1 /*
2 * IEC 61937 muxer
3 * Copyright (c) 2009 Bartlomiej Wolowiec
4 * Copyright (c) 2010, 2020 Anssi Hannula
5 * Copyright (c) 2010 Carl Eugen Hoyos
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 /**
25 * @file
26 * IEC-61937 encapsulation of various formats, used by S/PDIF
27 * @author Bartlomiej Wolowiec
28 * @author Anssi Hannula
29 * @author Carl Eugen Hoyos
30 */
31
32 /*
33 * Terminology used in specification:
34 * data-burst - IEC61937 frame, contains header and encapsuled frame
35 * burst-preamble - IEC61937 frame header, contains 16-bit words named Pa, Pb, Pc and Pd
36 * burst-payload - encapsuled frame
37 * Pa, Pb - syncword - 0xF872, 0x4E1F
38 * Pc - burst-info, contains data-type (bits 0-6), error flag (bit 7), data-type-dependent info (bits 8-12)
39 * and bitstream number (bits 13-15)
40 * data-type - determines type of encapsuled frames
41 * Pd - length code (number of bits or bytes of encapsuled frame - according to data_type)
42 *
43 * IEC 61937 frames at normal usage start every specific count of bytes,
44 * dependent from data-type (spaces between packets are filled by zeros)
45 */
46
47 #include <inttypes.h>
48
57
61 int length_code;
///< length code in bits or bytes, depending on data type
62 int pkt_offset;
///< data burst repetition period in bytes
63 uint8_t *
buffer;
///< allocated buffer, used for swap bytes
65
66 const uint8_t *
out_buf;
///< pointer to the outgoing data before byte-swapping
68
69 int use_preamble;
///< preamble enabled (disabled for exactly pre-padded DTS)
70 int extra_bswap;
///< extra bswap for payload (for LE DTS => standard BE DTS)
71
72 uint8_t *
hd_buf[2];
///< allocated buffers to concatenate hd audio frames
73 int hd_buf_size;
///< size of the hd audio buffer (eac3, dts4)
74 int hd_buf_count;
///< number of frames in the hd audio buffer (eac3)
75 int hd_buf_filled;
///< amount of bytes in the hd audio buffer (eac3, truehd)
77
78 int dtshd_skip;
///< counter used for skipping DTS-HD frames
79
83
84 /* AVOptions: */
87 #define SPDIF_FLAG_BIGENDIAN 0x01
89
90 /// function, which generates codec dependent header information.
91 /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
94
96 {
"spdif_flags",
"IEC 61937 encapsulation flags", offsetof(
IEC61937Context, spdif_flags),
AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX,
AV_OPT_FLAG_ENCODING_PARAM,
"spdif_flags" },
98 {
"dtshd_rate",
"mux complete DTS frames in HD mode at the specified IEC958 rate (in Hz, default 0=disabled)", offsetof(
IEC61937Context, dtshd_rate),
AV_OPT_TYPE_INT, {.i64 = 0}, 0, 768000,
AV_OPT_FLAG_ENCODING_PARAM },
99 {
"dtshd_fallback_time",
"min secs to strip HD for after an overflow (-1: till the end, default 60)", offsetof(
IEC61937Context, dtshd_fallback),
AV_OPT_TYPE_INT, {.i64 = 60}, -1, INT_MAX,
AV_OPT_FLAG_ENCODING_PARAM },
101 };
102
108 };
109
111 {
113 int bitstream_mode =
pkt->
data[5] & 0x7;
114
117 return 0;
118 }
119
121 {
123 static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
124 int repeat = 1;
126
128 if (bsid > 10 && (
pkt->
data[4] & 0xc0) != 0xc0)
/* fscod */
129 repeat = eac3_repeat[(
pkt->
data[4] & 0x30) >> 4];
/* numblkscod */
130
135
137
139 if (++
ctx->hd_buf_count < repeat){
141 return 0;
142 }
144 ctx->pkt_offset = 24576;
145 ctx->out_buf =
ctx->hd_buf[0];
146 ctx->out_bytes =
ctx->hd_buf_filled;
147 ctx->length_code =
ctx->hd_buf_filled;
148
149 ctx->hd_buf_count = 0;
150 ctx->hd_buf_filled = 0;
151 return 0;
152 }
153
154 /*
155 * DTS type IV (DTS-HD) can be transmitted with various frame repetition
156 * periods; longer repetition periods allow for longer packets and therefore
157 * higher bitrate. Longer repetition periods mean that the constant bitrate of
158 * the output IEC 61937 stream is higher.
159 * The repetition period is measured in IEC 60958 frames (4 bytes).
160 */
162 {
164 case 512: return 0x0;
165 case 1024: return 0x1;
166 case 2048: return 0x2;
167 case 4096: return 0x3;
168 case 8192: return 0x4;
169 case 16384: return 0x5;
170 }
171 return -1;
172 }
173
176 {
178 static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
181 int subtype;
182
183 if (!core_size) {
186 }
187
191 }
192
195
196 if (subtype < 0) {
198 "impossible repetition period of %d for the current DTS stream"
199 " (blocks = %d, sample rate = %d)\n",
ctx->dtshd_rate,
period,
202 }
203
204 /* set pkt_offset and DTS IV subtype according to the requested output
205 * rate */
208
209 /* If the bitrate is too high for transmitting at the selected
210 * repetition period setting, strip DTS-HD until a good amount
211 * of consecutive non-overflowing HD frames have been observed.
212 * This generally only happens if the caller is cramming a Master
213 * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
214 if (sizeof(dtshd_start_code) + 2 + pkt_size
216 if (!
ctx->dtshd_skip)
218 "temporarily sending core only\n");
219 if (
ctx->dtshd_fallback > 0)
221 else
222 /* skip permanently (dtshd_fallback == -1) or just once
223 * (dtshd_fallback == 0) */
225 }
226 if (
ctx->dtshd_skip && core_size) {
227 pkt_size = core_size;
228 if (
ctx->dtshd_fallback >= 0)
230 }
231
232 ctx->out_bytes =
sizeof(dtshd_start_code) + 2 + pkt_size;
233
234 /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
235 * with some receivers, but the exact requirement is unconfirmed. */
236 ctx->length_code =
FFALIGN(
ctx->out_bytes + 0x8, 0x10) - 0x8;
237
241
242 ctx->out_buf =
ctx->hd_buf[0];
243
244 memcpy(
ctx->hd_buf[0], dtshd_start_code,
sizeof(dtshd_start_code));
245 AV_WB16(
ctx->hd_buf[0] +
sizeof(dtshd_start_code), pkt_size);
246 memcpy(
ctx->hd_buf[0] +
sizeof(dtshd_start_code) + 2,
pkt->
data, pkt_size);
247
248 return 0;
249 }
250
252 {
255 int blocks;
257 int core_size = 0;
258
261
262 switch (syncword_dts) {
267 break;
270 ctx->extra_bswap = 1;
271 break;
273 blocks =
275 break;
277 blocks =
279 ctx->extra_bswap = 1;
280 break;
282 /* We only handle HD frames that are paired with core. However,
283 sometimes DTS-HD streams with core have a stray HD frame without
284 core in the beginning of the stream. */
287 default:
290 }
291 blocks++;
292
294 /* DTS type IV output requested */
296
297 switch (blocks) {
301 default:
303 blocks << 5);
305 }
306
307 /* discard extraneous data by default */
308 if (core_size && core_size < pkt->
size) {
309 ctx->out_bytes = core_size;
310 ctx->length_code = core_size << 3;
311 }
312
313 ctx->pkt_offset = blocks << 7;
314
315 if (
ctx->out_bytes ==
ctx->pkt_offset) {
316 /* The DTS stream fits exactly into the output stream, so skip the
317 * preamble as it would not fit in there. This is the case for dts
318 * discs and dts-in-wav. */
319 ctx->use_preamble = 0;
322 /* This will fail with a "bitrate too high" in the caller */
323 }
324
325 return 0;
326 }
327
329 // LAYER1 LAYER2 LAYER3
332 };
333
335 {
338 int layer = 3 - ((
pkt->
data[1] >> 1) & 3);
339 int extension =
pkt->
data[2] & 1;
340
341 if (layer == 3 ||
version == 1) {
344 }
346 if (
version == 2 && extension) {
348 ctx->pkt_offset = 4608;
349 } else {
352 }
353 // TODO Data type dependent info (normal/karaoke, dynamic range control)
354 return 0;
355 }
356
358 {
363
368 }
369
372 case 1:
374 break;
375 case 2:
377 break;
378 case 4:
380 break;
381 default:
383 "%"PRIu32
" samples in AAC frame not supported\n",
samples);
385 }
386 //TODO Data type dependent info (LC profile/SBR)
387 return 0;
388 }
389
390
391 /*
392 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
393 * they can be encapsulated in IEC 61937.
394 */
395 #define MAT_PKT_OFFSET 61440
396 #define MAT_FRAME_SIZE 61424
397
399 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83,
400 0x49, 0x80, 0x77, 0xE0,
401 };
403 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0,
404 };
406 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11,
407 };
408
409 #define MAT_CODE(position, data) { .pos = position, .code = data, .len = sizeof(data) }
410
411 static const struct {
419 };
420
422 {
424 uint8_t *hd_buf =
ctx->hd_buf[
ctx->hd_buf_idx];
425 int ratebits;
426 int padding_remaining = 0;
427 uint16_t input_timing;
428 int total_frame_size =
pkt->
size;
429 const uint8_t *dataptr =
pkt->
data;
430 int data_remaining =
pkt->
size;
431 int have_pkt = 0;
432 int next_code_idx;
433
436
438 /* major sync unit, fetch sample rate */
443 else
445
446 ctx->truehd_samples_per_frame = 40 << (ratebits & 3);
448 ctx->truehd_samples_per_frame);
449 }
450
451 if (!
ctx->truehd_samples_per_frame)
453
455 if (
ctx->truehd_prev_size) {
456 uint16_t delta_samples = input_timing -
ctx->truehd_prev_time;
457 /*
458 * One multiple-of-48kHz frame is 1/1200 sec and the IEC 61937 rate
459 * is 768kHz = 768000*4 bytes/sec.
460 * The nominal space per frame is therefore
461 * (768000*4 bytes/sec) * (1/1200 sec) = 2560 bytes.
462 * For multiple-of-44.1kHz frames: 1/1102.5 sec, 705.6kHz, 2560 bytes.
463 *
464 * 2560 is divisible by truehd_samples_per_frame.
465 */
466 int delta_bytes = delta_samples * 2560 /
ctx->truehd_samples_per_frame;
467
468 /* padding needed before this frame */
469 padding_remaining = delta_bytes -
ctx->truehd_prev_size;
470
472 delta_samples, delta_bytes);
473
474 /* sanity check */
475 if (padding_remaining < 0 || padding_remaining >=
MAT_FRAME_SIZE / 2) {
477 ctx->truehd_prev_time, input_timing,
ctx->truehd_samples_per_frame);
478 padding_remaining = 0;
479 }
480 }
481
484 break;
485
488
489 while (padding_remaining || data_remaining ||
491
493 /* time to insert MAT code */
494 int code_len =
mat_codes[next_code_idx].len;
495 int code_len_remaining = code_len;
498 ctx->hd_buf_filled += code_len;
499
500 next_code_idx++;
502 next_code_idx = 0;
503
504 /* this was the last code, move to the next MAT frame */
505 have_pkt = 1;
506 ctx->out_buf = hd_buf;
507 ctx->hd_buf_idx ^= 1;
508 hd_buf =
ctx->hd_buf[
ctx->hd_buf_idx];
509 ctx->hd_buf_filled = 0;
510
511 /* inter-frame gap has to be counted as well, add it */
513 }
514
515 if (padding_remaining) {
516 /* consider the MAT code as padding */
517 int counted_as_padding =
FFMIN(padding_remaining,
518 code_len_remaining);
519 padding_remaining -= counted_as_padding;
520 code_len_remaining -= counted_as_padding;
521 }
522 /* count the remainder of the code as part of frame size */
523 if (code_len_remaining)
524 total_frame_size += code_len_remaining;
525 }
526
527 if (padding_remaining) {
529 padding_remaining);
530
531 memset(hd_buf +
ctx->hd_buf_filled, 0, padding_to_insert);
532 ctx->hd_buf_filled += padding_to_insert;
533 padding_remaining -= padding_to_insert;
534
535 if (padding_remaining)
536 continue; /* time to insert MAT code */
537 }
538
539 if (data_remaining) {
541 data_remaining);
542
543 memcpy(hd_buf +
ctx->hd_buf_filled, dataptr, data_to_insert);
544 ctx->hd_buf_filled += data_to_insert;
545 dataptr += data_to_insert;
546 data_remaining -= data_to_insert;
547 }
548 }
549
550 ctx->truehd_prev_size = total_frame_size;
551 ctx->truehd_prev_time = input_timing;
552
554 total_frame_size,
ctx->hd_buf_filled);
555
556 if (!have_pkt) {
558 return 0;
559 }
560
565 return 0;
566 }
567
569 {
571
572 switch (
s->streams[0]->codecpar->codec_id) {
575 break;
578 break;
583 break;
586 break;
589 break;
597 }
598 break;
599 default:
601 s->streams[0]->codecpar->codec_id);
603 }
604 return 0;
605 }
606
608 {
613 }
614
617 {
620 else
622 }
623
625 {
628
632 ctx->use_preamble = 1;
633 ctx->extra_bswap = 0;
634
638 if (!
ctx->pkt_offset)
639 return 0;
640
642 if (padding < 0) {
645 }
646
647 if (
ctx->use_preamble) {
652 }
653
656 } else {
662 }
663
664 /* a final lone byte has to be MSB aligned */
665 if (
ctx->out_bytes & 1)
667
669
671 ctx->data_type,
ctx->out_bytes,
ctx->pkt_offset);
672
673 return 0;
674 }
675
679 .extensions = "spdif",
688 };