390

            /* arrangement: channel, block, coeff */
2391 2392
            block->exp[ch]         = &s->exp_buffer        [AC3_MAX_COEFS * (s->num_blocks * ch + blk)];
            block->mdct_coef[ch]   = &s->mdct_coef_buffer  [AC3_MAX_COEFS * (s->num_blocks * ch + blk)];
2393
        }
2394 2395
    }

2396
    if (!s->fixed_point) {
2397 2398 2399
        FF_ALLOCZ_OR_GOTO(avctx, s->fixed_coef_buffer, total_coefs *
                          sizeof(*s->fixed_coef_buffer), alloc_fail);
        for (blk = 0; blk < s->num_blocks; blk++) {
2400
            AC3Block *block = &s->blocks[blk];
2401
            FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, channels *
2402
                              sizeof(*block->fixed_coef), alloc_fail);
2403
            for (ch = 0; ch < channels; ch++)
2404
                block->fixed_coef[ch] = &s->fixed_coef_buffer[AC3_MAX_COEFS * (s->num_blocks * ch + blk)];
2405 2406
        }
    } else {
2407
        for (blk = 0; blk < s->num_blocks; blk++) {
2408
            AC3Block *block = &s->blocks[blk];
2409
            FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, channels *
2410
                              sizeof(*block->fixed_coef), alloc_fail);
2411
            for (ch = 0; ch < channels; ch++)
2412 2413 2414 2415
                block->fixed_coef[ch] = (int32_t *)block->mdct_coef[ch];
        }
    }

2416 2417 2418 2419 2420 2421
    return 0;
alloc_fail:
    return AVERROR(ENOMEM);
}


2422
av_cold int ff_ac3_encode_init(AVCodecContext *avctx)
2423 2424
{
    AC3EncodeContext *s = avctx->priv_data;
2425
    int ret, frame_size_58;
2426

2427 2428
    s->avctx = avctx;

2429
    s->eac3 = avctx->codec_id == AV_CODEC_ID_EAC3;
2430

2431
    ff_ac3_common_init();
2432

2433
    ret = validate_options(s);
2434 2435 2436
    if (ret)
        return ret;

2437
    avctx->frame_size = AC3_BLOCK_SIZE * s->num_blocks;
2438
    avctx->delay      = AC3_BLOCK_SIZE;
2439

2440 2441 2442
    s->bitstream_mode = avctx->audio_service_type;
    if (s->bitstream_mode == AV_AUDIO_SERVICE_TYPE_KARAOKE)
        s->bitstream_mode = 0x7;
2443

2444 2445 2446
    s->bits_written    = 0;
    s->samples_written = 0;

2447 2448 2449 2450 2451 2452 2453 2454
    /* calculate crc_inv for both possible frame sizes */
    frame_size_58 = (( s->frame_size    >> 2) + ( s->frame_size    >> 4)) << 1;
    s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
    if (s->bit_alloc.sr_code == 1) {
        frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
        s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
    }

2455
    /* set function pointers */
2456 2457 2458
    if (CONFIG_AC3_FIXED_ENCODER && s->fixed_point) {
        s->mdct_end                     = ff_ac3_fixed_mdct_end;
        s->mdct_init                    = ff_ac3_fixed_mdct_init;
2459
        s->allocate_sample_buffers      = ff_ac3_fixed_allocate_sample_buffers;
2460 2461 2462
    } else if (CONFIG_AC3_ENCODER || CONFIG_EAC3_ENCODER) {
        s->mdct_end                     = ff_ac3_float_mdct_end;
        s->mdct_init                    = ff_ac3_float_mdct_init;
2463
        s->allocate_sample_buffers      = ff_ac3_float_allocate_sample_buffers;
2464
    }
2465 2466 2467 2468 2469
    if (CONFIG_EAC3_ENCODER && s->eac3)
        s->output_frame_header = ff_eac3_output_frame_header;
    else
        s->output_frame_header = ac3_output_frame_header;

2470
    set_bandwidth(s);
2471

2472 2473
    exponent_init(s);

2474
    bit_alloc_init(s);
2475

2476
    ret = s->mdct_init(s);
2477
    if (ret)
2478
        goto init_fail;
2479

2480
    ret = allocate_buffers(s);
2481
    if (ret)
2482
        goto init_fail;
2483

2484
#if FF_API_OLD_ENCODE_AUDIO
2485
    avctx->coded_frame= avcodec_alloc_frame();
2486 2487
    if (!avctx->coded_frame) {
        ret = AVERROR(ENOMEM);
2488
        goto init_fail;
2489 2490
    }
#endif
2491

2492
    ff_dsputil_init(&s->dsp, avctx);
2493
    avpriv_float_dsp_init(&s->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
2494
    ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT);
2495

2496
    dprint_options(s);
2497

2498
    return 0;
2499
init_fail:
2500
    ff_ac3_encode_close(avctx);
2501
    return ret;
2502
}