FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
spdifenc.c
Go to the documentation of this file.
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 "avformat.h"
48 #include "avio_internal.h"
49 #include "spdif.h"
50 #include "libavcodec/ac3.h"
51 #include "libavcodec/dca.h"
52 #include "libavcodec/aacadtsdec.h"
53 #include "libavutil/opt.h"
54 
55 typedef struct IEC61937Context {
56  const AVClass *av_class;
57  enum IEC61937DataType data_type;///< burst info - reference to type of payload of the data-burst
58  int length_code; ///< length code in bits or bytes, depending on data type
59  int pkt_offset; ///< data burst repetition period in bytes
60  uint8_t *buffer; ///< allocated buffer, used for swap bytes
61  int buffer_size; ///< size of allocated buffer
62 
63  uint8_t *out_buf; ///< pointer to the outgoing data before byte-swapping
64  int out_bytes; ///< amount of outgoing bytes
65 
66  int use_preamble; ///< preamble enabled (disabled for exactly pre-padded DTS)
67  int extra_bswap; ///< extra bswap for payload (for LE DTS => standard BE DTS)
68 
69  uint8_t *hd_buf; ///< allocated buffer to concatenate hd audio frames
70  int hd_buf_size; ///< size of the hd audio buffer
71  int hd_buf_count; ///< number of frames in the hd audio buffer
72  int hd_buf_filled; ///< amount of bytes in the hd audio buffer
73 
74  int dtshd_skip; ///< counter used for skipping DTS-HD frames
75 
76  /* AVOptions: */
79 #define SPDIF_FLAG_BIGENDIAN 0x01
81 
82  /// function, which generates codec dependent header information.
83  /// Sets data_type and pkt_offset, and length_code, out_bytes, out_buf if necessary
86 
87 static const AVOption options[] = {
88 { "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" },
89 { "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" },
90 { "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 },
91 { "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 },
92 { NULL },
93 };
94 
95 static const AVClass spdif_class = {
96  .class_name = "spdif",
97  .item_name = av_default_item_name,
98  .option = options,
99  .version = LIBAVUTIL_VERSION_INT,
100 };
101 
103 {
104  IEC61937Context *ctx = s->priv_data;
105  int bitstream_mode = pkt->data[5] & 0x7;
106 
107  ctx->data_type = IEC61937_AC3 | (bitstream_mode << 8);
108  ctx->pkt_offset = AC3_FRAME_SIZE << 2;
109  return 0;
110 }
111 
113 {
114  IEC61937Context *ctx = s->priv_data;
115  static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
116  int repeat = 1;
117 
118  if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */
119  repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
120 
121  ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
122  if (!ctx->hd_buf)
123  return AVERROR(ENOMEM);
124 
125  memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);
126 
127  ctx->hd_buf_filled += pkt->size;
128  if (++ctx->hd_buf_count < repeat){
129  ctx->pkt_offset = 0;
130  return 0;
131  }
132  ctx->data_type = IEC61937_EAC3;
133  ctx->pkt_offset = 24576;
134  ctx->out_buf = ctx->hd_buf;
135  ctx->out_bytes = ctx->hd_buf_filled;
136  ctx->length_code = ctx->hd_buf_filled;
137 
138  ctx->hd_buf_count = 0;
139  ctx->hd_buf_filled = 0;
140  return 0;
141 }
142 
143 /*
144  * DTS type IV (DTS-HD) can be transmitted with various frame repetition
145  * periods; longer repetition periods allow for longer packets and therefore
146  * higher bitrate. Longer repetition periods mean that the constant bitrate of
147  * the outputted IEC 61937 stream is higher.
148  * The repetition period is measured in IEC 60958 frames (4 bytes).
149  */
150 static int spdif_dts4_subtype(int period)
151 {
152  switch (period) {
153  case 512: return 0x0;
154  case 1024: return 0x1;
155  case 2048: return 0x2;
156  case 4096: return 0x3;
157  case 8192: return 0x4;
158  case 16384: return 0x5;
159  }
160  return -1;
161 }
162 
163 static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
164  int sample_rate, int blocks)
165 {
166  IEC61937Context *ctx = s->priv_data;
167  static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
168  int pkt_size = pkt->size;
169  int period;
170  int subtype;
171 
172  if (!core_size) {
173  av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
174  return AVERROR(EINVAL);
175  }
176 
177  if (!sample_rate) {
178  av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
179  return AVERROR_INVALIDDATA;
180  }
181 
182  period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
183  subtype = spdif_dts4_subtype(period);
184 
185  if (subtype < 0) {
186  av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
187  "impossible repetition period of %d for the current DTS stream"
188  " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
189  blocks << 5, sample_rate);
190  return AVERROR(EINVAL);
191  }
192 
193  /* set pkt_offset and DTS IV subtype according to the requested output
194  * rate */
195  ctx->pkt_offset = period * 4;
196  ctx->data_type = IEC61937_DTSHD | subtype << 8;
197 
198  /* If the bitrate is too high for transmitting at the selected
199  * repetition period setting, strip DTS-HD until a good amount
200  * of consecutive non-overflowing HD frames have been observed.
201  * This generally only happens if the caller is cramming a Master
202  * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
203  if (sizeof(dtshd_start_code) + 2 + pkt_size
204  > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
205  if (!ctx->dtshd_skip)
206  av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
207  "temporarily sending core only\n");
208  if (ctx->dtshd_fallback > 0)
209  ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
210  else
211  /* skip permanently (dtshd_fallback == -1) or just once
212  * (dtshd_fallback == 0) */
213  ctx->dtshd_skip = 1;
214  }
215  if (ctx->dtshd_skip && core_size) {
216  pkt_size = core_size;
217  if (ctx->dtshd_fallback >= 0)
218  --ctx->dtshd_skip;
219  }
220 
221  ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;
222 
223  /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
224  * with some receivers, but the exact requirement is unconfirmed. */
225  ctx->length_code = FFALIGN(ctx->out_bytes + 0x8, 0x10) - 0x8;
226 
227  av_fast_malloc(&ctx->hd_buf, &ctx->hd_buf_size, ctx->out_bytes);
228  if (!ctx->hd_buf)
229  return AVERROR(ENOMEM);
230 
231  ctx->out_buf = ctx->hd_buf;
232 
233  memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));
234  AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);
235  memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
236 
237  return 0;
238 }
239 
241 {
242  IEC61937Context *ctx = s->priv_data;
243  uint32_t syncword_dts = AV_RB32(pkt->data);
244  int blocks;
245  int sample_rate = 0;
246  int core_size = 0;
247 
248  if (pkt->size < 9)
249  return AVERROR_INVALIDDATA;
250 
251  switch (syncword_dts) {
252  case DCA_MARKER_RAW_BE:
253  blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
254  core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
255  sample_rate = avpriv_dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
256  break;
257  case DCA_MARKER_RAW_LE:
258  blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
259  ctx->extra_bswap = 1;
260  break;
261  case DCA_MARKER_14B_BE:
262  blocks =
263  (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
264  break;
265  case DCA_MARKER_14B_LE:
266  blocks =
267  (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
268  ctx->extra_bswap = 1;
269  break;
270  case DCA_HD_MARKER:
271  /* We only handle HD frames that are paired with core. However,
272  sometimes DTS-HD streams with core have a stray HD frame without
273  core in the beginning of the stream. */
274  av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
275  return AVERROR_INVALIDDATA;
276  default:
277  av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
278  return AVERROR_INVALIDDATA;
279  }
280  blocks++;
281 
282  if (ctx->dtshd_rate)
283  /* DTS type IV output requested */
284  return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
285 
286  switch (blocks) {
287  case 512 >> 5: ctx->data_type = IEC61937_DTS1; break;
288  case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
289  case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
290  default:
291  av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
292  blocks << 5);
293  return AVERROR(ENOSYS);
294  }
295 
296  /* discard extraneous data by default */
297  if (core_size && core_size < pkt->size) {
298  ctx->out_bytes = core_size;
299  ctx->length_code = core_size << 3;
300  }
301 
302  ctx->pkt_offset = blocks << 7;
303 
304  if (ctx->out_bytes == ctx->pkt_offset) {
305  /* The DTS stream fits exactly into the output stream, so skip the
306  * preamble as it would not fit in there. This is the case for dts
307  * discs and dts-in-wav. */
308  ctx->use_preamble = 0;
309  } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
310  avpriv_request_sample(s, "Unrecognized large DTS frame");
311  /* This will fail with a "bitrate too high" in the caller */
312  }
313 
314  return 0;
315 }
316 
317 static const enum IEC61937DataType mpeg_data_type[2][3] = {
318  // LAYER1 LAYER2 LAYER3
320  { IEC61937_MPEG1_LAYER1, IEC61937_MPEG1_LAYER23, IEC61937_MPEG1_LAYER23 }, //MPEG1
321 };
322 
324 {
325  IEC61937Context *ctx = s->priv_data;
326  int version = (pkt->data[1] >> 3) & 3;
327  int layer = 3 - ((pkt->data[1] >> 1) & 3);
328  int extension = pkt->data[2] & 1;
329 
330  if (layer == 3 || version == 1) {
331  av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
332  return AVERROR_INVALIDDATA;
333  }
334  av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
335  if (version == 2 && extension) {
337  ctx->pkt_offset = 4608;
338  } else {
339  ctx->data_type = mpeg_data_type [version & 1][layer];
340  ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
341  }
342  // TODO Data type dependent info (normal/karaoke, dynamic range control)
343  return 0;
344 }
345 
347 {
348  IEC61937Context *ctx = s->priv_data;
349  AACADTSHeaderInfo hdr;
350  GetBitContext gbc;
351  int ret;
352 
353  init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
354  ret = avpriv_aac_parse_header(&gbc, &hdr);
355  if (ret < 0) {
356  av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
357  return AVERROR_INVALIDDATA;
358  }
359 
360  ctx->pkt_offset = hdr.samples << 2;
361  switch (hdr.num_aac_frames) {
362  case 1:
364  break;
365  case 2:
367  break;
368  case 4:
370  break;
371  default:
372  av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",
373  hdr.samples);
374  return AVERROR(EINVAL);
375  }
376  //TODO Data type dependent info (LC profile/SBR)
377  return 0;
378 }
379 
380 
381 /*
382  * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
383  * they can be encapsulated in IEC 61937.
384  * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them
385  * to achieve constant rate.
386  * The actual format of a MAT frame is unknown, but the below seems to work.
387  * However, it seems it is not actually necessary for the 24 TrueHD frames to
388  * be in an exact alignment with the MAT frame.
389  */
390 #define MAT_FRAME_SIZE 61424
391 #define TRUEHD_FRAME_OFFSET 2560
392 #define MAT_MIDDLE_CODE_OFFSET -4
393 
395 {
396  IEC61937Context *ctx = s->priv_data;
397  int mat_code_length = 0;
398  static const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };
399 
400  if (!ctx->hd_buf_count) {
401  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 };
402  mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;
403  memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));
404 
405  } else if (ctx->hd_buf_count == 12) {
406  static const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };
407  mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;
409  mat_middle_code, sizeof(mat_middle_code));
410  }
411 
412  if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {
413  /* if such frames exist, we'd need some more complex logic to
414  * distribute the TrueHD frames in the MAT frame */
415  avpriv_request_sample(s, "Too large TrueHD frame of %d bytes",
416  pkt->size);
417  return AVERROR_PATCHWELCOME;
418  }
419 
420  memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],
421  pkt->data, pkt->size);
422  memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],
423  0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);
424 
425  if (++ctx->hd_buf_count < 24){
426  ctx->pkt_offset = 0;
427  return 0;
428  }
429  memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));
430  ctx->hd_buf_count = 0;
431 
432  ctx->data_type = IEC61937_TRUEHD;
433  ctx->pkt_offset = 61440;
434  ctx->out_buf = ctx->hd_buf;
435  ctx->out_bytes = MAT_FRAME_SIZE;
437  return 0;
438 }
439 
441 {
442  IEC61937Context *ctx = s->priv_data;
443 
444  switch (s->streams[0]->codec->codec_id) {
445  case AV_CODEC_ID_AC3:
447  break;
448  case AV_CODEC_ID_EAC3:
450  break;
451  case AV_CODEC_ID_MP1:
452  case AV_CODEC_ID_MP2:
453  case AV_CODEC_ID_MP3:
455  break;
456  case AV_CODEC_ID_DTS:
458  break;
459  case AV_CODEC_ID_AAC:
461  break;
462  case AV_CODEC_ID_TRUEHD:
465  if (!ctx->hd_buf)
466  return AVERROR(ENOMEM);
467  break;
468  default:
469  av_log(s, AV_LOG_ERROR, "codec not supported\n");
470  return AVERROR_PATCHWELCOME;
471  }
472  return 0;
473 }
474 
476 {
477  IEC61937Context *ctx = s->priv_data;
478  av_freep(&ctx->buffer);
479  av_freep(&ctx->hd_buf);
480  return 0;
481 }
482 
484  AVIOContext *pb, unsigned int val)
485 {
487  avio_wb16(pb, val);
488  else
489  avio_wl16(pb, val);
490 }
491 
493 {
494  IEC61937Context *ctx = s->priv_data;
495  int ret, padding;
496 
497  ctx->out_buf = pkt->data;
498  ctx->out_bytes = pkt->size;
499  ctx->length_code = FFALIGN(pkt->size, 2) << 3;
500  ctx->use_preamble = 1;
501  ctx->extra_bswap = 0;
502 
503  ret = ctx->header_info(s, pkt);
504  if (ret < 0)
505  return ret;
506  if (!ctx->pkt_offset)
507  return 0;
508 
509  padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
510  if (padding < 0) {
511  av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
512  return AVERROR(EINVAL);
513  }
514 
515  if (ctx->use_preamble) {
516  spdif_put_16(ctx, s->pb, SYNCWORD1); //Pa
517  spdif_put_16(ctx, s->pb, SYNCWORD2); //Pb
518  spdif_put_16(ctx, s->pb, ctx->data_type); //Pc
519  spdif_put_16(ctx, s->pb, ctx->length_code);//Pd
520  }
521 
522  if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {
523  avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
524  } else {
526  if (!ctx->buffer)
527  return AVERROR(ENOMEM);
528  ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
529  avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);
530  }
531 
532  /* a final lone byte has to be MSB aligned */
533  if (ctx->out_bytes & 1)
534  spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);
535 
536  ffio_fill(s->pb, 0, padding);
537 
538  av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
539  ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
540 
541  return 0;
542 }
543 
545  .name = "spdif",
546  .long_name = NULL_IF_CONFIG_SMALL("IEC 61937 (used on S/PDIF - IEC958)"),
547  .extensions = "spdif",
548  .priv_data_size = sizeof(IEC61937Context),
549  .audio_codec = AV_CODEC_ID_AC3,
550  .video_codec = AV_CODEC_ID_NONE,
555  .priv_class = &spdif_class,
556 };