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spdifenc.c
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1 /*
2  * IEC 61937 muxer
3  * Copyright (c) 2009 Bartlomiej Wolowiec
4  * Copyright (c) 2010 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-preambule - IEC61937 frame header, contains 16-bits 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 
49 #include "avformat.h"
50 #include "avio_internal.h"
51 #include "spdif.h"
52 #include "libavcodec/ac3.h"
53 #include "libavcodec/dca.h"
54 #include "libavcodec/aacadtsdec.h"
55 #include "libavutil/opt.h"
56 
57 typedef struct IEC61937Context {
58  const AVClass *av_class;
59  enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst
60  int length_code; ///< length code in bits or bytes, depending on data type
61  int pkt_offset; ///< data burst repetition period in bytes
62  uint8_t *buffer; ///< allocated buffer, used for swap bytes
63  int buffer_size; ///< size of allocated buffer
64 
65  uint8_t *out_buf; ///< pointer to the outgoing data before byte-swapping
66  int out_bytes; ///< amount of outgoing bytes
67 
68  int use_preamble; ///< preamble enabled (disabled for exactly pre-padded DTS)
69  int extra_bswap; ///< extra bswap for payload (for LE DTS => standard BE DTS)
70 
71  uint8_t *hd_buf; ///< allocated buffer to concatenate hd audio frames
72  int hd_buf_size; ///< size of the hd audio buffer
73  int hd_buf_count; ///< number of frames in the hd audio buffer
74  int hd_buf_filled; ///< amount of bytes in the hd audio buffer
75 
76  int dtshd_skip; ///< counter used for skipping DTS-HD frames
77 
78  /* AVOptions: */
81 #define SPDIF_FLAG_BIGENDIAN 0x01
83 
84  /// function, which generates codec dependent header information.
85  /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
88 
89 static const AVOption options[] = {
90 { "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" },
91 { "be", "output in big-endian format (for use as s16be)", 0, AV_OPT_TYPE_CONST, {.i64 = SPDIF_FLAG_BIGENDIAN}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
92 { "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 },
93 { "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 },
94 { NULL },
95 };
96 
97 static const AVClass spdif_class = {
98  .class_name = "spdif",
99  .item_name = av_default_item_name,
100  .option = options,
101  .version = LIBAVUTIL_VERSION_INT,
102 };
103 
105 {
106  IEC61937Context *ctx = s->priv_data;
107  int bitstream_mode = pkt->data[5] & 0x7;
108 
109  ctx->data_type = IEC61937_AC3 | (bitstream_mode << 8);
110  ctx->pkt_offset = AC3_FRAME_SIZE << 2;
111  return 0;
112 }
113 
115 {
116  IEC61937Context *ctx = s->priv_data;
117  static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
118  int repeat = 1;
119 
120  if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */
121  repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
122 
123  ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
124  if (!ctx->hd_buf)
125  return AVERROR(ENOMEM);
126 
127  memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);
128 
129  ctx->hd_buf_filled += pkt->size;
130  if (++ctx->hd_buf_count < repeat){
131  ctx->pkt_offset = 0;
132  return 0;
133  }
134  ctx->data_type = IEC61937_EAC3;
135  ctx->pkt_offset = 24576;
136  ctx->out_buf = ctx->hd_buf;
137  ctx->out_bytes = ctx->hd_buf_filled;
138  ctx->length_code = ctx->hd_buf_filled;
139 
140  ctx->hd_buf_count = 0;
141  ctx->hd_buf_filled = 0;
142  return 0;
143 }
144 
145 /*
146  * DTS type IV (DTS-HD) can be transmitted with various frame repetition
147  * periods; longer repetition periods allow for longer packets and therefore
148  * higher bitrate. Longer repetition periods mean that the constant bitrate of
149  * the outputted IEC 61937 stream is higher.
150  * The repetition period is measured in IEC 60958 frames (4 bytes).
151  */
152 static int spdif_dts4_subtype(int period)
153 {
154  switch (period) {
155  case 512: return 0x0;
156  case 1024: return 0x1;
157  case 2048: return 0x2;
158  case 4096: return 0x3;
159  case 8192: return 0x4;
160  case 16384: return 0x5;
161  }
162  return -1;
163 }
164 
165 static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
166  int sample_rate, int blocks)
167 {
168  IEC61937Context *ctx = s->priv_data;
169  static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
170  int pkt_size = pkt->size;
171  int period;
172  int subtype;
173 
174  if (!core_size) {
175  av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
176  return AVERROR(EINVAL);
177  }
178 
179  if (!sample_rate) {
180  av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
181  return AVERROR_INVALIDDATA;
182  }
183 
184  period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
185  subtype = spdif_dts4_subtype(period);
186 
187  if (subtype < 0) {
188  av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
189  "impossible repetition period of %d for the current DTS stream"
190  " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
191  blocks << 5, sample_rate);
192  return AVERROR(EINVAL);
193  }
194 
195  /* set pkt_offset and DTS IV subtype according to the requested output
196  * rate */
197  ctx->pkt_offset = period * 4;
198  ctx->data_type = IEC61937_DTSHD | subtype << 8;
199 
200  /* If the bitrate is too high for transmitting at the selected
201  * repetition period setting, strip DTS-HD until a good amount
202  * of consecutive non-overflowing HD frames have been observed.
203  * This generally only happens if the caller is cramming a Master
204  * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
205  if (sizeof(dtshd_start_code) + 2 + pkt_size
206  > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
207  if (!ctx->dtshd_skip)
208  av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
209  "temporarily sending core only\n");
210  if (ctx->dtshd_fallback > 0)
211  ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
212  else
213  /* skip permanently (dtshd_fallback == -1) or just once
214  * (dtshd_fallback == 0) */
215  ctx->dtshd_skip = 1;
216  }
217  if (ctx->dtshd_skip && core_size) {
218  pkt_size = core_size;
219  if (ctx->dtshd_fallback >= 0)
220  --ctx->dtshd_skip;
221  }
222 
223  ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;
224 
225  /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
226  * with some receivers, but the exact requirement is unconfirmed. */
227  ctx->length_code = FFALIGN(ctx->out_bytes + 0x8, 0x10) - 0x8;
228 
229  av_fast_malloc(&ctx->hd_buf, &ctx->hd_buf_size, ctx->out_bytes);
230  if (!ctx->hd_buf)
231  return AVERROR(ENOMEM);
232 
233  ctx->out_buf = ctx->hd_buf;
234 
235  memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));
236  AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);
237  memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
238 
239  return 0;
240 }
241 
243 {
244  IEC61937Context *ctx = s->priv_data;
245  uint32_t syncword_dts = AV_RB32(pkt->data);
246  int blocks;
247  int sample_rate = 0;
248  int core_size = 0;
249 
250  if (pkt->size < 9)
251  return AVERROR_INVALIDDATA;
252 
253  switch (syncword_dts) {
254  case DCA_MARKER_RAW_BE:
255  blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
256  core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
257  sample_rate = avpriv_dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
258  break;
259  case DCA_MARKER_RAW_LE:
260  blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
261  ctx->extra_bswap = 1;
262  break;
263  case DCA_MARKER_14B_BE:
264  blocks =
265  (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
266  break;
267  case DCA_MARKER_14B_LE:
268  blocks =
269  (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
270  ctx->extra_bswap = 1;
271  break;
272  case DCA_HD_MARKER:
273  /* We only handle HD frames that are paired with core. However,
274  sometimes DTS-HD streams with core have a stray HD frame without
275  core in the beginning of the stream. */
276  av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
277  return AVERROR_INVALIDDATA;
278  default:
279  av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%"PRIx32"\n", syncword_dts);
280  return AVERROR_INVALIDDATA;
281  }
282  blocks++;
283 
284  if (ctx->dtshd_rate)
285  /* DTS type IV output requested */
286  return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
287 
288  switch (blocks) {
289  case 512 >> 5: ctx->data_type = IEC61937_DTS1; break;
290  case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
291  case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
292  default:
293  av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
294  blocks << 5);
295  return AVERROR(ENOSYS);
296  }
297 
298  /* discard extraneous data by default */
299  if (core_size && core_size < pkt->size) {
300  ctx->out_bytes = core_size;
301  ctx->length_code = core_size << 3;
302  }
303 
304  ctx->pkt_offset = blocks << 7;
305 
306  if (ctx->out_bytes == ctx->pkt_offset) {
307  /* The DTS stream fits exactly into the output stream, so skip the
308  * preamble as it would not fit in there. This is the case for dts
309  * discs and dts-in-wav. */
310  ctx->use_preamble = 0;
311  } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
312  avpriv_request_sample(s, "Unrecognized large DTS frame");
313  /* This will fail with a "bitrate too high" in the caller */
314  }
315 
316  return 0;
317 }
318 
319 static const enum IEC61937DataType mpeg_data_type[2][3] = {
320  // LAYER1 LAYER2 LAYER3
322  { IEC61937_MPEG1_LAYER1, IEC61937_MPEG1_LAYER23, IEC61937_MPEG1_LAYER23 }, //MPEG1
323 };
324 
326 {
327  IEC61937Context *ctx = s->priv_data;
328  int version = (pkt->data[1] >> 3) & 3;
329  int layer = 3 - ((pkt->data[1] >> 1) & 3);
330  int extension = pkt->data[2] & 1;
331 
332  if (layer == 3 || version == 1) {
333  av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
334  return AVERROR_INVALIDDATA;
335  }
336  av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
337  if (version == 2 && extension) {
339  ctx->pkt_offset = 4608;
340  } else {
341  ctx->data_type = mpeg_data_type [version & 1][layer];
342  ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
343  }
344  // TODO Data type dependent info (normal/karaoke, dynamic range control)
345  return 0;
346 }
347 
349 {
350  IEC61937Context *ctx = s->priv_data;
351  AACADTSHeaderInfo hdr;
352  GetBitContext gbc;
353  int ret;
354 
355  init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
356  ret = avpriv_aac_parse_header(&gbc, &hdr);
357  if (ret < 0) {
358  av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
359  return AVERROR_INVALIDDATA;
360  }
361 
362  ctx->pkt_offset = hdr.samples << 2;
363  switch (hdr.num_aac_frames) {
364  case 1:
366  break;
367  case 2:
369  break;
370  case 4:
372  break;
373  default:
374  av_log(s, AV_LOG_ERROR,
375  "%"PRIu32" samples in AAC frame not supported\n", hdr.samples);
376  return AVERROR(EINVAL);
377  }
378  //TODO Data type dependent info (LC profile/SBR)
379  return 0;
380 }
381 
382 
383 /*
384  * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
385  * they can be encapsulated in IEC 61937.
386  * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them
387  * to achieve constant rate.
388  * The actual format of a MAT frame is unknown, but the below seems to work.
389  * However, it seems it is not actually necessary for the 24 TrueHD frames to
390  * be in an exact alignment with the MAT frame.
391  */
392 #define MAT_FRAME_SIZE 61424
393 #define TRUEHD_FRAME_OFFSET 2560
394 #define MAT_MIDDLE_CODE_OFFSET -4
395 
397 {
398  IEC61937Context *ctx = s->priv_data;
399  int mat_code_length = 0;
400  static const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };
401 
402  if (!ctx->hd_buf_count) {
403  static const char mat_start_code[20] = { 0x07, 0x9E, 0x00, 0x03, 0x84, 0x01, 0x01, 0x01, 0x80, 0x00, 0x56, 0xA5, 0x3B, 0xF4, 0x81, 0x83, 0x49, 0x80, 0x77, 0xE0 };
404  mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;
405  memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));
406 
407  } else if (ctx->hd_buf_count == 12) {
408  static const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };
409  mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;
411  mat_middle_code, sizeof(mat_middle_code));
412  }
413 
414  if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {
415  /* if such frames exist, we'd need some more complex logic to
416  * distribute the TrueHD frames in the MAT frame */
417  avpriv_request_sample(s, "Too large TrueHD frame of %d bytes",
418  pkt->size);
419  return AVERROR_PATCHWELCOME;
420  }
421 
422  memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],
423  pkt->data, pkt->size);
424  memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],
425  0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);
426 
427  if (++ctx->hd_buf_count < 24){
428  ctx->pkt_offset = 0;
429  return 0;
430  }
431  memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));
432  ctx->hd_buf_count = 0;
433 
434  ctx->data_type = IEC61937_TRUEHD;
435  ctx->pkt_offset = 61440;
436  ctx->out_buf = ctx->hd_buf;
437  ctx->out_bytes = MAT_FRAME_SIZE;
439  return 0;
440 }
441 
443 {
444  IEC61937Context *ctx = s->priv_data;
445 
446  switch (s->streams[0]->codec->codec_id) {
447  case AV_CODEC_ID_AC3:
449  break;
450  case AV_CODEC_ID_EAC3:
452  break;
453  case AV_CODEC_ID_MP1:
454  case AV_CODEC_ID_MP2:
455  case AV_CODEC_ID_MP3:
457  break;
458  case AV_CODEC_ID_DTS:
460  break;
461  case AV_CODEC_ID_AAC:
463  break;
464  case AV_CODEC_ID_TRUEHD:
467  if (!ctx->hd_buf)
468  return AVERROR(ENOMEM);
469  break;
470  default:
471  av_log(s, AV_LOG_ERROR, "codec not supported\n");
472  return AVERROR_PATCHWELCOME;
473  }
474  return 0;
475 }
476 
478 {
479  IEC61937Context *ctx = s->priv_data;
480  av_freep(&ctx->buffer);
481  av_freep(&ctx->hd_buf);
482  return 0;
483 }
484 
486  AVIOContext *pb, unsigned int val)
487 {
489  avio_wb16(pb, val);
490  else
491  avio_wl16(pb, val);
492 }
493 
495 {
496  IEC61937Context *ctx = s->priv_data;
497  int ret, padding;
498 
499  ctx->out_buf = pkt->data;
500  ctx->out_bytes = pkt->size;
501  ctx->length_code = FFALIGN(pkt->size, 2) << 3;
502  ctx->use_preamble = 1;
503  ctx->extra_bswap = 0;
504 
505  ret = ctx->header_info(s, pkt);
506  if (ret < 0)
507  return ret;
508  if (!ctx->pkt_offset)
509  return 0;
510 
511  padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
512  if (padding < 0) {
513  av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
514  return AVERROR(EINVAL);
515  }
516 
517  if (ctx->use_preamble) {
518  spdif_put_16(ctx, s->pb, SYNCWORD1); //Pa
519  spdif_put_16(ctx, s->pb, SYNCWORD2); //Pb
520  spdif_put_16(ctx, s->pb, ctx->data_type); //Pc
521  spdif_put_16(ctx, s->pb, ctx->length_code);//Pd
522  }
523 
524  if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {
525  avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
526  } else {
528  if (!ctx->buffer)
529  return AVERROR(ENOMEM);
530  ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
531  avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);
532  }
533 
534  /* a final lone byte has to be MSB aligned */
535  if (ctx->out_bytes & 1)
536  spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);
537 
538  ffio_fill(s->pb, 0, padding);
539 
540  av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
541  ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
542 
543  return 0;
544 }
545 
547  .name = "spdif",
548  .long_name = NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
549  .extensions = "spdif",
550  .priv_data_size = sizeof(IEC61937Context),
551  .audio_codec = AV_CODEC_ID_AC3,
552  .video_codec = AV_CODEC_ID_NONE,
557  .priv_class = &spdif_class,
558 };