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/*
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 * The simplest AC-3 encoder
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 * 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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#include "libavcore/audioconvert.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 "ac3.h"
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#include "audioconvert.h"
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39

    
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#ifndef CONFIG_AC3ENC_FLOAT
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#define CONFIG_AC3ENC_FLOAT 0
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#endif
43

    
44

    
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/** Maximum number of exponent groups. +1 for separate DC exponent. */
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#define AC3_MAX_EXP_GROUPS 85
47

    
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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
53

    
54
/** 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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57

    
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#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
63

    
64

    
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/**
66
 * Data for a single audio block.
67
 */
68
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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    uint8_t  exp_strategy[AC3_MAX_CHANNELS];    ///< exponent strategies
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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
82
} AC3Block;
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84
/**
85
 * AC-3 encoder private context.
86
 */
87
typedef struct AC3EncodeContext {
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    PutBitContext pb;                       ///< bitstream writer context
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    DSPContext dsp;
90
    AC3MDCTContext mdct;                    ///< MDCT context
91

    
92
    AC3Block blocks[AC3_MAX_BLOCKS];        ///< per-block info
93

    
94
    int bitstream_id;                       ///< bitstream id                           (bsid)
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    int bitstream_mode;                     ///< bitstream mode                         (bsmod)
96

    
97
    int bit_rate;                           ///< target bit rate, in bits-per-second
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    int sample_rate;                        ///< sampling frequency, in Hz
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100
    int frame_size_min;                     ///< minimum frame size in case rounding is necessary
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    int frame_size;                         ///< current frame size in bytes
102
    int frame_size_code;                    ///< frame size code                        (frmsizecod)
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    uint16_t crc_inv[2];
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    int bits_written;                       ///< bit count    (used to avg. bitrate)
105
    int samples_written;                    ///< sample count (used to avg. bitrate)
106

    
107
    int fbw_channels;                       ///< number of full-bandwidth channels      (nfchans)
108
    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)
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    int nb_coefs[AC3_MAX_CHANNELS];
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118
    int rematrixing;                        ///< determines how rematrixing strategy is calculated
119

    
120
    /* bitrate allocation control */
121
    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)
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    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
127
    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
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134
    /* mantissa encoding */
135
    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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    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;
142
    int32_t *fixed_coef_buffer;
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    uint8_t *exp_buffer;
144
    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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150
    DECLARE_ALIGNED(16, SampleType, windowed_samples)[AC3_WINDOW_SIZE];
151
} AC3EncodeContext;
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153

    
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/* prototypes for functions in ac3enc_fixed.c and ac3enc_float.c */
155

    
156
static av_cold void mdct_end(AC3MDCTContext *mdct);
157

    
158
static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
159
                             int nbits);
160

    
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static void mdct512(AC3MDCTContext *mdct, CoefType *out, SampleType *in);
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163
static void apply_window(SampleType *output, const SampleType *input,
164
                         const SampleType *window, int n);
165

    
166
static int normalize_samples(AC3EncodeContext *s);
167

    
168
static void scale_coefficients(AC3EncodeContext *s);
169

    
170

    
171
/**
172
 * LUT for number of exponent groups.
173
 * exponent_group_tab[exponent strategy-1][number of coefficients]
174
 */
175
static uint8_t exponent_group_tab[3][256];
176

    
177

    
178
/**
179
 * List of supported channel layouts.
180
 */
181
static const int64_t ac3_channel_layouts[] = {
182
     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
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};
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203

    
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/**
205
 * Adjust the frame size to make the average bit rate match the target bit rate.
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 * This is only needed for 11025, 22050, and 44100 sample rates.
207
 */
208
static void adjust_frame_size(AC3EncodeContext *s)
209
{
210
    while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
211
        s->bits_written    -= s->bit_rate;
212
        s->samples_written -= s->sample_rate;
213
    }
214
    s->frame_size = s->frame_size_min +
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                    2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
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    s->bits_written    += s->frame_size * 8;
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    s->samples_written += AC3_FRAME_SIZE;
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}
219

    
220

    
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/**
222
 * Deinterleave input samples.
223
 * Channels are reordered from FFmpeg's default order to AC-3 order.
224
 */
225
static void deinterleave_input_samples(AC3EncodeContext *s,
226
                                       const SampleType *samples)
227
{
228
    int ch, i;
229

    
230
    /* deinterleave and remap input samples */
231
    for (ch = 0; ch < s->channels; ch++) {
232
        const SampleType *sptr;
233
        int sinc;
234

    
235
        /* copy last 256 samples of previous frame to the start of the current frame */
236
        memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
237
               AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
238

    
239
        /* deinterleave */
240
        sinc = s->channels;
241
        sptr = samples + s->channel_map[ch];
242
        for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
243
            s->planar_samples[ch][i] = *sptr;
244
            sptr += sinc;
245
        }
246
    }
247
}
248

    
249

    
250
/**
251
 * Apply the MDCT to input samples to generate frequency coefficients.
252
 * This applies the KBD window and normalizes the input to reduce precision
253
 * loss due to fixed-point calculations.
254
 */
255
static void apply_mdct(AC3EncodeContext *s)
256
{
257
    int blk, ch;
258

    
259
    for (ch = 0; ch < s->channels; ch++) {
260
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
261
            AC3Block *block = &s->blocks[blk];
262
            const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
263

    
264
            apply_window(s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
265

    
266
            block->exp_shift[ch] = normalize_samples(s);
267

    
268
            mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
269
        }
270
    }
271
}
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273

    
274
/**
275
 * Initialize stereo rematrixing.
276
 * If the strategy does not change for each frame, set the rematrixing flags.
277
 */
278
static void rematrixing_init(AC3EncodeContext *s)
279
{
280
    if (s->channel_mode == AC3_CHMODE_STEREO)
281
        s->rematrixing = AC3_REMATRIXING_SUMS;
282
    else
283
        s->rematrixing = AC3_REMATRIXING_NONE;
284
    /* NOTE: AC3_REMATRIXING_ALWAYS might be used in
285
             the future in conjunction with channel coupling. */
286

    
287
    if (s->rematrixing & AC3_REMATRIXING_IS_STATIC) {
288
        int flag = (s->rematrixing == AC3_REMATRIXING_ALWAYS);
289
        s->blocks[0].new_rematrixing_strategy = 1;
290
        memset(s->blocks[0].rematrixing_flags, flag,
291
               sizeof(s->blocks[0].rematrixing_flags));
292
    }
293
}
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295

    
296
/**
297
 * Determine rematrixing flags for each block and band.
298
 */
299
static void compute_rematrixing_strategy(AC3EncodeContext *s)
300
{
301
    int nb_coefs;
302
    int blk, bnd, i;
303
    AC3Block *block, *block0;
304

    
305
    if (s->rematrixing & AC3_REMATRIXING_IS_STATIC)
306
        return;
307

    
308
    nb_coefs = FFMIN(s->nb_coefs[0], s->nb_coefs[1]);
309

    
310
    s->blocks[0].new_rematrixing_strategy = 1;
311
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
312
        block = &s->blocks[blk];
313
        for (bnd = 0; bnd < 4; bnd++) {
314
            /* calculate calculate sum of squared coeffs for one band in one block */
315
            int start = ff_ac3_rematrix_band_tab[bnd];
316
            int end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
317
            CoefSumType sum[4] = {0,};
318
            for (i = start; i < end; i++) {
319
                CoefType lt = block->mdct_coef[0][i];
320
                CoefType rt = block->mdct_coef[1][i];
321
                CoefType md = lt + rt;
322
                CoefType sd = lt - rt;
323
                sum[0] += lt * lt;
324
                sum[1] += rt * rt;
325
                sum[2] += md * md;
326
                sum[3] += sd * sd;
327
            }
328

    
329
            /* compare sums to determine if rematrixing will be used for this band */
330
            if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1]))
331
                block->rematrixing_flags[bnd] = 1;
332
            else
333
                block->rematrixing_flags[bnd] = 0;
334

    
335
            /* determine if new rematrixing flags will be sent */
336
            if (blk &&
337
                !block->new_rematrixing_strategy &&
338
                block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) {
339
                block->new_rematrixing_strategy = 1;
340
            }
341
        }
342
        block0 = block;
343
    }
344
}
345

    
346

    
347
/**
348
 * Apply stereo rematrixing to coefficients based on rematrixing flags.
349
 */
350
static void apply_rematrixing(AC3EncodeContext *s)
351
{
352
    int nb_coefs;
353
    int blk, bnd, i;
354
    int start, end;
355
    uint8_t *flags;
356

    
357
    if (s->rematrixing == AC3_REMATRIXING_NONE)
358
        return;
359

    
360
    nb_coefs = FFMIN(s->nb_coefs[0], s->nb_coefs[1]);
361

    
362
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
363
        AC3Block *block = &s->blocks[blk];
364
        if (block->new_rematrixing_strategy)
365
            flags = block->rematrixing_flags;
366
        for (bnd = 0; bnd < 4; bnd++) {
367
            if (flags[bnd]) {
368
                start = ff_ac3_rematrix_band_tab[bnd];
369
                end   = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
370
                for (i = start; i < end; i++) {
371
                    int32_t lt = block->fixed_coef[0][i];
372
                    int32_t rt = block->fixed_coef[1][i];
373
                    block->fixed_coef[0][i] = (lt + rt) >> 1;
374
                    block->fixed_coef[1][i] = (lt - rt) >> 1;
375
                }
376
            }
377
        }
378
    }
379
}
380

    
381

    
382
/**
383
 * Initialize exponent tables.
384
 */
385
static av_cold void exponent_init(AC3EncodeContext *s)
386
{
387
    int i;
388
    for (i = 73; i < 256; i++) {
389
        exponent_group_tab[0][i] = (i - 1) /  3;
390
        exponent_group_tab[1][i] = (i + 2) /  6;
391
        exponent_group_tab[2][i] = (i + 8) / 12;
392
    }
393
    /* LFE */
394
    exponent_group_tab[0][7] = 2;
395
}
396

    
397

    
398
/**
399
 * Extract exponents from the MDCT coefficients.
400
 * This takes into account the normalization that was done to the input samples
401
 * by adjusting the exponents by the exponent shift values.
402
 */
403
static void extract_exponents(AC3EncodeContext *s)
404
{
405
    int blk, ch, i;
406

    
407
    for (ch = 0; ch < s->channels; ch++) {
408
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
409
            AC3Block *block = &s->blocks[blk];
410
            uint8_t *exp   = block->exp[ch];
411
            int32_t *coef = block->fixed_coef[ch];
412
            int exp_shift  = block->exp_shift[ch];
413
            for (i = 0; i < AC3_MAX_COEFS; i++) {
414
                int e;
415
                int v = abs(coef[i]);
416
                if (v == 0)
417
                    e = 24;
418
                else {
419
                    e = 23 - av_log2(v) + exp_shift;
420
                    if (e >= 24) {
421
                        e = 24;
422
                        coef[i] = 0;
423
                    }
424
                }
425
                exp[i] = e;
426
            }
427
        }
428
    }
429
}
430

    
431

    
432
/**
433
 * Exponent Difference Threshold.
434
 * New exponents are sent if their SAD exceed this number.
435
 */
436
#define EXP_DIFF_THRESHOLD 1000
437

    
438

    
439
/**
440
 * Calculate exponent strategies for all blocks in a single channel.
441
 */
442
static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy,
443
                                    uint8_t **exp)
444
{
445
    int blk, blk1;
446
    int exp_diff;
447

    
448
    /* estimate if the exponent variation & decide if they should be
449
       reused in the next frame */
450
    exp_strategy[0] = EXP_NEW;
451
    for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
452
        exp_diff = s->dsp.sad[0](NULL, exp[blk], exp[blk-1], 16, 16);
453
        if (exp_diff > EXP_DIFF_THRESHOLD)
454
            exp_strategy[blk] = EXP_NEW;
455
        else
456
            exp_strategy[blk] = EXP_REUSE;
457
    }
458
    emms_c();
459

    
460
    /* now select the encoding strategy type : if exponents are often
461
       recoded, we use a coarse encoding */
462
    blk = 0;
463
    while (blk < AC3_MAX_BLOCKS) {
464
        blk1 = blk + 1;
465
        while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
466
            blk1++;
467
        switch (blk1 - blk) {
468
        case 1:  exp_strategy[blk] = EXP_D45; break;
469
        case 2:
470
        case 3:  exp_strategy[blk] = EXP_D25; break;
471
        default: exp_strategy[blk] = EXP_D15; break;
472
        }
473
        blk = blk1;
474
    }
475
}
476

    
477

    
478
/**
479
 * Calculate exponent strategies for all channels.
480
 * Array arrangement is reversed to simplify the per-channel calculation.
481
 */
482
static void compute_exp_strategy(AC3EncodeContext *s)
483
{
484
    uint8_t *exp1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
485
    uint8_t exp_str1[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS];
486
    int ch, blk;
487

    
488
    for (ch = 0; ch < s->fbw_channels; ch++) {
489
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
490
            exp1[ch][blk]     = s->blocks[blk].exp[ch];
491
            exp_str1[ch][blk] = s->blocks[blk].exp_strategy[ch];
492
        }
493

    
494
        compute_exp_strategy_ch(s, exp_str1[ch], exp1[ch]);
495

    
496
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
497
            s->blocks[blk].exp_strategy[ch] = exp_str1[ch][blk];
498
    }
499
    if (s->lfe_on) {
500
        ch = s->lfe_channel;
501
        s->blocks[0].exp_strategy[ch] = EXP_D15;
502
        for (blk = 1; blk < AC3_MAX_BLOCKS; blk++)
503
            s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
504
    }
505
}
506

    
507

    
508
/**
509
 * Set each encoded exponent in a block to the minimum of itself and the
510
 * exponent in the same frequency bin of a following block.
511
 * exp[i] = min(exp[i], exp1[i]
512
 */
513
static void exponent_min(uint8_t *exp, uint8_t *exp1, int n)
514
{
515
    int i;
516
    for (i = 0; i < n; i++) {
517
        if (exp1[i] < exp[i])
518
            exp[i] = exp1[i];
519
    }
520
}
521

    
522

    
523
/**
524
 * Update the exponents so that they are the ones the decoder will decode.
525
 */
526
static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy)
527
{
528
    int nb_groups, i, k;
529

    
530
    nb_groups = exponent_group_tab[exp_strategy-1][nb_exps] * 3;
531

    
532
    /* for each group, compute the minimum exponent */
533
    switch(exp_strategy) {
534
    case EXP_D25:
535
        for (i = 1, k = 1; i <= nb_groups; i++) {
536
            uint8_t exp_min = exp[k];
537
            if (exp[k+1] < exp_min)
538
                exp_min = exp[k+1];
539
            exp[i] = exp_min;
540
            k += 2;
541
        }
542
        break;
543
    case EXP_D45:
544
        for (i = 1, k = 1; i <= nb_groups; i++) {
545
            uint8_t exp_min = exp[k];
546
            if (exp[k+1] < exp_min)
547
                exp_min = exp[k+1];
548
            if (exp[k+2] < exp_min)
549
                exp_min = exp[k+2];
550
            if (exp[k+3] < exp_min)
551
                exp_min = exp[k+3];
552
            exp[i] = exp_min;
553
            k += 4;
554
        }
555
        break;
556
    }
557

    
558
    /* constraint for DC exponent */
559
    if (exp[0] > 15)
560
        exp[0] = 15;
561

    
562
    /* decrease the delta between each groups to within 2 so that they can be
563
       differentially encoded */
564
    for (i = 1; i <= nb_groups; i++)
565
        exp[i] = FFMIN(exp[i], exp[i-1] + 2);
566
    i--;
567
    while (--i >= 0)
568
        exp[i] = FFMIN(exp[i], exp[i+1] + 2);
569

    
570
    /* now we have the exponent values the decoder will see */
571
    switch (exp_strategy) {
572
    case EXP_D25:
573
        for (i = nb_groups, k = nb_groups * 2; i > 0; i--) {
574
            uint8_t exp1 = exp[i];
575
            exp[k--] = exp1;
576
            exp[k--] = exp1;
577
        }
578
        break;
579
    case EXP_D45:
580
        for (i = nb_groups, k = nb_groups * 4; i > 0; i--) {
581
            exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i];
582
            k -= 4;
583
        }
584
        break;
585
    }
586
}
587

    
588

    
589
/**
590
 * Encode exponents from original extracted form to what the decoder will see.
591
 * This copies and groups exponents based on exponent strategy and reduces
592
 * deltas between adjacent exponent groups so that they can be differentially
593
 * encoded.
594
 */
595
static void encode_exponents(AC3EncodeContext *s)
596
{
597
    int blk, blk1, blk2, ch;
598
    AC3Block *block, *block1, *block2;
599

    
600
    for (ch = 0; ch < s->channels; ch++) {
601
        blk = 0;
602
        block = &s->blocks[0];
603
        while (blk < AC3_MAX_BLOCKS) {
604
            blk1 = blk + 1;
605
            block1 = block + 1;
606
            /* for the EXP_REUSE case we select the min of the exponents */
607
            while (blk1 < AC3_MAX_BLOCKS && block1->exp_strategy[ch] == EXP_REUSE) {
608
                exponent_min(block->exp[ch], block1->exp[ch], s->nb_coefs[ch]);
609
                blk1++;
610
                block1++;
611
            }
612
            encode_exponents_blk_ch(block->exp[ch], s->nb_coefs[ch],
613
                                    block->exp_strategy[ch]);
614
            /* copy encoded exponents for reuse case */
615
            block2 = block + 1;
616
            for (blk2 = blk+1; blk2 < blk1; blk2++, block2++) {
617
                memcpy(block2->exp[ch], block->exp[ch],
618
                       s->nb_coefs[ch] * sizeof(uint8_t));
619
            }
620
            blk = blk1;
621
            block = block1;
622
        }
623
    }
624
}
625

    
626

    
627
/**
628
 * Group exponents.
629
 * 3 delta-encoded exponents are in each 7-bit group. The number of groups
630
 * varies depending on exponent strategy and bandwidth.
631
 */
632
static void group_exponents(AC3EncodeContext *s)
633
{
634
    int blk, ch, i;
635
    int group_size, nb_groups, bit_count;
636
    uint8_t *p;
637
    int delta0, delta1, delta2;
638
    int exp0, exp1;
639

    
640
    bit_count = 0;
641
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
642
        AC3Block *block = &s->blocks[blk];
643
        for (ch = 0; ch < s->channels; ch++) {
644
            if (block->exp_strategy[ch] == EXP_REUSE) {
645
                continue;
646
            }
647
            group_size = block->exp_strategy[ch] + (block->exp_strategy[ch] == EXP_D45);
648
            nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
649
            bit_count += 4 + (nb_groups * 7);
650
            p = block->exp[ch];
651

    
652
            /* DC exponent */
653
            exp1 = *p++;
654
            block->grouped_exp[ch][0] = exp1;
655

    
656
            /* remaining exponents are delta encoded */
657
            for (i = 1; i <= nb_groups; i++) {
658
                /* merge three delta in one code */
659
                exp0   = exp1;
660
                exp1   = p[0];
661
                p     += group_size;
662
                delta0 = exp1 - exp0 + 2;
663

    
664
                exp0   = exp1;
665
                exp1   = p[0];
666
                p     += group_size;
667
                delta1 = exp1 - exp0 + 2;
668

    
669
                exp0   = exp1;
670
                exp1   = p[0];
671
                p     += group_size;
672
                delta2 = exp1 - exp0 + 2;
673

    
674
                block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
675
            }
676
        }
677
    }
678

    
679
    s->exponent_bits = bit_count;
680
}
681

    
682

    
683
/**
684
 * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
685
 * Extract exponents from MDCT coefficients, calculate exponent strategies,
686
 * and encode final exponents.
687
 */
688
static void process_exponents(AC3EncodeContext *s)
689
{
690
    extract_exponents(s);
691

    
692
    compute_exp_strategy(s);
693

    
694
    encode_exponents(s);
695

    
696
    group_exponents(s);
697
}
698

    
699

    
700
/**
701
 * Count frame bits that are based solely on fixed parameters.
702
 * This only has to be run once when the encoder is initialized.
703
 */
704
static void count_frame_bits_fixed(AC3EncodeContext *s)
705
{
706
    static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
707
    int blk;
708
    int frame_bits;
709

    
710
    /* assumptions:
711
     *   no dynamic range codes
712
     *   no channel coupling
713
     *   bit allocation parameters do not change between blocks
714
     *   SNR offsets do not change between blocks
715
     *   no delta bit allocation
716
     *   no skipped data
717
     *   no auxilliary data
718
     */
719

    
720
    /* header size */
721
    frame_bits = 65;
722
    frame_bits += frame_bits_inc[s->channel_mode];
723

    
724
    /* audio blocks */
725
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
726
        frame_bits += s->fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */
727
        if (s->channel_mode == AC3_CHMODE_STEREO) {
728
            frame_bits++; /* rematstr */
729
        }
730
        frame_bits += 2 * s->fbw_channels; /* chexpstr[2] * c */
731
        if (s->lfe_on)
732
            frame_bits++; /* lfeexpstr */
733
        frame_bits++; /* baie */
734
        frame_bits++; /* snr */
735
        frame_bits += 2; /* delta / skip */
736
    }
737
    frame_bits++; /* cplinu for block 0 */
738
    /* bit alloc info */
739
    /* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */
740
    /* csnroffset[6] */
741
    /* (fsnoffset[4] + fgaincod[4]) * c */
742
    frame_bits += 2*4 + 3 + 6 + s->channels * (4 + 3);
743

    
744
    /* auxdatae, crcrsv */
745
    frame_bits += 2;
746

    
747
    /* CRC */
748
    frame_bits += 16;
749

    
750
    s->frame_bits_fixed = frame_bits;
751
}
752

    
753

    
754
/**
755
 * Initialize bit allocation.
756
 * Set default parameter codes and calculate parameter values.
757
 */
758
static void bit_alloc_init(AC3EncodeContext *s)
759
{
760
    int ch;
761

    
762
    /* init default parameters */
763
    s->slow_decay_code = 2;
764
    s->fast_decay_code = 1;
765
    s->slow_gain_code  = 1;
766
    s->db_per_bit_code = 3;
767
    s->floor_code      = 4;
768
    for (ch = 0; ch < s->channels; ch++)
769
        s->fast_gain_code[ch] = 4;
770

    
771
    /* initial snr offset */
772
    s->coarse_snr_offset = 40;
773

    
774
    /* compute real values */
775
    /* currently none of these values change during encoding, so we can just
776
       set them once at initialization */
777
    s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
778
    s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
779
    s->bit_alloc.slow_gain  = ff_ac3_slow_gain_tab[s->slow_gain_code];
780
    s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
781
    s->bit_alloc.floor      = ff_ac3_floor_tab[s->floor_code];
782

    
783
    count_frame_bits_fixed(s);
784
}
785

    
786

    
787
/**
788
 * Count the bits used to encode the frame, minus exponents and mantissas.
789
 * Bits based on fixed parameters have already been counted, so now we just
790
 * have to add the bits based on parameters that change during encoding.
791
 */
792
static void count_frame_bits(AC3EncodeContext *s)
793
{
794
    int blk, ch;
795
    int frame_bits = 0;
796

    
797
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
798
        uint8_t *exp_strategy = s->blocks[blk].exp_strategy;
799

    
800
        /* stereo rematrixing */
801
        if (s->channel_mode == AC3_CHMODE_STEREO &&
802
            s->blocks[blk].new_rematrixing_strategy) {
803
            frame_bits += 4;
804
        }
805

    
806
        for (ch = 0; ch < s->fbw_channels; ch++) {
807
            if (exp_strategy[ch] != EXP_REUSE)
808
                frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */
809
        }
810
    }
811
    s->frame_bits = s->frame_bits_fixed + frame_bits;
812
}
813

    
814

    
815
/**
816
 * Calculate the number of bits needed to encode a set of mantissas.
817
 */
818
static int compute_mantissa_size(int mant_cnt[5], uint8_t *bap, int nb_coefs)
819
{
820
    int bits, b, i;
821

    
822
    bits = 0;
823
    for (i = 0; i < nb_coefs; i++) {
824
        b = bap[i];
825
        if (b <= 4) {
826
            // bap=1 to bap=4 will be counted in compute_mantissa_size_final
827
            mant_cnt[b]++;
828
        } else if (b <= 13) {
829
            // bap=5 to bap=13 use (bap-1) bits
830
            bits += b - 1;
831
        } else {
832
            // bap=14 uses 14 bits and bap=15 uses 16 bits
833
            bits += (b == 14) ? 14 : 16;
834
        }
835
    }
836
    return bits;
837
}
838

    
839

    
840
/**
841
 * Finalize the mantissa bit count by adding in the grouped mantissas.
842
 */
843
static int compute_mantissa_size_final(int mant_cnt[5])
844
{
845
    // bap=1 : 3 mantissas in 5 bits
846
    int bits = (mant_cnt[1] / 3) * 5;
847
    // bap=2 : 3 mantissas in 7 bits
848
    // bap=4 : 2 mantissas in 7 bits
849
    bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7;
850
    // bap=3 : each mantissa is 3 bits
851
    bits += mant_cnt[3] * 3;
852
    return bits;
853
}
854

    
855

    
856
/**
857
 * Calculate masking curve based on the final exponents.
858
 * Also calculate the power spectral densities to use in future calculations.
859
 */
860
static void bit_alloc_masking(AC3EncodeContext *s)
861
{
862
    int blk, ch;
863

    
864
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
865
        AC3Block *block = &s->blocks[blk];
866
        for (ch = 0; ch < s->channels; ch++) {
867
            /* We only need psd and mask for calculating bap.
868
               Since we currently do not calculate bap when exponent
869
               strategy is EXP_REUSE we do not need to calculate psd or mask. */
870
            if (block->exp_strategy[ch] != EXP_REUSE) {
871
                ff_ac3_bit_alloc_calc_psd(block->exp[ch], 0,
872
                                          s->nb_coefs[ch],
873
                                          block->psd[ch], block->band_psd[ch]);
874
                ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
875
                                           0, s->nb_coefs[ch],
876
                                           ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
877
                                           ch == s->lfe_channel,
878
                                           DBA_NONE, 0, NULL, NULL, NULL,
879
                                           block->mask[ch]);
880
            }
881
        }
882
    }
883
}
884

    
885

    
886
/**
887
 * Ensure that bap for each block and channel point to the current bap_buffer.
888
 * They may have been switched during the bit allocation search.
889
 */
890
static void reset_block_bap(AC3EncodeContext *s)
891
{
892
    int blk, ch;
893
    if (s->blocks[0].bap[0] == s->bap_buffer)
894
        return;
895
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
896
        for (ch = 0; ch < s->channels; ch++) {
897
            s->blocks[blk].bap[ch] = &s->bap_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
898
        }
899
    }
900
}
901

    
902

    
903
/**
904
 * Run the bit allocation with a given SNR offset.
905
 * This calculates the bit allocation pointers that will be used to determine
906
 * the quantization of each mantissa.
907
 * @return the number of bits needed for mantissas if the given SNR offset is
908
 *         is used.
909
 */
910
static int bit_alloc(AC3EncodeContext *s, int snr_offset)
911
{
912
    int blk, ch;
913
    int mantissa_bits;
914
    int mant_cnt[5];
915

    
916
    snr_offset = (snr_offset - 240) << 2;
917

    
918
    reset_block_bap(s);
919
    mantissa_bits = 0;
920
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
921
        AC3Block *block = &s->blocks[blk];
922
        // initialize grouped mantissa counts. these are set so that they are
923
        // padded to the next whole group size when bits are counted in
924
        // compute_mantissa_size_final
925
        mant_cnt[0] = mant_cnt[3] = 0;
926
        mant_cnt[1] = mant_cnt[2] = 2;
927
        mant_cnt[4] = 1;
928
        for (ch = 0; ch < s->channels; ch++) {
929
            /* Currently the only bit allocation parameters which vary across
930
               blocks within a frame are the exponent values.  We can take
931
               advantage of that by reusing the bit allocation pointers
932
               whenever we reuse exponents. */
933
            if (block->exp_strategy[ch] == EXP_REUSE) {
934
                memcpy(block->bap[ch], s->blocks[blk-1].bap[ch], AC3_MAX_COEFS);
935
            } else {
936
                ff_ac3_bit_alloc_calc_bap(block->mask[ch], block->psd[ch], 0,
937
                                          s->nb_coefs[ch], snr_offset,
938
                                          s->bit_alloc.floor, ff_ac3_bap_tab,
939
                                          block->bap[ch]);
940
            }
941
            mantissa_bits += compute_mantissa_size(mant_cnt, block->bap[ch], s->nb_coefs[ch]);
942
        }
943
        mantissa_bits += compute_mantissa_size_final(mant_cnt);
944
    }
945
    return mantissa_bits;
946
}
947

    
948

    
949
/**
950
 * Constant bitrate bit allocation search.
951
 * Find the largest SNR offset that will allow data to fit in the frame.
952
 */
953
static int cbr_bit_allocation(AC3EncodeContext *s)
954
{
955
    int ch;
956
    int bits_left;
957
    int snr_offset, snr_incr;
958

    
959
    bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
960

    
961
    snr_offset = s->coarse_snr_offset << 4;
962

    
963
    /* if previous frame SNR offset was 1023, check if current frame can also
964
       use SNR offset of 1023. if so, skip the search. */
965
    if ((snr_offset | s->fine_snr_offset[0]) == 1023) {
966
        if (bit_alloc(s, 1023) <= bits_left)
967
            return 0;
968
    }
969

    
970
    while (snr_offset >= 0 &&
971
           bit_alloc(s, snr_offset) > bits_left) {
972
        snr_offset -= 64;
973
    }
974
    if (snr_offset < 0)
975
        return AVERROR(EINVAL);
976

    
977
    FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
978
    for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
979
        while (snr_offset + snr_incr <= 1023 &&
980
               bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
981
            snr_offset += snr_incr;
982
            FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
983
        }
984
    }
985
    FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
986
    reset_block_bap(s);
987

    
988
    s->coarse_snr_offset = snr_offset >> 4;
989
    for (ch = 0; ch < s->channels; ch++)
990
        s->fine_snr_offset[ch] = snr_offset & 0xF;
991

    
992
    return 0;
993
}
994

    
995

    
996
/**
997
 * Downgrade exponent strategies to reduce the bits used by the exponents.
998
 * This is a fallback for when bit allocation fails with the normal exponent
999
 * strategies.  Each time this function is run it only downgrades the
1000
 * strategy in 1 channel of 1 block.
1001
 * @return non-zero if downgrade was unsuccessful
1002
 */
1003
static int downgrade_exponents(AC3EncodeContext *s)
1004
{
1005
    int ch, blk;
1006

    
1007
    for (ch = 0; ch < s->fbw_channels; ch++) {
1008
        for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
1009
            if (s->blocks[blk].exp_strategy[ch] == EXP_D15) {
1010
                s->blocks[blk].exp_strategy[ch] = EXP_D25;
1011
                return 0;
1012
            }
1013
        }
1014
    }
1015
    for (ch = 0; ch < s->fbw_channels; ch++) {
1016
        for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
1017
            if (s->blocks[blk].exp_strategy[ch] == EXP_D25) {
1018
                s->blocks[blk].exp_strategy[ch] = EXP_D45;
1019
                return 0;
1020
            }
1021
        }
1022
    }
1023
    for (ch = 0; ch < s->fbw_channels; ch++) {
1024
        /* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if
1025
           the block number > 0 */
1026
        for (blk = AC3_MAX_BLOCKS-1; blk > 0; blk--) {
1027
            if (s->blocks[blk].exp_strategy[ch] > EXP_REUSE) {
1028
                s->blocks[blk].exp_strategy[ch] = EXP_REUSE;
1029
                return 0;
1030
            }
1031
        }
1032
    }
1033
    return -1;
1034
}
1035

    
1036

    
1037
/**
1038
 * Reduce the bandwidth to reduce the number of bits used for a given SNR offset.
1039
 * This is a second fallback for when bit allocation still fails after exponents
1040
 * have been downgraded.
1041
 * @return non-zero if bandwidth reduction was unsuccessful
1042
 */
1043
static int reduce_bandwidth(AC3EncodeContext *s, int min_bw_code)
1044
{
1045
    int ch;
1046

    
1047
    if (s->bandwidth_code[0] > min_bw_code) {
1048
        for (ch = 0; ch < s->fbw_channels; ch++) {
1049
            s->bandwidth_code[ch]--;
1050
            s->nb_coefs[ch] = s->bandwidth_code[ch] * 3 + 73;
1051
        }
1052
        return 0;
1053
    }
1054
    return -1;
1055
}
1056

    
1057

    
1058
/**
1059
 * Perform bit allocation search.
1060
 * Finds the SNR offset value that maximizes quality and fits in the specified
1061
 * frame size.  Output is the SNR offset and a set of bit allocation pointers
1062
 * used to quantize the mantissas.
1063
 */
1064
static int compute_bit_allocation(AC3EncodeContext *s)
1065
{
1066
    int ret;
1067

    
1068
    count_frame_bits(s);
1069

    
1070
    bit_alloc_masking(s);
1071

    
1072
    ret = cbr_bit_allocation(s);
1073
    while (ret) {
1074
        /* fallback 1: downgrade exponents */
1075
        if (!downgrade_exponents(s)) {
1076
            extract_exponents(s);
1077
            encode_exponents(s);
1078
            group_exponents(s);
1079
            ret = compute_bit_allocation(s);
1080
            continue;
1081
        }
1082

    
1083
        /* fallback 2: reduce bandwidth */
1084
        /* only do this if the user has not specified a specific cutoff
1085
           frequency */
1086
        if (!s->cutoff && !reduce_bandwidth(s, 0)) {
1087
            process_exponents(s);
1088
            ret = compute_bit_allocation(s);
1089
            continue;
1090
        }
1091

    
1092
        /* fallbacks were not enough... */
1093
        break;
1094
    }
1095

    
1096
    return ret;
1097
}
1098

    
1099

    
1100
/**
1101
 * Symmetric quantization on 'levels' levels.
1102
 */
1103
static inline int sym_quant(int c, int e, int levels)
1104
{
1105
    int v;
1106

    
1107
    if (c >= 0) {
1108
        v = (levels * (c << e)) >> 24;
1109
        v = (v + 1) >> 1;
1110
        v = (levels >> 1) + v;
1111
    } else {
1112
        v = (levels * ((-c) << e)) >> 24;
1113
        v = (v + 1) >> 1;
1114
        v = (levels >> 1) - v;
1115
    }
1116
    assert(v >= 0 && v < levels);
1117
    return v;
1118
}
1119

    
1120

    
1121
/**
1122
 * Asymmetric quantization on 2^qbits levels.
1123
 */
1124
static inline int asym_quant(int c, int e, int qbits)
1125
{
1126
    int lshift, m, v;
1127

    
1128
    lshift = e + qbits - 24;
1129
    if (lshift >= 0)
1130
        v = c << lshift;
1131
    else
1132
        v = c >> (-lshift);
1133
    /* rounding */
1134
    v = (v + 1) >> 1;
1135
    m = (1 << (qbits-1));
1136
    if (v >= m)
1137
        v = m - 1;
1138
    assert(v >= -m);
1139
    return v & ((1 << qbits)-1);
1140
}
1141

    
1142

    
1143
/**
1144
 * Quantize a set of mantissas for a single channel in a single block.
1145
 */
1146
static void quantize_mantissas_blk_ch(AC3EncodeContext *s, int32_t *fixed_coef,
1147
                                      int8_t exp_shift, uint8_t *exp,
1148
                                      uint8_t *bap, uint16_t *qmant, int n)
1149
{
1150
    int i;
1151

    
1152
    for (i = 0; i < n; i++) {
1153
        int v;
1154
        int c = fixed_coef[i];
1155
        int e = exp[i] - exp_shift;
1156
        int b = bap[i];
1157
        switch (b) {
1158
        case 0:
1159
            v = 0;
1160
            break;
1161
        case 1:
1162
            v = sym_quant(c, e, 3);
1163
            switch (s->mant1_cnt) {
1164
            case 0:
1165
                s->qmant1_ptr = &qmant[i];
1166
                v = 9 * v;
1167
                s->mant1_cnt = 1;
1168
                break;
1169
            case 1:
1170
                *s->qmant1_ptr += 3 * v;
1171
                s->mant1_cnt = 2;
1172
                v = 128;
1173
                break;
1174
            default:
1175
                *s->qmant1_ptr += v;
1176
                s->mant1_cnt = 0;
1177
                v = 128;
1178
                break;
1179
            }
1180
            break;
1181
        case 2:
1182
            v = sym_quant(c, e, 5);
1183
            switch (s->mant2_cnt) {
1184
            case 0:
1185
                s->qmant2_ptr = &qmant[i];
1186
                v = 25 * v;
1187
                s->mant2_cnt = 1;
1188
                break;
1189
            case 1:
1190
                *s->qmant2_ptr += 5 * v;
1191
                s->mant2_cnt = 2;
1192
                v = 128;
1193
                break;
1194
            default:
1195
                *s->qmant2_ptr += v;
1196
                s->mant2_cnt = 0;
1197
                v = 128;
1198
                break;
1199
            }
1200
            break;
1201
        case 3:
1202
            v = sym_quant(c, e, 7);
1203
            break;
1204
        case 4:
1205
            v = sym_quant(c, e, 11);
1206
            switch (s->mant4_cnt) {
1207
            case 0:
1208
                s->qmant4_ptr = &qmant[i];
1209
                v = 11 * v;
1210
                s->mant4_cnt = 1;
1211
                break;
1212
            default:
1213
                *s->qmant4_ptr += v;
1214
                s->mant4_cnt = 0;
1215
                v = 128;
1216
                break;
1217
            }
1218
            break;
1219
        case 5:
1220
            v = sym_quant(c, e, 15);
1221
            break;
1222
        case 14:
1223
            v = asym_quant(c, e, 14);
1224
            break;
1225
        case 15:
1226
            v = asym_quant(c, e, 16);
1227
            break;
1228
        default:
1229
            v = asym_quant(c, e, b - 1);
1230
            break;
1231
        }
1232
        qmant[i] = v;
1233
    }
1234
}
1235

    
1236

    
1237
/**
1238
 * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
1239
 */
1240
static void quantize_mantissas(AC3EncodeContext *s)
1241
{
1242
    int blk, ch;
1243

    
1244

    
1245
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1246
        AC3Block *block = &s->blocks[blk];
1247
        s->mant1_cnt  = s->mant2_cnt  = s->mant4_cnt  = 0;
1248
        s->qmant1_ptr = s->qmant2_ptr = s->qmant4_ptr = NULL;
1249

    
1250
        for (ch = 0; ch < s->channels; ch++) {
1251
            quantize_mantissas_blk_ch(s, block->fixed_coef[ch], block->exp_shift[ch],
1252
                                      block->exp[ch], block->bap[ch],
1253
                                      block->qmant[ch], s->nb_coefs[ch]);
1254
        }
1255
    }
1256
}
1257

    
1258

    
1259
/**
1260
 * Write the AC-3 frame header to the output bitstream.
1261
 */
1262
static void output_frame_header(AC3EncodeContext *s)
1263
{
1264
    put_bits(&s->pb, 16, 0x0b77);   /* frame header */
1265
    put_bits(&s->pb, 16, 0);        /* crc1: will be filled later */
1266
    put_bits(&s->pb, 2,  s->bit_alloc.sr_code);
1267
    put_bits(&s->pb, 6,  s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
1268
    put_bits(&s->pb, 5,  s->bitstream_id);
1269
    put_bits(&s->pb, 3,  s->bitstream_mode);
1270
    put_bits(&s->pb, 3,  s->channel_mode);
1271
    if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
1272
        put_bits(&s->pb, 2, 1);     /* XXX -4.5 dB */
1273
    if (s->channel_mode & 0x04)
1274
        put_bits(&s->pb, 2, 1);     /* XXX -6 dB */
1275
    if (s->channel_mode == AC3_CHMODE_STEREO)
1276
        put_bits(&s->pb, 2, 0);     /* surround not indicated */
1277
    put_bits(&s->pb, 1, s->lfe_on); /* LFE */
1278
    put_bits(&s->pb, 5, 31);        /* dialog norm: -31 db */
1279
    put_bits(&s->pb, 1, 0);         /* no compression control word */
1280
    put_bits(&s->pb, 1, 0);         /* no lang code */
1281
    put_bits(&s->pb, 1, 0);         /* no audio production info */
1282
    put_bits(&s->pb, 1, 0);         /* no copyright */
1283
    put_bits(&s->pb, 1, 1);         /* original bitstream */
1284
    put_bits(&s->pb, 1, 0);         /* no time code 1 */
1285
    put_bits(&s->pb, 1, 0);         /* no time code 2 */
1286
    put_bits(&s->pb, 1, 0);         /* no additional bit stream info */
1287
}
1288

    
1289

    
1290
/**
1291
 * Write one audio block to the output bitstream.
1292
 */
1293
static void output_audio_block(AC3EncodeContext *s, int block_num)
1294
{
1295
    int ch, i, baie, rbnd;
1296
    AC3Block *block = &s->blocks[block_num];
1297

    
1298
    /* block switching */
1299
    for (ch = 0; ch < s->fbw_channels; ch++)
1300
        put_bits(&s->pb, 1, 0);
1301

    
1302
    /* dither flags */
1303
    for (ch = 0; ch < s->fbw_channels; ch++)
1304
        put_bits(&s->pb, 1, 1);
1305

    
1306
    /* dynamic range codes */
1307
    put_bits(&s->pb, 1, 0);
1308

    
1309
    /* channel coupling */
1310
    if (!block_num) {
1311
        put_bits(&s->pb, 1, 1); /* coupling strategy present */
1312
        put_bits(&s->pb, 1, 0); /* no coupling strategy */
1313
    } else {
1314
        put_bits(&s->pb, 1, 0); /* no new coupling strategy */
1315
    }
1316

    
1317
    /* stereo rematrixing */
1318
    if (s->channel_mode == AC3_CHMODE_STEREO) {
1319
        put_bits(&s->pb, 1, block->new_rematrixing_strategy);
1320
        if (block->new_rematrixing_strategy) {
1321
            /* rematrixing flags */
1322
            for (rbnd = 0; rbnd < 4; rbnd++)
1323
                put_bits(&s->pb, 1, block->rematrixing_flags[rbnd]);
1324
        }
1325
    }
1326

    
1327
    /* exponent strategy */
1328
    for (ch = 0; ch < s->fbw_channels; ch++)
1329
        put_bits(&s->pb, 2, block->exp_strategy[ch]);
1330
    if (s->lfe_on)
1331
        put_bits(&s->pb, 1, block->exp_strategy[s->lfe_channel]);
1332

    
1333
    /* bandwidth */
1334
    for (ch = 0; ch < s->fbw_channels; ch++) {
1335
        if (block->exp_strategy[ch] != EXP_REUSE)
1336
            put_bits(&s->pb, 6, s->bandwidth_code[ch]);
1337
    }
1338

    
1339
    /* exponents */
1340
    for (ch = 0; ch < s->channels; ch++) {
1341
        int nb_groups;
1342

    
1343
        if (block->exp_strategy[ch] == EXP_REUSE)
1344
            continue;
1345

    
1346
        /* DC exponent */
1347
        put_bits(&s->pb, 4, block->grouped_exp[ch][0]);
1348

    
1349
        /* exponent groups */
1350
        nb_groups = exponent_group_tab[block->exp_strategy[ch]-1][s->nb_coefs[ch]];
1351
        for (i = 1; i <= nb_groups; i++)
1352
            put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
1353

    
1354
        /* gain range info */
1355
        if (ch != s->lfe_channel)
1356
            put_bits(&s->pb, 2, 0);
1357
    }
1358

    
1359
    /* bit allocation info */
1360
    baie = (block_num == 0);
1361
    put_bits(&s->pb, 1, baie);
1362
    if (baie) {
1363
        put_bits(&s->pb, 2, s->slow_decay_code);
1364
        put_bits(&s->pb, 2, s->fast_decay_code);
1365
        put_bits(&s->pb, 2, s->slow_gain_code);
1366
        put_bits(&s->pb, 2, s->db_per_bit_code);
1367
        put_bits(&s->pb, 3, s->floor_code);
1368
    }
1369

    
1370
    /* snr offset */
1371
    put_bits(&s->pb, 1, baie);
1372
    if (baie) {
1373
        put_bits(&s->pb, 6, s->coarse_snr_offset);
1374
        for (ch = 0; ch < s->channels; ch++) {
1375
            put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
1376
            put_bits(&s->pb, 3, s->fast_gain_code[ch]);
1377
        }
1378
    }
1379

    
1380
    put_bits(&s->pb, 1, 0); /* no delta bit allocation */
1381
    put_bits(&s->pb, 1, 0); /* no data to skip */
1382

    
1383
    /* mantissas */
1384
    for (ch = 0; ch < s->channels; ch++) {
1385
        int b, q;
1386
        for (i = 0; i < s->nb_coefs[ch]; i++) {
1387
            q = block->qmant[ch][i];
1388
            b = block->bap[ch][i];
1389
            switch (b) {
1390
            case 0:                                         break;
1391
            case 1: if (q != 128) put_bits(&s->pb,   5, q); break;
1392
            case 2: if (q != 128) put_bits(&s->pb,   7, q); break;
1393
            case 3:               put_bits(&s->pb,   3, q); break;
1394
            case 4: if (q != 128) put_bits(&s->pb,   7, q); break;
1395
            case 14:              put_bits(&s->pb,  14, q); break;
1396
            case 15:              put_bits(&s->pb,  16, q); break;
1397
            default:              put_bits(&s->pb, b-1, q); break;
1398
            }
1399
        }
1400
    }
1401
}
1402

    
1403

    
1404
/** CRC-16 Polynomial */
1405
#define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
1406

    
1407

    
1408
static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly)
1409
{
1410
    unsigned int c;
1411

    
1412
    c = 0;
1413
    while (a) {
1414
        if (a & 1)
1415
            c ^= b;
1416
        a = a >> 1;
1417
        b = b << 1;
1418
        if (b & (1 << 16))
1419
            b ^= poly;
1420
    }
1421
    return c;
1422
}
1423

    
1424

    
1425
static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly)
1426
{
1427
    unsigned int r;
1428
    r = 1;
1429
    while (n) {
1430
        if (n & 1)
1431
            r = mul_poly(r, a, poly);
1432
        a = mul_poly(a, a, poly);
1433
        n >>= 1;
1434
    }
1435
    return r;
1436
}
1437

    
1438

    
1439
/**
1440
 * Fill the end of the frame with 0's and compute the two CRCs.
1441
 */
1442
static void output_frame_end(AC3EncodeContext *s)
1443
{
1444
    const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);
1445
    int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;
1446
    uint8_t *frame;
1447

    
1448
    frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1;
1449

    
1450
    /* pad the remainder of the frame with zeros */
1451
    flush_put_bits(&s->pb);
1452
    frame = s->pb.buf;
1453
    pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2;
1454
    assert(pad_bytes >= 0);
1455
    if (pad_bytes > 0)
1456
        memset(put_bits_ptr(&s->pb), 0, pad_bytes);
1457

    
1458
    /* compute crc1 */
1459
    /* this is not so easy because it is at the beginning of the data... */
1460
    crc1    = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4));
1461
    crc_inv = s->crc_inv[s->frame_size > s->frame_size_min];
1462
    crc1    = mul_poly(crc_inv, crc1, CRC16_POLY);
1463
    AV_WB16(frame + 2, crc1);
1464

    
1465
    /* compute crc2 */
1466
    crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,
1467
                          s->frame_size - frame_size_58 - 3);
1468
    crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1469
    /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */
1470
    if (crc2 == 0x770B) {
1471
        frame[s->frame_size - 3] ^= 0x1;
1472
        crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1);
1473
    }
1474
    crc2 = av_bswap16(crc2);
1475
    AV_WB16(frame + s->frame_size - 2, crc2);
1476
}
1477

    
1478

    
1479
/**
1480
 * Write the frame to the output bitstream.
1481
 */
1482
static void output_frame(AC3EncodeContext *s, unsigned char *frame)
1483
{
1484
    int blk;
1485

    
1486
    init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
1487

    
1488
    output_frame_header(s);
1489

    
1490
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
1491
        output_audio_block(s, blk);
1492

    
1493
    output_frame_end(s);
1494
}
1495

    
1496

    
1497
/**
1498
 * Encode a single AC-3 frame.
1499
 */
1500
static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
1501
                            int buf_size, void *data)
1502
{
1503
    AC3EncodeContext *s = avctx->priv_data;
1504
    const SampleType *samples = data;
1505
    int ret;
1506

    
1507
    if (s->bit_alloc.sr_code == 1)
1508
        adjust_frame_size(s);
1509

    
1510
    deinterleave_input_samples(s, samples);
1511

    
1512
    apply_mdct(s);
1513

    
1514
    compute_rematrixing_strategy(s);
1515

    
1516
    scale_coefficients(s);
1517

    
1518
    apply_rematrixing(s);
1519

    
1520
    process_exponents(s);
1521

    
1522
    ret = compute_bit_allocation(s);
1523
    if (ret) {
1524
        av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
1525
        return ret;
1526
    }
1527

    
1528
    quantize_mantissas(s);
1529

    
1530
    output_frame(s, frame);
1531

    
1532
    return s->frame_size;
1533
}
1534

    
1535

    
1536
/**
1537
 * Finalize encoding and free any memory allocated by the encoder.
1538
 */
1539
static av_cold int ac3_encode_close(AVCodecContext *avctx)
1540
{
1541
    int blk, ch;
1542
    AC3EncodeContext *s = avctx->priv_data;
1543

    
1544
    for (ch = 0; ch < s->channels; ch++)
1545
        av_freep(&s->planar_samples[ch]);
1546
    av_freep(&s->planar_samples);
1547
    av_freep(&s->bap_buffer);
1548
    av_freep(&s->bap1_buffer);
1549
    av_freep(&s->mdct_coef_buffer);
1550
    av_freep(&s->fixed_coef_buffer);
1551
    av_freep(&s->exp_buffer);
1552
    av_freep(&s->grouped_exp_buffer);
1553
    av_freep(&s->psd_buffer);
1554
    av_freep(&s->band_psd_buffer);
1555
    av_freep(&s->mask_buffer);
1556
    av_freep(&s->qmant_buffer);
1557
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1558
        AC3Block *block = &s->blocks[blk];
1559
        av_freep(&block->bap);
1560
        av_freep(&block->mdct_coef);
1561
        av_freep(&block->fixed_coef);
1562
        av_freep(&block->exp);
1563
        av_freep(&block->grouped_exp);
1564
        av_freep(&block->psd);
1565
        av_freep(&block->band_psd);
1566
        av_freep(&block->mask);
1567
        av_freep(&block->qmant);
1568
    }
1569

    
1570
    mdct_end(&s->mdct);
1571

    
1572
    av_freep(&avctx->coded_frame);
1573
    return 0;
1574
}
1575

    
1576

    
1577
/**
1578
 * Set channel information during initialization.
1579
 */
1580
static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
1581
                                    int64_t *channel_layout)
1582
{
1583
    int ch_layout;
1584

    
1585
    if (channels < 1 || channels > AC3_MAX_CHANNELS)
1586
        return AVERROR(EINVAL);
1587
    if ((uint64_t)*channel_layout > 0x7FF)
1588
        return AVERROR(EINVAL);
1589
    ch_layout = *channel_layout;
1590
    if (!ch_layout)
1591
        ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
1592
    if (av_get_channel_layout_nb_channels(ch_layout) != channels)
1593
        return AVERROR(EINVAL);
1594

    
1595
    s->lfe_on       = !!(ch_layout & AV_CH_LOW_FREQUENCY);
1596
    s->channels     = channels;
1597
    s->fbw_channels = channels - s->lfe_on;
1598
    s->lfe_channel  = s->lfe_on ? s->fbw_channels : -1;
1599
    if (s->lfe_on)
1600
        ch_layout -= AV_CH_LOW_FREQUENCY;
1601

    
1602
    switch (ch_layout) {
1603
    case AV_CH_LAYOUT_MONO:           s->channel_mode = AC3_CHMODE_MONO;   break;
1604
    case AV_CH_LAYOUT_STEREO:         s->channel_mode = AC3_CHMODE_STEREO; break;
1605
    case AV_CH_LAYOUT_SURROUND:       s->channel_mode = AC3_CHMODE_3F;     break;
1606
    case AV_CH_LAYOUT_2_1:            s->channel_mode = AC3_CHMODE_2F1R;   break;
1607
    case AV_CH_LAYOUT_4POINT0:        s->channel_mode = AC3_CHMODE_3F1R;   break;
1608
    case AV_CH_LAYOUT_QUAD:
1609
    case AV_CH_LAYOUT_2_2:            s->channel_mode = AC3_CHMODE_2F2R;   break;
1610
    case AV_CH_LAYOUT_5POINT0:
1611
    case AV_CH_LAYOUT_5POINT0_BACK:   s->channel_mode = AC3_CHMODE_3F2R;   break;
1612
    default:
1613
        return AVERROR(EINVAL);
1614
    }
1615

    
1616
    s->channel_map  = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on];
1617
    *channel_layout = ch_layout;
1618
    if (s->lfe_on)
1619
        *channel_layout |= AV_CH_LOW_FREQUENCY;
1620

    
1621
    return 0;
1622
}
1623

    
1624

    
1625
static av_cold int validate_options(AVCodecContext *avctx, AC3EncodeContext *s)
1626
{
1627
    int i, ret;
1628

    
1629
    /* validate channel layout */
1630
    if (!avctx->channel_layout) {
1631
        av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "
1632
                                      "encoder will guess the layout, but it "
1633
                                      "might be incorrect.\n");
1634
    }
1635
    ret = set_channel_info(s, avctx->channels, &avctx->channel_layout);
1636
    if (ret) {
1637
        av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");
1638
        return ret;
1639
    }
1640

    
1641
    /* validate sample rate */
1642
    for (i = 0; i < 9; i++) {
1643
        if ((ff_ac3_sample_rate_tab[i / 3] >> (i % 3)) == avctx->sample_rate)
1644
            break;
1645
    }
1646
    if (i == 9) {
1647
        av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
1648
        return AVERROR(EINVAL);
1649
    }
1650
    s->sample_rate        = avctx->sample_rate;
1651
    s->bit_alloc.sr_shift = i % 3;
1652
    s->bit_alloc.sr_code  = i / 3;
1653

    
1654
    /* validate bit rate */
1655
    for (i = 0; i < 19; i++) {
1656
        if ((ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift)*1000 == avctx->bit_rate)
1657
            break;
1658
    }
1659
    if (i == 19) {
1660
        av_log(avctx, AV_LOG_ERROR, "invalid bit rate\n");
1661
        return AVERROR(EINVAL);
1662
    }
1663
    s->bit_rate        = avctx->bit_rate;
1664
    s->frame_size_code = i << 1;
1665

    
1666
    /* validate cutoff */
1667
    if (avctx->cutoff < 0) {
1668
        av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");
1669
        return AVERROR(EINVAL);
1670
    }
1671
    s->cutoff = avctx->cutoff;
1672
    if (s->cutoff > (s->sample_rate >> 1))
1673
        s->cutoff = s->sample_rate >> 1;
1674

    
1675
    return 0;
1676
}
1677

    
1678

    
1679
/**
1680
 * Set bandwidth for all channels.
1681
 * The user can optionally supply a cutoff frequency. Otherwise an appropriate
1682
 * default value will be used.
1683
 */
1684
static av_cold void set_bandwidth(AC3EncodeContext *s)
1685
{
1686
    int ch, bw_code;
1687

    
1688
    if (s->cutoff) {
1689
        /* calculate bandwidth based on user-specified cutoff frequency */
1690
        int fbw_coeffs;
1691
        fbw_coeffs     = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate;
1692
        bw_code        = av_clip((fbw_coeffs - 73) / 3, 0, 60);
1693
    } else {
1694
        /* use default bandwidth setting */
1695
        /* XXX: should compute the bandwidth according to the frame
1696
           size, so that we avoid annoying high frequency artifacts */
1697
        bw_code = 50;
1698
    }
1699

    
1700
    /* set number of coefficients for each channel */
1701
    for (ch = 0; ch < s->fbw_channels; ch++) {
1702
        s->bandwidth_code[ch] = bw_code;
1703
        s->nb_coefs[ch]       = bw_code * 3 + 73;
1704
    }
1705
    if (s->lfe_on)
1706
        s->nb_coefs[s->lfe_channel] = 7; /* LFE channel always has 7 coefs */
1707
}
1708

    
1709

    
1710
static av_cold int allocate_buffers(AVCodecContext *avctx)
1711
{
1712
    int blk, ch;
1713
    AC3EncodeContext *s = avctx->priv_data;
1714

    
1715
    FF_ALLOC_OR_GOTO(avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
1716
                     alloc_fail);
1717
    for (ch = 0; ch < s->channels; ch++) {
1718
        FF_ALLOCZ_OR_GOTO(avctx, s->planar_samples[ch],
1719
                          (AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
1720
                          alloc_fail);
1721
    }
1722
    FF_ALLOC_OR_GOTO(avctx, s->bap_buffer,  AC3_MAX_BLOCKS * s->channels *
1723
                     AC3_MAX_COEFS * sizeof(*s->bap_buffer),  alloc_fail);
1724
    FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, AC3_MAX_BLOCKS * s->channels *
1725
                     AC3_MAX_COEFS * sizeof(*s->bap1_buffer), alloc_fail);
1726
    FF_ALLOC_OR_GOTO(avctx, s->mdct_coef_buffer, AC3_MAX_BLOCKS * s->channels *
1727
                     AC3_MAX_COEFS * sizeof(*s->mdct_coef_buffer), alloc_fail);
1728
    FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, AC3_MAX_BLOCKS * s->channels *
1729
                     AC3_MAX_COEFS * sizeof(*s->exp_buffer), alloc_fail);
1730
    FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, AC3_MAX_BLOCKS * s->channels *
1731
                     128 * sizeof(*s->grouped_exp_buffer), alloc_fail);
1732
    FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, AC3_MAX_BLOCKS * s->channels *
1733
                     AC3_MAX_COEFS * sizeof(*s->psd_buffer), alloc_fail);
1734
    FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, AC3_MAX_BLOCKS * s->channels *
1735
                     64 * sizeof(*s->band_psd_buffer), alloc_fail);
1736
    FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, AC3_MAX_BLOCKS * s->channels *
1737
                     64 * sizeof(*s->mask_buffer), alloc_fail);
1738
    FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, AC3_MAX_BLOCKS * s->channels *
1739
                     AC3_MAX_COEFS * sizeof(*s->qmant_buffer), alloc_fail);
1740
    for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1741
        AC3Block *block = &s->blocks[blk];
1742
        FF_ALLOC_OR_GOTO(avctx, block->bap, s->channels * sizeof(*block->bap),
1743
                         alloc_fail);
1744
        FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, s->channels * sizeof(*block->mdct_coef),
1745
                          alloc_fail);
1746
        FF_ALLOCZ_OR_GOTO(avctx, block->exp, s->channels * sizeof(*block->exp),
1747
                          alloc_fail);
1748
        FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, s->channels * sizeof(*block->grouped_exp),
1749
                          alloc_fail);
1750
        FF_ALLOCZ_OR_GOTO(avctx, block->psd, s->channels * sizeof(*block->psd),
1751
                          alloc_fail);
1752
        FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, s->channels * sizeof(*block->band_psd),
1753
                          alloc_fail);
1754
        FF_ALLOCZ_OR_GOTO(avctx, block->mask, s->channels * sizeof(*block->mask),
1755
                          alloc_fail);
1756
        FF_ALLOCZ_OR_GOTO(avctx, block->qmant, s->channels * sizeof(*block->qmant),
1757
                          alloc_fail);
1758

    
1759
        for (ch = 0; ch < s->channels; ch++) {
1760
            block->bap[ch]         = &s->bap_buffer        [AC3_MAX_COEFS * (blk * s->channels + ch)];
1761
            block->mdct_coef[ch]   = &s->mdct_coef_buffer  [AC3_MAX_COEFS * (blk * s->channels + ch)];
1762
            block->exp[ch]         = &s->exp_buffer        [AC3_MAX_COEFS * (blk * s->channels + ch)];
1763
            block->grouped_exp[ch] = &s->grouped_exp_buffer[128           * (blk * s->channels + ch)];
1764
            block->psd[ch]         = &s->psd_buffer        [AC3_MAX_COEFS * (blk * s->channels + ch)];
1765
            block->band_psd[ch]    = &s->band_psd_buffer   [64            * (blk * s->channels + ch)];
1766
            block->mask[ch]        = &s->mask_buffer       [64            * (blk * s->channels + ch)];
1767
            block->qmant[ch]       = &s->qmant_buffer      [AC3_MAX_COEFS * (blk * s->channels + ch)];
1768
        }
1769
    }
1770

    
1771
    if (CONFIG_AC3ENC_FLOAT) {
1772
        FF_ALLOC_OR_GOTO(avctx, s->fixed_coef_buffer, AC3_MAX_BLOCKS * s->channels *
1773
                         AC3_MAX_COEFS * sizeof(*s->fixed_coef_buffer), alloc_fail);
1774
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1775
            AC3Block *block = &s->blocks[blk];
1776
            FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, s->channels *
1777
                              sizeof(*block->fixed_coef), alloc_fail);
1778
            for (ch = 0; ch < s->channels; ch++)
1779
                block->fixed_coef[ch] = &s->fixed_coef_buffer[AC3_MAX_COEFS * (blk * s->channels + ch)];
1780
        }
1781
    } else {
1782
        for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
1783
            AC3Block *block = &s->blocks[blk];
1784
            FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, s->channels *
1785
                              sizeof(*block->fixed_coef), alloc_fail);
1786
            for (ch = 0; ch < s->channels; ch++)
1787
                block->fixed_coef[ch] = (int32_t *)block->mdct_coef[ch];
1788
        }
1789
    }
1790

    
1791
    return 0;
1792
alloc_fail:
1793
    return AVERROR(ENOMEM);
1794
}
1795

    
1796

    
1797
/**
1798
 * Initialize the encoder.
1799
 */
1800
static av_cold int ac3_encode_init(AVCodecContext *avctx)
1801
{
1802
    AC3EncodeContext *s = avctx->priv_data;
1803
    int ret, frame_size_58;
1804

    
1805
    avctx->frame_size = AC3_FRAME_SIZE;
1806

    
1807
    ac3_common_init();
1808

    
1809
    ret = validate_options(avctx, s);
1810
    if (ret)
1811
        return ret;
1812

    
1813
    s->bitstream_id   = 8 + s->bit_alloc.sr_shift;
1814
    s->bitstream_mode = 0; /* complete main audio service */
1815

    
1816
    s->frame_size_min  = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
1817
    s->bits_written    = 0;
1818
    s->samples_written = 0;
1819
    s->frame_size      = s->frame_size_min;
1820

    
1821
    /* calculate crc_inv for both possible frame sizes */
1822
    frame_size_58 = (( s->frame_size    >> 2) + ( s->frame_size    >> 4)) << 1;
1823
    s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
1824
    if (s->bit_alloc.sr_code == 1) {
1825
        frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1;
1826
        s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY);
1827
    }
1828

    
1829
    set_bandwidth(s);
1830

    
1831
    rematrixing_init(s);
1832

    
1833
    exponent_init(s);
1834

    
1835
    bit_alloc_init(s);
1836

    
1837
    ret = mdct_init(avctx, &s->mdct, 9);
1838
    if (ret)
1839
        goto init_fail;
1840

    
1841
    ret = allocate_buffers(avctx);
1842
    if (ret)
1843
        goto init_fail;
1844

    
1845
    avctx->coded_frame= avcodec_alloc_frame();
1846

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

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