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
59
63 int length_code;
///< length code in bits or bytes, depending on data type
64 int pkt_offset;
///< data burst repetition period in bytes
65 uint8_t *
buffer;
///< allocated buffer, used for swap bytes
67
68 const uint8_t *
out_buf;
///< pointer to the outgoing data before byte-swapping
70
71 int use_preamble;
///< preamble enabled (disabled for exactly pre-padded DTS)
72 int extra_bswap;
///< extra bswap for payload (for LE DTS => standard BE DTS)
73
74 uint8_t *
hd_buf[2];
///< allocated buffers to concatenate hd audio frames
75 int hd_buf_size;
///< size of the hd audio buffer (eac3, dts4)
76 int hd_buf_count;
///< number of frames in the hd audio buffer (eac3)
77 int hd_buf_filled;
///< amount of bytes in the hd audio buffer (eac3, truehd)
79
80 int dtshd_skip;
///< counter used for skipping DTS-HD frames
81
85
86 /* AVOptions: */
89 #define SPDIF_FLAG_BIGENDIAN 0x01
91
92 /// function, which generates codec dependent header information.
93 /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
96
98 {
"spdif_flags",
"IEC 61937 encapsulation flags", offsetof(
IEC61937Context, spdif_flags),
AV_OPT_TYPE_FLAGS, {.i64 = 0}, 0, INT_MAX,
AV_OPT_FLAG_ENCODING_PARAM, .unit =
"spdif_flags" },
100 {
"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 },
101 {
"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 },
103 };
104
110 };
111
113 {
115 int bitstream_mode =
pkt->
data[5] & 0x7;
116
119 return 0;
120 }
121
123 {
125 static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
126 int repeat = 1;
128
130 if (bsid > 10 && (
pkt->
data[4] & 0xc0) != 0xc0)
/* fscod */
131 repeat = eac3_repeat[(
pkt->
data[4] & 0x30) >> 4];
/* numblkscod */
132
137
139
141 if (++
ctx->hd_buf_count < repeat){
143 return 0;
144 }
146 ctx->pkt_offset = 24576;
147 ctx->out_buf =
ctx->hd_buf[0];
148 ctx->out_bytes =
ctx->hd_buf_filled;
149 ctx->length_code =
ctx->hd_buf_filled;
150
151 ctx->hd_buf_count = 0;
152 ctx->hd_buf_filled = 0;
153 return 0;
154 }
155
156 /*
157 * DTS type IV (DTS-HD) can be transmitted with various frame repetition
158 * periods; longer repetition periods allow for longer packets and therefore
159 * higher bitrate. Longer repetition periods mean that the constant bitrate of
160 * the output IEC 61937 stream is higher.
161 * The repetition period is measured in IEC 60958 frames (4 bytes).
162 */
164 {
166 case 512: return 0x0;
167 case 1024: return 0x1;
168 case 2048: return 0x2;
169 case 4096: return 0x3;
170 case 8192: return 0x4;
171 case 16384: return 0x5;
172 }
173 return -1;
174 }
175
177 int sample_rate, int blocks)
178 {
180 static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
183 int subtype;
184
185 if (!core_size) {
188 }
189
190 if (!sample_rate) {
193 }
194
195 period =
ctx->dtshd_rate * (blocks << 5) / sample_rate;
197
198 if (subtype < 0) {
200 "impossible repetition period of %d for the current DTS stream"
201 " (blocks = %d, sample rate = %d)\n",
ctx->dtshd_rate,
period,
202 blocks << 5, sample_rate);
204 }
205
206 /* set pkt_offset and DTS IV subtype according to the requested output
207 * rate */
210
211 /* If the bitrate is too high for transmitting at the selected
212 * repetition period setting, strip DTS-HD until a good amount
213 * of consecutive non-overflowing HD frames have been observed.
214 * This generally only happens if the caller is cramming a Master
215 * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
216 if (sizeof(dtshd_start_code) + 2 + pkt_size
218 if (!
ctx->dtshd_skip)
220 "temporarily sending core only\n");
221 if (
ctx->dtshd_fallback > 0)
222 ctx->dtshd_skip = sample_rate *
ctx->dtshd_fallback / (blocks << 5);
223 else
224 /* skip permanently (dtshd_fallback == -1) or just once
225 * (dtshd_fallback == 0) */
227 }
228 if (
ctx->dtshd_skip && core_size) {
229 pkt_size = core_size;
230 if (
ctx->dtshd_fallback >= 0)
232 }
233
234 ctx->out_bytes =
sizeof(dtshd_start_code) + 2 + pkt_size;
235
236 /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
237 * with some receivers, but the exact requirement is unconfirmed. */
238 ctx->length_code =
FFALIGN(
ctx->out_bytes + 0x8, 0x10) - 0x8;
239
243
244 ctx->out_buf =
ctx->hd_buf[0];
245
246 memcpy(
ctx->hd_buf[0], dtshd_start_code,
sizeof(dtshd_start_code));
247 AV_WB16(
ctx->hd_buf[0] +
sizeof(dtshd_start_code), pkt_size);
248 memcpy(
ctx->hd_buf[0] +
sizeof(dtshd_start_code) + 2,
pkt->
data, pkt_size);
249
250 return 0;
251 }
252
254 {
257 int blocks;
258 int sample_rate = 0;
259 int core_size = 0;
260
263
264 switch (syncword_dts) {
269 break;
272 ctx->extra_bswap = 1;
273 break;
275 blocks =
277 break;
279 blocks =
281 ctx->extra_bswap = 1;
282 break;
284 /* We only handle HD frames that are paired with core. However,
285 sometimes DTS-HD streams with core have a stray HD frame without
286 core in the beginning of the stream. */
289 default:
292 }
293 blocks++;
294
296 /* DTS type IV output requested */
298
299 switch (blocks) {
303 default:
305 blocks << 5);
307 }
308
309 /* discard extraneous data by default */
310 if (core_size && core_size < pkt->
size) {
311 ctx->out_bytes = core_size;
312 ctx->length_code = core_size << 3;
313 }
314
315 ctx->pkt_offset = blocks << 7;
316
317 if (
ctx->out_bytes ==
ctx->pkt_offset) {
318 /* The DTS stream fits exactly into the output stream, so skip the
319 * preamble as it would not fit in there. This is the case for dts
320 * discs and dts-in-wav. */
321 ctx->use_preamble = 0;
324 /* This will fail with a "bitrate too high" in the caller */
325 }
326
327 return 0;
328 }
329
331 // LAYER1 LAYER2 LAYER3
334 };
335
337 {
340 int layer = 3 - ((
pkt->
data[1] >> 1) & 3);
341 int extension =
pkt->
data[2] & 1;
342
343 if (layer == 3 ||
version == 1) {
346 }
348 if (
version == 2 && extension) {
350 ctx->pkt_offset = 4608;
351 } else {
354 }
355 // TODO Data type dependent info (normal/karaoke, dynamic range control)
356 return 0;
357 }
358
360 {
365
370 }
371
374 case 1:
376 break;
377 case 2:
379 break;
380 case 4:
382 break;
383 default:
385 "%"PRIu32
" samples in AAC frame not supported\n",
samples);
387 }
388 //TODO Data type dependent info (LC profile/SBR)
389 return 0;
390 }
391
392
393 /*
394 * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
395 * they can be encapsulated in IEC 61937.
396 */
397 #define MAT_PKT_OFFSET 61440
398 #define MAT_FRAME_SIZE 61424
399
401 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83,
402 0x49, 0x80, 0x77, 0xE0,
403 };
405 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0,
406 };
408 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11,
409 };
410
411 #define MAT_CODE(position, data) { .pos = position, .code = data, .len = sizeof(data) }
412
413 static const struct {
421 };
422
424 {
426 uint8_t *hd_buf =
ctx->hd_buf[
ctx->hd_buf_idx];
427 int ratebits;
428 int padding_remaining = 0;
429 uint16_t input_timing;
430 int total_frame_size =
pkt->
size;
431 const uint8_t *dataptr =
pkt->
data;
432 int data_remaining =
pkt->
size;
433 int have_pkt = 0;
434 int next_code_idx;
435
438
440 /* major sync unit, fetch sample rate */
445 else
447
448 ctx->truehd_samples_per_frame = 40 << (ratebits & 3);
450 ctx->truehd_samples_per_frame);
451 }
452
453 if (!
ctx->truehd_samples_per_frame)
455
457 if (
ctx->truehd_prev_size) {
458 uint16_t delta_samples = input_timing -
ctx->truehd_prev_time;
459 /*
460 * One multiple-of-48kHz frame is 1/1200 sec and the IEC 61937 rate
461 * is 768kHz = 768000*4 bytes/sec.
462 * The nominal space per frame is therefore
463 * (768000*4 bytes/sec) * (1/1200 sec) = 2560 bytes.
464 * For multiple-of-44.1kHz frames: 1/1102.5 sec, 705.6kHz, 2560 bytes.
465 *
466 * 2560 is divisible by truehd_samples_per_frame.
467 */
468 int delta_bytes = delta_samples * 2560 /
ctx->truehd_samples_per_frame;
469
470 /* padding needed before this frame */
471 padding_remaining = delta_bytes -
ctx->truehd_prev_size;
472
474 delta_samples, delta_bytes);
475
476 /* sanity check */
477 if (padding_remaining < 0 || padding_remaining >=
MAT_FRAME_SIZE / 2) {
479 ctx->truehd_prev_time, input_timing,
ctx->truehd_samples_per_frame);
480 padding_remaining = 0;
481 }
482 }
483
486 break;
487
490
491 while (padding_remaining || data_remaining ||
493
495 /* time to insert MAT code */
496 int code_len =
mat_codes[next_code_idx].len;
497 int code_len_remaining = code_len;
500 ctx->hd_buf_filled += code_len;
501
502 next_code_idx++;
504 next_code_idx = 0;
505
506 /* this was the last code, move to the next MAT frame */
507 have_pkt = 1;
508 ctx->out_buf = hd_buf;
509 ctx->hd_buf_idx ^= 1;
510 hd_buf =
ctx->hd_buf[
ctx->hd_buf_idx];
511 ctx->hd_buf_filled = 0;
512
513 /* inter-frame gap has to be counted as well, add it */
515 }
516
517 if (padding_remaining) {
518 /* consider the MAT code as padding */
519 int counted_as_padding =
FFMIN(padding_remaining,
520 code_len_remaining);
521 padding_remaining -= counted_as_padding;
522 code_len_remaining -= counted_as_padding;
523 }
524 /* count the remainder of the code as part of frame size */
525 if (code_len_remaining)
526 total_frame_size += code_len_remaining;
527 }
528
529 if (padding_remaining) {
531 padding_remaining);
532
533 memset(hd_buf +
ctx->hd_buf_filled, 0, padding_to_insert);
534 ctx->hd_buf_filled += padding_to_insert;
535 padding_remaining -= padding_to_insert;
536
537 if (padding_remaining)
538 continue; /* time to insert MAT code */
539 }
540
541 if (data_remaining) {
543 data_remaining);
544
545 memcpy(hd_buf +
ctx->hd_buf_filled, dataptr, data_to_insert);
546 ctx->hd_buf_filled += data_to_insert;
547 dataptr += data_to_insert;
548 data_remaining -= data_to_insert;
549 }
550 }
551
552 ctx->truehd_prev_size = total_frame_size;
553 ctx->truehd_prev_time = input_timing;
554
556 total_frame_size,
ctx->hd_buf_filled);
557
558 if (!have_pkt) {
560 return 0;
561 }
562
567 return 0;
568 }
569
571 {
573
574 switch (
s->streams[0]->codecpar->codec_id) {
577 break;
580 break;
585 break;
588 break;
591 break;
599 }
600 break;
601 default:
603 s->streams[0]->codecpar->codec_id);
605 }
606 return 0;
607 }
608
610 {
615 }
616
619 {
622 else
624 }
625
627 {
630
634 ctx->use_preamble = 1;
635 ctx->extra_bswap = 0;
636
640 if (!
ctx->pkt_offset)
641 return 0;
642
644 if (padding < 0) {
647 }
648
649 if (
ctx->use_preamble) {
654 }
655
658 } else {
664 }
665
666 /* a final lone byte has to be MSB aligned */
667 if (
ctx->out_bytes & 1)
669
671
673 ctx->data_type,
ctx->out_bytes,
ctx->pkt_offset);
674
675 return 0;
676 }
677
681 .p.extensions = "spdif",
692 };