Add MPEG-4 Audio Lossless Coding (ALS) decoder.
[libav.git] / libavcodec / alsdec.c
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1/*
2 * MPEG-4 ALS decoder
3 * Copyright (c) 2009 Thilo Borgmann <thilo.borgmann _at_ googlemail.com>
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/**
23 * @file libavcodec/alsdec.c
24 * MPEG-4 ALS decoder
25 * @author Thilo Borgmann <thilo.borgmann _at_ googlemail.com>
26 */
27
28
29//#define DEBUG
30
31
32#include "avcodec.h"
33#include "get_bits.h"
34#include "unary.h"
35#include "mpeg4audio.h"
36#include "bytestream.h"
37
38#include "als_data.h"
39
40enum RA_Flag {
41 RA_FLAG_NONE,
42 RA_FLAG_FRAMES,
43 RA_FLAG_HEADER
44};
45
46
47typedef struct {
48 uint32_t samples; ///< number of samples, 0xFFFFFFFF if unknown
49 int resolution; ///< 000 = 8-bit; 001 = 16-bit; 010 = 24-bit; 011 = 32-bit
50 int floating; ///< 1 = IEEE 32-bit floating-point, 0 = integer
51 int frame_length; ///< frame length for each frame (last frame may differ)
52 int ra_distance; ///< distance between RA frames (in frames, 0...255)
53 enum RA_Flag ra_flag; ///< indicates where the size of ra units is stored
54 int adapt_order; ///< adaptive order: 1 = on, 0 = off
55 int coef_table; ///< table index of Rice code parameters
56 int long_term_prediction; ///< long term prediction (LTP): 1 = on, 0 = off
57 int max_order; ///< maximum prediction order (0..1023)
58 int block_switching; ///< number of block switching levels
59 int bgmc; ///< "Block Gilbert-Moore Code": 1 = on, 0 = off (Rice coding only)
60 int sb_part; ///< sub-block partition
61 int joint_stereo; ///< joint stereo: 1 = on, 0 = off
62 int mc_coding; ///< extended inter-channel coding (multi channel coding): 1 = on, 0 = off
63 int chan_config; ///< indicates that a chan_config_info field is present
64 int chan_sort; ///< channel rearrangement: 1 = on, 0 = off
65 int rlslms; ///< use "Recursive Least Square-Least Mean Square" predictor: 1 = on, 0 = off
66 int chan_config_info; ///< mapping of channels to loudspeaker locations. Unused until setting channel configuration is implemented.
67 int *chan_pos; ///< original channel positions
68 uint32_t header_size; ///< header size of original audio file in bytes, provided for debugging
69 uint32_t trailer_size; ///< trailer size of original audio file in bytes, provided for debugging
70} ALSSpecificConfig;
71
72
73typedef struct {
74 AVCodecContext *avctx;
75 ALSSpecificConfig sconf;
76 GetBitContext gb;
77 unsigned int cur_frame_length; ///< length of the current frame to decode
78 unsigned int frame_id; ///< the frame ID / number of the current frame
79 unsigned int js_switch; ///< if true, joint-stereo decoding is enforced
80 unsigned int num_blocks; ///< number of blocks used in the current frame
81 int32_t *quant_cof; ///< quantized parcor coefficients
82 int32_t *lpc_cof; ///< coefficients of the direct form prediction filter
83 int32_t *prev_raw_samples; ///< contains unshifted raw samples from the previous block
84 int32_t **raw_samples; ///< decoded raw samples for each channel
85 int32_t *raw_buffer; ///< contains all decoded raw samples including carryover samples
86} ALSDecContext;
87
88
89static av_cold void dprint_specific_config(ALSDecContext *ctx)
90{
91#ifdef DEBUG
92 AVCodecContext *avctx = ctx->avctx;
93 ALSSpecificConfig *sconf = &ctx->sconf;
94
95 dprintf(avctx, "resolution = %i\n", sconf->resolution);
96 dprintf(avctx, "floating = %i\n", sconf->floating);
97 dprintf(avctx, "frame_length = %i\n", sconf->frame_length);
98 dprintf(avctx, "ra_distance = %i\n", sconf->ra_distance);
99 dprintf(avctx, "ra_flag = %i\n", sconf->ra_flag);
100 dprintf(avctx, "adapt_order = %i\n", sconf->adapt_order);
101 dprintf(avctx, "coef_table = %i\n", sconf->coef_table);
102 dprintf(avctx, "long_term_prediction = %i\n", sconf->long_term_prediction);
103 dprintf(avctx, "max_order = %i\n", sconf->max_order);
104 dprintf(avctx, "block_switching = %i\n", sconf->block_switching);
105 dprintf(avctx, "bgmc = %i\n", sconf->bgmc);
106 dprintf(avctx, "sb_part = %i\n", sconf->sb_part);
107 dprintf(avctx, "joint_stereo = %i\n", sconf->joint_stereo);
108 dprintf(avctx, "mc_coding = %i\n", sconf->mc_coding);
109 dprintf(avctx, "chan_config = %i\n", sconf->chan_config);
110 dprintf(avctx, "chan_sort = %i\n", sconf->chan_sort);
111 dprintf(avctx, "RLSLMS = %i\n", sconf->rlslms);
112 dprintf(avctx, "chan_config_info = %i\n", sconf->chan_config_info);
113 dprintf(avctx, "header_size = %i\n", sconf->header_size);
114 dprintf(avctx, "trailer_size = %i\n", sconf->trailer_size);
115#endif
116}
117
118
119/** Reads an ALSSpecificConfig from a buffer into the output struct.
120 */
121static av_cold int read_specific_config(ALSDecContext *ctx)
122{
123 GetBitContext gb;
124 uint64_t ht_size;
125 int i, config_offset, crc_enabled;
126 MPEG4AudioConfig m4ac;
127 ALSSpecificConfig *sconf = &ctx->sconf;
128 AVCodecContext *avctx = ctx->avctx;
129 uint32_t als_id;
130
131 init_get_bits(&gb, avctx->extradata, avctx->extradata_size * 8);
132
133 config_offset = ff_mpeg4audio_get_config(&m4ac, avctx->extradata,
134 avctx->extradata_size);
135
136 if (config_offset < 0)
137 return -1;
138
139 skip_bits_long(&gb, config_offset);
140
141 if (get_bits_left(&gb) < (30 << 3))
142 return -1;
143
144 // read the fixed items
145 als_id = get_bits_long(&gb, 32);
146 avctx->sample_rate = m4ac.sample_rate;
147 skip_bits_long(&gb, 32); // sample rate already known
148 sconf->samples = get_bits_long(&gb, 32);
149 avctx->channels = m4ac.channels;
150 skip_bits(&gb, 16); // number of channels already knwon
151 skip_bits(&gb, 3); // skip file_type
152 sconf->resolution = get_bits(&gb, 3);
153 sconf->floating = get_bits1(&gb);
154 skip_bits1(&gb); // skip msb_first
155 sconf->frame_length = get_bits(&gb, 16) + 1;
156 sconf->ra_distance = get_bits(&gb, 8);
157 sconf->ra_flag = get_bits(&gb, 2);
158 sconf->adapt_order = get_bits1(&gb);
159 sconf->coef_table = get_bits(&gb, 2);
160 sconf->long_term_prediction = get_bits1(&gb);
161 sconf->max_order = get_bits(&gb, 10);
162 sconf->block_switching = get_bits(&gb, 2);
163 sconf->bgmc = get_bits1(&gb);
164 sconf->sb_part = get_bits1(&gb);
165 sconf->joint_stereo = get_bits1(&gb);
166 sconf->mc_coding = get_bits1(&gb);
167 sconf->chan_config = get_bits1(&gb);
168 sconf->chan_sort = get_bits1(&gb);
169 crc_enabled = get_bits1(&gb);
170 sconf->rlslms = get_bits1(&gb);
171 skip_bits(&gb, 5); // skip 5 reserved bits
172 skip_bits1(&gb); // skip aux_data_enabled
173
174
175 // check for ALSSpecificConfig struct
176 if (als_id != MKBETAG('A','L','S','\0'))
177 return -1;
178
179 ctx->cur_frame_length = sconf->frame_length;
180
181 // allocate quantized parcor coefficient buffer
182 if (!(ctx->quant_cof = av_malloc(sizeof(*ctx->quant_cof) * sconf->max_order)) ||
183 !(ctx->lpc_cof = av_malloc(sizeof(*ctx->lpc_cof) * sconf->max_order))) {
184 av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
185 return AVERROR(ENOMEM);
186 }
187
188 // read channel config
189 if (sconf->chan_config)
190 sconf->chan_config_info = get_bits(&gb, 16);
191 // TODO: use this to set avctx->channel_layout
192
193
194 // read channel sorting
195 if (sconf->chan_sort && avctx->channels > 1) {
196 int chan_pos_bits = av_ceil_log2(avctx->channels);
197 int bits_needed = avctx->channels * chan_pos_bits + 7;
198 if (get_bits_left(&gb) < bits_needed)
199 return -1;
200
201 if (!(sconf->chan_pos = av_malloc(avctx->channels * sizeof(*sconf->chan_pos))))
202 return AVERROR(ENOMEM);
203
204 for (i = 0; i < avctx->channels; i++)
205 sconf->chan_pos[i] = get_bits(&gb, chan_pos_bits);
206
207 align_get_bits(&gb);
208 // TODO: use this to actually do channel sorting
209 } else {
210 sconf->chan_sort = 0;
211 }
212
213
214 // read fixed header and trailer sizes,
215 // if size = 0xFFFFFFFF then there is no data field!
216 if (get_bits_left(&gb) < 64)
217 return -1;
218
219 sconf->header_size = get_bits_long(&gb, 32);
220 sconf->trailer_size = get_bits_long(&gb, 32);
221 if (sconf->header_size == 0xFFFFFFFF)
222 sconf->header_size = 0;
223 if (sconf->trailer_size == 0xFFFFFFFF)
224 sconf->trailer_size = 0;
225
226 ht_size = ((int64_t)(sconf->header_size) + (int64_t)(sconf->trailer_size)) << 3;
227
228
229 // skip the header and trailer data
230 if (get_bits_left(&gb) < ht_size)
231 return -1;
232
233 if (ht_size > INT32_MAX)
234 return -1;
235
236 skip_bits_long(&gb, ht_size);
237
238
239 // skip the crc data
240 if (crc_enabled) {
241 if (get_bits_left(&gb) < 32)
242 return -1;
243
244 skip_bits_long(&gb, 32);
245 }
246
247
248 // no need to read the rest of ALSSpecificConfig (ra_unit_size & aux data)
249
250 dprint_specific_config(ctx);
251
252 return 0;
253}
254
255
256/** Checks the ALSSpecificConfig for unsupported features.
257 */
258static int check_specific_config(ALSDecContext *ctx)
259{
260 ALSSpecificConfig *sconf = &ctx->sconf;
261 int error = 0;
262
263 // report unsupported feature and set error value
264 #define MISSING_ERR(cond, str, errval) \
265 { \
266 if (cond) { \
267 av_log_missing_feature(ctx->avctx, str, 0); \
268 error = errval; \
269 } \
270 }
271
272 MISSING_ERR(sconf->floating, "Floating point decoding", -1);
273 MISSING_ERR(sconf->long_term_prediction, "Long-term prediction", -1);
274 MISSING_ERR(sconf->bgmc, "BGMC entropy decoding", -1);
275 MISSING_ERR(sconf->mc_coding, "Multi-channel correlation", -1);
276 MISSING_ERR(sconf->rlslms, "Adaptive RLS-LMS prediction", -1);
277 MISSING_ERR(sconf->chan_sort, "Channel sorting", 0);
278
279 return error;
280}
281
282
283/** Parses the bs_info field to extract the block partitioning used in
284 * block switching mode, refer to ISO/IEC 14496-3, section 11.6.2.
285 */
286static void parse_bs_info(const uint32_t bs_info, unsigned int n,
287 unsigned int div, unsigned int **div_blocks,
288 unsigned int *num_blocks)
289{
290 if (n < 31 && ((bs_info << n) & 0x40000000)) {
291 // if the level is valid and the investigated bit n is set
292 // then recursively check both children at bits (2n+1) and (2n+2)
293 n *= 2;
294 div += 1;
295 parse_bs_info(bs_info, n + 1, div, div_blocks, num_blocks);
296 parse_bs_info(bs_info, n + 2, div, div_blocks, num_blocks);
297 } else {
298 // else the bit is not set or the last level has been reached
299 // (bit implicitly not set)
300 **div_blocks = div;
301 (*div_blocks)++;
302 (*num_blocks)++;
303 }
304}
305
306
307/** Reads and decodes a Rice codeword.
308 */
309static int32_t decode_rice(GetBitContext *gb, unsigned int k)
310{
311 int max = gb->size_in_bits - get_bits_count(gb) - k;
312 int q = get_unary(gb, 0, max);
313 int r = k ? get_bits1(gb) : !(q & 1);
314
315 if (k > 1) {
316 q <<= (k - 1);
317 q += get_bits_long(gb, k - 1);
318 } else if (!k) {
319 q >>= 1;
320 }
321 return r ? q : ~q;
322}
323
324
325/** Converts PARCOR coefficient k to direct filter coefficient.
326 */
327static void parcor_to_lpc(unsigned int k, const int32_t *par, int32_t *cof)
328{
329 int i, j;
330
331 for (i = 0, j = k - 1; i < j; i++, j--) {
332 int tmp1 = ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
333 cof[j] += ((MUL64(par[k], cof[i]) + (1 << 19)) >> 20);
334 cof[i] += tmp1;
335 }
336 if (i == j)
337 cof[i] += ((MUL64(par[k], cof[j]) + (1 << 19)) >> 20);
338
339 cof[k] = par[k];
340}
341
342
343/** Reads block switching field if necessary and sets actual block sizes.
344 * Also assures that the block sizes of the last frame correspond to the
345 * actual number of samples.
346 */
347static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
348 uint32_t *bs_info)
349{
350 ALSSpecificConfig *sconf = &ctx->sconf;
351 GetBitContext *gb = &ctx->gb;
352 unsigned int *ptr_div_blocks = div_blocks;
353 unsigned int b;
354
355 if (sconf->block_switching) {
356 unsigned int bs_info_len = 1 << (sconf->block_switching + 2);
357 *bs_info = get_bits_long(gb, bs_info_len);
358 *bs_info <<= (32 - bs_info_len);
359 }
360
361 ctx->num_blocks = 0;
362 parse_bs_info(*bs_info, 0, 0, &ptr_div_blocks, &ctx->num_blocks);
363
364 // The last frame may have an overdetermined block structure given in
365 // the bitstream. In that case the defined block structure would need
366 // more samples than available to be consistent.
367 // The block structure is actually used but the block sizes are adapted
368 // to fit the actual number of available samples.
369 // Example: 5 samples, 2nd level block sizes: 2 2 2 2.
370 // This results in the actual block sizes: 2 2 1 0.
371 // This is not specified in 14496-3 but actually done by the reference
372 // codec RM22 revision 2.
373 // This appears to happen in case of an odd number of samples in the last
374 // frame which is actually not allowed by the block length switching part
375 // of 14496-3.
376 // The ALS conformance files feature an odd number of samples in the last
377 // frame.
378
379 for (b = 0; b < ctx->num_blocks; b++)
380 div_blocks[b] = ctx->sconf.frame_length >> div_blocks[b];
381
382 if (ctx->cur_frame_length != ctx->sconf.frame_length) {
383 unsigned int remaining = ctx->cur_frame_length;
384
385 for (b = 0; b < ctx->num_blocks; b++) {
386 if (remaining < div_blocks[b]) {
387 div_blocks[b] = remaining;
388 ctx->num_blocks = b + 1;
389 break;
390 }
391
392 remaining -= div_blocks[b];
393 }
394 }
395}
396
397
398/** Reads the block data for a constant block
399 */
400static void read_const_block(ALSDecContext *ctx, int32_t *raw_samples,
401 unsigned int block_length, unsigned int *js_blocks)
402{
403 ALSSpecificConfig *sconf = &ctx->sconf;
404 AVCodecContext *avctx = ctx->avctx;
405 GetBitContext *gb = &ctx->gb;
406 int32_t const_val = 0;
407 unsigned int const_block, k;
408
409 const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence)
410 *js_blocks = get_bits1(gb);
411
412 // skip 5 reserved bits
413 skip_bits(gb, 5);
414
415 if (const_block) {
416 unsigned int const_val_bits = sconf->floating ? 24 : avctx->bits_per_raw_sample;
417 const_val = get_sbits_long(gb, const_val_bits);
418 }
419
420 // write raw samples into buffer
421 for (k = 0; k < block_length; k++)
422 raw_samples[k] = const_val;
423}
424
425
426/** Reads the block data for a non-constant block
427 */
428static int read_var_block(ALSDecContext *ctx, unsigned int ra_block,
429 int32_t *raw_samples, unsigned int block_length,
430 unsigned int *js_blocks, int32_t *raw_other,
431 unsigned int *shift_lsbs)
432{
433 ALSSpecificConfig *sconf = &ctx->sconf;
434 AVCodecContext *avctx = ctx->avctx;
435 GetBitContext *gb = &ctx->gb;
436 unsigned int k;
437 unsigned int s[8];
438 unsigned int sub_blocks, log2_sub_blocks, sb_length;
439 unsigned int opt_order = 1;
440 int32_t *quant_cof = ctx->quant_cof;
441 int32_t *lpc_cof = ctx->lpc_cof;
442 unsigned int start = 0;
443 int smp = 0;
444 int sb, store_prev_samples;
445 int64_t y;
446
447 *js_blocks = get_bits1(gb);
448
449 // determine the number of subblocks for entropy decoding
450 if (!sconf->bgmc && !sconf->sb_part) {
451 log2_sub_blocks = 0;
452 } else {
453 if (sconf->bgmc && sconf->sb_part)
454 log2_sub_blocks = get_bits(gb, 2);
455 else
456 log2_sub_blocks = 2 * get_bits1(gb);
457 }
458
459 sub_blocks = 1 << log2_sub_blocks;
460
461 // do not continue in case of a damaged stream since
462 // block_length must be evenly divisible by sub_blocks
463 if (block_length & (sub_blocks - 1)) {
464 av_log(avctx, AV_LOG_WARNING,
465 "Block length is not evenly divisible by the number of subblocks.\n");
466 return -1;
467 }
468
469 sb_length = block_length >> log2_sub_blocks;
470
471
472 if (sconf->bgmc) {
473 // TODO: BGMC mode
474 } else {
475 s[0] = get_bits(gb, 4 + (sconf->resolution > 1));
476 for (k = 1; k < sub_blocks; k++)
477 s[k] = s[k - 1] + decode_rice(gb, 0);
478 }
479
480 if (get_bits1(gb))
481 *shift_lsbs = get_bits(gb, 4) + 1;
482
483 store_prev_samples = (*js_blocks && raw_other) || *shift_lsbs;
484
485
486 if (!sconf->rlslms) {
487 if (sconf->adapt_order) {
488 int opt_order_length = av_ceil_log2(av_clip((block_length >> 3) - 1,
489 2, sconf->max_order + 1));
490 opt_order = get_bits(gb, opt_order_length);
491 } else {
492 opt_order = sconf->max_order;
493 }
494
495 if (opt_order) {
496 int add_base;
497
498 if (sconf->coef_table == 3) {
499 add_base = 0x7F;
500
501 // read coefficient 0
502 quant_cof[0] = 32 * parcor_scaled_values[get_bits(gb, 7)];
503
504 // read coefficient 1
505 if (opt_order > 1)
506 quant_cof[1] = -32 * parcor_scaled_values[get_bits(gb, 7)];
507
508 // read coefficients 2 to opt_order
509 for (k = 2; k < opt_order; k++)
510 quant_cof[k] = get_bits(gb, 7);
511 } else {
512 int k_max;
513 add_base = 1;
514
515 // read coefficient 0 to 19
516 k_max = FFMIN(opt_order, 20);
517 for (k = 0; k < k_max; k++) {
518 int rice_param = parcor_rice_table[sconf->coef_table][k][1];
519 int offset = parcor_rice_table[sconf->coef_table][k][0];
520 quant_cof[k] = decode_rice(gb, rice_param) + offset;
521 }
522
523 // read coefficients 20 to 126
524 k_max = FFMIN(opt_order, 127);
525 for (; k < k_max; k++)
526 quant_cof[k] = decode_rice(gb, 2) + (k & 1);
527
528 // read coefficients 127 to opt_order
529 for (; k < opt_order; k++)
530 quant_cof[k] = decode_rice(gb, 1);
531
532 quant_cof[0] = 32 * parcor_scaled_values[quant_cof[0] + 64];
533
534 if (opt_order > 1)
535 quant_cof[1] = -32 * parcor_scaled_values[quant_cof[1] + 64];
536 }
537
538 for (k = 2; k < opt_order; k++)
539 quant_cof[k] = (quant_cof[k] << 14) + (add_base << 13);
540 }
541 }
542
543 // TODO: LTP mode
544
545 // read first value and residuals in case of a random access block
546 if (ra_block) {
547 if (opt_order)
548 raw_samples[0] = decode_rice(gb, avctx->bits_per_raw_sample - 4);
549 if (opt_order > 1)
550 raw_samples[1] = decode_rice(gb, s[0] + 3);
551 if (opt_order > 2)
552 raw_samples[2] = decode_rice(gb, s[0] + 1);
553
554 start = FFMIN(opt_order, 3);
555 }
556
557 // read all residuals
558 if (sconf->bgmc) {
559 // TODO: BGMC mode
560 } else {
561 int32_t *current_res = raw_samples + start;
562
563 for (sb = 0; sb < sub_blocks; sb++, start = 0)
564 for (; start < sb_length; start++)
565 *current_res++ = decode_rice(gb, s[sb]);
566 }
567
568 // reconstruct all samples from residuals
569 if (ra_block) {
570 for (smp = 0; smp < opt_order; smp++) {
571 y = 1 << 19;
572
573 for (sb = 0; sb < smp; sb++)
574 y += MUL64(lpc_cof[sb],raw_samples[smp - (sb + 1)]);
575
576 raw_samples[smp] -= y >> 20;
577 parcor_to_lpc(smp, quant_cof, lpc_cof);
578 }
579 } else {
580 for (k = 0; k < opt_order; k++)
581 parcor_to_lpc(k, quant_cof, lpc_cof);
582
583 // store previous samples in case that they have to be altered
584 if (store_prev_samples)
585 memcpy(ctx->prev_raw_samples, raw_samples - sconf->max_order,
586 sizeof(*ctx->prev_raw_samples) * sconf->max_order);
587
588 // reconstruct difference signal for prediction (joint-stereo)
589 if (*js_blocks && raw_other) {
590 int32_t *left, *right;
591
592 if (raw_other > raw_samples) { // D = R - L
593 left = raw_samples;
594 right = raw_other;
595 } else { // D = R - L
596 left = raw_other;
597 right = raw_samples;
598 }
599
600 for (sb = -1; sb >= -sconf->max_order; sb--)
601 raw_samples[sb] = right[sb] - left[sb];
602 }
603
604 // reconstruct shifted signal
605 if (*shift_lsbs)
606 for (sb = -1; sb >= -sconf->max_order; sb--)
607 raw_samples[sb] >>= *shift_lsbs;
608 }
609
610 // reconstruct raw samples
611 for (; smp < block_length; smp++) {
612 y = 1 << 19;
613
614 for (sb = 0; sb < opt_order; sb++)
615 y += MUL64(lpc_cof[sb],raw_samples[smp - (sb + 1)]);
616
617 raw_samples[smp] -= y >> 20;
618 }
619
620 // restore previous samples in case that they have been altered
621 if (store_prev_samples)
622 memcpy(raw_samples - sconf->max_order, ctx->prev_raw_samples,
623 sizeof(*raw_samples) * sconf->max_order);
624
625 return 0;
626}
627
628
629/** Reads the block data.
630 */
631static int read_block_data(ALSDecContext *ctx, unsigned int ra_block,
632 int32_t *raw_samples, unsigned int block_length,
633 unsigned int *js_blocks, int32_t *raw_other)
634{
635 ALSSpecificConfig *sconf = &ctx->sconf;
636 GetBitContext *gb = &ctx->gb;
637 unsigned int shift_lsbs = 0;
638 unsigned int k;
639
640 // read block type flag and read the samples accordingly
641 if (get_bits1(gb)) {
642 if (read_var_block(ctx, ra_block, raw_samples, block_length, js_blocks,
643 raw_other, &shift_lsbs))
644 return -1;
645 } else {
646 read_const_block(ctx, raw_samples, block_length, js_blocks);
647 }
648
649 // TODO: read RLSLMS extension data
650
651 if (!sconf->mc_coding || ctx->js_switch)
652 align_get_bits(gb);
653
654 if (shift_lsbs)
655 for (k = 0; k < block_length; k++)
656 raw_samples[k] <<= shift_lsbs;
657
658 return 0;
659}
660
661
662/** Computes the number of samples left to decode for the current frame and
663 * sets these samples to zero.
664 */
665static void zero_remaining(unsigned int b, unsigned int b_max,
666 const unsigned int *div_blocks, int32_t *buf)
667{
668 unsigned int count = 0;
669
670 while (b < b_max)
671 count += div_blocks[b];
672
673 memset(buf, 0, sizeof(*buf) * count);
674}
675
676
677/** Decodes blocks independently.
678 */
679static int decode_blocks_ind(ALSDecContext *ctx, unsigned int ra_frame,
680 unsigned int c, const unsigned int *div_blocks,
681 unsigned int *js_blocks)
682{
683 int32_t *raw_sample;
684 unsigned int b;
685 raw_sample = ctx->raw_samples[c];
686
687 for (b = 0; b < ctx->num_blocks; b++) {
688 if (read_block_data(ctx, ra_frame, raw_sample,
689 div_blocks[b], &js_blocks[0], NULL)) {
690 // damaged block, write zero for the rest of the frame
691 zero_remaining(b, ctx->num_blocks, div_blocks, raw_sample);
692 return -1;
693 }
694 raw_sample += div_blocks[b];
695 ra_frame = 0;
696 }
697
698 return 0;
699}
700
701
702/** Decodes blocks dependently.
703 */
704static int decode_blocks(ALSDecContext *ctx, unsigned int ra_frame,
705 unsigned int c, const unsigned int *div_blocks,
706 unsigned int *js_blocks)
707{
708 ALSSpecificConfig *sconf = &ctx->sconf;
709 unsigned int offset = 0;
710 int32_t *raw_samples_R;
711 int32_t *raw_samples_L;
712 unsigned int b;
713
714 // decode all blocks
715 for (b = 0; b < ctx->num_blocks; b++) {
716 unsigned int s;
717 raw_samples_L = ctx->raw_samples[c ] + offset;
718 raw_samples_R = ctx->raw_samples[c + 1] + offset;
719 if (read_block_data(ctx, ra_frame, raw_samples_L, div_blocks[b],
720 &js_blocks[0], raw_samples_R) ||
721 read_block_data(ctx, ra_frame, raw_samples_R, div_blocks[b],
722 &js_blocks[1], raw_samples_L)) {
723 // damaged block, write zero for the rest of the frame
724 zero_remaining(b, ctx->num_blocks, div_blocks, raw_samples_L);
725 zero_remaining(b, ctx->num_blocks, div_blocks, raw_samples_R);
726 return -1;
727 }
728
729 // reconstruct joint-stereo blocks
730 if (js_blocks[0]) {
731 if (js_blocks[1])
732 av_log(ctx->avctx, AV_LOG_WARNING, "Invalid channel pair!\n");
733
734 for (s = 0; s < div_blocks[b]; s++)
735 raw_samples_L[s] = raw_samples_R[s] - raw_samples_L[s];
736 } else if (js_blocks[1]) {
737 for (s = 0; s < div_blocks[b]; s++)
738 raw_samples_R[s] = raw_samples_R[s] + raw_samples_L[s];
739 }
740
741 offset += div_blocks[b];
742 ra_frame = 0;
743 }
744
745 // store carryover raw samples,
746 // the others channel raw samples are stored by the calling function.
747 memmove(ctx->raw_samples[c] - sconf->max_order,
748 ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
749 sizeof(*ctx->raw_samples[c]) * sconf->max_order);
750
751 return 0;
752}
753
754
755/** Reads the frame data.
756 */
757static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
758{
759 ALSSpecificConfig *sconf = &ctx->sconf;
760 AVCodecContext *avctx = ctx->avctx;
761 GetBitContext *gb = &ctx->gb;
762 unsigned int div_blocks[32]; ///< block sizes.
763 unsigned int c;
764 unsigned int js_blocks[2];
765
766 uint32_t bs_info = 0;
767
768 // skip the size of the ra unit if present in the frame
769 if (sconf->ra_flag == RA_FLAG_FRAMES && ra_frame)
770 skip_bits_long(gb, 32);
771
772 if (sconf->mc_coding && sconf->joint_stereo) {
773 ctx->js_switch = get_bits1(gb);
774 align_get_bits(gb);
775 }
776
777 if (!sconf->mc_coding || ctx->js_switch) {
778 int independent_bs = !sconf->joint_stereo;
779
780 for (c = 0; c < avctx->channels; c++) {
781 js_blocks[0] = 0;
782 js_blocks[1] = 0;
783
784 get_block_sizes(ctx, div_blocks, &bs_info);
785
786 // if joint_stereo and block_switching is set, independent decoding
787 // is signaled via the first bit of bs_info
788 if (sconf->joint_stereo && sconf->block_switching)
789 if (bs_info >> 31)
790 independent_bs = 2;
791
792 // if this is the last channel, it has to be decoded independently
793 if (c == avctx->channels - 1)
794 independent_bs = 1;
795
796 if (independent_bs) {
797 if (decode_blocks_ind(ctx, ra_frame, c, div_blocks, js_blocks))
798 return -1;
799
800 independent_bs--;
801 } else {
802 if (decode_blocks(ctx, ra_frame, c, div_blocks, js_blocks))
803 return -1;
804
805 c++;
806 }
807
808 // store carryover raw samples
809 memmove(ctx->raw_samples[c] - sconf->max_order,
810 ctx->raw_samples[c] - sconf->max_order + sconf->frame_length,
811 sizeof(*ctx->raw_samples[c]) * sconf->max_order);
812 }
813 } else { // multi-channel coding
814 get_block_sizes(ctx, div_blocks, &bs_info);
815
816 // TODO: multi channel coding might use a temporary buffer instead as
817 // the actual channel is not known when read_block-data is called
818 if (decode_blocks_ind(ctx, ra_frame, 0, div_blocks, js_blocks))
819 return -1;
820 // TODO: read_channel_data
821 }
822
823 // TODO: read_diff_float_data
824
825 return 0;
826}
827
828
829/** Decodes an ALS frame.
830 */
831static int decode_frame(AVCodecContext *avctx,
832 void *data, int *data_size,
833 AVPacket *avpkt)
834{
835 ALSDecContext *ctx = avctx->priv_data;
836 ALSSpecificConfig *sconf = &ctx->sconf;
837 const uint8_t *buffer = avpkt->data;
838 int buffer_size = avpkt->size;
839 int invalid_frame, size;
840 unsigned int c, sample, ra_frame, bytes_read, shift;
841
842 init_get_bits(&ctx->gb, buffer, buffer_size * 8);
843
844 // In the case that the distance between random access frames is set to zero
845 // (sconf->ra_distance == 0) no frame is treated as a random access frame.
846 // For the first frame, if prediction is used, all samples used from the
847 // previous frame are assumed to be zero.
848 ra_frame = sconf->ra_distance && !(ctx->frame_id % sconf->ra_distance);
849
850 // the last frame to decode might have a different length
851 if (sconf->samples != 0xFFFFFFFF)
852 ctx->cur_frame_length = FFMIN(sconf->samples - ctx->frame_id * (uint64_t) sconf->frame_length,
853 sconf->frame_length);
854 else
855 ctx->cur_frame_length = sconf->frame_length;
856
857 // decode the frame data
858 if ((invalid_frame = read_frame_data(ctx, ra_frame) < 0))
859 av_log(ctx->avctx, AV_LOG_WARNING,
860 "Reading frame data failed. Skipping RA unit.\n");
861
862 ctx->frame_id++;
863
864 // check for size of decoded data
865 size = ctx->cur_frame_length * avctx->channels *
866 (av_get_bits_per_sample_format(avctx->sample_fmt) >> 3);
867
868 if (size > *data_size) {
869 av_log(avctx, AV_LOG_ERROR, "Decoded data exceeds buffer size.\n");
870 return -1;
871 }
872
873 *data_size = size;
874
875 // transform decoded frame into output format
876 #define INTERLEAVE_OUTPUT(bps) \
877 { \
878 int##bps##_t *dest = (int##bps##_t*) data; \
879 shift = bps - ctx->avctx->bits_per_raw_sample; \
880 for (sample = 0; sample < ctx->cur_frame_length; sample++) \
881 for (c = 0; c < avctx->channels; c++) \
882 *dest++ = ctx->raw_samples[c][sample] << shift; \
883 }
884
885 if (ctx->avctx->bits_per_raw_sample <= 16) {
886 INTERLEAVE_OUTPUT(16)
887 } else {
888 INTERLEAVE_OUTPUT(32)
889 }
890
891 bytes_read = invalid_frame ? buffer_size :
892 (get_bits_count(&ctx->gb) + 7) >> 3;
893
894 return bytes_read;
895}
896
897
898/** Uninitializes the ALS decoder.
899 */
900static av_cold int decode_end(AVCodecContext *avctx)
901{
902 ALSDecContext *ctx = avctx->priv_data;
903
904 av_freep(&ctx->sconf.chan_pos);
905
906 av_freep(&ctx->quant_cof);
907 av_freep(&ctx->lpc_cof);
908 av_freep(&ctx->prev_raw_samples);
909 av_freep(&ctx->raw_samples);
910 av_freep(&ctx->raw_buffer);
911
912 return 0;
913}
914
915
916/** Initializes the ALS decoder.
917 */
918static av_cold int decode_init(AVCodecContext *avctx)
919{
920 unsigned int c;
921 unsigned int channel_size;
922 ALSDecContext *ctx = avctx->priv_data;
923 ALSSpecificConfig *sconf = &ctx->sconf;
924 ctx->avctx = avctx;
925
926 if (!avctx->extradata) {
927 av_log(avctx, AV_LOG_ERROR, "Missing required ALS extradata.\n");
928 return -1;
929 }
930
931 if (read_specific_config(ctx)) {
932 av_log(avctx, AV_LOG_ERROR, "Reading ALSSpecificConfig failed.\n");
933 decode_end(avctx);
934 return -1;
935 }
936
937 if (check_specific_config(ctx)) {
938 decode_end(avctx);
939 return -1;
940 }
941
942 if (sconf->floating) {
943 avctx->sample_fmt = SAMPLE_FMT_FLT;
944 avctx->bits_per_raw_sample = 32;
945 } else {
946 avctx->sample_fmt = sconf->resolution > 1
947 ? SAMPLE_FMT_S32 : SAMPLE_FMT_S16;
948 avctx->bits_per_raw_sample = (sconf->resolution + 1) * 8;
949 }
950
951 avctx->frame_size = sconf->frame_length;
952 channel_size = sconf->frame_length + sconf->max_order;
953
954 ctx->prev_raw_samples = av_malloc (sizeof(*ctx->prev_raw_samples) * sconf->max_order);
955 ctx->raw_buffer = av_mallocz(sizeof(*ctx-> raw_buffer) * avctx->channels * channel_size);
956 ctx->raw_samples = av_malloc (sizeof(*ctx-> raw_samples) * avctx->channels);
957
958 // allocate previous raw sample buffer
959 if (!ctx->prev_raw_samples || !ctx->raw_buffer|| !ctx->raw_samples) {
960 av_log(avctx, AV_LOG_ERROR, "Allocating buffer memory failed.\n");
961 decode_end(avctx);
962 return AVERROR(ENOMEM);
963 }
964
965 // assign raw samples buffers
966 ctx->raw_samples[0] = ctx->raw_buffer + sconf->max_order;
967 for (c = 1; c < avctx->channels; c++)
968 ctx->raw_samples[c] = ctx->raw_samples[c - 1] + channel_size;
969
970 return 0;
971}
972
973
974/** Flushes (resets) the frame ID after seeking.
975 */
976static av_cold void flush(AVCodecContext *avctx)
977{
978 ALSDecContext *ctx = avctx->priv_data;
979
980 ctx->frame_id = 0;
981}
982
983
984AVCodec als_decoder = {
985 "als",
986 CODEC_TYPE_AUDIO,
987 CODEC_ID_MP4ALS,
988 sizeof(ALSDecContext),
989 decode_init,
990 NULL,
991 decode_end,
992 decode_frame,
993 .flush = flush,
994 .capabilities = CODEC_CAP_SUBFRAMES,
995 .long_name = NULL_IF_CONFIG_SMALL("MPEG-4 Audio Lossless Coding (ALS)"),
996};
997