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 Libav.
8  *
9  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 
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/dcadata.h"
53 #include "libavcodec/aacadtsdec.h"
54 #include "libavutil/opt.h"
55 
56 typedef struct IEC61937Context {
57  const AVClass *av_class;
60  int pkt_offset;
61  uint8_t *buffer;
63 
64  uint8_t *out_buf;
65  int out_bytes;
66 
69 
70  uint8_t *hd_buf;
74 
75  int dtshd_skip;
76 
77  /* AVOptions: */
80 #define SPDIF_FLAG_BIGENDIAN 0x01
82 
87 
88 static const AVOption options[] = {
89 { "spdif_flags", "IEC 61937 encapsulation flags", offsetof(IEC61937Context, spdif_flags), AV_OPT_TYPE_FLAGS, {.dbl = 0}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
90 { "be", "output in big-endian format (for use as s16be)", 0, AV_OPT_TYPE_CONST, {.dbl = SPDIF_FLAG_BIGENDIAN}, 0, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM, "spdif_flags" },
91 { "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, {.dbl = 0}, 0, 768000, AV_OPT_FLAG_ENCODING_PARAM },
92 { "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, {.dbl = 60}, -1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
93 { NULL },
94 };
95 
96 static const AVClass class = {
97  .class_name = "spdif",
98  .item_name = av_default_item_name,
99  .option = options,
101 };
102 
104 {
105  IEC61937Context *ctx = s->priv_data;
106  int bitstream_mode = pkt->data[5] & 0x7;
107 
108  ctx->data_type = IEC61937_AC3 | (bitstream_mode << 8);
109  ctx->pkt_offset = AC3_FRAME_SIZE << 2;
110  return 0;
111 }
112 
114 {
115  IEC61937Context *ctx = s->priv_data;
116  static const uint8_t eac3_repeat[4] = {6, 3, 2, 1};
117  int repeat = 1;
118 
119  if ((pkt->data[4] & 0xc0) != 0xc0) /* fscod */
120  repeat = eac3_repeat[(pkt->data[4] & 0x30) >> 4]; /* numblkscod */
121 
122  ctx->hd_buf = av_fast_realloc(ctx->hd_buf, &ctx->hd_buf_size, ctx->hd_buf_filled + pkt->size);
123  if (!ctx->hd_buf)
124  return AVERROR(ENOMEM);
125 
126  memcpy(&ctx->hd_buf[ctx->hd_buf_filled], pkt->data, pkt->size);
127 
128  ctx->hd_buf_filled += pkt->size;
129  if (++ctx->hd_buf_count < repeat){
130  ctx->pkt_offset = 0;
131  return 0;
132  }
133  ctx->data_type = IEC61937_EAC3;
134  ctx->pkt_offset = 24576;
135  ctx->out_buf = ctx->hd_buf;
136  ctx->out_bytes = ctx->hd_buf_filled;
137  ctx->length_code = ctx->hd_buf_filled;
138 
139  ctx->hd_buf_count = 0;
140  ctx->hd_buf_filled = 0;
141  return 0;
142 }
143 
144 /*
145  * DTS type IV (DTS-HD) can be transmitted with various frame repetition
146  * periods; longer repetition periods allow for longer packets and therefore
147  * higher bitrate. Longer repetition periods mean that the constant bitrate of
148  * the outputted IEC 61937 stream is higher.
149  * The repetition period is measured in IEC 60958 frames (4 bytes).
150  */
151 static int spdif_dts4_subtype(int period)
152 {
153  switch (period) {
154  case 512: return 0x0;
155  case 1024: return 0x1;
156  case 2048: return 0x2;
157  case 4096: return 0x3;
158  case 8192: return 0x4;
159  case 16384: return 0x5;
160  }
161  return -1;
162 }
163 
164 static int spdif_header_dts4(AVFormatContext *s, AVPacket *pkt, int core_size,
165  int sample_rate, int blocks)
166 {
167  IEC61937Context *ctx = s->priv_data;
168  static const char dtshd_start_code[10] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xfe, 0xfe };
169  int pkt_size = pkt->size;
170  int period;
171  int subtype;
172 
173  if (!core_size) {
174  av_log(s, AV_LOG_ERROR, "HD mode not supported for this format\n");
175  return AVERROR(EINVAL);
176  }
177 
178  if (!sample_rate) {
179  av_log(s, AV_LOG_ERROR, "Unknown DTS sample rate for HD\n");
180  return AVERROR_INVALIDDATA;
181  }
182 
183  period = ctx->dtshd_rate * (blocks << 5) / sample_rate;
184  subtype = spdif_dts4_subtype(period);
185 
186  if (subtype < 0) {
187  av_log(s, AV_LOG_ERROR, "Specified HD rate of %d Hz would require an "
188  "impossible repetition period of %d for the current DTS stream"
189  " (blocks = %d, sample rate = %d)\n", ctx->dtshd_rate, period,
190  blocks << 5, sample_rate);
191  return AVERROR(EINVAL);
192  }
193 
194  /* set pkt_offset and DTS IV subtype according to the requested output
195  * rate */
196  ctx->pkt_offset = period * 4;
197  ctx->data_type = IEC61937_DTSHD | subtype << 8;
198 
199  /* If the bitrate is too high for transmitting at the selected
200  * repetition period setting, strip DTS-HD until a good amount
201  * of consecutive non-overflowing HD frames have been observed.
202  * This generally only happens if the caller is cramming a Master
203  * Audio stream into 192kHz IEC 60958 (which may or may not fit). */
204  if (sizeof(dtshd_start_code) + 2 + pkt_size
205  > ctx->pkt_offset - BURST_HEADER_SIZE && core_size) {
206  if (!ctx->dtshd_skip)
207  av_log(s, AV_LOG_WARNING, "DTS-HD bitrate too high, "
208  "temporarily sending core only\n");
209  if (ctx->dtshd_fallback > 0)
210  ctx->dtshd_skip = sample_rate * ctx->dtshd_fallback / (blocks << 5);
211  else
212  /* skip permanently (dtshd_fallback == -1) or just once
213  * (dtshd_fallback == 0) */
214  ctx->dtshd_skip = 1;
215  }
216  if (ctx->dtshd_skip && core_size) {
217  pkt_size = core_size;
218  if (ctx->dtshd_fallback >= 0)
219  --ctx->dtshd_skip;
220  }
221 
222  ctx->out_bytes = sizeof(dtshd_start_code) + 2 + pkt_size;
223 
224  /* Align so that (length_code & 0xf) == 0x8. This is reportedly needed
225  * with some receivers, but the exact requirement is unconfirmed. */
226  ctx->length_code = FFALIGN(ctx->out_bytes + 0x8, 0x10) - 0x8;
227 
228  av_fast_malloc(&ctx->hd_buf, &ctx->hd_buf_size, ctx->out_bytes);
229  if (!ctx->hd_buf)
230  return AVERROR(ENOMEM);
231 
232  ctx->out_buf = ctx->hd_buf;
233 
234  memcpy(ctx->hd_buf, dtshd_start_code, sizeof(dtshd_start_code));
235  AV_WB16(ctx->hd_buf + sizeof(dtshd_start_code), pkt_size);
236  memcpy(ctx->hd_buf + sizeof(dtshd_start_code) + 2, pkt->data, pkt_size);
237 
238  return 0;
239 }
240 
242 {
243  IEC61937Context *ctx = s->priv_data;
244  uint32_t syncword_dts = AV_RB32(pkt->data);
245  int blocks;
246  int sample_rate = 0;
247  int core_size = 0;
248 
249  if (pkt->size < 9)
250  return AVERROR_INVALIDDATA;
251 
252  switch (syncword_dts) {
253  case DCA_MARKER_RAW_BE:
254  blocks = (AV_RB16(pkt->data + 4) >> 2) & 0x7f;
255  core_size = ((AV_RB24(pkt->data + 5) >> 4) & 0x3fff) + 1;
256  sample_rate = dca_sample_rates[(pkt->data[8] >> 2) & 0x0f];
257  break;
258  case DCA_MARKER_RAW_LE:
259  blocks = (AV_RL16(pkt->data + 4) >> 2) & 0x7f;
260  ctx->extra_bswap = 1;
261  break;
262  case DCA_MARKER_14B_BE:
263  blocks =
264  (((pkt->data[5] & 0x07) << 4) | ((pkt->data[6] & 0x3f) >> 2));
265  break;
266  case DCA_MARKER_14B_LE:
267  blocks =
268  (((pkt->data[4] & 0x07) << 4) | ((pkt->data[7] & 0x3f) >> 2));
269  ctx->extra_bswap = 1;
270  break;
271  case DCA_HD_MARKER:
272  /* We only handle HD frames that are paired with core. However,
273  sometimes DTS-HD streams with core have a stray HD frame without
274  core in the beginning of the stream. */
275  av_log(s, AV_LOG_ERROR, "stray DTS-HD frame\n");
276  return AVERROR_INVALIDDATA;
277  default:
278  av_log(s, AV_LOG_ERROR, "bad DTS syncword 0x%x\n", syncword_dts);
279  return AVERROR_INVALIDDATA;
280  }
281  blocks++;
282 
283  if (ctx->dtshd_rate)
284  /* DTS type IV output requested */
285  return spdif_header_dts4(s, pkt, core_size, sample_rate, blocks);
286 
287  switch (blocks) {
288  case 512 >> 5: ctx->data_type = IEC61937_DTS1; break;
289  case 1024 >> 5: ctx->data_type = IEC61937_DTS2; break;
290  case 2048 >> 5: ctx->data_type = IEC61937_DTS3; break;
291  default:
292  av_log(s, AV_LOG_ERROR, "%i samples in DTS frame not supported\n",
293  blocks << 5);
294  return AVERROR(ENOSYS);
295  }
296 
297  /* discard extraneous data by default */
298  if (core_size && core_size < pkt->size) {
299  ctx->out_bytes = core_size;
300  ctx->length_code = core_size << 3;
301  }
302 
303  ctx->pkt_offset = blocks << 7;
304 
305  if (ctx->out_bytes == ctx->pkt_offset) {
306  /* The DTS stream fits exactly into the output stream, so skip the
307  * preamble as it would not fit in there. This is the case for dts
308  * discs and dts-in-wav. */
309  ctx->use_preamble = 0;
310  } else if (ctx->out_bytes > ctx->pkt_offset - BURST_HEADER_SIZE) {
311  av_log_ask_for_sample(s, "Unrecognized large DTS frame.");
312  /* This will fail with a "bitrate too high" in the caller */
313  }
314 
315  return 0;
316 }
317 
318 static const enum IEC61937DataType mpeg_data_type[2][3] = {
319  // LAYER1 LAYER2 LAYER3
321  { IEC61937_MPEG1_LAYER1, IEC61937_MPEG1_LAYER23, IEC61937_MPEG1_LAYER23 }, //MPEG1
322 };
323 
325 {
326  IEC61937Context *ctx = s->priv_data;
327  int version = (pkt->data[1] >> 3) & 3;
328  int layer = 3 - ((pkt->data[1] >> 1) & 3);
329  int extension = pkt->data[2] & 1;
330 
331  if (layer == 3 || version == 1) {
332  av_log(s, AV_LOG_ERROR, "Wrong MPEG file format\n");
333  return AVERROR_INVALIDDATA;
334  }
335  av_log(s, AV_LOG_DEBUG, "version: %i layer: %i extension: %i\n", version, layer, extension);
336  if (version == 2 && extension) {
338  ctx->pkt_offset = 4608;
339  } else {
340  ctx->data_type = mpeg_data_type [version & 1][layer];
341  ctx->pkt_offset = spdif_mpeg_pkt_offset[version & 1][layer];
342  }
343  // TODO Data type dependant info (normal/karaoke, dynamic range control)
344  return 0;
345 }
346 
348 {
349  IEC61937Context *ctx = s->priv_data;
350  AACADTSHeaderInfo hdr;
351  GetBitContext gbc;
352  int ret;
353 
354  init_get_bits(&gbc, pkt->data, AAC_ADTS_HEADER_SIZE * 8);
355  ret = avpriv_aac_parse_header(&gbc, &hdr);
356  if (ret < 0) {
357  av_log(s, AV_LOG_ERROR, "Wrong AAC file format\n");
358  return AVERROR_INVALIDDATA;
359  }
360 
361  ctx->pkt_offset = hdr.samples << 2;
362  switch (hdr.num_aac_frames) {
363  case 1:
365  break;
366  case 2:
368  break;
369  case 4:
371  break;
372  default:
373  av_log(s, AV_LOG_ERROR, "%i samples in AAC frame not supported\n",
374  hdr.samples);
375  return AVERROR(EINVAL);
376  }
377  //TODO Data type dependent info (LC profile/SBR)
378  return 0;
379 }
380 
381 
382 /*
383  * It seems Dolby TrueHD frames have to be encapsulated in MAT frames before
384  * they can be encapsulated in IEC 61937.
385  * Here we encapsulate 24 TrueHD frames in a single MAT frame, padding them
386  * to achieve constant rate.
387  * The actual format of a MAT frame is unknown, but the below seems to work.
388  * However, it seems it is not actually necessary for the 24 TrueHD frames to
389  * be in an exact alignment with the MAT frame.
390  */
391 #define MAT_FRAME_SIZE 61424
392 #define TRUEHD_FRAME_OFFSET 2560
393 #define MAT_MIDDLE_CODE_OFFSET -4
394 
396 {
397  IEC61937Context *ctx = s->priv_data;
398  int mat_code_length = 0;
399  const char mat_end_code[16] = { 0xC3, 0xC2, 0xC0, 0xC4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x97, 0x11 };
400 
401  if (!ctx->hd_buf_count) {
402  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 };
403  mat_code_length = sizeof(mat_start_code) + BURST_HEADER_SIZE;
404  memcpy(ctx->hd_buf, mat_start_code, sizeof(mat_start_code));
405 
406  } else if (ctx->hd_buf_count == 12) {
407  const char mat_middle_code[12] = { 0xC3, 0xC1, 0x42, 0x49, 0x3B, 0xFA, 0x82, 0x83, 0x49, 0x80, 0x77, 0xE0 };
408  mat_code_length = sizeof(mat_middle_code) + MAT_MIDDLE_CODE_OFFSET;
410  mat_middle_code, sizeof(mat_middle_code));
411  }
412 
413  if (pkt->size > TRUEHD_FRAME_OFFSET - mat_code_length) {
414  /* if such frames exist, we'd need some more complex logic to
415  * distribute the TrueHD frames in the MAT frame */
416  av_log(s, AV_LOG_ERROR, "TrueHD frame too big, %d bytes\n", pkt->size);
418  return AVERROR_INVALIDDATA;
419  }
420 
421  memcpy(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length],
422  pkt->data, pkt->size);
423  memset(&ctx->hd_buf[ctx->hd_buf_count * TRUEHD_FRAME_OFFSET - BURST_HEADER_SIZE + mat_code_length + pkt->size],
424  0, TRUEHD_FRAME_OFFSET - pkt->size - mat_code_length);
425 
426  if (++ctx->hd_buf_count < 24){
427  ctx->pkt_offset = 0;
428  return 0;
429  }
430  memcpy(&ctx->hd_buf[MAT_FRAME_SIZE - sizeof(mat_end_code)], mat_end_code, sizeof(mat_end_code));
431  ctx->hd_buf_count = 0;
432 
433  ctx->data_type = IEC61937_TRUEHD;
434  ctx->pkt_offset = 61440;
435  ctx->out_buf = ctx->hd_buf;
436  ctx->out_bytes = MAT_FRAME_SIZE;
438  return 0;
439 }
440 
442 {
443  IEC61937Context *ctx = s->priv_data;
444 
445  switch (s->streams[0]->codec->codec_id) {
446  case CODEC_ID_AC3:
448  break;
449  case CODEC_ID_EAC3:
451  break;
452  case CODEC_ID_MP1:
453  case CODEC_ID_MP2:
454  case CODEC_ID_MP3:
456  break;
457  case CODEC_ID_DTS:
459  break;
460  case CODEC_ID_AAC:
462  break;
463  case CODEC_ID_TRUEHD:
466  if (!ctx->hd_buf)
467  return AVERROR(ENOMEM);
468  break;
469  default:
470  av_log(s, AV_LOG_ERROR, "codec not supported\n");
471  return AVERROR_PATCHWELCOME;
472  }
473  return 0;
474 }
475 
477 {
478  IEC61937Context *ctx = s->priv_data;
479  av_freep(&ctx->buffer);
480  av_freep(&ctx->hd_buf);
481  return 0;
482 }
483 
485  AVIOContext *pb, unsigned int val)
486 {
488  avio_wb16(pb, val);
489  else
490  avio_wl16(pb, val);
491 }
492 
493 static int spdif_write_packet(struct AVFormatContext *s, AVPacket *pkt)
494 {
495  IEC61937Context *ctx = s->priv_data;
496  int ret, padding;
497 
498  ctx->out_buf = pkt->data;
499  ctx->out_bytes = pkt->size;
500  ctx->length_code = FFALIGN(pkt->size, 2) << 3;
501  ctx->use_preamble = 1;
502  ctx->extra_bswap = 0;
503 
504  ret = ctx->header_info(s, pkt);
505  if (ret < 0)
506  return ret;
507  if (!ctx->pkt_offset)
508  return 0;
509 
510  padding = (ctx->pkt_offset - ctx->use_preamble * BURST_HEADER_SIZE - ctx->out_bytes) & ~1;
511  if (padding < 0) {
512  av_log(s, AV_LOG_ERROR, "bitrate is too high\n");
513  return AVERROR(EINVAL);
514  }
515 
516  if (ctx->use_preamble) {
517  spdif_put_16(ctx, s->pb, SYNCWORD1); //Pa
518  spdif_put_16(ctx, s->pb, SYNCWORD2); //Pb
519  spdif_put_16(ctx, s->pb, ctx->data_type); //Pc
520  spdif_put_16(ctx, s->pb, ctx->length_code);//Pd
521  }
522 
523  if (ctx->extra_bswap ^ (ctx->spdif_flags & SPDIF_FLAG_BIGENDIAN)) {
524  avio_write(s->pb, ctx->out_buf, ctx->out_bytes & ~1);
525  } else {
527  if (!ctx->buffer)
528  return AVERROR(ENOMEM);
529  ff_spdif_bswap_buf16((uint16_t *)ctx->buffer, (uint16_t *)ctx->out_buf, ctx->out_bytes >> 1);
530  avio_write(s->pb, ctx->buffer, ctx->out_bytes & ~1);
531  }
532 
533  /* a final lone byte has to be MSB aligned */
534  if (ctx->out_bytes & 1)
535  spdif_put_16(ctx, s->pb, ctx->out_buf[ctx->out_bytes - 1] << 8);
536 
537  ffio_fill(s->pb, 0, padding);
538 
539  av_log(s, AV_LOG_DEBUG, "type=%x len=%i pkt_offset=%i\n",
540  ctx->data_type, ctx->out_bytes, ctx->pkt_offset);
541 
542  avio_flush(s->pb);
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 = CODEC_ID_AC3,
552  .video_codec = CODEC_ID_NONE,
557  .priv_class = &class,
558 };