FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/alacenc.c
Date: 2026-01-23 14:02:51
Exec Total Coverage
Lines: 290 310 93.5%
Functions: 14 14 100.0%
Branches: 137 154 89.0%
Line Branch Exec Source
1 /*
2 * ALAC audio encoder
3 * Copyright (c) 2008 Jaikrishnan Menon <realityman@gmx.net>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavutil/mem.h"
23 #include "libavutil/opt.h"
24
25 #include "avcodec.h"
26 #include "codec_internal.h"
27 #include "encode.h"
28 #include "put_bits.h"
29 #include "lpc.h"
30 #include "mathops.h"
31 #include "alac_data.h"
32
33 #define DEFAULT_FRAME_SIZE 4096
34 #define ALAC_EXTRADATA_SIZE 36
35 #define ALAC_FRAME_HEADER_SIZE 55
36 #define ALAC_FRAME_FOOTER_SIZE 3
37
38 #define ALAC_ESCAPE_CODE 0x1FF
39 #define ALAC_MAX_LPC_ORDER 30
40 #define DEFAULT_MAX_PRED_ORDER 6
41 #define DEFAULT_MIN_PRED_ORDER 4
42 #define ALAC_MAX_LPC_PRECISION 9
43 #define ALAC_MIN_LPC_SHIFT 0
44 #define ALAC_MAX_LPC_SHIFT 9
45
46 #define ALAC_CHMODE_LEFT_RIGHT 0
47 #define ALAC_CHMODE_LEFT_SIDE 1
48 #define ALAC_CHMODE_RIGHT_SIDE 2
49 #define ALAC_CHMODE_MID_SIDE 3
50
51 typedef struct RiceContext {
52 int history_mult;
53 int initial_history;
54 int k_modifier;
55 int rice_modifier;
56 } RiceContext;
57
58 typedef struct AlacLPCContext {
59 int lpc_order;
60 int lpc_coeff[ALAC_MAX_LPC_ORDER+1];
61 int lpc_quant;
62 } AlacLPCContext;
63
64 typedef struct AlacEncodeContext {
65 const AVClass *class;
66 AVCodecContext *avctx;
67 int frame_size; /**< current frame size */
68 int verbatim; /**< current frame verbatim mode flag */
69 int compression_level;
70 int min_prediction_order;
71 int max_prediction_order;
72 int max_coded_frame_size;
73 int write_sample_size;
74 int extra_bits;
75 int32_t sample_buf[2][DEFAULT_FRAME_SIZE];
76 int32_t predictor_buf[2][DEFAULT_FRAME_SIZE];
77 int interlacing_shift;
78 int interlacing_leftweight;
79 PutBitContext pbctx;
80 RiceContext rc;
81 AlacLPCContext lpc[2];
82 LPCContext lpc_ctx;
83 } AlacEncodeContext;
84
85
86 1781 static void init_sample_buffers(AlacEncodeContext *s, int channels,
87 const uint8_t *samples[2])
88 {
89 int ch, i;
90 1781 int shift = av_get_bytes_per_sample(s->avctx->sample_fmt) * 8 -
91 1781 s->avctx->bits_per_raw_sample;
92
93 #define COPY_SAMPLES(type) do { \
94 for (ch = 0; ch < channels; ch++) { \
95 int32_t *bptr = s->sample_buf[ch]; \
96 const type *sptr = (const type *)samples[ch]; \
97 for (i = 0; i < s->frame_size; i++) \
98 bptr[i] = sptr[i] >> shift; \
99 } \
100 } while (0)
101
102
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 1781 if (s->avctx->sample_fmt == AV_SAMPLE_FMT_S32P)
103
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 11524221 COPY_SAMPLES(int32_t);
104 else
105
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 3044022 COPY_SAMPLES(int16_t);
106 1781 }
107
108 14430194 static void encode_scalar(AlacEncodeContext *s, int x,
109 int k, int write_sample_size)
110 {
111 int divisor, q, r;
112
113 14430194 k = FFMIN(k, s->rc.k_modifier);
114 14430194 divisor = (1<<k) - 1;
115 14430194 q = x / divisor;
116 14430194 r = x % divisor;
117
118
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 14430194 if (q > 8) {
119 // write escape code and sample value directly
120 25847 put_bits(&s->pbctx, 9, ALAC_ESCAPE_CODE);
121 25847 put_bits(&s->pbctx, write_sample_size, x);
122 } else {
123
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 14404347 if (q)
124 7865003 put_bits(&s->pbctx, q, (1<<q) - 1);
125 14404347 put_bits(&s->pbctx, 1, 0);
126
127
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 14404347 if (k != 1) {
128
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 14401767 if (r > 0)
129 12874329 put_bits(&s->pbctx, k, r+1);
130 else
131 1527438 put_bits(&s->pbctx, k-1, 0);
132 }
133 }
134 14430194 }
135
136 2353 static void write_element_header(AlacEncodeContext *s,
137 enum AlacRawDataBlockType element,
138 int instance)
139 {
140 2353 int encode_fs = 0;
141
142
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 2353 if (s->frame_size < DEFAULT_FRAME_SIZE)
143 9 encode_fs = 1;
144
145 2353 put_bits(&s->pbctx, 3, element); // element type
146 2353 put_bits(&s->pbctx, 4, instance); // element instance
147 2353 put_bits(&s->pbctx, 12, 0); // unused header bits
148 2353 put_bits(&s->pbctx, 1, encode_fs); // Sample count is in the header
149 2353 put_bits(&s->pbctx, 2, s->extra_bits >> 3); // Extra bytes (for 24-bit)
150 2353 put_bits(&s->pbctx, 1, s->verbatim); // Audio block is verbatim
151
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 2353 if (encode_fs)
152 9 put_bits32(&s->pbctx, s->frame_size); // No. of samples in the frame
153 2353 }
154
155 3562 static void calc_predictor_params(AlacEncodeContext *s, int ch)
156 {
157 int32_t coefs[MAX_LPC_ORDER][MAX_LPC_ORDER];
158 int shift[MAX_LPC_ORDER];
159 int opt_order;
160
161
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 3562 if (s->compression_level == 1) {
162 1274 s->lpc[ch].lpc_order = 6;
163 1274 s->lpc[ch].lpc_quant = 6;
164 1274 s->lpc[ch].lpc_coeff[0] = 160;
165 1274 s->lpc[ch].lpc_coeff[1] = -190;
166 1274 s->lpc[ch].lpc_coeff[2] = 170;
167 1274 s->lpc[ch].lpc_coeff[3] = -130;
168 1274 s->lpc[ch].lpc_coeff[4] = 80;
169 1274 s->lpc[ch].lpc_coeff[5] = -25;
170 } else {
171 2288 opt_order = ff_lpc_calc_coefs(&s->lpc_ctx, s->sample_buf[ch],
172 s->frame_size,
173 s->min_prediction_order,
174 s->max_prediction_order,
175 ALAC_MAX_LPC_PRECISION, coefs, shift,
176 FF_LPC_TYPE_LEVINSON, 0,
177 ORDER_METHOD_EST, ALAC_MIN_LPC_SHIFT,
178 ALAC_MAX_LPC_SHIFT, 1);
179
180 2288 s->lpc[ch].lpc_order = opt_order;
181 2288 s->lpc[ch].lpc_quant = shift[opt_order-1];
182 2288 memcpy(s->lpc[ch].lpc_coeff, coefs[opt_order-1], opt_order*sizeof(int));
183 }
184 3562 }
185
186 1781 static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
187 {
188 int i, best;
189 int32_t lt, rt;
190 uint64_t sum[4];
191 uint64_t score[4];
192
193 /* calculate sum of 2nd order residual for each channel */
194 1781 sum[0] = sum[1] = sum[2] = sum[3] = 0;
195
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 7279669 for (i = 2; i < n; i++) {
196 7277888 lt = left_ch[i] - 2 * left_ch[i - 1] + left_ch[i - 2];
197 7277888 rt = right_ch[i] - 2 * right_ch[i - 1] + right_ch[i - 2];
198
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 7277888 sum[2] += FFABS((lt + rt) >> 1);
199
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 7277888 sum[3] += FFABS(lt - rt);
200
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 7277888 sum[0] += FFABS(lt);
201
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 7277888 sum[1] += FFABS(rt);
202 }
203
204 /* calculate score for each mode */
205 1781 score[0] = sum[0] + sum[1];
206 1781 score[1] = sum[0] + sum[3];
207 1781 score[2] = sum[1] + sum[3];
208 1781 score[3] = sum[2] + sum[3];
209
210 /* return mode with lowest score */
211 1781 best = 0;
212
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 7124 for (i = 1; i < 4; i++) {
213
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 5343 if (score[i] < score[best])
214 597 best = i;
215 }
216 1781 return best;
217 }
218
219 1781 static void alac_stereo_decorrelation(AlacEncodeContext *s)
220 {
221 1781 int32_t *left = s->sample_buf[0], *right = s->sample_buf[1];
222 1781 int i, mode, n = s->frame_size;
223 int32_t tmp;
224
225 1781 mode = estimate_stereo_mode(left, right, n);
226
227
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 1781 switch (mode) {
228 1425 case ALAC_CHMODE_LEFT_RIGHT:
229 1425 s->interlacing_leftweight = 0;
230 1425 s->interlacing_shift = 0;
231 1425 break;
232 145 case ALAC_CHMODE_LEFT_SIDE:
233
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 592425 for (i = 0; i < n; i++)
234 592280 right[i] = left[i] - right[i];
235 145 s->interlacing_leftweight = 1;
236 145 s->interlacing_shift = 0;
237 145 break;
238 90 case ALAC_CHMODE_RIGHT_SIDE:
239
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 368730 for (i = 0; i < n; i++) {
240 368640 tmp = right[i];
241 368640 right[i] = left[i] - right[i];
242 368640 left[i] = tmp + (right[i] >> 31);
243 }
244 90 s->interlacing_leftweight = 1;
245 90 s->interlacing_shift = 31;
246 90 break;
247 121 default:
248
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 486923 for (i = 0; i < n; i++) {
249 486802 tmp = left[i];
250 486802 left[i] = (tmp + right[i]) >> 1;
251 486802 right[i] = tmp - right[i];
252 }
253 121 s->interlacing_leftweight = 1;
254 121 s->interlacing_shift = 1;
255 121 break;
256 }
257 1781 }
258
259 3562 static void alac_linear_predictor(AlacEncodeContext *s, int ch)
260 {
261 int i;
262 3562 AlacLPCContext lpc = s->lpc[ch];
263 3562 int32_t *residual = s->predictor_buf[ch];
264
265
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 3562 if (lpc.lpc_order == 31) {
266 ✗ residual[0] = s->sample_buf[ch][0];
267
268 ✗ for (i = 1; i < s->frame_size; i++) {
269 ✗ residual[i] = s->sample_buf[ch][i ] -
270 ✗ s->sample_buf[ch][i - 1];
271 }
272
273 ✗ return;
274 }
275
276 // generalised linear predictor
277
278
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 3562 if (lpc.lpc_order > 0) {
279 3562 int32_t *samples = s->sample_buf[ch];
280
281 // generate warm-up samples
282 3562 residual[0] = samples[0];
283
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 34759 for (i = 1; i <= lpc.lpc_order; i++)
284 31197 residual[i] = sign_extend(samples[i] - samples[i-1], s->write_sample_size);
285
286 // perform lpc on remaining samples
287
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 14531703 for (i = lpc.lpc_order + 1; i < s->frame_size; i++) {
288 14528141 int sum = 1 << (lpc.lpc_quant - 1), res_val, j;
289
290
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 141644105 for (j = 0; j < lpc.lpc_order; j++) {
291 127115964 sum += (samples[lpc.lpc_order-j] - samples[0]) *
292 127115964 lpc.lpc_coeff[j];
293 }
294
295 14528141 sum >>= lpc.lpc_quant;
296 14528141 sum += samples[0];
297 14528141 residual[i] = sign_extend(samples[lpc.lpc_order+1] - sum,
298 14528141 s->write_sample_size);
299 14528141 res_val = residual[i];
300
301
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 14528141 if (res_val) {
302 13747876 int index = lpc.lpc_order - 1;
303 13747876 int neg = (res_val < 0);
304
305
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 74211438 while (index >= 0 && (neg ? (res_val < 0) : (res_val > 0))) {
306 60463562 int val = samples[0] - samples[lpc.lpc_order - index];
307
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 60463562 int sign = (val ? FFSIGN(val) : 0);
308
309
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 60463562 if (neg)
310 28132311 sign *= -1;
311
312 60463562 lpc.lpc_coeff[index] -= sign;
313 60463562 val *= sign;
314 60463562 res_val -= (val >> lpc.lpc_quant) * (lpc.lpc_order - index);
315 60463562 index--;
316 }
317 }
318 14528141 samples++;
319 }
320 }
321 }
322
323 3562 static void alac_entropy_coder(AlacEncodeContext *s, int ch)
324 {
325 3562 unsigned int history = s->rc.initial_history;
326 3562 int sign_modifier = 0, i, k;
327 3562 int32_t *samples = s->predictor_buf[ch];
328
329
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 14433625 for (i = 0; i < s->frame_size;) {
330 int x;
331
332 14430063 k = av_log2((history >> 9) + 3);
333
334 14430063 x = -2 * (*samples) -1;
335 14430063 x ^= x >> 31;
336
337 14430063 samples++;
338 14430063 i++;
339
340 14430063 encode_scalar(s, x - sign_modifier, k, s->write_sample_size);
341
342 14430063 history += x * s->rc.history_mult -
343 14430063 ((history * s->rc.history_mult) >> 9);
344
345 14430063 sign_modifier = 0;
346
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 14430063 if (x > 0xFFFF)
347 11363 history = 0xFFFF;
348
349
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 14430063 if (history < 128 && i < s->frame_size) {
350 131 unsigned int block_size = 0;
351
352 131 k = 7 - av_log2(history) + ((history + 16) >> 6);
353
354
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 132968 while (*samples == 0 && i < s->frame_size) {
355 132837 samples++;
356 132837 i++;
357 132837 block_size++;
358 }
359 131 encode_scalar(s, block_size, k, 16);
360 131 sign_modifier = (block_size <= 0xFFFF);
361 131 history = 0;
362 }
363
364 }
365 3562 }
366
367 2353 static void write_element(AlacEncodeContext *s,
368 enum AlacRawDataBlockType element, int instance,
369 const uint8_t *samples0, const uint8_t *samples1)
370 {
371 2353 const uint8_t *samples[2] = { samples0, samples1 };
372 int i, j, channels;
373 2353 int prediction_type = 0;
374 2353 PutBitContext *pb = &s->pbctx;
375
376
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 2353 channels = element == TYPE_CPE ? 2 : 1;
377
378
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 2353 if (s->verbatim) {
379 572 write_element_header(s, element, instance);
380 /* samples are channel-interleaved in verbatim mode */
381
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 572 if (s->avctx->sample_fmt == AV_SAMPLE_FMT_S32P) {
382 469 int shift = 32 - s->avctx->bits_per_raw_sample;
383 469 const int32_t *samples_s32[2] = { (const int32_t *)samples0,
384 (const int32_t *)samples1 };
385
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 1920469 for (i = 0; i < s->frame_size; i++)
386
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 5760000 for (j = 0; j < channels; j++)
387 3840000 put_sbits(pb, s->avctx->bits_per_raw_sample,
388 3840000 samples_s32[j][i] >> shift);
389 } else {
390 103 const int16_t *samples_s16[2] = { (const int16_t *)samples0,
391 (const int16_t *)samples1 };
392
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393
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 1256850 for (j = 0; j < channels; j++)
394 837900 put_sbits(pb, s->avctx->bits_per_raw_sample,
395 837900 samples_s16[j][i]);
396 }
397 } else {
398 1781 s->write_sample_size = s->avctx->bits_per_raw_sample - s->extra_bits +
399 1781 channels - 1;
400
401 1781 init_sample_buffers(s, channels, samples);
402 1781 write_element_header(s, element, instance);
403
404 // extract extra bits if needed
405
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 1781 if (s->extra_bits) {
406 1407 uint32_t mask = (1 << s->extra_bits) - 1;
407
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 4221 for (j = 0; j < channels; j++) {
408 2814 int32_t *extra = s->predictor_buf[j];
409 2814 int32_t *smp = s->sample_buf[j];
410
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 11522814 for (i = 0; i < s->frame_size; i++) {
411 11520000 extra[i] = smp[i] & mask;
412 11520000 smp[i] >>= s->extra_bits;
413 }
414 }
415 }
416
417
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 1781 if (channels == 2)
418 1781 alac_stereo_decorrelation(s);
419 else
420 ✗ s->interlacing_shift = s->interlacing_leftweight = 0;
421 1781 put_bits(pb, 8, s->interlacing_shift);
422 1781 put_bits(pb, 8, s->interlacing_leftweight);
423
424
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 5343 for (i = 0; i < channels; i++) {
425 3562 calc_predictor_params(s, i);
426
427 3562 put_bits(pb, 4, prediction_type);
428 3562 put_bits(pb, 4, s->lpc[i].lpc_quant);
429
430 3562 put_bits(pb, 3, s->rc.rice_modifier);
431 3562 put_bits(pb, 5, s->lpc[i].lpc_order);
432 // predictor coeff. table
433
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 34759 for (j = 0; j < s->lpc[i].lpc_order; j++)
434 31197 put_sbits(pb, 16, s->lpc[i].lpc_coeff[j]);
435 }
436
437 // write extra bits if needed
438
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 1781 if (s->extra_bits) {
439
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440
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 17280000 for (j = 0; j < channels; j++) {
441 11520000 put_bits(pb, s->extra_bits, s->predictor_buf[j][i]);
442 }
443 }
444 }
445
446 // apply lpc and entropy coding to audio samples
447
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 5343 for (i = 0; i < channels; i++) {
448 3562 alac_linear_predictor(s, i);
449
450 // TODO: determine when this will actually help. for now it's not used.
451
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 3562 if (prediction_type == 15) {
452 // 2nd pass 1st order filter
453 ✗ int32_t *residual = s->predictor_buf[i];
454 ✗ for (j = s->frame_size - 1; j > 0; j--)
455 ✗ residual[j] -= residual[j - 1];
456 }
457 3562 alac_entropy_coder(s, i);
458 }
459 }
460 2353 }
461
462 2353 static int write_frame(AlacEncodeContext *s, AVPacket *avpkt,
463 uint8_t * const *samples)
464 {
465 2353 PutBitContext *pb = &s->pbctx;
466 2353 int channels = s->avctx->ch_layout.nb_channels;
467 2353 const enum AlacRawDataBlockType *ch_elements = ff_alac_channel_elements[channels - 1];
468 2353 const uint8_t *ch_map = ff_alac_channel_layout_offsets[channels - 1];
469 int ch, element, sce, cpe;
470
471 2353 init_put_bits(pb, avpkt->data, avpkt->size);
472
473 2353 ch = element = sce = cpe = 0;
474
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 4706 while (ch < channels) {
475
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 2353 if (ch_elements[element] == TYPE_CPE) {
476 2353 write_element(s, TYPE_CPE, cpe, samples[ch_map[ch]],
477 2353 samples[ch_map[ch + 1]]);
478 2353 cpe++;
479 2353 ch += 2;
480 } else {
481 ✗ write_element(s, TYPE_SCE, sce, samples[ch_map[ch]], NULL);
482 ✗ sce++;
483 ✗ ch++;
484 }
485 2353 element++;
486 }
487
488 2353 put_bits(pb, 3, TYPE_END);
489 2353 flush_put_bits(pb);
490
491 2353 return put_bytes_output(pb);
492 }
493
494 18 static av_always_inline int get_max_frame_size(int frame_size, int ch, int bps)
495 {
496
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 18 int header_bits = 23 + 32 * (frame_size < DEFAULT_FRAME_SIZE);
497 18 return FFALIGN(header_bits + bps * ch * frame_size + 3, 8) / 8;
498 }
499
500 9 static av_cold int alac_encode_close(AVCodecContext *avctx)
501 {
502 9 AlacEncodeContext *s = avctx->priv_data;
503 9 ff_lpc_end(&s->lpc_ctx);
504 9 return 0;
505 }
506
507 9 static av_cold int alac_encode_init(AVCodecContext *avctx)
508 {
509 9 AlacEncodeContext *s = avctx->priv_data;
510 int ret;
511 uint8_t *alac_extradata;
512
513 9 avctx->frame_size = s->frame_size = DEFAULT_FRAME_SIZE;
514
515
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 9 if (avctx->sample_fmt == AV_SAMPLE_FMT_S32P) {
516
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 4 if (avctx->bits_per_raw_sample != 24)
517 4 av_log(avctx, AV_LOG_WARNING, "encoding as 24 bits-per-sample\n");
518 4 avctx->bits_per_raw_sample = 24;
519 } else {
520 5 avctx->bits_per_raw_sample = 16;
521 5 s->extra_bits = 0;
522 }
523
524 // Set default compression level
525
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 9 if (avctx->compression_level == FF_COMPRESSION_DEFAULT)
526 2 s->compression_level = 2;
527 else
528 7 s->compression_level = av_clip(avctx->compression_level, 0, 2);
529
530 // Initialize default Rice parameters
531 9 s->rc.history_mult = 40;
532 9 s->rc.initial_history = 10;
533 9 s->rc.k_modifier = 14;
534 9 s->rc.rice_modifier = 4;
535
536 9 s->max_coded_frame_size = get_max_frame_size(avctx->frame_size,
537 avctx->ch_layout.nb_channels,
538 avctx->bits_per_raw_sample);
539
540 9 avctx->extradata = av_mallocz(ALAC_EXTRADATA_SIZE + AV_INPUT_BUFFER_PADDING_SIZE);
541
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 9 if (!avctx->extradata)
542 ✗ return AVERROR(ENOMEM);
543 9 avctx->extradata_size = ALAC_EXTRADATA_SIZE;
544
545 9 alac_extradata = avctx->extradata;
546 9 AV_WB32(alac_extradata, ALAC_EXTRADATA_SIZE);
547 9 AV_WB32(alac_extradata+4, MKBETAG('a','l','a','c'));
548 9 AV_WB32(alac_extradata+12, avctx->frame_size);
549 9 AV_WB8 (alac_extradata+17, avctx->bits_per_raw_sample);
550 9 AV_WB8 (alac_extradata+21, avctx->ch_layout.nb_channels);
551 9 AV_WB32(alac_extradata+24, s->max_coded_frame_size);
552 9 AV_WB32(alac_extradata+28,
553 avctx->sample_rate * avctx->ch_layout.nb_channels * avctx->bits_per_raw_sample); // average bitrate
554 9 AV_WB32(alac_extradata+32, avctx->sample_rate);
555
556 // Set relevant extradata fields
557
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 9 if (s->compression_level > 0) {
558 7 AV_WB8(alac_extradata+18, s->rc.history_mult);
559 7 AV_WB8(alac_extradata+19, s->rc.initial_history);
560 7 AV_WB8(alac_extradata+20, s->rc.k_modifier);
561 }
562
563
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 9 if (s->max_prediction_order < s->min_prediction_order) {
564 ✗ av_log(avctx, AV_LOG_ERROR,
565 "invalid prediction orders: min=%d max=%d\n",
566 s->min_prediction_order, s->max_prediction_order);
567 ✗ return AVERROR(EINVAL);
568 }
569
570 9 s->avctx = avctx;
571
572
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 9 if ((ret = ff_lpc_init(&s->lpc_ctx, avctx->frame_size,
573 s->max_prediction_order,
574 FF_LPC_TYPE_LEVINSON)) < 0) {
575 ✗ return ret;
576 }
577
578 9 return 0;
579 }
580
581 2353 static int alac_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
582 const AVFrame *frame, int *got_packet_ptr)
583 {
584 2353 AlacEncodeContext *s = avctx->priv_data;
585 int out_bytes, max_frame_size, ret;
586
587 2353 s->frame_size = frame->nb_samples;
588
589
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 2353 if (frame->nb_samples < DEFAULT_FRAME_SIZE)
590 9 max_frame_size = get_max_frame_size(s->frame_size, avctx->ch_layout.nb_channels,
591 avctx->bits_per_raw_sample);
592 else
593 2344 max_frame_size = s->max_coded_frame_size;
594
595
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 2353 if ((ret = ff_alloc_packet(avctx, avpkt, 4 * max_frame_size)) < 0)
596 ✗ return ret;
597
598 /* use verbatim mode for compression_level 0 */
599
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 2353 if (s->compression_level) {
600 1781 s->verbatim = 0;
601 1781 s->extra_bits = avctx->bits_per_raw_sample - 16;
602 } else {
603 572 s->verbatim = 1;
604 572 s->extra_bits = 0;
605 }
606
607 2353 out_bytes = write_frame(s, avpkt, frame->extended_data);
608
609
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 2353 if (out_bytes > max_frame_size) {
610 /* frame too large. use verbatim mode */
611 ✗ s->verbatim = 1;
612 ✗ s->extra_bits = 0;
613 ✗ out_bytes = write_frame(s, avpkt, frame->extended_data);
614 }
615
616 2353 avpkt->size = out_bytes;
617 2353 *got_packet_ptr = 1;
618 2353 return 0;
619 }
620
621 #define OFFSET(x) offsetof(AlacEncodeContext, x)
622 #define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
623 static const AVOption options[] = {
624 { "min_prediction_order", NULL, OFFSET(min_prediction_order), AV_OPT_TYPE_INT, { .i64 = DEFAULT_MIN_PRED_ORDER }, MIN_LPC_ORDER, ALAC_MAX_LPC_ORDER, AE },
625 { "max_prediction_order", NULL, OFFSET(max_prediction_order), AV_OPT_TYPE_INT, { .i64 = DEFAULT_MAX_PRED_ORDER }, MIN_LPC_ORDER, ALAC_MAX_LPC_ORDER, AE },
626
627 { NULL },
628 };
629
630 static const AVClass alacenc_class = {
631 .class_name = "alacenc",
632 .item_name = av_default_item_name,
633 .option = options,
634 .version = LIBAVUTIL_VERSION_INT,
635 };
636
637 const FFCodec ff_alac_encoder = {
638 .p.name = "alac",
639 CODEC_LONG_NAME("ALAC (Apple Lossless Audio Codec)"),
640 .p.type = AVMEDIA_TYPE_AUDIO,
641 .p.id = AV_CODEC_ID_ALAC,
642 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SMALL_LAST_FRAME |
643 AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
644 .priv_data_size = sizeof(AlacEncodeContext),
645 .p.priv_class = &alacenc_class,
646 .init = alac_encode_init,
647 FF_CODEC_ENCODE_CB(alac_encode_frame),
648 .close = alac_encode_close,
649 CODEC_CH_LAYOUTS_ARRAY(ff_alac_ch_layouts),
650 CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_S32P, AV_SAMPLE_FMT_S16P),
651 };
652