Libav
dv.c
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1 /*
2  * General DV muxer/demuxer
3  * Copyright (c) 2003 Roman Shaposhnik
4  *
5  * Many thanks to Dan Dennedy <dan@dennedy.org> for providing wealth
6  * of DV technical info.
7  *
8  * Raw DV format
9  * Copyright (c) 2002 Fabrice Bellard
10  *
11  * 50 Mbps (DVCPRO50) and 100 Mbps (DVCPRO HD) support
12  * Copyright (c) 2006 Daniel Maas <dmaas@maasdigital.com>
13  * Funded by BBC Research & Development
14  *
15  * This file is part of Libav.
16  *
17  * Libav is free software; you can redistribute it and/or
18  * modify it under the terms of the GNU Lesser General Public
19  * License as published by the Free Software Foundation; either
20  * version 2.1 of the License, or (at your option) any later version.
21  *
22  * Libav is distributed in the hope that it will be useful,
23  * but WITHOUT ANY WARRANTY; without even the implied warranty of
24  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
25  * Lesser General Public License for more details.
26  *
27  * You should have received a copy of the GNU Lesser General Public
28  * License along with Libav; if not, write to the Free Software
29  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30  */
31 #include <time.h>
32 #include "avformat.h"
33 #include "internal.h"
34 #include "libavcodec/dv_profile.h"
35 #include "libavcodec/dv.h"
37 #include "libavutil/intreadwrite.h"
38 #include "libavutil/mathematics.h"
39 #include "dv.h"
40 
42  const DVprofile* sys; /* Current DV profile. E.g.: 525/60, 625/50 */
47  uint8_t audio_buf[4][8192];
48  int ach;
49  int frames;
50  uint64_t abytes;
51 };
52 
53 static inline uint16_t dv_audio_12to16(uint16_t sample)
54 {
55  uint16_t shift, result;
56 
57  sample = (sample < 0x800) ? sample : sample | 0xf000;
58  shift = (sample & 0xf00) >> 8;
59 
60  if (shift < 0x2 || shift > 0xd) {
61  result = sample;
62  } else if (shift < 0x8) {
63  shift--;
64  result = (sample - (256 * shift)) << shift;
65  } else {
66  shift = 0xe - shift;
67  result = ((sample + ((256 * shift) + 1)) << shift) - 1;
68  }
69 
70  return result;
71 }
72 
73 /*
74  * This is the dumbest implementation of all -- it simply looks at
75  * a fixed offset and if pack isn't there -- fails. We might want
76  * to have a fallback mechanism for complete search of missing packs.
77  */
78 static const uint8_t *dv_extract_pack(uint8_t *frame, enum dv_pack_type t)
79 {
80  int offs;
81 
82  switch (t) {
83  case dv_audio_source:
84  offs = (80 * 6 + 80 * 16 * 3 + 3);
85  break;
86  case dv_audio_control:
87  offs = (80 * 6 + 80 * 16 * 4 + 3);
88  break;
89  case dv_video_control:
90  offs = (80 * 5 + 48 + 5);
91  break;
92  default:
93  return NULL;
94  }
95 
96  return frame[offs] == t ? &frame[offs] : NULL;
97 }
98 
99 static const int dv_audio_frequency[3] = {
100  48000, 44100, 32000,
101 };
102 
103 /*
104  * There's a couple of assumptions being made here:
105  * 1. By default we silence erroneous (0x8000/16bit 0x800/12bit) audio samples.
106  * We can pass them upwards when libavcodec will be ready to deal with them.
107  * 2. We don't do software emphasis.
108  * 3. Audio is always returned as 16bit linear samples: 12bit nonlinear samples
109  * are converted into 16bit linear ones.
110  */
111 static int dv_extract_audio(uint8_t *frame, uint8_t **ppcm,
112  const DVprofile *sys)
113 {
114  int size, chan, i, j, d, of, smpls, freq, quant, half_ch;
115  uint16_t lc, rc;
116  const uint8_t *as_pack;
117  uint8_t *pcm, ipcm;
118 
119  as_pack = dv_extract_pack(frame, dv_audio_source);
120  if (!as_pack) /* No audio ? */
121  return 0;
122 
123  smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */
124  freq = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
125  quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
126 
127  if (quant > 1)
128  return -1; /* unsupported quantization */
129 
130  if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency))
131  return AVERROR_INVALIDDATA;
132 
133  size = (sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
134  half_ch = sys->difseg_size / 2;
135 
136  /* We work with 720p frames split in half, thus even frames have
137  * channels 0,1 and odd 2,3. */
138  ipcm = (sys->height == 720 && !(frame[1] & 0x0C)) ? 2 : 0;
139 
140  /* for each DIF channel */
141  for (chan = 0; chan < sys->n_difchan; chan++) {
142  /* next stereo channel (50Mbps and 100Mbps only) */
143  pcm = ppcm[ipcm++];
144  if (!pcm)
145  break;
146 
147  /* for each DIF segment */
148  for (i = 0; i < sys->difseg_size; i++) {
149  frame += 6 * 80; /* skip DIF segment header */
150  if (quant == 1 && i == half_ch) {
151  /* next stereo channel (12bit mode only) */
152  pcm = ppcm[ipcm++];
153  if (!pcm)
154  break;
155  }
156 
157  /* for each AV sequence */
158  for (j = 0; j < 9; j++) {
159  for (d = 8; d < 80; d += 2) {
160  if (quant == 0) { /* 16bit quantization */
161  of = sys->audio_shuffle[i][j] +
162  (d - 8) / 2 * sys->audio_stride;
163  if (of * 2 >= size)
164  continue;
165 
166  /* FIXME: maybe we have to admit that DV is a
167  * big-endian PCM */
168  pcm[of * 2] = frame[d + 1];
169  pcm[of * 2 + 1] = frame[d];
170 
171  if (pcm[of * 2 + 1] == 0x80 && pcm[of * 2] == 0x00)
172  pcm[of * 2 + 1] = 0;
173  } else { /* 12bit quantization */
174  lc = ((uint16_t)frame[d] << 4) |
175  ((uint16_t)frame[d + 2] >> 4);
176  rc = ((uint16_t)frame[d + 1] << 4) |
177  ((uint16_t)frame[d + 2] & 0x0f);
178  lc = (lc == 0x800 ? 0 : dv_audio_12to16(lc));
179  rc = (rc == 0x800 ? 0 : dv_audio_12to16(rc));
180 
181  of = sys->audio_shuffle[i % half_ch][j] +
182  (d - 8) / 3 * sys->audio_stride;
183  if (of * 2 >= size)
184  continue;
185 
186  /* FIXME: maybe we have to admit that DV is a
187  * big-endian PCM */
188  pcm[of * 2] = lc & 0xff;
189  pcm[of * 2 + 1] = lc >> 8;
190  of = sys->audio_shuffle[i % half_ch + half_ch][j] +
191  (d - 8) / 3 * sys->audio_stride;
192  /* FIXME: maybe we have to admit that DV is a
193  * big-endian PCM */
194  pcm[of * 2] = rc & 0xff;
195  pcm[of * 2 + 1] = rc >> 8;
196  ++d;
197  }
198  }
199 
200  frame += 16 * 80; /* 15 Video DIFs + 1 Audio DIF */
201  }
202  }
203  }
204 
205  return size;
206 }
207 
209 {
210  const uint8_t *as_pack;
211  int freq, stype, smpls, quant, i, ach;
212 
213  as_pack = dv_extract_pack(frame, dv_audio_source);
214  if (!as_pack || !c->sys) { /* No audio ? */
215  c->ach = 0;
216  return 0;
217  }
218 
219  smpls = as_pack[1] & 0x3f; /* samples in this frame - min. samples */
220  freq = as_pack[4] >> 3 & 0x07; /* 0 - 48kHz, 1 - 44,1kHz, 2 - 32kHz */
221  stype = as_pack[3] & 0x1f; /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
222  quant = as_pack[4] & 0x07; /* 0 - 16bit linear, 1 - 12bit nonlinear */
223 
224  if (freq >= FF_ARRAY_ELEMS(dv_audio_frequency)) {
226  "Unrecognized audio sample rate index (%d)\n", freq);
227  return 0;
228  }
229 
230  if (stype > 3) {
231  av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
232  c->ach = 0;
233  return 0;
234  }
235 
236  /* note: ach counts PAIRS of channels (i.e. stereo channels) */
237  ach = ((int[4]) { 1, 0, 2, 4 })[stype];
238  if (ach == 1 && quant && freq == 2)
239  ach = 2;
240 
241  /* Dynamic handling of the audio streams in DV */
242  for (i = 0; i < ach; i++) {
243  if (!c->ast[i]) {
244  c->ast[i] = avformat_new_stream(c->fctx, NULL);
245  if (!c->ast[i])
246  break;
247  avpriv_set_pts_info(c->ast[i], 64, 1, 30000);
250 
251  av_init_packet(&c->audio_pkt[i]);
252  c->audio_pkt[i].size = 0;
253  c->audio_pkt[i].data = c->audio_buf[i];
254  c->audio_pkt[i].stream_index = c->ast[i]->index;
256  }
257  c->ast[i]->codec->sample_rate = dv_audio_frequency[freq];
258  c->ast[i]->codec->channels = 2;
260  c->ast[i]->codec->bit_rate = 2 * dv_audio_frequency[freq] * 16;
261  c->ast[i]->start_time = 0;
262  }
263  c->ach = i;
264 
265  return (c->sys->audio_min_samples[freq] + smpls) * 4; /* 2ch, 2bytes */
266 }
267 
269 {
270  const uint8_t *vsc_pack;
271  AVCodecContext *avctx;
272  int apt, is16_9;
273  int size = 0;
274 
275  if (c->sys) {
276  avctx = c->vst->codec;
277 
279  c->sys->time_base.den);
280  avctx->time_base = c->sys->time_base;
281  if (!avctx->width) {
282  avctx->width = c->sys->width;
283  avctx->height = c->sys->height;
284  }
285  avctx->pix_fmt = c->sys->pix_fmt;
286 
287  /* finding out SAR is a little bit messy */
288  vsc_pack = dv_extract_pack(frame, dv_video_control);
289  apt = frame[4] & 0x07;
290  is16_9 = (vsc_pack && ((vsc_pack[2] & 0x07) == 0x02 ||
291  (!apt && (vsc_pack[2] & 0x07) == 0x07)));
292  c->vst->sample_aspect_ratio = c->sys->sar[is16_9];
293  avctx->bit_rate = av_rescale_q(c->sys->frame_size,
294  (AVRational) { 8, 1 },
295  c->sys->time_base);
296  size = c->sys->frame_size;
297  }
298  return size;
299 }
300 
301 /* The following 3 functions constitute our interface to the world */
302 
304 {
305  DVDemuxContext *c;
306 
307  c = av_mallocz(sizeof(DVDemuxContext));
308  if (!c)
309  return NULL;
310 
311  c->vst = avformat_new_stream(s, NULL);
312  if (!c->vst) {
313  av_free(c);
314  return NULL;
315  }
316 
317  c->fctx = s;
320  c->vst->codec->bit_rate = 25000000;
321  c->vst->start_time = 0;
322 
323  return c;
324 }
325 
327 {
328  int size = -1;
329  int i;
330 
331  for (i = 0; i < c->ach; i++) {
332  if (c->ast[i] && c->audio_pkt[i].size) {
333  *pkt = c->audio_pkt[i];
334  c->audio_pkt[i].size = 0;
335  size = pkt->size;
336  break;
337  }
338  }
339 
340  return size;
341 }
342 
344  uint8_t *buf, int buf_size)
345 {
346  int size, i;
347  uint8_t *ppcm[5] = { 0 };
348 
349  if (buf_size < DV_PROFILE_BYTES ||
350  !(c->sys = avpriv_dv_frame_profile(c->sys, buf, buf_size)) ||
351  buf_size < c->sys->frame_size) {
352  return -1; /* Broken frame, or not enough data */
353  }
354 
355  /* Queueing audio packet */
356  /* FIXME: in case of no audio/bad audio we have to do something */
357  size = dv_extract_audio_info(c, buf);
358  for (i = 0; i < c->ach; i++) {
359  c->audio_pkt[i].size = size;
360  c->audio_pkt[i].pts = c->abytes * 30000 * 8 /
361  c->ast[i]->codec->bit_rate;
362  ppcm[i] = c->audio_buf[i];
363  }
364  if (c->ach)
365  dv_extract_audio(buf, ppcm, c->sys);
366 
367  /* We work with 720p frames split in half, thus even frames have
368  * channels 0,1 and odd 2,3. */
369  if (c->sys->height == 720) {
370  if (buf[1] & 0x0C) {
371  c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
372  } else {
373  c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
374  c->abytes += size;
375  }
376  } else {
377  c->abytes += size;
378  }
379 
380  /* Now it's time to return video packet */
381  size = dv_extract_video_info(c, buf);
382  av_init_packet(pkt);
383  pkt->data = buf;
384  pkt->size = size;
385  pkt->flags |= AV_PKT_FLAG_KEY;
386  pkt->stream_index = c->vst->index;
387  pkt->pts = c->frames;
388 
389  c->frames++;
390 
391  return size;
392 }
393 
395  int64_t timestamp, int flags)
396 {
397  // FIXME: sys may be wrong if last dv_read_packet() failed (buffer is junk)
398  const DVprofile *sys = avpriv_dv_codec_profile(c->vst->codec);
399  int64_t offset;
400  int64_t size = avio_size(s->pb) - s->data_offset;
401  int64_t max_offset = ((size - 1) / sys->frame_size) * sys->frame_size;
402 
403  offset = sys->frame_size * timestamp;
404 
405  if (size >= 0 && offset > max_offset)
406  offset = max_offset;
407  else if (offset < 0)
408  offset = 0;
409 
410  return offset + s->data_offset;
411 }
412 
413 void ff_dv_offset_reset(DVDemuxContext *c, int64_t frame_offset)
414 {
415  c->frames = frame_offset;
416  if (c->ach)
417  c->abytes = av_rescale_q(c->frames, c->sys->time_base,
418  (AVRational) { 8, c->ast[0]->codec->bit_rate });
419 
420  c->audio_pkt[0].size = c->audio_pkt[1].size = 0;
421  c->audio_pkt[2].size = c->audio_pkt[3].size = 0;
422 }
423 
424 /************************************************************
425  * Implementation of the easiest DV storage of all -- raw DV.
426  ************************************************************/
427 
428 typedef struct RawDVContext {
431 } RawDVContext;
432 
434 {
435  unsigned state, marker_pos = 0;
436  RawDVContext *c = s->priv_data;
437 
439  if (!c->dv_demux)
440  return -1;
441 
442  state = avio_rb32(s->pb);
443  while ((state & 0xffffff7f) != 0x1f07003f) {
444  if (s->pb->eof_reached) {
445  av_log(s, AV_LOG_ERROR, "Cannot find DV header.\n");
446  return -1;
447  }
448  if (state == 0x003f0700 || state == 0xff3f0700)
449  marker_pos = avio_tell(s->pb);
450  if (state == 0xff3f0701 && avio_tell(s->pb) - marker_pos == 80) {
451  avio_seek(s->pb, -163, SEEK_CUR);
452  state = avio_rb32(s->pb);
453  break;
454  }
455  state = (state << 8) | avio_r8(s->pb);
456  }
457  AV_WB32(c->buf, state);
458 
459  if (avio_read(s->pb, c->buf + 4, DV_PROFILE_BYTES - 4) <= 0 ||
460  avio_seek(s->pb, -DV_PROFILE_BYTES, SEEK_CUR) < 0)
461  return AVERROR(EIO);
462 
464  c->buf,
466  if (!c->dv_demux->sys) {
467  av_log(s, AV_LOG_ERROR,
468  "Can't determine profile of DV input stream.\n");
469  return -1;
470  }
471 
473  (AVRational) { 8, 1 },
474  c->dv_demux->sys->time_base);
475 
476  return 0;
477 }
478 
480 {
481  int size;
482  RawDVContext *c = s->priv_data;
483 
484  size = avpriv_dv_get_packet(c->dv_demux, pkt);
485 
486  if (size < 0) {
487  if (!c->dv_demux->sys)
488  return AVERROR(EIO);
489  size = c->dv_demux->sys->frame_size;
490  if (avio_read(s->pb, c->buf, size) <= 0)
491  return AVERROR(EIO);
492 
493  size = avpriv_dv_produce_packet(c->dv_demux, pkt, c->buf, size);
494  }
495 
496  return size;
497 }
498 
499 static int dv_read_seek(AVFormatContext *s, int stream_index,
500  int64_t timestamp, int flags)
501 {
502  RawDVContext *r = s->priv_data;
503  DVDemuxContext *c = r->dv_demux;
504  int64_t offset = dv_frame_offset(s, c, timestamp, flags);
505 
506  if (avio_seek(s->pb, offset, SEEK_SET) < 0)
507  return -1;
508 
509  ff_dv_offset_reset(c, offset / c->sys->frame_size);
510  return 0;
511 }
512 
514 {
515  RawDVContext *c = s->priv_data;
516  av_free(c->dv_demux);
517  return 0;
518 }
519 
520 static int dv_probe(AVProbeData *p)
521 {
522  unsigned state, marker_pos = 0;
523  int i;
524  int matches = 0;
525  int secondary_matches = 0;
526 
527  if (p->buf_size < 5)
528  return 0;
529 
530  state = AV_RB32(p->buf);
531  for (i = 4; i < p->buf_size; i++) {
532  if ((state & 0xffffff7f) == 0x1f07003f)
533  matches++;
534  // any section header, also with seq/chan num != 0,
535  // should appear around every 12000 bytes, at least 10 per frame
536  if ((state & 0xff07ff7f) == 0x1f07003f)
537  secondary_matches++;
538  if (state == 0x003f0700 || state == 0xff3f0700)
539  marker_pos = i;
540  if (state == 0xff3f0701 && i - marker_pos == 80)
541  matches++;
542  state = (state << 8) | p->buf[i];
543  }
544 
545  if (matches && p->buf_size / matches < 1024 * 1024) {
546  if (matches > 4 ||
547  (secondary_matches >= 10 &&
548  p->buf_size / secondary_matches < 24000))
549  // not max to avoid dv in mov to match
550  return AVPROBE_SCORE_MAX * 3 / 4;
551  return AVPROBE_SCORE_MAX / 4;
552  }
553  return 0;
554 }
555 
556 #if CONFIG_DV_DEMUXER
557 AVInputFormat ff_dv_demuxer = {
558  .name = "dv",
559  .long_name = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
560  .priv_data_size = sizeof(RawDVContext),
561  .read_probe = dv_probe,
566  .extensions = "dv,dif",
567 };
568 #endif