ffmpeg / libavcodec / ac3enc.c @ 7100d63c
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1 
/*


2 
* The simplest AC3 encoder

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* Copyright (c) 2000 Fabrice Bellard

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* Copyright (c) 20062010 Justin Ruggles <justin.ruggles@gmail.com>

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* Copyright (c) 20062010 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 021101301 USA

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*/

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/**

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* @file

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* The simplest AC3 encoder.

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*/

28  
29 
//#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" 
41  
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 
56  
57 
/** 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))) 
59  
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.

70 
*/

71 
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; ///< fixedpoint MDCT coefficients

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uint8_t **exp; ///< original exponents

76 
uint8_t **grouped_exp; ///< grouped exponents

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int16_t **psd; ///< psd per frequency bin

78 
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

82 
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 
* AC3 encoder private context.

88 
*/

89 
typedef struct AC3EncodeContext { 
90 
PutBitContext pb; ///< bitstream writer context

91 
DSPContext dsp; 
92 
AC3DSPContext ac3dsp; ///< AC3 optimized functions

93 
AC3MDCTContext mdct; ///< MDCT context

94  
95 
AC3Block blocks[AC3_MAX_BLOCKS]; ///< perblock info

96  
97 
int bitstream_id; ///< bitstream id (bsid) 
98 
int bitstream_mode; ///< bitstream mode (bsmod) 
99  
100 
int bit_rate; ///< target bit rate, in bitspersecond 
101 
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 
105 
int frame_size_code; ///< frame size code (frmsizecod) 
106 
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 fullbandwidth channels (nfchans) 
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int channels; ///< total number of channels (nchans) 
112 
int lfe_on; ///< indicates if there is an LFE channel (lfeon) 
113 
int lfe_channel; ///< channel index of the LFE channel 
114 
int channel_mode; ///< channel mode (acmod) 
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const uint8_t *channel_map; ///< channel map used to reorder channels 
116  
117 
int cutoff; ///< userspecified cutoff frequency, in Hz 
118 
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  
124 
/* 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) 
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int db_per_bit_code; ///< dB/bit code (dbpbcod) 
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int floor_code; ///< floor code (floorcod) 
130 
AC3BitAllocParameters bit_alloc; ///< bit allocation parameters

131 
int coarse_snr_offset; ///< coarse SNR offsets (csnroffst) 
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int fast_gain_code[AC3_MAX_CHANNELS]; ///< fast gain codes (signaltomask ratio) (fgaincod) 
133 
int fine_snr_offset[AC3_MAX_CHANNELS]; ///< fine SNR offsets (fsnroffst) 
134 
int frame_bits_fixed; ///< number of noncoefficient bits for fixed parameters 
135 
int frame_bits; ///< all frame bits except exponents and mantissas 
136 
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 
140 
uint16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4

141  
142 
SampleType **planar_samples; 
143 
uint8_t *bap_buffer; 
144 
uint8_t *bap1_buffer; 
145 
CoefType *mdct_coef_buffer; 
146 
int32_t *fixed_coef_buffer; 
147 
uint8_t *exp_buffer; 
148 
uint8_t *grouped_exp_buffer; 
149 
int16_t *psd_buffer; 
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int16_t *band_psd_buffer; 
151 
int16_t *mask_buffer; 
152 
uint16_t *qmant_buffer; 
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154 
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 strategy1][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[] = { 
188 
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, 
194 
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 
} 
220 
s>frame_size = s>frame_size_min + 
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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 
} 
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226  
227 
/**

228 
* Deinterleave input samples.

229 
* Channels are reordered from FFmpeg's default order to AC3 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;

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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 fixedpoint 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] += lt * lt;

332 
sum[1] += rt * rt;

333 
sum[2] += md * md;

334 
sum[3] += 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 
} 
432 
exp[i] = e; 
433 
} 
434 
} 
435 
} 
436 
} 
437  
438  
439 
/**

440 
* Exponent Difference Threshold.

441 
* New exponents are sent if their SAD exceed this number.

442 
*/

443 
#define EXP_DIFF_THRESHOLD 500 
444  
445  
446 
/**

447 
* Calculate exponent strategies for all blocks in a single channel.

448 
*/

449 
static void compute_exp_strategy_ch(AC3EncodeContext *s, uint8_t *exp_strategy, 
450 
uint8_t *exp) 
451 
{ 
452 
int blk, blk1;

453 
int exp_diff;

454  
455 
/* estimate if the exponent variation & decide if they should be

456 
reused in the next frame */

457 
exp_strategy[0] = EXP_NEW;

458 
exp += AC3_MAX_COEFS; 
459 
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) { 
460 
exp_diff = s>dsp.sad[0](NULL, exp, exp  AC3_MAX_COEFS, 16, 16); 
461 
if (exp_diff > EXP_DIFF_THRESHOLD)

462 
exp_strategy[blk] = EXP_NEW; 
463 
else

464 
exp_strategy[blk] = EXP_REUSE; 
465 
exp += AC3_MAX_COEFS; 
466 
} 
467  
468 
/* now select the encoding strategy type : if exponents are often

469 
recoded, we use a coarse encoding */

470 
blk = 0;

471 
while (blk < AC3_MAX_BLOCKS) {

472 
blk1 = blk + 1;

473 
while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)

474 
blk1++; 
475 
switch (blk1  blk) {

476 
case 1: exp_strategy[blk] = EXP_D45; break; 
477 
case 2: 
478 
case 3: exp_strategy[blk] = EXP_D25; break; 
479 
default: exp_strategy[blk] = EXP_D15; break; 
480 
} 
481 
blk = blk1; 
482 
} 
483 
} 
484  
485  
486 
/**

487 
* Calculate exponent strategies for all channels.

488 
* Array arrangement is reversed to simplify the perchannel calculation.

489 
*/

490 
static void compute_exp_strategy(AC3EncodeContext *s) 
491 
{ 
492 
int ch, blk;

493  
494 
for (ch = 0; ch < s>fbw_channels; ch++) { 
495 
compute_exp_strategy_ch(s, s>exp_strategy[ch], s>blocks[0].exp[ch]);

496 
} 
497 
if (s>lfe_on) {

498 
ch = s>lfe_channel; 
499 
s>exp_strategy[ch][0] = EXP_D15;

500 
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) 
501 
s>exp_strategy[ch][blk] = EXP_REUSE; 
502 
} 
503 
} 
504  
505  
506 
/**

507 
* Update the exponents so that they are the ones the decoder will decode.

508 
*/

509 
static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy) 
510 
{ 
511 
int nb_groups, i, k;

512  
513 
nb_groups = exponent_group_tab[exp_strategy1][nb_exps] * 3; 
514  
515 
/* for each group, compute the minimum exponent */

516 
switch(exp_strategy) {

517 
case EXP_D25:

518 
for (i = 1, k = 1; i <= nb_groups; i++) { 
519 
uint8_t exp_min = exp[k]; 
520 
if (exp[k+1] < exp_min) 
521 
exp_min = exp[k+1];

522 
exp[i] = exp_min; 
523 
k += 2;

524 
} 
525 
break;

526 
case EXP_D45:

527 
for (i = 1, k = 1; i <= nb_groups; i++) { 
528 
uint8_t exp_min = exp[k]; 
529 
if (exp[k+1] < exp_min) 
530 
exp_min = exp[k+1];

531 
if (exp[k+2] < exp_min) 
532 
exp_min = exp[k+2];

533 
if (exp[k+3] < exp_min) 
534 
exp_min = exp[k+3];

535 
exp[i] = exp_min; 
536 
k += 4;

537 
} 
538 
break;

539 
} 
540  
541 
/* constraint for DC exponent */

542 
if (exp[0] > 15) 
543 
exp[0] = 15; 
544  
545 
/* decrease the delta between each groups to within 2 so that they can be

546 
differentially encoded */

547 
for (i = 1; i <= nb_groups; i++) 
548 
exp[i] = FFMIN(exp[i], exp[i1] + 2); 
549 
i; 
550 
while (i >= 0) 
551 
exp[i] = FFMIN(exp[i], exp[i+1] + 2); 
552  
553 
/* now we have the exponent values the decoder will see */

554 
switch (exp_strategy) {

555 
case EXP_D25:

556 
for (i = nb_groups, k = nb_groups * 2; i > 0; i) { 
557 
uint8_t exp1 = exp[i]; 
558 
exp[k] = exp1; 
559 
exp[k] = exp1; 
560 
} 
561 
break;

562 
case EXP_D45:

563 
for (i = nb_groups, k = nb_groups * 4; i > 0; i) { 
564 
exp[k] = exp[k1] = exp[k2] = exp[k3] = exp[i]; 
565 
k = 4;

566 
} 
567 
break;

568 
} 
569 
} 
570  
571  
572 
/**

573 
* Encode exponents from original extracted form to what the decoder will see.

574 
* This copies and groups exponents based on exponent strategy and reduces

575 
* deltas between adjacent exponent groups so that they can be differentially

576 
* encoded.

577 
*/

578 
static void encode_exponents(AC3EncodeContext *s) 
579 
{ 
580 
int blk, blk1, ch;

581 
uint8_t *exp, *exp1, *exp_strategy; 
582 
int nb_coefs, num_reuse_blocks;

583  
584 
for (ch = 0; ch < s>channels; ch++) { 
585 
exp = s>blocks[0].exp[ch];

586 
exp_strategy = s>exp_strategy[ch]; 
587 
nb_coefs = s>nb_coefs[ch]; 
588  
589 
blk = 0;

590 
while (blk < AC3_MAX_BLOCKS) {

591 
blk1 = blk + 1;

592  
593 
/* count the number of EXP_REUSE blocks after the current block */

594 
while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)

595 
blk1++; 
596 
num_reuse_blocks = blk1  blk  1;

597  
598 
/* for the EXP_REUSE case we select the min of the exponents */

599 
s>ac3dsp.ac3_exponent_min(exp, num_reuse_blocks, nb_coefs); 
600  
601 
encode_exponents_blk_ch(exp, nb_coefs, exp_strategy[blk]); 
602  
603 
/* copy encoded exponents for reuse case */

604 
exp1 = exp + AC3_MAX_COEFS; 
605 
while (blk < blk11) { 
606 
memcpy(exp1, exp, nb_coefs * sizeof(*exp));

607 
exp1 += AC3_MAX_COEFS; 
608 
blk++; 
609 
} 
610 
blk = blk1; 
611 
exp = exp1; 
612 
} 
613 
} 
614 
} 
615  
616  
617 
/**

618 
* Group exponents.

619 
* 3 deltaencoded exponents are in each 7bit group. The number of groups

620 
* varies depending on exponent strategy and bandwidth.

621 
*/

622 
static void group_exponents(AC3EncodeContext *s) 
623 
{ 
624 
int blk, ch, i;

625 
int group_size, nb_groups, bit_count;

626 
uint8_t *p; 
627 
int delta0, delta1, delta2;

628 
int exp0, exp1;

629  
630 
bit_count = 0;

631 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
632 
AC3Block *block = &s>blocks[blk]; 
633 
for (ch = 0; ch < s>channels; ch++) { 
634 
int exp_strategy = s>exp_strategy[ch][blk];

635 
if (exp_strategy == EXP_REUSE)

636 
continue;

637 
group_size = exp_strategy + (exp_strategy == EXP_D45); 
638 
nb_groups = exponent_group_tab[exp_strategy1][s>nb_coefs[ch]];

639 
bit_count += 4 + (nb_groups * 7); 
640 
p = block>exp[ch]; 
641  
642 
/* DC exponent */

643 
exp1 = *p++; 
644 
block>grouped_exp[ch][0] = exp1;

645  
646 
/* remaining exponents are delta encoded */

647 
for (i = 1; i <= nb_groups; i++) { 
648 
/* merge three delta in one code */

649 
exp0 = exp1; 
650 
exp1 = p[0];

651 
p += group_size; 
652 
delta0 = exp1  exp0 + 2;

653  
654 
exp0 = exp1; 
655 
exp1 = p[0];

656 
p += group_size; 
657 
delta1 = exp1  exp0 + 2;

658  
659 
exp0 = exp1; 
660 
exp1 = p[0];

661 
p += group_size; 
662 
delta2 = exp1  exp0 + 2;

663  
664 
block>grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2; 
665 
} 
666 
} 
667 
} 
668  
669 
s>exponent_bits = bit_count; 
670 
} 
671  
672  
673 
/**

674 
* Calculate final exponents from the supplied MDCT coefficients and exponent shift.

675 
* Extract exponents from MDCT coefficients, calculate exponent strategies,

676 
* and encode final exponents.

677 
*/

678 
static void process_exponents(AC3EncodeContext *s) 
679 
{ 
680 
extract_exponents(s); 
681  
682 
compute_exp_strategy(s); 
683  
684 
encode_exponents(s); 
685  
686 
group_exponents(s); 
687  
688 
emms_c(); 
689 
} 
690  
691  
692 
/**

693 
* Count frame bits that are based solely on fixed parameters.

694 
* This only has to be run once when the encoder is initialized.

695 
*/

696 
static void count_frame_bits_fixed(AC3EncodeContext *s) 
697 
{ 
698 
static const int frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 }; 
699 
int blk;

700 
int frame_bits;

701  
702 
/* assumptions:

703 
* no dynamic range codes

704 
* no channel coupling

705 
* bit allocation parameters do not change between blocks

706 
* SNR offsets do not change between blocks

707 
* no delta bit allocation

708 
* no skipped data

709 
* no auxilliary data

710 
*/

711  
712 
/* header size */

713 
frame_bits = 65;

714 
frame_bits += frame_bits_inc[s>channel_mode]; 
715  
716 
/* audio blocks */

717 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
718 
frame_bits += s>fbw_channels * 2 + 2; /* blksw * c, dithflag * c, dynrnge, cplstre */ 
719 
if (s>channel_mode == AC3_CHMODE_STEREO) {

720 
frame_bits++; /* rematstr */

721 
} 
722 
frame_bits += 2 * s>fbw_channels; /* chexpstr[2] * c */ 
723 
if (s>lfe_on)

724 
frame_bits++; /* lfeexpstr */

725 
frame_bits++; /* baie */

726 
frame_bits++; /* snr */

727 
frame_bits += 2; /* delta / skip */ 
728 
} 
729 
frame_bits++; /* cplinu for block 0 */

730 
/* bit alloc info */

731 
/* sdcycod[2], fdcycod[2], sgaincod[2], dbpbcod[2], floorcod[3] */

732 
/* csnroffset[6] */

733 
/* (fsnoffset[4] + fgaincod[4]) * c */

734 
frame_bits += 2*4 + 3 + 6 + s>channels * (4 + 3); 
735  
736 
/* auxdatae, crcrsv */

737 
frame_bits += 2;

738  
739 
/* CRC */

740 
frame_bits += 16;

741  
742 
s>frame_bits_fixed = frame_bits; 
743 
} 
744  
745  
746 
/**

747 
* Initialize bit allocation.

748 
* Set default parameter codes and calculate parameter values.

749 
*/

750 
static void bit_alloc_init(AC3EncodeContext *s) 
751 
{ 
752 
int ch;

753  
754 
/* init default parameters */

755 
s>slow_decay_code = 2;

756 
s>fast_decay_code = 1;

757 
s>slow_gain_code = 1;

758 
s>db_per_bit_code = 3;

759 
s>floor_code = 7;

760 
for (ch = 0; ch < s>channels; ch++) 
761 
s>fast_gain_code[ch] = 4;

762  
763 
/* initial snr offset */

764 
s>coarse_snr_offset = 40;

765  
766 
/* compute real values */

767 
/* currently none of these values change during encoding, so we can just

768 
set them once at initialization */

769 
s>bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s>slow_decay_code] >> s>bit_alloc.sr_shift; 
770 
s>bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s>fast_decay_code] >> s>bit_alloc.sr_shift; 
771 
s>bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s>slow_gain_code]; 
772 
s>bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s>db_per_bit_code]; 
773 
s>bit_alloc.floor = ff_ac3_floor_tab[s>floor_code]; 
774  
775 
count_frame_bits_fixed(s); 
776 
} 
777  
778  
779 
/**

780 
* Count the bits used to encode the frame, minus exponents and mantissas.

781 
* Bits based on fixed parameters have already been counted, so now we just

782 
* have to add the bits based on parameters that change during encoding.

783 
*/

784 
static void count_frame_bits(AC3EncodeContext *s) 
785 
{ 
786 
int blk, ch;

787 
int frame_bits = 0; 
788  
789 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
790 
/* stereo rematrixing */

791 
if (s>channel_mode == AC3_CHMODE_STEREO &&

792 
s>blocks[blk].new_rematrixing_strategy) { 
793 
frame_bits += s>num_rematrixing_bands; 
794 
} 
795  
796 
for (ch = 0; ch < s>fbw_channels; ch++) { 
797 
if (s>exp_strategy[ch][blk] != EXP_REUSE)

798 
frame_bits += 6 + 2; /* chbwcod[6], gainrng[2] */ 
799 
} 
800 
} 
801 
s>frame_bits = s>frame_bits_fixed + frame_bits; 
802 
} 
803  
804  
805 
/**

806 
* Calculate the number of bits needed to encode a set of mantissas.

807 
*/

808 
static int compute_mantissa_size(int mant_cnt[5], uint8_t *bap, int nb_coefs) 
809 
{ 
810 
int bits, b, i;

811  
812 
bits = 0;

813 
for (i = 0; i < nb_coefs; i++) { 
814 
b = bap[i]; 
815 
if (b <= 4) { 
816 
// bap=1 to bap=4 will be counted in compute_mantissa_size_final

817 
mant_cnt[b]++; 
818 
} else if (b <= 13) { 
819 
// bap=5 to bap=13 use (bap1) bits

820 
bits += b  1;

821 
} else {

822 
// bap=14 uses 14 bits and bap=15 uses 16 bits

823 
bits += (b == 14) ? 14 : 16; 
824 
} 
825 
} 
826 
return bits;

827 
} 
828  
829  
830 
/**

831 
* Finalize the mantissa bit count by adding in the grouped mantissas.

832 
*/

833 
static int compute_mantissa_size_final(int mant_cnt[5]) 
834 
{ 
835 
// bap=1 : 3 mantissas in 5 bits

836 
int bits = (mant_cnt[1] / 3) * 5; 
837 
// bap=2 : 3 mantissas in 7 bits

838 
// bap=4 : 2 mantissas in 7 bits

839 
bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7; 
840 
// bap=3 : each mantissa is 3 bits

841 
bits += mant_cnt[3] * 3; 
842 
return bits;

843 
} 
844  
845  
846 
/**

847 
* Calculate masking curve based on the final exponents.

848 
* Also calculate the power spectral densities to use in future calculations.

849 
*/

850 
static void bit_alloc_masking(AC3EncodeContext *s) 
851 
{ 
852 
int blk, ch;

853  
854 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
855 
AC3Block *block = &s>blocks[blk]; 
856 
for (ch = 0; ch < s>channels; ch++) { 
857 
/* We only need psd and mask for calculating bap.

858 
Since we currently do not calculate bap when exponent

859 
strategy is EXP_REUSE we do not need to calculate psd or mask. */

860 
if (s>exp_strategy[ch][blk] != EXP_REUSE) {

861 
ff_ac3_bit_alloc_calc_psd(block>exp[ch], 0,

862 
s>nb_coefs[ch], 
863 
block>psd[ch], block>band_psd[ch]); 
864 
ff_ac3_bit_alloc_calc_mask(&s>bit_alloc, block>band_psd[ch], 
865 
0, s>nb_coefs[ch],

866 
ff_ac3_fast_gain_tab[s>fast_gain_code[ch]], 
867 
ch == s>lfe_channel, 
868 
DBA_NONE, 0, NULL, NULL, NULL, 
869 
block>mask[ch]); 
870 
} 
871 
} 
872 
} 
873 
} 
874  
875  
876 
/**

877 
* Ensure that bap for each block and channel point to the current bap_buffer.

878 
* They may have been switched during the bit allocation search.

879 
*/

880 
static void reset_block_bap(AC3EncodeContext *s) 
881 
{ 
882 
int blk, ch;

883 
if (s>blocks[0].bap[0] == s>bap_buffer) 
884 
return;

885 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
886 
for (ch = 0; ch < s>channels; ch++) { 
887 
s>blocks[blk].bap[ch] = &s>bap_buffer[AC3_MAX_COEFS * (blk * s>channels + ch)]; 
888 
} 
889 
} 
890 
} 
891  
892  
893 
/**

894 
* Run the bit allocation with a given SNR offset.

895 
* This calculates the bit allocation pointers that will be used to determine

896 
* the quantization of each mantissa.

897 
* @return the number of bits needed for mantissas if the given SNR offset is

898 
* is used.

899 
*/

900 
static int bit_alloc(AC3EncodeContext *s, int snr_offset) 
901 
{ 
902 
int blk, ch;

903 
int mantissa_bits;

904 
int mant_cnt[5]; 
905  
906 
snr_offset = (snr_offset  240) << 2; 
907  
908 
reset_block_bap(s); 
909 
mantissa_bits = 0;

910 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
911 
AC3Block *block = &s>blocks[blk]; 
912 
// initialize grouped mantissa counts. these are set so that they are

913 
// padded to the next whole group size when bits are counted in

914 
// compute_mantissa_size_final

915 
mant_cnt[0] = mant_cnt[3] = 0; 
916 
mant_cnt[1] = mant_cnt[2] = 2; 
917 
mant_cnt[4] = 1; 
918 
for (ch = 0; ch < s>channels; ch++) { 
919 
/* Currently the only bit allocation parameters which vary across

920 
blocks within a frame are the exponent values. We can take

921 
advantage of that by reusing the bit allocation pointers

922 
whenever we reuse exponents. */

923 
if (s>exp_strategy[ch][blk] == EXP_REUSE) {

924 
memcpy(block>bap[ch], s>blocks[blk1].bap[ch], AC3_MAX_COEFS);

925 
} else {

926 
ff_ac3_bit_alloc_calc_bap(block>mask[ch], block>psd[ch], 0,

927 
s>nb_coefs[ch], snr_offset, 
928 
s>bit_alloc.floor, ff_ac3_bap_tab, 
929 
block>bap[ch]); 
930 
} 
931 
mantissa_bits += compute_mantissa_size(mant_cnt, block>bap[ch], s>nb_coefs[ch]); 
932 
} 
933 
mantissa_bits += compute_mantissa_size_final(mant_cnt); 
934 
} 
935 
return mantissa_bits;

936 
} 
937  
938  
939 
/**

940 
* Constant bitrate bit allocation search.

941 
* Find the largest SNR offset that will allow data to fit in the frame.

942 
*/

943 
static int cbr_bit_allocation(AC3EncodeContext *s) 
944 
{ 
945 
int ch;

946 
int bits_left;

947 
int snr_offset, snr_incr;

948  
949 
bits_left = 8 * s>frame_size  (s>frame_bits + s>exponent_bits);

950  
951 
snr_offset = s>coarse_snr_offset << 4;

952  
953 
/* if previous frame SNR offset was 1023, check if current frame can also

954 
use SNR offset of 1023. if so, skip the search. */

955 
if ((snr_offset  s>fine_snr_offset[0]) == 1023) { 
956 
if (bit_alloc(s, 1023) <= bits_left) 
957 
return 0; 
958 
} 
959  
960 
while (snr_offset >= 0 && 
961 
bit_alloc(s, snr_offset) > bits_left) { 
962 
snr_offset = 64;

963 
} 
964 
if (snr_offset < 0) 
965 
return AVERROR(EINVAL);

966  
967 
FFSWAP(uint8_t *, s>bap_buffer, s>bap1_buffer); 
968 
for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) { 
969 
while (snr_offset + snr_incr <= 1023 && 
970 
bit_alloc(s, snr_offset + snr_incr) <= bits_left) { 
971 
snr_offset += snr_incr; 
972 
FFSWAP(uint8_t *, s>bap_buffer, s>bap1_buffer); 
973 
} 
974 
} 
975 
FFSWAP(uint8_t *, s>bap_buffer, s>bap1_buffer); 
976 
reset_block_bap(s); 
977  
978 
s>coarse_snr_offset = snr_offset >> 4;

979 
for (ch = 0; ch < s>channels; ch++) 
980 
s>fine_snr_offset[ch] = snr_offset & 0xF;

981  
982 
return 0; 
983 
} 
984  
985  
986 
/**

987 
* Downgrade exponent strategies to reduce the bits used by the exponents.

988 
* This is a fallback for when bit allocation fails with the normal exponent

989 
* strategies. Each time this function is run it only downgrades the

990 
* strategy in 1 channel of 1 block.

991 
* @return nonzero if downgrade was unsuccessful

992 
*/

993 
static int downgrade_exponents(AC3EncodeContext *s) 
994 
{ 
995 
int ch, blk;

996  
997 
for (ch = 0; ch < s>fbw_channels; ch++) { 
998 
for (blk = AC3_MAX_BLOCKS1; blk >= 0; blk) { 
999 
if (s>exp_strategy[ch][blk] == EXP_D15) {

1000 
s>exp_strategy[ch][blk] = EXP_D25; 
1001 
return 0; 
1002 
} 
1003 
} 
1004 
} 
1005 
for (ch = 0; ch < s>fbw_channels; ch++) { 
1006 
for (blk = AC3_MAX_BLOCKS1; blk >= 0; blk) { 
1007 
if (s>exp_strategy[ch][blk] == EXP_D25) {

1008 
s>exp_strategy[ch][blk] = EXP_D45; 
1009 
return 0; 
1010 
} 
1011 
} 
1012 
} 
1013 
for (ch = 0; ch < s>fbw_channels; ch++) { 
1014 
/* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if

1015 
the block number > 0 */

1016 
for (blk = AC3_MAX_BLOCKS1; blk > 0; blk) { 
1017 
if (s>exp_strategy[ch][blk] > EXP_REUSE) {

1018 
s>exp_strategy[ch][blk] = EXP_REUSE; 
1019 
return 0; 
1020 
} 
1021 
} 
1022 
} 
1023 
return 1; 
1024 
} 
1025  
1026  
1027 
/**

1028 
* Reduce the bandwidth to reduce the number of bits used for a given SNR offset.

1029 
* This is a second fallback for when bit allocation still fails after exponents

1030 
* have been downgraded.

1031 
* @return nonzero if bandwidth reduction was unsuccessful

1032 
*/

1033 
static int reduce_bandwidth(AC3EncodeContext *s, int min_bw_code) 
1034 
{ 
1035 
int ch;

1036  
1037 
if (s>bandwidth_code[0] > min_bw_code) { 
1038 
for (ch = 0; ch < s>fbw_channels; ch++) { 
1039 
s>bandwidth_code[ch]; 
1040 
s>nb_coefs[ch] = s>bandwidth_code[ch] * 3 + 73; 
1041 
} 
1042 
return 0; 
1043 
} 
1044 
return 1; 
1045 
} 
1046  
1047  
1048 
/**

1049 
* Perform bit allocation search.

1050 
* Finds the SNR offset value that maximizes quality and fits in the specified

1051 
* frame size. Output is the SNR offset and a set of bit allocation pointers

1052 
* used to quantize the mantissas.

1053 
*/

1054 
static int compute_bit_allocation(AC3EncodeContext *s) 
1055 
{ 
1056 
int ret;

1057  
1058 
count_frame_bits(s); 
1059  
1060 
bit_alloc_masking(s); 
1061  
1062 
ret = cbr_bit_allocation(s); 
1063 
while (ret) {

1064 
/* fallback 1: downgrade exponents */

1065 
if (!downgrade_exponents(s)) {

1066 
extract_exponents(s); 
1067 
encode_exponents(s); 
1068 
group_exponents(s); 
1069 
ret = compute_bit_allocation(s); 
1070 
continue;

1071 
} 
1072  
1073 
/* fallback 2: reduce bandwidth */

1074 
/* only do this if the user has not specified a specific cutoff

1075 
frequency */

1076 
if (!s>cutoff && !reduce_bandwidth(s, 0)) { 
1077 
process_exponents(s); 
1078 
ret = compute_bit_allocation(s); 
1079 
continue;

1080 
} 
1081  
1082 
/* fallbacks were not enough... */

1083 
break;

1084 
} 
1085  
1086 
return ret;

1087 
} 
1088  
1089  
1090 
/**

1091 
* Symmetric quantization on 'levels' levels.

1092 
*/

1093 
static inline int sym_quant(int c, int e, int levels) 
1094 
{ 
1095 
int v;

1096  
1097 
if (c >= 0) { 
1098 
v = (levels * (c << e)) >> 24;

1099 
v = (v + 1) >> 1; 
1100 
v = (levels >> 1) + v;

1101 
} else {

1102 
v = (levels * ((c) << e)) >> 24;

1103 
v = (v + 1) >> 1; 
1104 
v = (levels >> 1)  v;

1105 
} 
1106 
av_assert2(v >= 0 && v < levels);

1107 
return v;

1108 
} 
1109  
1110  
1111 
/**

1112 
* Asymmetric quantization on 2^qbits levels.

1113 
*/

1114 
static inline int asym_quant(int c, int e, int qbits) 
1115 
{ 
1116 
int lshift, m, v;

1117  
1118 
lshift = e + qbits  24;

1119 
if (lshift >= 0) 
1120 
v = c << lshift; 
1121 
else

1122 
v = c >> (lshift); 
1123 
/* rounding */

1124 
v = (v + 1) >> 1; 
1125 
m = (1 << (qbits1)); 
1126 
if (v >= m)

1127 
v = m  1;

1128 
av_assert2(v >= m); 
1129 
return v & ((1 << qbits)1); 
1130 
} 
1131  
1132  
1133 
/**

1134 
* Quantize a set of mantissas for a single channel in a single block.

1135 
*/

1136 
static void quantize_mantissas_blk_ch(AC3EncodeContext *s, int32_t *fixed_coef, 
1137 
int8_t exp_shift, uint8_t *exp, 
1138 
uint8_t *bap, uint16_t *qmant, int n)

1139 
{ 
1140 
int i;

1141  
1142 
for (i = 0; i < n; i++) { 
1143 
int v;

1144 
int c = fixed_coef[i];

1145 
int e = exp[i]  exp_shift;

1146 
int b = bap[i];

1147 
switch (b) {

1148 
case 0: 
1149 
v = 0;

1150 
break;

1151 
case 1: 
1152 
v = sym_quant(c, e, 3);

1153 
switch (s>mant1_cnt) {

1154 
case 0: 
1155 
s>qmant1_ptr = &qmant[i]; 
1156 
v = 9 * v;

1157 
s>mant1_cnt = 1;

1158 
break;

1159 
case 1: 
1160 
*s>qmant1_ptr += 3 * v;

1161 
s>mant1_cnt = 2;

1162 
v = 128;

1163 
break;

1164 
default:

1165 
*s>qmant1_ptr += v; 
1166 
s>mant1_cnt = 0;

1167 
v = 128;

1168 
break;

1169 
} 
1170 
break;

1171 
case 2: 
1172 
v = sym_quant(c, e, 5);

1173 
switch (s>mant2_cnt) {

1174 
case 0: 
1175 
s>qmant2_ptr = &qmant[i]; 
1176 
v = 25 * v;

1177 
s>mant2_cnt = 1;

1178 
break;

1179 
case 1: 
1180 
*s>qmant2_ptr += 5 * v;

1181 
s>mant2_cnt = 2;

1182 
v = 128;

1183 
break;

1184 
default:

1185 
*s>qmant2_ptr += v; 
1186 
s>mant2_cnt = 0;

1187 
v = 128;

1188 
break;

1189 
} 
1190 
break;

1191 
case 3: 
1192 
v = sym_quant(c, e, 7);

1193 
break;

1194 
case 4: 
1195 
v = sym_quant(c, e, 11);

1196 
switch (s>mant4_cnt) {

1197 
case 0: 
1198 
s>qmant4_ptr = &qmant[i]; 
1199 
v = 11 * v;

1200 
s>mant4_cnt = 1;

1201 
break;

1202 
default:

1203 
*s>qmant4_ptr += v; 
1204 
s>mant4_cnt = 0;

1205 
v = 128;

1206 
break;

1207 
} 
1208 
break;

1209 
case 5: 
1210 
v = sym_quant(c, e, 15);

1211 
break;

1212 
case 14: 
1213 
v = asym_quant(c, e, 14);

1214 
break;

1215 
case 15: 
1216 
v = asym_quant(c, e, 16);

1217 
break;

1218 
default:

1219 
v = asym_quant(c, e, b  1);

1220 
break;

1221 
} 
1222 
qmant[i] = v; 
1223 
} 
1224 
} 
1225  
1226  
1227 
/**

1228 
* Quantize mantissas using coefficients, exponents, and bit allocation pointers.

1229 
*/

1230 
static void quantize_mantissas(AC3EncodeContext *s) 
1231 
{ 
1232 
int blk, ch;

1233  
1234  
1235 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
1236 
AC3Block *block = &s>blocks[blk]; 
1237 
s>mant1_cnt = s>mant2_cnt = s>mant4_cnt = 0;

1238 
s>qmant1_ptr = s>qmant2_ptr = s>qmant4_ptr = NULL;

1239  
1240 
for (ch = 0; ch < s>channels; ch++) { 
1241 
quantize_mantissas_blk_ch(s, block>fixed_coef[ch], block>exp_shift[ch], 
1242 
block>exp[ch], block>bap[ch], 
1243 
block>qmant[ch], s>nb_coefs[ch]); 
1244 
} 
1245 
} 
1246 
} 
1247  
1248  
1249 
/**

1250 
* Write the AC3 frame header to the output bitstream.

1251 
*/

1252 
static void output_frame_header(AC3EncodeContext *s) 
1253 
{ 
1254 
put_bits(&s>pb, 16, 0x0b77); /* frame header */ 
1255 
put_bits(&s>pb, 16, 0); /* crc1: will be filled later */ 
1256 
put_bits(&s>pb, 2, s>bit_alloc.sr_code);

1257 
put_bits(&s>pb, 6, s>frame_size_code + (s>frame_size  s>frame_size_min) / 2); 
1258 
put_bits(&s>pb, 5, s>bitstream_id);

1259 
put_bits(&s>pb, 3, s>bitstream_mode);

1260 
put_bits(&s>pb, 3, s>channel_mode);

1261 
if ((s>channel_mode & 0x01) && s>channel_mode != AC3_CHMODE_MONO) 
1262 
put_bits(&s>pb, 2, 1); /* XXX 4.5 dB */ 
1263 
if (s>channel_mode & 0x04) 
1264 
put_bits(&s>pb, 2, 1); /* XXX 6 dB */ 
1265 
if (s>channel_mode == AC3_CHMODE_STEREO)

1266 
put_bits(&s>pb, 2, 0); /* surround not indicated */ 
1267 
put_bits(&s>pb, 1, s>lfe_on); /* LFE */ 
1268 
put_bits(&s>pb, 5, 31); /* dialog norm: 31 db */ 
1269 
put_bits(&s>pb, 1, 0); /* no compression control word */ 
1270 
put_bits(&s>pb, 1, 0); /* no lang code */ 
1271 
put_bits(&s>pb, 1, 0); /* no audio production info */ 
1272 
put_bits(&s>pb, 1, 0); /* no copyright */ 
1273 
put_bits(&s>pb, 1, 1); /* original bitstream */ 
1274 
put_bits(&s>pb, 1, 0); /* no time code 1 */ 
1275 
put_bits(&s>pb, 1, 0); /* no time code 2 */ 
1276 
put_bits(&s>pb, 1, 0); /* no additional bit stream info */ 
1277 
} 
1278  
1279  
1280 
/**

1281 
* Write one audio block to the output bitstream.

1282 
*/

1283 
static void output_audio_block(AC3EncodeContext *s, int blk) 
1284 
{ 
1285 
int ch, i, baie, rbnd;

1286 
AC3Block *block = &s>blocks[blk]; 
1287  
1288 
/* block switching */

1289 
for (ch = 0; ch < s>fbw_channels; ch++) 
1290 
put_bits(&s>pb, 1, 0); 
1291  
1292 
/* dither flags */

1293 
for (ch = 0; ch < s>fbw_channels; ch++) 
1294 
put_bits(&s>pb, 1, 1); 
1295  
1296 
/* dynamic range codes */

1297 
put_bits(&s>pb, 1, 0); 
1298  
1299 
/* channel coupling */

1300 
if (!blk) {

1301 
put_bits(&s>pb, 1, 1); /* coupling strategy present */ 
1302 
put_bits(&s>pb, 1, 0); /* no coupling strategy */ 
1303 
} else {

1304 
put_bits(&s>pb, 1, 0); /* no new coupling strategy */ 
1305 
} 
1306  
1307 
/* stereo rematrixing */

1308 
if (s>channel_mode == AC3_CHMODE_STEREO) {

1309 
put_bits(&s>pb, 1, block>new_rematrixing_strategy);

1310 
if (block>new_rematrixing_strategy) {

1311 
/* rematrixing flags */

1312 
for (rbnd = 0; rbnd < s>num_rematrixing_bands; rbnd++) 
1313 
put_bits(&s>pb, 1, block>rematrixing_flags[rbnd]);

1314 
} 
1315 
} 
1316  
1317 
/* exponent strategy */

1318 
for (ch = 0; ch < s>fbw_channels; ch++) 
1319 
put_bits(&s>pb, 2, s>exp_strategy[ch][blk]);

1320 
if (s>lfe_on)

1321 
put_bits(&s>pb, 1, s>exp_strategy[s>lfe_channel][blk]);

1322  
1323 
/* bandwidth */

1324 
for (ch = 0; ch < s>fbw_channels; ch++) { 
1325 
if (s>exp_strategy[ch][blk] != EXP_REUSE)

1326 
put_bits(&s>pb, 6, s>bandwidth_code[ch]);

1327 
} 
1328  
1329 
/* exponents */

1330 
for (ch = 0; ch < s>channels; ch++) { 
1331 
int nb_groups;

1332  
1333 
if (s>exp_strategy[ch][blk] == EXP_REUSE)

1334 
continue;

1335  
1336 
/* DC exponent */

1337 
put_bits(&s>pb, 4, block>grouped_exp[ch][0]); 
1338  
1339 
/* exponent groups */

1340 
nb_groups = exponent_group_tab[s>exp_strategy[ch][blk]1][s>nb_coefs[ch]];

1341 
for (i = 1; i <= nb_groups; i++) 
1342 
put_bits(&s>pb, 7, block>grouped_exp[ch][i]);

1343  
1344 
/* gain range info */

1345 
if (ch != s>lfe_channel)

1346 
put_bits(&s>pb, 2, 0); 
1347 
} 
1348  
1349 
/* bit allocation info */

1350 
baie = (blk == 0);

1351 
put_bits(&s>pb, 1, baie);

1352 
if (baie) {

1353 
put_bits(&s>pb, 2, s>slow_decay_code);

1354 
put_bits(&s>pb, 2, s>fast_decay_code);

1355 
put_bits(&s>pb, 2, s>slow_gain_code);

1356 
put_bits(&s>pb, 2, s>db_per_bit_code);

1357 
put_bits(&s>pb, 3, s>floor_code);

1358 
} 
1359  
1360 
/* snr offset */

1361 
put_bits(&s>pb, 1, baie);

1362 
if (baie) {

1363 
put_bits(&s>pb, 6, s>coarse_snr_offset);

1364 
for (ch = 0; ch < s>channels; ch++) { 
1365 
put_bits(&s>pb, 4, s>fine_snr_offset[ch]);

1366 
put_bits(&s>pb, 3, s>fast_gain_code[ch]);

1367 
} 
1368 
} 
1369  
1370 
put_bits(&s>pb, 1, 0); /* no delta bit allocation */ 
1371 
put_bits(&s>pb, 1, 0); /* no data to skip */ 
1372  
1373 
/* mantissas */

1374 
for (ch = 0; ch < s>channels; ch++) { 
1375 
int b, q;

1376 
for (i = 0; i < s>nb_coefs[ch]; i++) { 
1377 
q = block>qmant[ch][i]; 
1378 
b = block>bap[ch][i]; 
1379 
switch (b) {

1380 
case 0: break; 
1381 
case 1: if (q != 128) put_bits(&s>pb, 5, q); break; 
1382 
case 2: if (q != 128) put_bits(&s>pb, 7, q); break; 
1383 
case 3: put_bits(&s>pb, 3, q); break; 
1384 
case 4: if (q != 128) put_bits(&s>pb, 7, q); break; 
1385 
case 14: put_bits(&s>pb, 14, q); break; 
1386 
case 15: put_bits(&s>pb, 16, q); break; 
1387 
default: put_bits(&s>pb, b1, q); break; 
1388 
} 
1389 
} 
1390 
} 
1391 
} 
1392  
1393  
1394 
/** CRC16 Polynomial */

1395 
#define CRC16_POLY ((1 << 0)  (1 << 2)  (1 << 15)  (1 << 16)) 
1396  
1397  
1398 
static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly) 
1399 
{ 
1400 
unsigned int c; 
1401  
1402 
c = 0;

1403 
while (a) {

1404 
if (a & 1) 
1405 
c ^= b; 
1406 
a = a >> 1;

1407 
b = b << 1;

1408 
if (b & (1 << 16)) 
1409 
b ^= poly; 
1410 
} 
1411 
return c;

1412 
} 
1413  
1414  
1415 
static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly) 
1416 
{ 
1417 
unsigned int r; 
1418 
r = 1;

1419 
while (n) {

1420 
if (n & 1) 
1421 
r = mul_poly(r, a, poly); 
1422 
a = mul_poly(a, a, poly); 
1423 
n >>= 1;

1424 
} 
1425 
return r;

1426 
} 
1427  
1428  
1429 
/**

1430 
* Fill the end of the frame with 0's and compute the two CRCs.

1431 
*/

1432 
static void output_frame_end(AC3EncodeContext *s) 
1433 
{ 
1434 
const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI);

1435 
int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv;

1436 
uint8_t *frame; 
1437  
1438 
frame_size_58 = ((s>frame_size >> 2) + (s>frame_size >> 4)) << 1; 
1439  
1440 
/* pad the remainder of the frame with zeros */

1441 
flush_put_bits(&s>pb); 
1442 
frame = s>pb.buf; 
1443 
pad_bytes = s>frame_size  (put_bits_ptr(&s>pb)  frame)  2;

1444 
av_assert2(pad_bytes >= 0);

1445 
if (pad_bytes > 0) 
1446 
memset(put_bits_ptr(&s>pb), 0, pad_bytes);

1447  
1448 
/* compute crc1 */

1449 
/* this is not so easy because it is at the beginning of the data... */

1450 
crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58  4)); 
1451 
crc_inv = s>crc_inv[s>frame_size > s>frame_size_min]; 
1452 
crc1 = mul_poly(crc_inv, crc1, CRC16_POLY); 
1453 
AV_WB16(frame + 2, crc1);

1454  
1455 
/* compute crc2 */

1456 
crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58,

1457 
s>frame_size  frame_size_58  3);

1458 
crc2 = av_crc(crc_ctx, crc2_partial, frame + s>frame_size  3, 1); 
1459 
/* ensure crc2 does not match sync word by flipping crcrsv bit if needed */

1460 
if (crc2 == 0x770B) { 
1461 
frame[s>frame_size  3] ^= 0x1; 
1462 
crc2 = av_crc(crc_ctx, crc2_partial, frame + s>frame_size  3, 1); 
1463 
} 
1464 
crc2 = av_bswap16(crc2); 
1465 
AV_WB16(frame + s>frame_size  2, crc2);

1466 
} 
1467  
1468  
1469 
/**

1470 
* Write the frame to the output bitstream.

1471 
*/

1472 
static void output_frame(AC3EncodeContext *s, unsigned char *frame) 
1473 
{ 
1474 
int blk;

1475  
1476 
init_put_bits(&s>pb, frame, AC3_MAX_CODED_FRAME_SIZE); 
1477  
1478 
output_frame_header(s); 
1479  
1480 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) 
1481 
output_audio_block(s, blk); 
1482  
1483 
output_frame_end(s); 
1484 
} 
1485  
1486  
1487 
/**

1488 
* Encode a single AC3 frame.

1489 
*/

1490 
static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame, 
1491 
int buf_size, void *data) 
1492 
{ 
1493 
AC3EncodeContext *s = avctx>priv_data; 
1494 
const SampleType *samples = data;

1495 
int ret;

1496  
1497 
if (s>bit_alloc.sr_code == 1) 
1498 
adjust_frame_size(s); 
1499  
1500 
deinterleave_input_samples(s, samples); 
1501  
1502 
apply_mdct(s); 
1503  
1504 
compute_rematrixing_strategy(s); 
1505  
1506 
scale_coefficients(s); 
1507  
1508 
apply_rematrixing(s); 
1509  
1510 
process_exponents(s); 
1511  
1512 
ret = compute_bit_allocation(s); 
1513 
if (ret) {

1514 
av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");

1515 
return ret;

1516 
} 
1517  
1518 
quantize_mantissas(s); 
1519  
1520 
output_frame(s, frame); 
1521  
1522 
return s>frame_size;

1523 
} 
1524  
1525  
1526 
/**

1527 
* Finalize encoding and free any memory allocated by the encoder.

1528 
*/

1529 
static av_cold int ac3_encode_close(AVCodecContext *avctx) 
1530 
{ 
1531 
int blk, ch;

1532 
AC3EncodeContext *s = avctx>priv_data; 
1533  
1534 
for (ch = 0; ch < s>channels; ch++) 
1535 
av_freep(&s>planar_samples[ch]); 
1536 
av_freep(&s>planar_samples); 
1537 
av_freep(&s>bap_buffer); 
1538 
av_freep(&s>bap1_buffer); 
1539 
av_freep(&s>mdct_coef_buffer); 
1540 
av_freep(&s>fixed_coef_buffer); 
1541 
av_freep(&s>exp_buffer); 
1542 
av_freep(&s>grouped_exp_buffer); 
1543 
av_freep(&s>psd_buffer); 
1544 
av_freep(&s>band_psd_buffer); 
1545 
av_freep(&s>mask_buffer); 
1546 
av_freep(&s>qmant_buffer); 
1547 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
1548 
AC3Block *block = &s>blocks[blk]; 
1549 
av_freep(&block>bap); 
1550 
av_freep(&block>mdct_coef); 
1551 
av_freep(&block>fixed_coef); 
1552 
av_freep(&block>exp); 
1553 
av_freep(&block>grouped_exp); 
1554 
av_freep(&block>psd); 
1555 
av_freep(&block>band_psd); 
1556 
av_freep(&block>mask); 
1557 
av_freep(&block>qmant); 
1558 
} 
1559  
1560 
mdct_end(&s>mdct); 
1561  
1562 
av_freep(&avctx>coded_frame); 
1563 
return 0; 
1564 
} 
1565  
1566  
1567 
/**

1568 
* Set channel information during initialization.

1569 
*/

1570 
static av_cold int set_channel_info(AC3EncodeContext *s, int channels, 
1571 
int64_t *channel_layout) 
1572 
{ 
1573 
int ch_layout;

1574  
1575 
if (channels < 1  channels > AC3_MAX_CHANNELS) 
1576 
return AVERROR(EINVAL);

1577 
if ((uint64_t)*channel_layout > 0x7FF) 
1578 
return AVERROR(EINVAL);

1579 
ch_layout = *channel_layout; 
1580 
if (!ch_layout)

1581 
ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);

1582 
if (av_get_channel_layout_nb_channels(ch_layout) != channels)

1583 
return AVERROR(EINVAL);

1584  
1585 
s>lfe_on = !!(ch_layout & AV_CH_LOW_FREQUENCY); 
1586 
s>channels = channels; 
1587 
s>fbw_channels = channels  s>lfe_on; 
1588 
s>lfe_channel = s>lfe_on ? s>fbw_channels : 1;

1589 
if (s>lfe_on)

1590 
ch_layout = AV_CH_LOW_FREQUENCY; 
1591  
1592 
switch (ch_layout) {

1593 
case AV_CH_LAYOUT_MONO: s>channel_mode = AC3_CHMODE_MONO; break; 
1594 
case AV_CH_LAYOUT_STEREO: s>channel_mode = AC3_CHMODE_STEREO; break; 
1595 
case AV_CH_LAYOUT_SURROUND: s>channel_mode = AC3_CHMODE_3F; break; 
1596 
case AV_CH_LAYOUT_2_1: s>channel_mode = AC3_CHMODE_2F1R; break; 
1597 
case AV_CH_LAYOUT_4POINT0: s>channel_mode = AC3_CHMODE_3F1R; break; 
1598 
case AV_CH_LAYOUT_QUAD:

1599 
case AV_CH_LAYOUT_2_2: s>channel_mode = AC3_CHMODE_2F2R; break; 
1600 
case AV_CH_LAYOUT_5POINT0:

1601 
case AV_CH_LAYOUT_5POINT0_BACK: s>channel_mode = AC3_CHMODE_3F2R; break; 
1602 
default:

1603 
return AVERROR(EINVAL);

1604 
} 
1605  
1606 
s>channel_map = ff_ac3_enc_channel_map[s>channel_mode][s>lfe_on]; 
1607 
*channel_layout = ch_layout; 
1608 
if (s>lfe_on)

1609 
*channel_layout = AV_CH_LOW_FREQUENCY; 
1610  
1611 
return 0; 
1612 
} 
1613  
1614  
1615 
static av_cold int validate_options(AVCodecContext *avctx, AC3EncodeContext *s) 
1616 
{ 
1617 
int i, ret;

1618  
1619 
/* validate channel layout */

1620 
if (!avctx>channel_layout) {

1621 
av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The "

1622 
"encoder will guess the layout, but it "

1623 
"might be incorrect.\n");

1624 
} 
1625 
ret = set_channel_info(s, avctx>channels, &avctx>channel_layout); 
1626 
if (ret) {

1627 
av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n");

1628 
return ret;

1629 
} 
1630  
1631 
/* validate sample rate */

1632 
for (i = 0; i < 9; i++) { 
1633 
if ((ff_ac3_sample_rate_tab[i / 3] >> (i % 3)) == avctx>sample_rate) 
1634 
break;

1635 
} 
1636 
if (i == 9) { 
1637 
av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");

1638 
return AVERROR(EINVAL);

1639 
} 
1640 
s>sample_rate = avctx>sample_rate; 
1641 
s>bit_alloc.sr_shift = i % 3;

1642 
s>bit_alloc.sr_code = i / 3;

1643  
1644 
/* validate bit rate */

1645 
for (i = 0; i < 19; i++) { 
1646 
if ((ff_ac3_bitrate_tab[i] >> s>bit_alloc.sr_shift)*1000 == avctx>bit_rate) 
1647 
break;

1648 
} 
1649 
if (i == 19) { 
1650 
av_log(avctx, AV_LOG_ERROR, "invalid bit rate\n");

1651 
return AVERROR(EINVAL);

1652 
} 
1653 
s>bit_rate = avctx>bit_rate; 
1654 
s>frame_size_code = i << 1;

1655  
1656 
/* validate cutoff */

1657 
if (avctx>cutoff < 0) { 
1658 
av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n");

1659 
return AVERROR(EINVAL);

1660 
} 
1661 
s>cutoff = avctx>cutoff; 
1662 
if (s>cutoff > (s>sample_rate >> 1)) 
1663 
s>cutoff = s>sample_rate >> 1;

1664  
1665 
return 0; 
1666 
} 
1667  
1668  
1669 
/**

1670 
* Set bandwidth for all channels.

1671 
* The user can optionally supply a cutoff frequency. Otherwise an appropriate

1672 
* default value will be used.

1673 
*/

1674 
static av_cold void set_bandwidth(AC3EncodeContext *s) 
1675 
{ 
1676 
int ch, bw_code;

1677  
1678 
if (s>cutoff) {

1679 
/* calculate bandwidth based on userspecified cutoff frequency */

1680 
int fbw_coeffs;

1681 
fbw_coeffs = s>cutoff * 2 * AC3_MAX_COEFS / s>sample_rate;

1682 
bw_code = av_clip((fbw_coeffs  73) / 3, 0, 60); 
1683 
} else {

1684 
/* use default bandwidth setting */

1685 
/* XXX: should compute the bandwidth according to the frame

1686 
size, so that we avoid annoying high frequency artifacts */

1687 
bw_code = 50;

1688 
} 
1689  
1690 
/* set number of coefficients for each channel */

1691 
for (ch = 0; ch < s>fbw_channels; ch++) { 
1692 
s>bandwidth_code[ch] = bw_code; 
1693 
s>nb_coefs[ch] = bw_code * 3 + 73; 
1694 
} 
1695 
if (s>lfe_on)

1696 
s>nb_coefs[s>lfe_channel] = 7; /* LFE channel always has 7 coefs */ 
1697 
} 
1698  
1699  
1700 
static av_cold int allocate_buffers(AVCodecContext *avctx) 
1701 
{ 
1702 
int blk, ch;

1703 
AC3EncodeContext *s = avctx>priv_data; 
1704  
1705 
FF_ALLOC_OR_GOTO(avctx, s>planar_samples, s>channels * sizeof(*s>planar_samples),

1706 
alloc_fail); 
1707 
for (ch = 0; ch < s>channels; ch++) { 
1708 
FF_ALLOCZ_OR_GOTO(avctx, s>planar_samples[ch], 
1709 
(AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s>planar_samples),

1710 
alloc_fail); 
1711 
} 
1712 
FF_ALLOC_OR_GOTO(avctx, s>bap_buffer, AC3_MAX_BLOCKS * s>channels * 
1713 
AC3_MAX_COEFS * sizeof(*s>bap_buffer), alloc_fail);

1714 
FF_ALLOC_OR_GOTO(avctx, s>bap1_buffer, AC3_MAX_BLOCKS * s>channels * 
1715 
AC3_MAX_COEFS * sizeof(*s>bap1_buffer), alloc_fail);

1716 
FF_ALLOC_OR_GOTO(avctx, s>mdct_coef_buffer, AC3_MAX_BLOCKS * s>channels * 
1717 
AC3_MAX_COEFS * sizeof(*s>mdct_coef_buffer), alloc_fail);

1718 
FF_ALLOC_OR_GOTO(avctx, s>exp_buffer, AC3_MAX_BLOCKS * s>channels * 
1719 
AC3_MAX_COEFS * sizeof(*s>exp_buffer), alloc_fail);

1720 
FF_ALLOC_OR_GOTO(avctx, s>grouped_exp_buffer, AC3_MAX_BLOCKS * s>channels * 
1721 
128 * sizeof(*s>grouped_exp_buffer), alloc_fail); 
1722 
FF_ALLOC_OR_GOTO(avctx, s>psd_buffer, AC3_MAX_BLOCKS * s>channels * 
1723 
AC3_MAX_COEFS * sizeof(*s>psd_buffer), alloc_fail);

1724 
FF_ALLOC_OR_GOTO(avctx, s>band_psd_buffer, AC3_MAX_BLOCKS * s>channels * 
1725 
64 * sizeof(*s>band_psd_buffer), alloc_fail); 
1726 
FF_ALLOC_OR_GOTO(avctx, s>mask_buffer, AC3_MAX_BLOCKS * s>channels * 
1727 
64 * sizeof(*s>mask_buffer), alloc_fail); 
1728 
FF_ALLOC_OR_GOTO(avctx, s>qmant_buffer, AC3_MAX_BLOCKS * s>channels * 
1729 
AC3_MAX_COEFS * sizeof(*s>qmant_buffer), alloc_fail);

1730 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
1731 
AC3Block *block = &s>blocks[blk]; 
1732 
FF_ALLOC_OR_GOTO(avctx, block>bap, s>channels * sizeof(*block>bap),

1733 
alloc_fail); 
1734 
FF_ALLOCZ_OR_GOTO(avctx, block>mdct_coef, s>channels * sizeof(*block>mdct_coef),

1735 
alloc_fail); 
1736 
FF_ALLOCZ_OR_GOTO(avctx, block>exp, s>channels * sizeof(*block>exp),

1737 
alloc_fail); 
1738 
FF_ALLOCZ_OR_GOTO(avctx, block>grouped_exp, s>channels * sizeof(*block>grouped_exp),

1739 
alloc_fail); 
1740 
FF_ALLOCZ_OR_GOTO(avctx, block>psd, s>channels * sizeof(*block>psd),

1741 
alloc_fail); 
1742 
FF_ALLOCZ_OR_GOTO(avctx, block>band_psd, s>channels * sizeof(*block>band_psd),

1743 
alloc_fail); 
1744 
FF_ALLOCZ_OR_GOTO(avctx, block>mask, s>channels * sizeof(*block>mask),

1745 
alloc_fail); 
1746 
FF_ALLOCZ_OR_GOTO(avctx, block>qmant, s>channels * sizeof(*block>qmant),

1747 
alloc_fail); 
1748  
1749 
for (ch = 0; ch < s>channels; ch++) { 
1750 
/* arrangement: block, channel, coeff */

1751 
block>bap[ch] = &s>bap_buffer [AC3_MAX_COEFS * (blk * s>channels + ch)]; 
1752 
block>mdct_coef[ch] = &s>mdct_coef_buffer [AC3_MAX_COEFS * (blk * s>channels + ch)]; 
1753 
block>grouped_exp[ch] = &s>grouped_exp_buffer[128 * (blk * s>channels + ch)];

1754 
block>psd[ch] = &s>psd_buffer [AC3_MAX_COEFS * (blk * s>channels + ch)]; 
1755 
block>band_psd[ch] = &s>band_psd_buffer [64 * (blk * s>channels + ch)];

1756 
block>mask[ch] = &s>mask_buffer [64 * (blk * s>channels + ch)];

1757 
block>qmant[ch] = &s>qmant_buffer [AC3_MAX_COEFS * (blk * s>channels + ch)]; 
1758  
1759 
/* arrangement: channel, block, coeff */

1760 
block>exp[ch] = &s>exp_buffer [AC3_MAX_COEFS * (AC3_MAX_BLOCKS * ch + blk)]; 
1761 
} 
1762 
} 
1763  
1764 
if (CONFIG_AC3ENC_FLOAT) {

1765 
FF_ALLOC_OR_GOTO(avctx, s>fixed_coef_buffer, AC3_MAX_BLOCKS * s>channels * 
1766 
AC3_MAX_COEFS * sizeof(*s>fixed_coef_buffer), alloc_fail);

1767 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
1768 
AC3Block *block = &s>blocks[blk]; 
1769 
FF_ALLOCZ_OR_GOTO(avctx, block>fixed_coef, s>channels * 
1770 
sizeof(*block>fixed_coef), alloc_fail);

1771 
for (ch = 0; ch < s>channels; ch++) 
1772 
block>fixed_coef[ch] = &s>fixed_coef_buffer[AC3_MAX_COEFS * (blk * s>channels + ch)]; 
1773 
} 
1774 
} else {

1775 
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) { 
1776 
AC3Block *block = &s>blocks[blk]; 
1777 
FF_ALLOCZ_OR_GOTO(avctx, block>fixed_coef, s>channels * 
1778 
sizeof(*block>fixed_coef), alloc_fail);

1779 
for (ch = 0; ch < s>channels; ch++) 
1780 
block>fixed_coef[ch] = (int32_t *)block>mdct_coef[ch]; 
1781 
} 
1782 
} 
1783  
1784 
return 0; 
1785 
alloc_fail:

1786 
return AVERROR(ENOMEM);

1787 
} 
1788  
1789  
1790 
/**

1791 
* Initialize the encoder.

1792 
*/

1793 
static av_cold int ac3_encode_init(AVCodecContext *avctx) 
1794 
{ 
1795 
AC3EncodeContext *s = avctx>priv_data; 
1796 
int ret, frame_size_58;

1797  
1798 
avctx>frame_size = AC3_FRAME_SIZE; 
1799  
1800 
ff_ac3_common_init(); 
1801  
1802 
ret = validate_options(avctx, s); 
1803 
if (ret)

1804 
return ret;

1805  
1806 
s>bitstream_id = 8 + s>bit_alloc.sr_shift;

1807 
s>bitstream_mode = 0; /* complete main audio service */ 
1808  
1809 
s>frame_size_min = 2 * ff_ac3_frame_size_tab[s>frame_size_code][s>bit_alloc.sr_code];

1810 
s>bits_written = 0;

1811 
s>samples_written = 0;

1812 
s>frame_size = s>frame_size_min; 
1813  
1814 
/* calculate crc_inv for both possible frame sizes */

1815 
frame_size_58 = (( s>frame_size >> 2) + ( s>frame_size >> 4)) << 1; 
1816 
s>crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58)  16, CRC16_POLY); 
1817 
if (s>bit_alloc.sr_code == 1) { 
1818 
frame_size_58 = (((s>frame_size+2) >> 2) + ((s>frame_size+2) >> 4)) << 1; 
1819 
s>crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58)  16, CRC16_POLY); 
1820 
} 
1821  
1822 
set_bandwidth(s); 
1823  
1824 
rematrixing_init(s); 
1825  
1826 
exponent_init(s); 
1827  
1828 
bit_alloc_init(s); 
1829  
1830 
ret = mdct_init(avctx, &s>mdct, 9);

1831 
if (ret)

1832 
goto init_fail;

1833  
1834 
ret = allocate_buffers(avctx); 
1835 
if (ret)

1836 
goto init_fail;

1837  
1838 
avctx>coded_frame= avcodec_alloc_frame(); 
1839  
1840 
dsputil_init(&s>dsp, avctx); 
1841 
ff_ac3dsp_init(&s>ac3dsp); 
1842  
1843 
return 0; 
1844 
init_fail:

1845 
ac3_encode_close(avctx); 
1846 
return ret;

1847 
} 