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/*
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 * The simplest AC-3 encoder
3
 * Copyright (c) 2000 Fabrice Bellard
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 * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
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 * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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24
/**
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 * @file
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 * The simplest AC-3 encoder.
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 */
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//#define DEBUG
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//#define ASSERT_LEVEL 2
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#include "libavutil/audioconvert.h"
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#include "libavutil/avassert.h"
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#include "libavutil/crc.h"
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#include "avcodec.h"
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#include "put_bits.h"
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#include "dsputil.h"
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#include "ac3dsp.h"
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#include "ac3.h"
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#include "audioconvert.h"
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42

    
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#ifndef CONFIG_AC3ENC_FLOAT
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#define CONFIG_AC3ENC_FLOAT 0
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#endif
46

    
47

    
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/** Maximum number of exponent groups. +1 for separate DC exponent. */
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#define AC3_MAX_EXP_GROUPS 85
50

    
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/* stereo rematrixing algorithms */
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#define AC3_REMATRIXING_IS_STATIC 0x1
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#define AC3_REMATRIXING_SUMS    0
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#define AC3_REMATRIXING_NONE    1
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#define AC3_REMATRIXING_ALWAYS  3
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/** Scale a float value by 2^bits and convert to an integer. */
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#define SCALE_FLOAT(a, bits) lrintf((a) * (float)(1 << (bits)))
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60

    
61
#if CONFIG_AC3ENC_FLOAT
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#include "ac3enc_float.h"
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#else
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#include "ac3enc_fixed.h"
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#endif
66

    
67

    
68
/**
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 * Data for a single audio block.
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 */
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typedef struct AC3Block {
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    uint8_t  **bap;                             ///< bit allocation pointers (bap)
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    CoefType **mdct_coef;                       ///< MDCT coefficients
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    int32_t  **fixed_coef;                      ///< fixed-point MDCT coefficients
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    uint8_t  **exp;                             ///< original exponents
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    uint8_t  **grouped_exp;                     ///< grouped exponents
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    int16_t  **psd;                             ///< psd per frequency bin
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    int16_t  **band_psd;                        ///< psd per critical band
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    int16_t  **mask;                            ///< masking curve
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    uint16_t **qmant;                           ///< quantized mantissas
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    int8_t   exp_shift[AC3_MAX_CHANNELS];       ///< exponent shift values
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    uint8_t  new_rematrixing_strategy;          ///< send new rematrixing flags in this block
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    uint8_t  rematrixing_flags[4];              ///< rematrixing flags
84
} AC3Block;
85

    
86
/**
87
 * AC-3 encoder private context.
88
 */
89
typedef struct AC3EncodeContext {
90
    PutBitContext pb;                       ///< bitstream writer context
91
    DSPContext dsp;
92
    AC3DSPContext ac3dsp;                   ///< AC-3 optimized functions
93
    AC3MDCTContext mdct;                    ///< MDCT context
94

    
95
    AC3Block blocks[AC3_MAX_BLOCKS];        ///< per-block info
96

    
97
    int bitstream_id;                       ///< bitstream id                           (bsid)
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    int bitstream_mode;                     ///< bitstream mode                         (bsmod)
99

    
100
    int bit_rate;                           ///< target bit rate, in bits-per-second
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    int sample_rate;                        ///< sampling frequency, in Hz
102

    
103
    int frame_size_min;                     ///< minimum frame size in case rounding is necessary
104
    int frame_size;                         ///< current frame size in bytes
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    int frame_size_code;                    ///< frame size code                        (frmsizecod)
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    uint16_t crc_inv[2];
107
    int bits_written;                       ///< bit count    (used to avg. bitrate)
108
    int samples_written;                    ///< sample count (used to avg. bitrate)
109

    
110
    int fbw_channels;                       ///< number of full-bandwidth channels      (nfchans)
111
    int channels;                           ///< total number of channels               (nchans)
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    int lfe_on;                             ///< indicates if there is an LFE channel   (lfeon)
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    int lfe_channel;                        ///< channel index of the LFE channel
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    int channel_mode;                       ///< channel mode                           (acmod)
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    const uint8_t *channel_map;             ///< channel map used to reorder channels
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    int cutoff;                             ///< user-specified cutoff frequency, in Hz
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    int bandwidth_code[AC3_MAX_CHANNELS];   ///< bandwidth code (0 to 60)               (chbwcod)
119
    int nb_coefs[AC3_MAX_CHANNELS];
120

    
121
    int rematrixing;                        ///< determines how rematrixing strategy is calculated
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    int num_rematrixing_bands;              ///< number of rematrixing bands
123

    
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    /* bitrate allocation control */
125
    int slow_gain_code;                     ///< slow gain code                         (sgaincod)
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    int slow_decay_code;                    ///< slow decay code                        (sdcycod)
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    int fast_decay_code;                    ///< fast decay code                        (fdcycod)
128
    int db_per_bit_code;                    ///< dB/bit code                            (dbpbcod)
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    int floor_code;                         ///< floor code                             (floorcod)
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    AC3BitAllocParameters bit_alloc;        ///< bit allocation parameters
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    int coarse_snr_offset;                  ///< coarse SNR offsets                     (csnroffst)
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    int fast_gain_code[AC3_MAX_CHANNELS];   ///< fast gain codes (signal-to-mask ratio) (fgaincod)
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    int fine_snr_offset[AC3_MAX_CHANNELS];  ///< fine SNR offsets                       (fsnroffst)
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    int frame_bits_fixed;                   ///< number of non-coefficient bits for fixed parameters
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    int frame_bits;                         ///< all frame bits except exponents and mantissas
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    int exponent_bits;                      ///< number of bits used for exponents
137

    
138
    /* mantissa encoding */
139
    int mant1_cnt, mant2_cnt, mant4_cnt;    ///< mantissa counts for bap=1,2,4
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    uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
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142
    SampleType **planar_samples;
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    uint8_t *bap_buffer;
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    uint8_t *bap1_buffer;
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    CoefType *mdct_coef_buffer;
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    int32_t *fixed_coef_buffer;
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    uint8_t *exp_buffer;
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    uint8_t *grouped_exp_buffer;
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    int16_t *psd_buffer;
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    int16_t *band_psd_buffer;
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    int16_t *mask_buffer;
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    uint16_t *qmant_buffer;
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    uint8_t exp_strategy[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< exponent strategies
155

    
156
    DECLARE_ALIGNED(16, SampleType, windowed_samples)[AC3_WINDOW_SIZE];
157
} AC3EncodeContext;
158

    
159

    
160
/* prototypes for functions in ac3enc_fixed.c and ac3enc_float.c */
161

    
162
static av_cold void mdct_end(AC3MDCTContext *mdct);
163

    
164
static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
165
                             int nbits);
166

    
167
static void mdct512(AC3MDCTContext *mdct, CoefType *out, SampleType *in);
168

    
169
static void apply_window(DSPContext *dsp, SampleType *output, const SampleType *input,
170
                         const SampleType *window, int n);
171

    
172
static int normalize_samples(AC3EncodeContext *s);
173

    
174
static void scale_coefficients(AC3EncodeContext *s);
175

    
176

    
177
/**
178
 * LUT for number of exponent groups.
179
 * exponent_group_tab[exponent strategy-1][number of coefficients]
180
 */
181
static uint8_t exponent_group_tab[3][256];
182

    
183

    
184
/**
185
 * List of supported channel layouts.
186
 */
187
static const int64_t ac3_channel_layouts[] = {
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     AV_CH_LAYOUT_MONO,
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     AV_CH_LAYOUT_STEREO,
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     AV_CH_LAYOUT_2_1,
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     AV_CH_LAYOUT_SURROUND,
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     AV_CH_LAYOUT_2_2,
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     AV_CH_LAYOUT_QUAD,
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     AV_CH_LAYOUT_4POINT0,
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     AV_CH_LAYOUT_5POINT0,
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     AV_CH_LAYOUT_5POINT0_BACK,
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    (AV_CH_LAYOUT_MONO     | AV_CH_LOW_FREQUENCY),
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    (AV_CH_LAYOUT_STEREO   | AV_CH_LOW_FREQUENCY),
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    (AV_CH_LAYOUT_2_1      | AV_CH_LOW_FREQUENCY),
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    (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
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    (AV_CH_LAYOUT_2_2      | AV_CH_LOW_FREQUENCY),
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    (AV_CH_LAYOUT_QUAD     | AV_CH_LOW_FREQUENCY),
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    (AV_CH_LAYOUT_4POINT0  | AV_CH_LOW_FREQUENCY),
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     AV_CH_LAYOUT_5POINT1,
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     AV_CH_LAYOUT_5POINT1_BACK,
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     0
207
};
208

    
209

    
210
/**
211
 * Adjust the frame size to make the average bit rate match the target bit rate.
212
 * This is only needed for 11025, 22050, and 44100 sample rates.
213
 */
214
static void adjust_frame_size(AC3EncodeContext *s)
215
{
216
    while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
217
        s->bits_written    -= s->bit_rate;
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        s->samples_written -= s->sample_rate;
219
    }
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    s->frame_size = s->frame_size_min +
221
                    2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
222
    s->bits_written    += s->frame_size * 8;
223
    s->samples_written += AC3_FRAME_SIZE;
224
}
225

    
226

    
227
/**
228
 * Deinterleave input samples.
229
 * Channels are reordered from FFmpeg's default order to AC-3 order.
230
 */
231
static void deinterleave_input_samples(AC3EncodeContext *s,
232
                                       const SampleType *samples)
233
{
234
    int ch, i;
235

    
236
    /* deinterleave and remap input samples */
237
    for (ch = 0; ch < s->channels; ch++) {
238
        const SampleType *sptr;
239
        int sinc;
240

    
241
        /* copy last 256 samples of previous frame to the start of the current frame */
242
        memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
243
               AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
244

    
245
        /* deinterleave */
246
        sinc = s->channels;
247
        sptr = samples + s->channel_map[ch];
248
        for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
249
            s->planar_samples[ch][i] = *sptr;
250
            sptr += sinc;
251
        }
252
    }
253
}
254

    
255

    
256
/**
257
 * Apply the MDCT to input samples to generate frequency coefficients.
258
 * This applies the KBD window and normalizes the input to reduce precision
259
 * loss due to fixed-point calculations.
260
 */
261
static void apply_mdct(AC3EncodeContext *s)
262
{
263
    int blk, ch;
264

    
265
    for (ch = 0; ch < s->channels; ch++) {
266
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
267
            AC3Block *block = &s->blocks[blk];
268
            const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
269

    
270
            apply_window(&s->dsp, s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
271

    
272
            block->exp_shift[ch] = normalize_samples(s);
273

    
274
            mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
275
        }
276
    }
277
}
278

    
279

    
280
/**
281
 * Initialize stereo rematrixing.
282
 * If the strategy does not change for each frame, set the rematrixing flags.
283
 */
284
static void rematrixing_init(AC3EncodeContext *s)
285
{
286
    if (s->channel_mode == AC3_CHMODE_STEREO)
287
        s->rematrixing = AC3_REMATRIXING_SUMS;
288
    else
289
        s->rematrixing = AC3_REMATRIXING_NONE;
290
    /* NOTE: AC3_REMATRIXING_ALWAYS might be used in
291
             the future in conjunction with channel coupling. */
292

    
293
    if (s->rematrixing & AC3_REMATRIXING_IS_STATIC) {
294
        int flag = (s->rematrixing == AC3_REMATRIXING_ALWAYS);
295
        s->blocks[0].new_rematrixing_strategy = 1;
296
        memset(s->blocks[0].rematrixing_flags, flag,
297
               sizeof(s->blocks[0].rematrixing_flags));
298
    }
299
}
300

    
301

    
302
/**
303
 * Determine rematrixing flags for each block and band.
304
 */
305
static void compute_rematrixing_strategy(AC3EncodeContext *s)
306
{
307
    int nb_coefs;
308
    int blk, bnd, i;
309
    AC3Block *block, *block0;
310

    
311
    s->num_rematrixing_bands = 4;
312

    
313
    if (s->rematrixing & AC3_REMATRIXING_IS_STATIC)
314
        return;
315

    
316
    nb_coefs = FFMIN(s->nb_coefs[0], s->nb_coefs[1]);
317

    
318
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
319
        block = &s->blocks[blk];
320
        block->new_rematrixing_strategy = !blk;
321
        for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) {
322
            /* calculate calculate sum of squared coeffs for one band in one block */
323
            int start = ff_ac3_rematrix_band_tab[bnd];
324
            int end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
325
            CoefSumType sum[4] = {0,};
326
            for (i = start; i < end; i++) {
327
                CoefType lt = block->mdct_coef[0][i];
328
                CoefType rt = block->mdct_coef[1][i];
329
                CoefType md = lt + rt;
330
                CoefType sd = lt - rt;
331
                sum[0] += MUL_COEF(lt, lt);
332
                sum[1] += MUL_COEF(rt, rt);
333
                sum[2] += MUL_COEF(md, md);
334
                sum[3] += MUL_COEF(sd, sd);
335
            }
336

    
337
            /* compare sums to determine if rematrixing will be used for this band */
338
            if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1]))
339
                block->rematrixing_flags[bnd] = 1;
340
            else
341
                block->rematrixing_flags[bnd] = 0;
342

    
343
            /* determine if new rematrixing flags will be sent */
344
            if (blk &&
345
                block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) {
346
                block->new_rematrixing_strategy = 1;
347
            }
348
        }
349
        block0 = block;
350
    }
351
}
352

    
353

    
354
/**
355
 * Apply stereo rematrixing to coefficients based on rematrixing flags.
356
 */
357
static void apply_rematrixing(AC3EncodeContext *s)
358
{
359
    int nb_coefs;
360
    int blk, bnd, i;
361
    int start, end;
362
    uint8_t *flags;
363

    
364
    if (s->rematrixing == AC3_REMATRIXING_NONE)
365
        return;
366

    
367
    nb_coefs = FFMIN(s->nb_coefs[0], s->nb_coefs[1]);
368

    
369
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
370
        AC3Block *block = &s->blocks[blk];
371
        if (block->new_rematrixing_strategy)
372
            flags = block->rematrixing_flags;
373
        for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++) {
374
            if (flags[bnd]) {
375
                start = ff_ac3_rematrix_band_tab[bnd];
376
                end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
377
                for (i = start; i < end; i++) {
378
                    int32_t lt = block->fixed_coef[0][i];
379
                    int32_t rt = block->fixed_coef[1][i];
380
                    block->fixed_coef[0][i] = (lt + rt) >> 1;
381
                    block->fixed_coef[1][i] = (lt - rt) >> 1;
382
                }
383
            }
384
        }
385
    }
386
}
387

    
388

    
389
/**
390
 * Initialize exponent tables.
391
 */
392
static av_cold void exponent_init(AC3EncodeContext *s)
393
{
394
    int i;
395
    for (i = 73; i < 256; i++) {
396
        exponent_group_tab[0][i] = (i - 1) /  3;
397
        exponent_group_tab[1][i] = (i + 2) /  6;
398
        exponent_group_tab[2][i] = (i + 8) / 12;
399
    }
400
    /* LFE */
401
    exponent_group_tab[0][7] = 2;
402
}
403

    
404

    
405
/**
406
 * Extract exponents from the MDCT coefficients.
407
 * This takes into account the normalization that was done to the input samples
408
 * by adjusting the exponents by the exponent shift values.
409
 */
410
static void extract_exponents(AC3EncodeContext *s)
411
{
412
    int blk, ch, i;
413

    
414
    for (ch = 0; ch < s->channels; ch++) {
415
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
416
            AC3Block *block = &s->blocks[blk];
417
            uint8_t *exp   = block->exp[ch];
418
            int32_t *coef = block->fixed_coef[ch];
419
            int exp_shift  = block->exp_shift[ch];
420
            for (i = 0; i < AC3_MAX_COEFS; i++) {
421
                int e;
422
                int v = abs(coef[i]);
423
                if (v == 0)
424
                    e = 24;
425
                else {
426
                    e = 23 - av_log2(v) + exp_shift;
427
                    if (e >= 24) {
428
                        e = 24;
429
                        coef[i] = 0;
430
                    }
431
                    av_assert2(e >= 0);
432
                }
433
                exp[i] = e;
434
            }
435
        }
436
    }
437
}
438

    
439

    
440
/**
441
 * Exponent Difference Threshold.
442
 * New exponents are sent if their SAD exceed this number.
443
 */
444
#define EXP_DIFF_THRESHOLD 500
445

    
446

    
447
/**
448
 * Calculate exponent strategies for all blocks in a single channel.
449
 */
450
static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy,
451
                                    uint8_t *exp)
452
{
453
    int blk, blk1;
454
    int exp_diff;
455

    
456
    /* estimate if the exponent variation & decide if they should be
457
       reused in the next frame */
458
    exp_strategy[0] = EXP_NEW;
459
    exp += AC3_MAX_COEFS;
460
    for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
461
        exp_diff = s->dsp.sad[0](NULL, exp, exp - AC3_MAX_COEFS, 16, 16);
462
        if (exp_diff > EXP_DIFF_THRESHOLD)
463
            exp_strategy[blk] = EXP_NEW;
464
        else
465
            exp_strategy[blk] = EXP_REUSE;
466
        exp += AC3_MAX_COEFS;
467
    }
468

    
469
    /* now select the encoding strategy type : if exponents are often
470
       recoded, we use a coarse encoding */
471
    blk = 0;
472
    while (blk < AC3_MAX_BLOCKS) {
473
        blk1 = blk + 1;
474
        while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
475
            blk1++;
476
        switch (blk1 - blk) {
477
        case 1:  exp_strategy[blk] = EXP_D45; break;
478
        case 2:
479
        case 3:  exp_strategy[blk] = EXP_D25; break;
480
        default: exp_strategy[blk] = EXP_D15; break;
481
        }
482
        blk = blk1;
483
    }
484
}
485

    
486

    
487
/**
488
 * Calculate exponent strategies for all channels.
489
 * Array arrangement is reversed to simplify the per-channel calculation.
490
 */
491
static void compute_exp_strategy(AC3EncodeContext *s)
492
{
493
    int ch, blk;
494

    
495
    for (ch = 0; ch < s->fbw_channels; ch++) {
496
        compute_exp_strategy_ch(s, s->exp_strategy[ch], s->blocks[0].exp[ch]);
497
    }
498
    if (s->lfe_on) {
499
        ch = s->lfe_channel;
500
        s->exp_strategy[ch][0] = EXP_D15;
501
        for (blk = 1; blk < AC3_MAX_BLOCKS; blk++)
502
            s->exp_strategy[ch][blk] = EXP_REUSE;
503
    }
504
}
505

    
506

    
507
/**
508
 * Update the exponents so that they are the ones the decoder will decode.
509
 */
510
static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy)
511
{
512
    int nb_groups, i, k;
513

    
514
    nb_groups = exponent_group_tab[exp_strategy-1][nb_exps] * 3;
515

    
516
    /* for each group, compute the minimum exponent */
517
    switch(exp_strategy) {
518
    case EXP_D25:
519
        for (i = 1, k = 1; i <= nb_groups; i++) {
520
            uint8_t exp_min = exp[k];
521
            if (exp[k+1] < exp_min)
522
                exp_min = exp[k+1];
523
            exp[i] = exp_min;
524
            k += 2;
525
        }
526
        break;
527
    case EXP_D45:
528
        for (i = 1, k = 1; i <= nb_groups; i++) {
529
            uint8_t exp_min = exp[k];
530
            if (exp[k+1] < exp_min)
531
                exp_min = exp[k+1];
532
            if (exp[k+2] < exp_min)
533
                exp_min = exp[k+2];
534
            if (exp[k+3] < exp_min)
535
                exp_min = exp[k+3];
536
            exp[i] = exp_min;
537
            k += 4;
538
        }
539
        break;
540
    }
541

    
542
    /* constraint for DC exponent */
543
    if (exp[0] > 15)
544
        exp[0] = 15;
545

    
546
    /* decrease the delta between each groups to within 2 so that they can be
547
       differentially encoded */
548
    for (i = 1; i <= nb_groups; i++)
549
        exp[i] = FFMIN(exp[i], exp[i-1] + 2);
550
    i--;
551
    while (--i >= 0)
552
        exp[i] = FFMIN(exp[i], exp[i+1] + 2);
553

    
554
    /* now we have the exponent values the decoder will see */
555
    switch (exp_strategy) {
556
    case EXP_D25:
557
        for (i = nb_groups, k = nb_groups * 2; i > 0; i--) {
558
            uint8_t exp1 = exp[i];
559
            exp[k--] = exp1;
560
            exp[k--] = exp1;
561
        }
562
        break;
563
    case EXP_D45:
564
        for (i = nb_groups, k = nb_groups * 4; i > 0; i--) {
565
            exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i];
566
            k -= 4;
567
        }
568
        break;
569
    }
570
}
571

    
572

    
573
/**
574
 * Encode exponents from original extracted form to what the decoder will see.
575
 * This copies and groups exponents based on exponent strategy and reduces
576
 * deltas between adjacent exponent groups so that they can be differentially
577
 * encoded.
578
 */
579
static void encode_exponents(AC3EncodeContext *s)
580
{
581
    int blk, blk1, ch;
582
    uint8_t *exp, *exp1, *exp_strategy;
583
    int nb_coefs, num_reuse_blocks;
584

    
585
    for (ch = 0; ch < s->channels; ch++) {
586
        exp          = s->blocks[0].exp[ch];
587
        exp_strategy = s->exp_strategy[ch];
588
        nb_coefs     = s->nb_coefs[ch];
589

    
590
        blk = 0;
591
        while (blk < AC3_MAX_BLOCKS) {
592
            blk1 = blk + 1;
593

    
594
            /* count the number of EXP_REUSE blocks after the current block */
595
            while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
596
                blk1++;
597
            num_reuse_blocks = blk1 - blk - 1;
598

    
599
            /* for the EXP_REUSE case we select the min of the exponents */
600
            s->ac3dsp.ac3_exponent_min(exp, num_reuse_blocks, nb_coefs);
601

    
602
            encode_exponents_blk_ch(exp, nb_coefs, exp_strategy[blk]);
603

    
604
            /* copy encoded exponents for reuse case */
605
            exp1 = exp + AC3_MAX_COEFS;
606
            while (blk < blk1-1) {
607
                memcpy(exp1, exp, nb_coefs * sizeof(*exp));
608
                exp1 += AC3_MAX_COEFS;
609
                blk++;
610
            }
611
            blk = blk1;
612
            exp = exp1;
613
        }
614
    }
615
}
616

    
617

    
618
/**
619
 * Group exponents.
620
 * 3 delta-encoded exponents are in each 7-bit group. The number of groups
621
 * varies depending on exponent strategy and bandwidth.
622
 */
623
static void group_exponents(AC3EncodeContext *s)
624
{
625
    int blk, ch, i;
626
    int group_size, nb_groups, bit_count;
627
    uint8_t *p;
628
    int delta0, delta1, delta2;
629
    int exp0, exp1;
630

    
631
    bit_count = 0;
632
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
633
        AC3Block *block = &s->blocks[blk];
634
        for (ch = 0; ch < s->channels; ch++) {
635
            int exp_strategy = s->exp_strategy[ch][blk];
636
            if (exp_strategy == EXP_REUSE)
637
                continue;
638
            group_size = exp_strategy + (exp_strategy == EXP_D45);
639
            nb_groups = exponent_group_tab[exp_strategy-1][s->nb_coefs[ch]];
640
            bit_count += 4 + (nb_groups * 7);
641
            p = block->exp[ch];
642

    
643
            /* DC exponent */
644
            exp1 = *p++;
645
            block->grouped_exp[ch][0] = exp1;
646

    
647
            /* remaining exponents are delta encoded */
648
            for (i = 1; i <= nb_groups; i++) {
649
                /* merge three delta in one code */
650
                exp0   = exp1;
651
                exp1   = p[0];
652
                p     += group_size;
653
                delta0 = exp1 - exp0 + 2;
654
                av_assert2(delta0 >= 0 && delta0 <= 4);
655

    
656
                exp0   = exp1;
657
                exp1   = p[0];
658
                p     += group_size;
659
                delta1 = exp1 - exp0 + 2;
660
                av_assert2(delta1 >= 0 && delta1 <= 4);
661

    
662
                exp0   = exp1;
663
                exp1   = p[0];
664
                p     += group_size;
665
                delta2 = exp1 - exp0 + 2;
666
                av_assert2(delta2 >= 0 && delta2 <= 4);
667

    
668
                block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
669
            }
670
        }
671
    }
672

    
673
    s->exponent_bits = bit_count;
674
}
675

    
676

    
677
/**
678
 * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
679
 * Extract exponents from MDCT coefficients, calculate exponent strategies,
680
 * and encode final exponents.
681
 */
682
static void process_exponents(AC3EncodeContext *s)
683
{
684
    extract_exponents(s);
685

    
686
    compute_exp_strategy(s);
687

    
688
    encode_exponents(s);
689

    
690
    group_exponents(s);
691

    
692
    emms_c();
693
}
694

    
695

    
696
/**
697
 * Count frame bits that are based solely on fixed parameters.
698
 * This only has to be run once when the encoder is initialized.
699
 */
700
static void count_frame_bits_fixed(AC3EncodeContext *s)
701
{
702
    static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
703
    int blk;
704
    int frame_bits;
705

    
706
    /* assumptions:
707
     *   no dynamic range codes
708
     *   no channel coupling
709
     *   bit allocation parameters do not change between blocks
710
     *   SNR offsets do not change between blocks
711
     *   no delta bit allocation
712
     *   no skipped data
713
     *   no auxilliary data
714
     */
715

    
716
    /* header size */
717
    frame_bits = 65;
718
    frame_bits += frame_bits_inc[s->channel_mode];
719

    
720
    /* audio blocks */
721
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
722
        frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
723
        if (s->channel_mode == AC3_CHMODE_STEREO) {
724
            frame_bits++; /* rematstr */
725
        }
726
        frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
727
        if (s->lfe_on)
728
            frame_bits++; /* lfeexpstr */
729
        frame_bits++; /* baie */
730
        frame_bits++; /* snr */
731
        frame_bits += 2; /* delta / skip */
732
    }
733
    frame_bits++; /* cplinu for block 0 */
734
    /* bit alloc info */
735
    /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
736
    /* csnroffset[6] */
737
    /* (fsnoffset[4] + fgaincod[4]) * c */
738
    frame_bits += 2*4 + 3 + 6 + s->channels * (4 + 3);
739

    
740
    /* auxdatae, crcrsv */
741
    frame_bits += 2;
742

    
743
    /* CRC */
744
    frame_bits += 16;
745

    
746
    s->frame_bits_fixed = frame_bits;
747
}
748

    
749

    
750
/**
751
 * Initialize bit allocation.
752
 * Set default parameter codes and calculate parameter values.
753
 */
754
static void bit_alloc_init(AC3EncodeContext *s)
755
{
756
    int ch;
757

    
758
    /* init default parameters */
759
    s->slow_decay_code = 2;
760
    s->fast_decay_code = 1;
761
    s->slow_gain_code  = 1;
762
    s->db_per_bit_code = 3;
763
    s->floor_code      = 7;
764
    for (ch = 0; ch < s->channels; ch++)
765
        s->fast_gain_code[ch] = 4;
766

    
767
    /* initial snr offset */
768
    s->coarse_snr_offset = 40;
769

    
770
    /* compute real values */
771
    /* currently none of these values change during encoding, so we can just
772
       set them once at initialization */
773
    s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
774
    s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
775
    s->bit_alloc.slow_gain  = ff_ac3_slow_gain_tab[s->slow_gain_code];
776
    s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
777
    s->bit_alloc.floor      = ff_ac3_floor_tab[s->floor_code];
778

    
779
    count_frame_bits_fixed(s);
780
}
781

    
782

    
783
/**
784
 * Count the bits used to encode the frame, minus exponents and mantissas.
785
 * Bits based on fixed parameters have already been counted, so now we just
786
 * have to add the bits based on parameters that change during encoding.
787
 */
788
static void count_frame_bits(AC3EncodeContext *s)
789
{
790
    int blk, ch;
791
    int frame_bits = 0;
792

    
793
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
794
        /* stereo rematrixing */
795
        if (s->channel_mode == AC3_CHMODE_STEREO &&
796
            s->blocks[blk].new_rematrixing_strategy) {
797
            frame_bits += s->num_rematrixing_bands;
798
        }
799

    
800
        for (ch = 0; ch < s->fbw_channels; ch++) {
801
            if (s->exp_strategy[ch][blk] != EXP_REUSE)
802
                frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
803
        }
804
    }
805
    s->frame_bits = s->frame_bits_fixed + frame_bits;
806
}
807

    
808

    
809
/**
810
 * Calculate the number of bits needed to encode a set of mantissas.
811
 */
812
static int compute_mantissa_size(int mant_cnt[5], uint8_t *bap, int nb_coefs)
813
{
814
    int bits, b, i;
815

    
816
    bits = 0;
817
    for (i = 0; i < nb_coefs; i++) {
818
        b = bap[i];
819
        if (b <= 4) {
820
            // bap=1 to bap=4 will be counted in compute_mantissa_size_final
821
            mant_cnt[b]++;
822
        } else if (b <= 13) {
823
            // bap=5 to bap=13 use (bap-1) bits
824
            bits += b - 1;
825
        } else {
826
            // bap=14 uses 14 bits and bap=15 uses 16 bits
827
            bits += (b == 14) ? 14 : 16;
828
        }
829
    }
830
    return bits;
831
}
832

    
833

    
834
/**
835
 * Finalize the mantissa bit count by adding in the grouped mantissas.
836
 */
837
static int compute_mantissa_size_final(int mant_cnt[5])
838
{
839
    // bap=1 : 3 mantissas in 5 bits
840
    int bits = (mant_cnt[1] / 3) * 5;
841
    // bap=2 : 3 mantissas in 7 bits
842
    // bap=4 : 2 mantissas in 7 bits
843
    bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7;
844
    // bap=3 : each mantissa is 3 bits
845
    bits += mant_cnt[3] * 3;
846
    return bits;
847
}
848

    
849

    
850
/**
851
 * Calculate masking curve based on the final exponents.
852
 * Also calculate the power spectral densities to use in future calculations.
853
 */
854
static void bit_alloc_masking(AC3EncodeContext *s)
855
{
856
    int blk, ch;
857

    
858
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
859
        AC3Block *block = &s->blocks[blk];
860
        for (ch = 0; ch < s->channels; ch++) {
861
            /* We only need psd and mask for calculating bap.
862
               Since we currently do not calculate bap when exponent
863
               strategy is EXP_REUSE we do not need to calculate psd or mask. */
864
            if (s->exp_strategy[ch][blk] != EXP_REUSE) {
865
                ff_ac3_bit_alloc_calc_psd(block->exp[ch], 0,
866
                                          s->nb_coefs[ch],
867
                                          block->psd[ch], block->band_psd[ch]);
868
                ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
869
                                           0, s->nb_coefs[ch],
870
                                           ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
871
                                           ch == s->lfe_channel,
872
                                           DBA_NONE, 0, NULL, NULL, NULL,
873
                                           block->mask[ch]);
874
            }
875
        }
876
    }
877
}
878

    
879

    
880
/**
881
 * Ensure that bap for each block and channel point to the current bap_buffer.
882
 * They may have been switched during the bit allocation search.
883
 */
884
static void reset_block_bap(AC3EncodeContext *s)
885
{
886
    int blk, ch;
887
    if (s->blocks[0].bap[0] == s->bap_buffer)
888
        return;
889
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
890
        for (ch = 0; ch < s->channels; ch++) {
891
            s->blocks[blk].bap[ch] = &s->bap_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
892
        }
893
    }
894
}
895

    
896

    
897
/**
898
 * Run the bit allocation with a given SNR offset.
899
 * This calculates the bit allocation pointers that will be used to determine
900
 * the quantization of each mantissa.
901
 * @return the number of bits needed for mantissas if the given SNR offset is
902
 *         is used.
903
 */
904
static int bit_alloc(AC3EncodeContext *s, int snr_offset)
905
{
906
    int blk, ch;
907
    int mantissa_bits;
908
    int mant_cnt[5];
909

    
910
    snr_offset = (snr_offset - 240) << 2;
911

    
912
    reset_block_bap(s);
913
    mantissa_bits = 0;
914
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
915
        AC3Block *block = &s->blocks[blk];
916
        // initialize grouped mantissa counts. these are set so that they are
917
        // padded to the next whole group size when bits are counted in
918
        // compute_mantissa_size_final
919
        mant_cnt[0] = mant_cnt[3] = 0;
920
        mant_cnt[1] = mant_cnt[2] = 2;
921
        mant_cnt[4] = 1;
922
        for (ch = 0; ch < s->channels; ch++) {
923
            /* Currently the only bit allocation parameters which vary across
924
               blocks within a frame are the exponent values.  We can take
925
               advantage of that by reusing the bit allocation pointers
926
               whenever we reuse exponents. */
927
            if (s->exp_strategy[ch][blk] == EXP_REUSE) {
928
                memcpy(block->bap[ch], s->blocks[blk-1].bap[ch], AC3_MAX_COEFS);
929
            } else {
930
                ff_ac3_bit_alloc_calc_bap(block->mask[ch], block->psd[ch], 0,
931
                                          s->nb_coefs[ch], snr_offset,
932
                                          s->bit_alloc.floor, ff_ac3_bap_tab,
933
                                          block->bap[ch]);
934
            }
935
            mantissa_bits += compute_mantissa_size(mant_cnt, block->bap[ch], s->nb_coefs[ch]);
936
        }
937
        mantissa_bits += compute_mantissa_size_final(mant_cnt);
938
    }
939
    return mantissa_bits;
940
}
941

    
942

    
943
/**
944
 * Constant bitrate bit allocation search.
945
 * Find the largest SNR offset that will allow data to fit in the frame.
946
 */
947
static int cbr_bit_allocation(AC3EncodeContext *s)
948
{
949
    int ch;
950
    int bits_left;
951
    int snr_offset, snr_incr;
952

    
953
    bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
954
    av_assert2(bits_left >= 0);
955

    
956
    snr_offset = s->coarse_snr_offset << 4;
957

    
958
    /* if previous frame SNR offset was 1023, check if current frame can also
959
       use SNR offset of 1023. if so, skip the search. */
960
    if ((snr_offset | s->fine_snr_offset[0]) == 1023) {
961
        if (bit_alloc(s, 1023) <= bits_left)
962
            return 0;
963
    }
964

    
965
    while (snr_offset >= 0 &&
966
           bit_alloc(s, snr_offset) > bits_left) {
967
        snr_offset -= 64;
968
    }
969
    if (snr_offset < 0)
970
        return AVERROR(EINVAL);
971

    
972
    FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
973
    for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
974
        while (snr_offset + snr_incr <= 1023 &&
975
               bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
976
            snr_offset += snr_incr;
977
            FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
978
        }
979
    }
980
    FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
981
    reset_block_bap(s);
982

    
983
    s->coarse_snr_offset = snr_offset >> 4;
984
    for (ch = 0; ch < s->channels; ch++)
985
        s->fine_snr_offset[ch] = snr_offset & 0xF;
986

    
987
    return 0;
988
}
989

    
990

    
991
/**
992
 * Downgrade exponent strategies to reduce the bits used by the exponents.
993
 * This is a fallback for when bit allocation fails with the normal exponent
994
 * strategies.  Each time this function is run it only downgrades the
995
 * strategy in 1 channel of 1 block.
996
 * @return non-zero if downgrade was unsuccessful
997
 */
998
static int downgrade_exponents(AC3EncodeContext *s)
999
{
1000
    int ch, blk;
1001

    
1002
    for (ch = 0; ch < s->fbw_channels; ch++) {
1003
        for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
1004
            if (s->exp_strategy[ch][blk] == EXP_D15) {
1005
                s->exp_strategy[ch][blk] = EXP_D25;
1006
                return 0;
1007
            }
1008
        }
1009
    }
1010
    for (ch = 0; ch < s->fbw_channels; ch++) {
1011
        for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
1012
            if (s->exp_strategy[ch][blk] == EXP_D25) {
1013
                s->exp_strategy[ch][blk] = EXP_D45;
1014
                return 0;
1015
            }
1016
        }
1017
    }
1018
    for (ch = 0; ch < s->fbw_channels; ch++) {
1019
        /* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if
1020
           the block number > 0 */
1021
        for (blk = AC3_MAX_BLOCKS-1; blk > 0; blk--) {
1022
            if (s->exp_strategy[ch][blk] > EXP_REUSE) {
1023
                s->exp_strategy[ch][blk] = EXP_REUSE;
1024
                return 0;
1025
            }
1026
        }
1027
    }
1028
    return -1;
1029
}
1030

    
1031

    
1032
/**
1033
 * Reduce the bandwidth to reduce the number of bits used for a given SNR offset.
1034
 * This is a second fallback for when bit allocation still fails after exponents
1035
 * have been downgraded.
1036
 * @return non-zero if bandwidth reduction was unsuccessful
1037
 */
1038
static int reduce_bandwidth(AC3EncodeContext *s, int min_bw_code)
1039
{
1040
    int ch;
1041

    
1042
    if (s->bandwidth_code[0] > min_bw_code) {
1043
        for (ch = 0; ch < s->fbw_channels; ch++) {
1044
            s->bandwidth_code[ch]--;
1045
            s->nb_coefs[ch] = s->bandwidth_code[ch] * 3 + 73;
1046
        }
1047
        return 0;
1048
    }
1049
    return -1;
1050
}
1051

    
1052

    
1053
/**
1054
 * Perform bit allocation search.
1055
 * Finds the SNR offset value that maximizes quality and fits in the specified
1056
 * frame size.  Output is the SNR offset and a set of bit allocation pointers
1057
 * used to quantize the mantissas.
1058
 */
1059
static int compute_bit_allocation(AC3EncodeContext *s)
1060
{
1061
    int ret;
1062

    
1063
    count_frame_bits(s);
1064

    
1065
    bit_alloc_masking(s);
1066

    
1067
    ret = cbr_bit_allocation(s);
1068
    while (ret) {
1069
        /* fallback 1: downgrade exponents */
1070
        if (!downgrade_exponents(s)) {
1071
            extract_exponents(s);
1072
            encode_exponents(s);
1073
            group_exponents(s);
1074
            ret = compute_bit_allocation(s);
1075
            continue;
1076
        }
1077

    
1078
        /* fallback 2: reduce bandwidth */
1079
        /* only do this if the user has not specified a specific cutoff
1080
           frequency */
1081
        if (!s->cutoff && !reduce_bandwidth(s, 0)) {
1082
            process_exponents(s);
1083
            ret = compute_bit_allocation(s);
1084
            continue;
1085
        }
1086

    
1087
        /* fallbacks were not enough... */
1088
        break;
1089
    }
1090

    
1091
    return ret;
1092
}
1093

    
1094

    
1095
/**
1096
 * Symmetric quantization on 'levels' levels.
1097
 */
1098
static inline int sym_quant(int c, int e, int levels)
1099
{
1100
    int v;
1101

    
1102
    if (c >= 0) {
1103
        v = (levels * (c << e)) >> 24;
1104
        v = (v + 1) >> 1;
1105
        v = (levels >> 1) + v;
1106
    } else {
1107
        v = (levels * ((-c) << e)) >> 24;
1108
        v = (v + 1) >> 1;
1109
        v = (levels >> 1) - v;
1110
    }
1111
    av_assert2(v >= 0 && v < levels);
1112
    return v;
1113
}
1114

    
1115

    
1116
/**
1117
 * Asymmetric quantization on 2^qbits levels.
1118
 */
1119
static inline int asym_quant(int c, int e, int qbits)
1120
{
1121
    int lshift, m, v;
1122

    
1123
    lshift = e + qbits - 24;
1124
    if (lshift >= 0)
1125
        v = c << lshift;
1126
    else
1127
        v = c >> (-lshift);
1128
    /* rounding */
1129
    v = (v + 1) >> 1;
1130
    m = (1 << (qbits-1));
1131
    if (v >= m)
1132
        v = m - 1;
1133
    av_assert2(v >= -m);
1134
    return v & ((1 << qbits)-1);
1135
}
1136

    
1137

    
1138
/**
1139
 * Quantize a set of mantissas for a single channel in a single block.
1140
 */
1141
static void quantize_mantissas_blk_ch(AC3EncodeContext *s, int32_t *fixed_coef,
1142
                                      int8_t exp_shift, uint8_t *exp,
1143
                                      uint8_t *bap, uint16_t *qmant, int n)
1144
{
1145
    int i;
1146

    
1147
    for (i = 0; i < n; i++) {
1148
        int v;
1149
        int c = fixed_coef[i];
1150
        int e = exp[i] - exp_shift;
1151
        int b = bap[i];
1152
        switch (b) {
1153
        case 0:
1154
            v = 0;
1155
            break;
1156
        case 1:
1157
            v = sym_quant(c, e, 3);
1158
            switch (s->mant1_cnt) {
1159
            case 0:
1160
                s->qmant1_ptr = &qmant[i];
1161
                v = 9 * v;
1162
                s->mant1_cnt = 1;
1163
                break;
1164
            case 1:
1165
                *s->qmant1_ptr += 3 * v;
1166
                s->mant1_cnt = 2;
1167
                v = 128;
1168
                break;
1169
            default:
1170
                *s->qmant1_ptr += v;
1171
                s->mant1_cnt = 0;
1172
                v = 128;
1173
                break;
1174
            }
1175
            break;
1176
        case 2:
1177
            v = sym_quant(c, e, 5);
1178
            switch (s->mant2_cnt) {
1179
            case 0:
1180
                s->qmant2_ptr = &qmant[i];
1181
                v = 25 * v;
1182
                s->mant2_cnt = 1;
1183
                break;
1184
            case 1:
1185
                *s->qmant2_ptr += 5 * v;
1186
                s->mant2_cnt = 2;
1187
                v = 128;
1188
                break;
1189
            default:
1190
                *s->qmant2_ptr += v;
1191
                s->mant2_cnt = 0;
1192
                v = 128;
1193
                break;
1194
            }
1195
            break;
1196
        case 3:
1197
            v = sym_quant(c, e, 7);
1198
            break;
1199
        case 4:
1200
            v = sym_quant(c, e, 11);
1201
            switch (s->mant4_cnt) {
1202
            case 0:
1203
                s->qmant4_ptr = &qmant[i];
1204
                v = 11 * v;
1205
                s->mant4_cnt = 1;
1206
                break;
1207
            default:
1208
                *s->qmant4_ptr += v;
1209
                s->mant4_cnt = 0;
1210
                v = 128;
1211
                break;
1212
            }
1213
            break;
1214
        case 5:
1215
            v = sym_quant(c, e, 15);
1216
            break;
1217
        case 14:
1218
            v = asym_quant(c, e, 14);
1219
            break;
1220
        case 15:
1221
            v = asym_quant(c, e, 16);
1222
            break;
1223
        default:
1224
            v = asym_quant(c, e, b - 1);
1225
            break;
1226
        }
1227
        qmant[i] = v;
1228
    }
1229
}
1230

    
1231

    
1232
/**
1233
 * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
1234
 */
1235
static void quantize_mantissas(AC3EncodeContext *s)
1236
{
1237
    int blk, ch;
1238

    
1239

    
1240
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1241
        AC3Block *block = &s->blocks[blk];
1242
        s->mant1_cnt  = s->mant2_cnt  = s->mant4_cnt  = 0;
1243
        s->qmant1_ptr = s->qmant2_ptr = s->qmant4_ptr = NULL;
1244

    
1245
        for (ch = 0; ch < s->channels; ch++) {
1246
            quantize_mantissas_blk_ch(s, block->fixed_coef[ch], block->exp_shift[ch],
1247
                                      block->exp[ch], block->bap[ch],
1248
                                      block->qmant[ch], s->nb_coefs[ch]);
1249
        }
1250
    }
1251
}
1252

    
1253

    
1254
/**
1255
 * Write the AC-3 frame header to the output bitstream.
1256
 */
1257
static void output_frame_header(AC3EncodeContext *s)
1258
{
1259
    put_bits(&s->pb, 16, 0x0b77);   /* frame header */
1260
    put_bits(&s->pb, 16, 0);        /* crc1: will be filled later */
1261
    put_bits(&s->pb, 2,  s->bit_alloc.sr_code);
1262
    put_bits(&s->pb, 6,  s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
1263
    put_bits(&s->pb, 5,  s->bitstream_id);
1264
    put_bits(&s->pb, 3,  s->bitstream_mode);
1265
    put_bits(&s->pb, 3,  s->channel_mode);
1266
    if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
1267
        put_bits(&s->pb, 2, 1);     /* XXX -4.5 dB */
1268
    if (s->channel_mode & 0x04)
1269
        put_bits(&s->pb, 2, 1);     /* XXX -6 dB */
1270
    if (s->channel_mode == AC3_CHMODE_STEREO)
1271
        put_bits(&s->pb, 2, 0);     /* surround not indicated */
1272
    put_bits(&s->pb, 1, s->lfe_on); /* LFE */
1273
    put_bits(&s->pb, 5, 31);        /* dialog norm: -31 db */
1274
    put_bits(&s->pb, 1, 0);         /* no compression control word */
1275
    put_bits(&s->pb, 1, 0);         /* no lang code */
1276
    put_bits(&s->pb, 1, 0);         /* no audio production info */
1277
    put_bits(&s->pb, 1, 0);         /* no copyright */
1278
    put_bits(&s->pb, 1, 1);         /* original bitstream */
1279
    put_bits(&s->pb, 1, 0);         /* no time code 1 */
1280
    put_bits(&s->pb, 1, 0);         /* no time code 2 */
1281
    put_bits(&s->pb, 1, 0);         /* no additional bit stream info */
1282
}
1283

    
1284

    
1285
/**
1286
 * Write one audio block to the output bitstream.
1287
 */
1288
static void output_audio_block(AC3EncodeContext *s, int blk)
1289
{
1290
    int ch, i, baie, rbnd;
1291
    AC3Block *block = &s->blocks[blk];
1292

    
1293
    /* block switching */
1294
    for (ch = 0; ch < s->fbw_channels; ch++)
1295
        put_bits(&s->pb, 1, 0);
1296

    
1297
    /* dither flags */
1298
    for (ch = 0; ch < s->fbw_channels; ch++)
1299
        put_bits(&s->pb, 1, 1);
1300

    
1301
    /* dynamic range codes */
1302
    put_bits(&s->pb, 1, 0);
1303

    
1304
    /* channel coupling */
1305
    if (!blk) {
1306
        put_bits(&s->pb, 1, 1); /* coupling strategy present */
1307
        put_bits(&s->pb, 1, 0); /* no coupling strategy */
1308
    } else {
1309
        put_bits(&s->pb, 1, 0); /* no new coupling strategy */
1310
    }
1311

    
1312
    /* stereo rematrixing */
1313
    if (s->channel_mode == AC3_CHMODE_STEREO) {
1314
        put_bits(&s->pb, 1, block->new_rematrixing_strategy);
1315
        if (block->new_rematrixing_strategy) {
1316
            /* rematrixing flags */
1317
            for (rbnd = 0; rbnd < s->num_rematrixing_bands; rbnd++)
1318
                put_bits(&s->pb, 1, block->rematrixing_flags[rbnd]);
1319
        }
1320
    }
1321

    
1322
    /* exponent strategy */
1323
    for (ch = 0; ch < s->fbw_channels; ch++)
1324
        put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
1325
    if (s->lfe_on)
1326
        put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
1327

    
1328
    /* bandwidth */
1329
    for (ch = 0; ch < s->fbw_channels; ch++) {
1330
        if (s->exp_strategy[ch][blk] != EXP_REUSE)
1331
            put_bits(&s->pb, 6, s->bandwidth_code[ch]);
1332
    }
1333

    
1334
    /* exponents */
1335
    for (ch = 0; ch < s->channels; ch++) {
1336
        int nb_groups;
1337

    
1338
        if (s->exp_strategy[ch][blk] == EXP_REUSE)
1339
            continue;
1340

    
1341
        /* DC exponent */
1342
        put_bits(&s->pb, 4, block->grouped_exp[ch][0]);
1343

    
1344
        /* exponent groups */
1345
        nb_groups = exponent_group_tab[s->exp_strategy[ch][blk]-1][s->nb_coefs[ch]];
1346
        for (i = 1; i <= nb_groups; i++)
1347
            put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
1348

    
1349
        /* gain range info */
1350
        if (ch != s->lfe_channel)
1351
            put_bits(&s->pb, 2, 0);
1352
    }
1353

    
1354
    /* bit allocation info */
1355
    baie = (blk == 0);
1356
    put_bits(&s->pb, 1, baie);
1357
    if (baie) {
1358
        put_bits(&s->pb, 2, s->slow_decay_code);
1359
        put_bits(&s->pb, 2, s->fast_decay_code);
1360
        put_bits(&s->pb, 2, s->slow_gain_code);
1361
        put_bits(&s->pb, 2, s->db_per_bit_code);
1362
        put_bits(&s->pb, 3, s->floor_code);
1363
    }
1364

    
1365
    /* snr offset */
1366
    put_bits(&s->pb, 1, baie);
1367
    if (baie) {
1368
        put_bits(&s->pb, 6, s->coarse_snr_offset);
1369
        for (ch = 0; ch < s->channels; ch++) {
1370
            put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
1371
            put_bits(&s->pb, 3, s->fast_gain_code[ch]);
1372
        }
1373
    }
1374

    
1375
    put_bits(&s->pb, 1, 0); /* no delta bit allocation */
1376
    put_bits(&s->pb, 1, 0); /* no data to skip */
1377

    
1378
    /* mantissas */
1379
    for (ch = 0; ch < s->channels; ch++) {
1380
        int b, q;
1381
        for (i = 0; i < s->nb_coefs[ch]; i++) {
1382
            q = block->qmant[ch][i];
1383
            b = block->bap[ch][i];
1384
            switch (b) {
1385
            case 0:                                         break;
1386
            case 1: if (q != 128) put_bits(&s->pb,   5, q); break;
1387
            case 2: if (q != 128) put_bits(&s->pb,   7, q); break;
1388
            case 3:               put_bits(&s->pb,   3, q); break;
1389
            case 4: if (q != 128) put_bits(&s->pb,   7, q); break;
1390
            case 14:              put_bits(&s->pb,  14, q); break;
1391
            case 15:              put_bits(&s->pb,  16, q); break;
1392
            default:              put_bits(&s->pb, b-1, q); break;
1393
            }
1394
        }
1395
    }
1396
}
1397

    
1398

    
1399
/** CRC-16 Polynomial */
1400
#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
1401

    
1402

    
1403
static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
1404
{
1405
    unsigned int c;
1406

    
1407
    c = 0;
1408
    while (a) {
1409
        if (a & 1)
1410
            c ^= b;
1411
        a = a >> 1;
1412
        b = b << 1;
1413
        if (b & (1 << 16))
1414
            b ^= poly;
1415
    }
1416
    return c;
1417
}
1418

    
1419

    
1420
static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
1421
{
1422
    unsigned int r;
1423
    r = 1;
1424
    while (n) {
1425
        if (n & 1)
1426
            r = mul_poly(r, a, poly);
1427
        a = mul_poly(a, a, poly);
1428
        n >>= 1;
1429
    }
1430
    return r;
1431
}
1432

    
1433

    
1434
/**
1435
 * Fill the end of the frame with 0's and compute the two CRCs.
1436
 */
1437
static void output_frame_end(AC3EncodeContext *s)
1438
{
1439
    const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
1440
    int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
1441
    uint8_t *frame;
1442

    
1443
    frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
1444

    
1445
    /* pad the remainder of the frame with zeros */
1446
    av_assert2(s->frame_size * 8 - put_bits_count(&s->pb) >= 18);
1447
    flush_put_bits(&s->pb);
1448
    frame = s->pb.buf;
1449
    pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
1450
    av_assert2(pad_bytes >= 0);
1451
    if (pad_bytes > 0)
1452
        memset(put_bits_ptr(&s->pb), 0, pad_bytes);
1453

    
1454
    /* compute crc1 */
1455
    /* this is not so easy because it is at the beginning of the data... */
1456
    crc1    = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
1457
    crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
1458
    crc1    = mul_poly(crc_inv, crc1, CRC16_POLY);
1459
    AV_WB16(frame + 2, crc1);
1460

    
1461
    /* compute crc2 */
1462
    crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
1463
                          s->frame_size - frame_size_58 - 3);
1464
    crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1465
    /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
1466
    if (crc2 == 0x770B) {
1467
        frame[s->frame_size - 3] ^= 0x1;
1468
        crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1469
    }
1470
    crc2 = av_bswap16(crc2);
1471
    AV_WB16(frame + s->frame_size - 2, crc2);
1472
}
1473

    
1474

    
1475
/**
1476
 * Write the frame to the output bitstream.
1477
 */
1478
static void output_frame(AC3EncodeContext *s, unsigned char *frame)
1479
{
1480
    int blk;
1481

    
1482
    init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
1483

    
1484
    output_frame_header(s);
1485

    
1486
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
1487
        output_audio_block(s, blk);
1488

    
1489
    output_frame_end(s);
1490
}
1491

    
1492

    
1493
/**
1494
 * Encode a single AC-3 frame.
1495
 */
1496
static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
1497
                            int buf_size, void *data)
1498
{
1499
    AC3EncodeContext *s = avctx->priv_data;
1500
    const SampleType *samples = data;
1501
    int ret;
1502

    
1503
    if (s->bit_alloc.sr_code == 1)
1504
        adjust_frame_size(s);
1505

    
1506
    deinterleave_input_samples(s, samples);
1507

    
1508
    apply_mdct(s);
1509

    
1510
    compute_rematrixing_strategy(s);
1511

    
1512
    scale_coefficients(s);
1513

    
1514
    apply_rematrixing(s);
1515

    
1516
    process_exponents(s);
1517

    
1518
    ret = compute_bit_allocation(s);
1519
    if (ret) {
1520
        av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
1521
        return ret;
1522
    }
1523

    
1524
    quantize_mantissas(s);
1525

    
1526
    output_frame(s, frame);
1527

    
1528
    return s->frame_size;
1529
}
1530

    
1531

    
1532
/**
1533
 * Finalize encoding and free any memory allocated by the encoder.
1534
 */
1535
static av_cold int ac3_encode_close(AVCodecContext *avctx)
1536
{
1537
    int blk, ch;
1538
    AC3EncodeContext *s = avctx->priv_data;
1539

    
1540
    for (ch = 0; ch < s->channels; ch++)
1541
        av_freep(&s->planar_samples[ch]);
1542
    av_freep(&s->planar_samples);
1543
    av_freep(&s->bap_buffer);
1544
    av_freep(&s->bap1_buffer);
1545
    av_freep(&s->mdct_coef_buffer);
1546
    av_freep(&s->fixed_coef_buffer);
1547
    av_freep(&s->exp_buffer);
1548
    av_freep(&s->grouped_exp_buffer);
1549
    av_freep(&s->psd_buffer);
1550
    av_freep(&s->band_psd_buffer);
1551
    av_freep(&s->mask_buffer);
1552
    av_freep(&s->qmant_buffer);
1553
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1554
        AC3Block *block = &s->blocks[blk];
1555
        av_freep(&block->bap);
1556
        av_freep(&block->mdct_coef);
1557
        av_freep(&block->fixed_coef);
1558
        av_freep(&block->exp);
1559
        av_freep(&block->grouped_exp);
1560
        av_freep(&block->psd);
1561
        av_freep(&block->band_psd);
1562
        av_freep(&block->mask);
1563
        av_freep(&block->qmant);
1564
    }
1565

    
1566
    mdct_end(&s->mdct);
1567

    
1568
    av_freep(&avctx->coded_frame);
1569
    return 0;
1570
}
1571

    
1572

    
1573
/**
1574
 * Set channel information during initialization.
1575
 */
1576
static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
1577
                                    int64_t *channel_layout)
1578
{
1579
    int ch_layout;
1580

    
1581
    if (channels < 1 || channels > AC3_MAX_CHANNELS)
1582
        return AVERROR(EINVAL);
1583
    if ((uint64_t)*channel_layout > 0x7FF)
1584
        return AVERROR(EINVAL);
1585
    ch_layout = *channel_layout;
1586
    if (!ch_layout)
1587
        ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
1588
    if (av_get_channel_layout_nb_channels(ch_layout) != channels)
1589
        return AVERROR(EINVAL);
1590

    
1591
    s->lfe_on       = !!(ch_layout & AV_CH_LOW_FREQUENCY);
1592
    s->channels     = channels;
1593
    s->fbw_channels = channels - s->lfe_on;
1594
    s->lfe_channel  = s->lfe_on ? s->fbw_channels : -1;
1595
    if (s->lfe_on)
1596
        ch_layout -= AV_CH_LOW_FREQUENCY;
1597

    
1598
    switch (ch_layout) {
1599
    case AV_CH_LAYOUT_MONO:           s->channel_mode = AC3_CHMODE_MONO;   break;
1600
    case AV_CH_LAYOUT_STEREO:         s->channel_mode = AC3_CHMODE_STEREO; break;
1601
    case AV_CH_LAYOUT_SURROUND:       s->channel_mode = AC3_CHMODE_3F;     break;
1602
    case AV_CH_LAYOUT_2_1:            s->channel_mode = AC3_CHMODE_2F1R;   break;
1603
    case AV_CH_LAYOUT_4POINT0:        s->channel_mode = AC3_CHMODE_3F1R;   break;
1604
    case AV_CH_LAYOUT_QUAD:
1605
    case AV_CH_LAYOUT_2_2:            s->channel_mode = AC3_CHMODE_2F2R;   break;
1606
    case AV_CH_LAYOUT_5POINT0:
1607
    case AV_CH_LAYOUT_5POINT0_BACK:   s->channel_mode = AC3_CHMODE_3F2R;   break;
1608
    default:
1609
        return AVERROR(EINVAL);
1610
    }
1611

    
1612
    s->channel_map  = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
1613
    *channel_layout = ch_layout;
1614
    if (s->lfe_on)
1615
        *channel_layout |= AV_CH_LOW_FREQUENCY;
1616

    
1617
    return 0;
1618
}
1619

    
1620

    
1621
static av_cold int validate_options(AVCodecContext *avctx, AC3EncodeContext *s)
1622
{
1623
    int i, ret;
1624

    
1625
    /* validate channel layout */
1626
    if (!avctx->channel_layout) {
1627
        av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
1628
                                      "encoder will guess the layout, but it "
1629
                                      "might be incorrect.\n");
1630
    }
1631
    ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
1632
    if (ret) {
1633
        av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
1634
        return ret;
1635
    }
1636

    
1637
    /* validate sample rate */
1638
    for (i = 0; i < 9; i++) {
1639
        if ((ff_ac3_sample_rate_tab[i / 3] >> (i % 3)) == avctx->sample_rate)
1640
            break;
1641
    }
1642
    if (i == 9) {
1643
        av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
1644
        return AVERROR(EINVAL);
1645
    }
1646
    s->sample_rate        = avctx->sample_rate;
1647
    s->bit_alloc.sr_shift = i % 3;
1648
    s->bit_alloc.sr_code  = i / 3;
1649

    
1650
    /* validate bit rate */
1651
    for (i = 0; i < 19; i++) {
1652
        if ((ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift)*1000 == avctx->bit_rate)
1653
            break;
1654
    }
1655
    if (i == 19) {
1656
        av_log(avctx, AV_LOG_ERROR, "invalid bit rate\n");
1657
        return AVERROR(EINVAL);
1658
    }
1659
    s->bit_rate        = avctx->bit_rate;
1660
    s->frame_size_code = i << 1;
1661

    
1662
    /* validate cutoff */
1663
    if (avctx->cutoff < 0) {
1664
        av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
1665
        return AVERROR(EINVAL);
1666
    }
1667
    s->cutoff = avctx->cutoff;
1668
    if (s->cutoff > (s->sample_rate >> 1))
1669
        s->cutoff = s->sample_rate >> 1;
1670

    
1671
    return 0;
1672
}
1673

    
1674

    
1675
/**
1676
 * Set bandwidth for all channels.
1677
 * The user can optionally supply a cutoff frequency. Otherwise an appropriate
1678
 * default value will be used.
1679
 */
1680
static av_cold void set_bandwidth(AC3EncodeContext *s)
1681
{
1682
    int ch, bw_code;
1683

    
1684
    if (s->cutoff) {
1685
        /* calculate bandwidth based on user-specified cutoff frequency */
1686
        int fbw_coeffs;
1687
        fbw_coeffs     = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
1688
        bw_code        = av_clip((fbw_coeffs - 73) / 3, 0, 60);
1689
    } else {
1690
        /* use default bandwidth setting */
1691
        /* XXX: should compute the bandwidth according to the frame
1692
           size, so that we avoid annoying high frequency artifacts */
1693
        bw_code = 50;
1694
    }
1695

    
1696
    /* set number of coefficients for each channel */
1697
    for (ch = 0; ch < s->fbw_channels; ch++) {
1698
        s->bandwidth_code[ch] = bw_code;
1699
        s->nb_coefs[ch]       = bw_code * 3 + 73;
1700
    }
1701
    if (s->lfe_on)
1702
        s->nb_coefs[s->lfe_channel] = 7; /* LFE channel always has 7 coefs */
1703
}
1704

    
1705

    
1706
static av_cold int allocate_buffers(AVCodecContext *avctx)
1707
{
1708
    int blk, ch;
1709
    AC3EncodeContext *s = avctx->priv_data;
1710

    
1711
    FF_ALLOC_OR_GOTO(avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
1712
                     alloc_fail);
1713
    for (ch = 0; ch < s->channels; ch++) {
1714
        FF_ALLOCZ_OR_GOTO(avctx, s->planar_samples[ch],
1715
                          (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
1716
                          alloc_fail);
1717
    }
1718
    FF_ALLOC_OR_GOTO(avctx, s->bap_buffer,  AC3_MAX_BLOCKS * s->channels *
1719
                     AC3_MAX_COEFS * sizeof(*s->bap_buffer),  alloc_fail);
1720
    FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, AC3_MAX_BLOCKS * s->channels *
1721
                     AC3_MAX_COEFS * sizeof(*s->bap1_buffer), alloc_fail);
1722
    FF_ALLOC_OR_GOTO(avctx, s->mdct_coef_buffer, AC3_MAX_BLOCKS * s->channels *
1723
                     AC3_MAX_COEFS * sizeof(*s->mdct_coef_buffer), alloc_fail);
1724
    FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, AC3_MAX_BLOCKS * s->channels *
1725
                     AC3_MAX_COEFS * sizeof(*s->exp_buffer), alloc_fail);
1726
    FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, AC3_MAX_BLOCKS * s->channels *
1727
                     128 * sizeof(*s->grouped_exp_buffer), alloc_fail);
1728
    FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, AC3_MAX_BLOCKS * s->channels *
1729
                     AC3_MAX_COEFS * sizeof(*s->psd_buffer), alloc_fail);
1730
    FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, AC3_MAX_BLOCKS * s->channels *
1731
                     64 * sizeof(*s->band_psd_buffer), alloc_fail);
1732
    FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, AC3_MAX_BLOCKS * s->channels *
1733
                     64 * sizeof(*s->mask_buffer), alloc_fail);
1734
    FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, AC3_MAX_BLOCKS * s->channels *
1735
                     AC3_MAX_COEFS * sizeof(*s->qmant_buffer), alloc_fail);
1736
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1737
        AC3Block *block = &s->blocks[blk];
1738
        FF_ALLOC_OR_GOTO(avctx, block->bap, s->channels * sizeof(*block->bap),
1739
                         alloc_fail);
1740
        FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, s->channels * sizeof(*block->mdct_coef),
1741
                          alloc_fail);
1742
        FF_ALLOCZ_OR_GOTO(avctx, block->exp, s->channels * sizeof(*block->exp),
1743
                          alloc_fail);
1744
        FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, s->channels * sizeof(*block->grouped_exp),
1745
                          alloc_fail);
1746
        FF_ALLOCZ_OR_GOTO(avctx, block->psd, s->channels * sizeof(*block->psd),
1747
                          alloc_fail);
1748
        FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, s->channels * sizeof(*block->band_psd),
1749
                          alloc_fail);
1750
        FF_ALLOCZ_OR_GOTO(avctx, block->mask, s->channels * sizeof(*block->mask),
1751
                          alloc_fail);
1752
        FF_ALLOCZ_OR_GOTO(avctx, block->qmant, s->channels * sizeof(*block->qmant),
1753
                          alloc_fail);
1754

    
1755
        for (ch = 0; ch < s->channels; ch++) {
1756
            /* arrangement: block, channel, coeff */
1757
            block->bap[ch]         = &s->bap_buffer        [AC3_MAX_COEFS * (blk * s->channels + ch)];
1758
            block->mdct_coef[ch]   = &s->mdct_coef_buffer  [AC3_MAX_COEFS * (blk * s->channels + ch)];
1759
            block->grouped_exp[ch] = &s->grouped_exp_buffer[128           * (blk * s->channels + ch)];
1760
            block->psd[ch]         = &s->psd_buffer        [AC3_MAX_COEFS * (blk * s->channels + ch)];
1761
            block->band_psd[ch]    = &s->band_psd_buffer   [64            * (blk * s->channels + ch)];
1762
            block->mask[ch]        = &s->mask_buffer       [64            * (blk * s->channels + ch)];
1763
            block->qmant[ch]       = &s->qmant_buffer      [AC3_MAX_COEFS * (blk * s->channels + ch)];
1764

    
1765
            /* arrangement: channel, block, coeff */
1766
            block->exp[ch]         = &s->exp_buffer        [AC3_MAX_COEFS * (AC3_MAX_BLOCKS * ch + blk)];
1767
        }
1768
    }
1769

    
1770
    if (CONFIG_AC3ENC_FLOAT) {
1771
        FF_ALLOC_OR_GOTO(avctx, s->fixed_coef_buffer, AC3_MAX_BLOCKS * s->channels *
1772
                         AC3_MAX_COEFS * sizeof(*s->fixed_coef_buffer), alloc_fail);
1773
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1774
            AC3Block *block = &s->blocks[blk];
1775
            FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, s->channels *
1776
                              sizeof(*block->fixed_coef), alloc_fail);
1777
            for (ch = 0; ch < s->channels; ch++)
1778
                block->fixed_coef[ch] = &s->fixed_coef_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
1779
        }
1780
    } else {
1781
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1782
            AC3Block *block = &s->blocks[blk];
1783
            FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, s->channels *
1784
                              sizeof(*block->fixed_coef), alloc_fail);
1785
            for (ch = 0; ch < s->channels; ch++)
1786
                block->fixed_coef[ch] = (int32_t *)block->mdct_coef[ch];
1787
        }
1788
    }
1789

    
1790
    return 0;
1791
alloc_fail:
1792
    return AVERROR(ENOMEM);
1793
}
1794

    
1795

    
1796
/**
1797
 * Initialize the encoder.
1798
 */
1799
static av_cold int ac3_encode_init(AVCodecContext *avctx)
1800
{
1801
    AC3EncodeContext *s = avctx->priv_data;
1802
    int ret, frame_size_58;
1803

    
1804
    avctx->frame_size = AC3_FRAME_SIZE;
1805

    
1806
    ff_ac3_common_init();
1807

    
1808
    ret = validate_options(avctx, s);
1809
    if (ret)
1810
        return ret;
1811

    
1812
    s->bitstream_id   = 8 + s->bit_alloc.sr_shift;
1813
    s->bitstream_mode = 0; /* complete main audio service */
1814

    
1815
    s->frame_size_min  = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
1816
    s->bits_written    = 0;
1817
    s->samples_written = 0;
1818
    s->frame_size      = s->frame_size_min;
1819

    
1820
    /* calculate crc_inv for both possible frame sizes */
1821
    frame_size_58 = (( s->frame_size    >> 2) + ( s->frame_size    >> 4)) << 1;
1822
    s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
1823
    if (s->bit_alloc.sr_code == 1) {
1824
        frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
1825
        s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
1826
    }
1827

    
1828
    set_bandwidth(s);
1829

    
1830
    rematrixing_init(s);
1831

    
1832
    exponent_init(s);
1833

    
1834
    bit_alloc_init(s);
1835

    
1836
    ret = mdct_init(avctx, &s->mdct, 9);
1837
    if (ret)
1838
        goto init_fail;
1839

    
1840
    ret = allocate_buffers(avctx);
1841
    if (ret)
1842
        goto init_fail;
1843

    
1844
    avctx->coded_frame= avcodec_alloc_frame();
1845

    
1846
    dsputil_init(&s->dsp, avctx);
1847
    ff_ac3dsp_init(&s->ac3dsp);
1848

    
1849
    return 0;
1850
init_fail:
1851
    ac3_encode_close(avctx);
1852
    return ret;
1853
}