FFmpeg
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ffmdec.c
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1 /*
2  * FFM (ffserver live feed) demuxer
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <stdint.h>
23 
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/intfloat.h"
26 #include "avformat.h"
27 #include "internal.h"
28 #include "ffm.h"
29 #include "avio_internal.h"
30 
32 {
33  FFMContext *ffm = s->priv_data;
34  int64_t pos, avail_size;
35  int len;
36 
37  len = ffm->packet_end - ffm->packet_ptr;
38  if (size <= len)
39  return 1;
40  pos = avio_tell(s->pb);
41  if (!ffm->write_index) {
42  if (pos == ffm->file_size)
43  return AVERROR_EOF;
44  avail_size = ffm->file_size - pos;
45  } else {
46  if (pos == ffm->write_index) {
47  /* exactly at the end of stream */
48  return AVERROR(EAGAIN);
49  } else if (pos < ffm->write_index) {
50  avail_size = ffm->write_index - pos;
51  } else {
52  avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
53  }
54  }
55  avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
56  if (size <= avail_size)
57  return 1;
58  else
59  return AVERROR(EAGAIN);
60 }
61 
62 static int ffm_resync(AVFormatContext *s, int state)
63 {
64  av_log(s, AV_LOG_ERROR, "resyncing\n");
65  while (state != PACKET_ID) {
66  if (avio_feof(s->pb)) {
67  av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");
68  return -1;
69  }
70  state = (state << 8) | avio_r8(s->pb);
71  }
72  return 0;
73 }
74 
75 /* first is true if we read the frame header */
77  uint8_t *buf, int size, int header)
78 {
79  FFMContext *ffm = s->priv_data;
80  AVIOContext *pb = s->pb;
81  int len, fill_size, size1, frame_offset, id;
82 
83  size1 = size;
84  while (size > 0) {
85  redo:
86  len = ffm->packet_end - ffm->packet_ptr;
87  if (len < 0)
88  return -1;
89  if (len > size)
90  len = size;
91  if (len == 0) {
92  if (avio_tell(pb) == ffm->file_size)
93  avio_seek(pb, ffm->packet_size, SEEK_SET);
94  retry_read:
95  if (pb->buffer_size != ffm->packet_size) {
96  int64_t tell = avio_tell(pb);
98  avio_seek(pb, tell, SEEK_SET);
99  }
100  id = avio_rb16(pb); /* PACKET_ID */
101  if (id != PACKET_ID)
102  if (ffm_resync(s, id) < 0)
103  return -1;
104  fill_size = avio_rb16(pb);
105  ffm->dts = avio_rb64(pb);
106  frame_offset = avio_rb16(pb);
107  avio_read(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
108  ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
109  if (ffm->packet_end < ffm->packet || frame_offset < 0)
110  return -1;
111  /* if first packet or resynchronization packet, we must
112  handle it specifically */
113  if (ffm->first_packet || (frame_offset & 0x8000)) {
114  if (!frame_offset) {
115  /* This packet has no frame headers in it */
116  if (avio_tell(pb) >= ffm->packet_size * 3LL) {
117  avio_seek(pb, -ffm->packet_size * 2LL, SEEK_CUR);
118  goto retry_read;
119  }
120  /* This is bad, we cannot find a valid frame header */
121  return 0;
122  }
123  ffm->first_packet = 0;
124  if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
125  return -1;
126  ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
127  if (!header)
128  break;
129  } else {
130  ffm->packet_ptr = ffm->packet;
131  }
132  goto redo;
133  }
134  memcpy(buf, ffm->packet_ptr, len);
135  buf += len;
136  ffm->packet_ptr += len;
137  size -= len;
138  header = 0;
139  }
140  return size1 - size;
141 }
142 
143 /* ensure that acutal seeking happens between FFM_PACKET_SIZE
144  and file_size - FFM_PACKET_SIZE */
145 static int64_t ffm_seek1(AVFormatContext *s, int64_t pos1)
146 {
147  FFMContext *ffm = s->priv_data;
148  AVIOContext *pb = s->pb;
149  int64_t pos;
150 
151  pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);
152  pos = FFMAX(pos, FFM_PACKET_SIZE);
153  av_dlog(s, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
154  return avio_seek(pb, pos, SEEK_SET);
155 }
156 
157 static int64_t get_dts(AVFormatContext *s, int64_t pos)
158 {
159  AVIOContext *pb = s->pb;
160  int64_t dts;
161 
162  ffm_seek1(s, pos);
163  avio_skip(pb, 4);
164  dts = avio_rb64(pb);
165  av_dlog(s, "dts=%0.6f\n", dts / 1000000.0);
166  return dts;
167 }
168 
170 {
171  FFMContext *ffm = s->priv_data;
172  AVIOContext *pb = s->pb;
173  int64_t pts;
174  //int64_t orig_write_index = ffm->write_index;
175  int64_t pos_min, pos_max;
176  int64_t pts_start;
177  int64_t ptr = avio_tell(pb);
178 
179 
180  pos_min = 0;
181  pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
182 
183  pts_start = get_dts(s, pos_min);
184 
185  pts = get_dts(s, pos_max);
186 
187  if (pts - 100000 > pts_start)
188  goto end;
189 
191 
192  pts_start = get_dts(s, pos_min);
193 
194  pts = get_dts(s, pos_max);
195 
196  if (pts - 100000 <= pts_start) {
197  while (1) {
198  int64_t newpos;
199  int64_t newpts;
200 
201  newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
202 
203  if (newpos == pos_min)
204  break;
205 
206  newpts = get_dts(s, newpos);
207 
208  if (newpts - 100000 <= pts) {
209  pos_max = newpos;
210  pts = newpts;
211  } else {
212  pos_min = newpos;
213  }
214  }
215  ffm->write_index += pos_max;
216  }
217 
218  end:
219  avio_seek(pb, ptr, SEEK_SET);
220 }
221 
222 
224 {
225  int i;
226 
227  for (i = 0; i < s->nb_streams; i++)
228  av_freep(&s->streams[i]->codec->rc_eq);
229 
230  return 0;
231 }
232 
234 {
235  FFMContext *ffm = s->priv_data;
236  AVStream *st;
237  AVIOContext *pb = s->pb;
238  AVCodecContext *codec;
239 
240  ffm->packet_size = avio_rb32(pb);
241  if (ffm->packet_size != FFM_PACKET_SIZE)
242  goto fail;
243  ffm->write_index = avio_rb64(pb);
244  /* get also filesize */
245  if (pb->seekable) {
246  ffm->file_size = avio_size(pb);
247  if (ffm->write_index && 0)
249  } else {
250  ffm->file_size = (UINT64_C(1) << 63) - 1;
251  }
252 
253  while(!avio_feof(pb)) {
254  unsigned id = avio_rb32(pb);
255  unsigned size = avio_rb32(pb);
256  int64_t next = avio_tell(pb) + size;
257  char rc_eq_buf[128];
258 
259  if(!id)
260  break;
261 
262  switch(id) {
263  case MKBETAG('M', 'A', 'I', 'N'):
264  avio_rb32(pb); /* nb_streams */
265  avio_rb32(pb); /* total bitrate */
266  break;
267  case MKBETAG('C', 'O', 'M', 'M'):
268  st = avformat_new_stream(s, NULL);
269  if (!st)
270  goto fail;
271 
272  avpriv_set_pts_info(st, 64, 1, 1000000);
273 
274  codec = st->codec;
275  /* generic info */
276  codec->codec_id = avio_rb32(pb);
277  codec->codec_type = avio_r8(pb);
278  codec->bit_rate = avio_rb32(pb);
279  codec->flags = avio_rb32(pb);
280  codec->flags2 = avio_rb32(pb);
281  codec->debug = avio_rb32(pb);
282  if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
283  if (ff_get_extradata(codec, pb, avio_rb32(pb)) < 0)
284  return AVERROR(ENOMEM);
285  }
286  avio_seek(pb, next, SEEK_SET);
287  id = avio_rb32(pb);
288  size = avio_rb32(pb);
289  next = avio_tell(pb) + size;
290  switch(id) {
291  case MKBETAG('S', 'T', 'V', 'I'):
292  codec->time_base.num = avio_rb32(pb);
293  codec->time_base.den = avio_rb32(pb);
294  codec->width = avio_rb16(pb);
295  codec->height = avio_rb16(pb);
296  codec->gop_size = avio_rb16(pb);
297  codec->pix_fmt = avio_rb32(pb);
298  codec->qmin = avio_r8(pb);
299  codec->qmax = avio_r8(pb);
300  codec->max_qdiff = avio_r8(pb);
301  codec->qcompress = avio_rb16(pb) / 10000.0;
302  codec->qblur = avio_rb16(pb) / 10000.0;
303  codec->bit_rate_tolerance = avio_rb32(pb);
304  avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));
305  codec->rc_eq = av_strdup(rc_eq_buf);
306  codec->rc_max_rate = avio_rb32(pb);
307  codec->rc_min_rate = avio_rb32(pb);
308  codec->rc_buffer_size = avio_rb32(pb);
309  codec->i_quant_factor = av_int2double(avio_rb64(pb));
310  codec->b_quant_factor = av_int2double(avio_rb64(pb));
311  codec->i_quant_offset = av_int2double(avio_rb64(pb));
312  codec->b_quant_offset = av_int2double(avio_rb64(pb));
313  codec->dct_algo = avio_rb32(pb);
314  codec->strict_std_compliance = avio_rb32(pb);
315  codec->max_b_frames = avio_rb32(pb);
316  codec->mpeg_quant = avio_rb32(pb);
317  codec->intra_dc_precision = avio_rb32(pb);
318  codec->me_method = avio_rb32(pb);
319  codec->mb_decision = avio_rb32(pb);
320  codec->nsse_weight = avio_rb32(pb);
321  codec->frame_skip_cmp = avio_rb32(pb);
323  codec->codec_tag = avio_rb32(pb);
324  codec->thread_count = avio_r8(pb);
325  codec->coder_type = avio_rb32(pb);
326  codec->me_cmp = avio_rb32(pb);
327  codec->me_subpel_quality = avio_rb32(pb);
328  codec->me_range = avio_rb32(pb);
329  codec->keyint_min = avio_rb32(pb);
330  codec->scenechange_threshold = avio_rb32(pb);
331  codec->b_frame_strategy = avio_rb32(pb);
332  codec->qcompress = av_int2double(avio_rb64(pb));
333  codec->qblur = av_int2double(avio_rb64(pb));
334  codec->max_qdiff = avio_rb32(pb);
335  codec->refs = avio_rb32(pb);
336  break;
337  case MKBETAG('S', 'T', 'A', 'U'):
338  codec->sample_rate = avio_rb32(pb);
339  codec->channels = avio_rl16(pb);
340  codec->frame_size = avio_rl16(pb);
341  break;
342  }
343  break;
344  }
345  avio_seek(pb, next, SEEK_SET);
346  }
347 
348  /* get until end of block reached */
349  while ((avio_tell(pb) % ffm->packet_size) != 0)
350  avio_r8(pb);
351 
352  /* init packet demux */
353  ffm->packet_ptr = ffm->packet;
354  ffm->packet_end = ffm->packet;
355  ffm->frame_offset = 0;
356  ffm->dts = 0;
357  ffm->read_state = READ_HEADER;
358  ffm->first_packet = 1;
359  return 0;
360  fail:
361  ffm_close(s);
362  return -1;
363 }
364 
366 {
367  FFMContext *ffm = s->priv_data;
368  AVStream *st;
369  AVIOContext *pb = s->pb;
370  AVCodecContext *codec;
371  int i, nb_streams;
372  uint32_t tag;
373 
374  /* header */
375  tag = avio_rl32(pb);
376  if (tag == MKTAG('F', 'F', 'M', '2'))
377  return ffm2_read_header(s);
378  if (tag != MKTAG('F', 'F', 'M', '1'))
379  goto fail;
380  ffm->packet_size = avio_rb32(pb);
381  if (ffm->packet_size != FFM_PACKET_SIZE)
382  goto fail;
383  ffm->write_index = avio_rb64(pb);
384  /* get also filesize */
385  if (pb->seekable) {
386  ffm->file_size = avio_size(pb);
387  if (ffm->write_index && 0)
389  } else {
390  ffm->file_size = (UINT64_C(1) << 63) - 1;
391  }
392 
393  nb_streams = avio_rb32(pb);
394  avio_rb32(pb); /* total bitrate */
395  /* read each stream */
396  for(i=0;i<nb_streams;i++) {
397  char rc_eq_buf[128];
398 
399  st = avformat_new_stream(s, NULL);
400  if (!st)
401  goto fail;
402 
403  avpriv_set_pts_info(st, 64, 1, 1000000);
404 
405  codec = st->codec;
406  /* generic info */
407  codec->codec_id = avio_rb32(pb);
408  codec->codec_type = avio_r8(pb); /* codec_type */
409  codec->bit_rate = avio_rb32(pb);
410  codec->flags = avio_rb32(pb);
411  codec->flags2 = avio_rb32(pb);
412  codec->debug = avio_rb32(pb);
413  /* specific info */
414  switch(codec->codec_type) {
415  case AVMEDIA_TYPE_VIDEO:
416  codec->time_base.num = avio_rb32(pb);
417  codec->time_base.den = avio_rb32(pb);
418  codec->width = avio_rb16(pb);
419  codec->height = avio_rb16(pb);
420  codec->gop_size = avio_rb16(pb);
421  codec->pix_fmt = avio_rb32(pb);
422  codec->qmin = avio_r8(pb);
423  codec->qmax = avio_r8(pb);
424  codec->max_qdiff = avio_r8(pb);
425  codec->qcompress = avio_rb16(pb) / 10000.0;
426  codec->qblur = avio_rb16(pb) / 10000.0;
427  codec->bit_rate_tolerance = avio_rb32(pb);
428  avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));
429  codec->rc_eq = av_strdup(rc_eq_buf);
430  codec->rc_max_rate = avio_rb32(pb);
431  codec->rc_min_rate = avio_rb32(pb);
432  codec->rc_buffer_size = avio_rb32(pb);
433  codec->i_quant_factor = av_int2double(avio_rb64(pb));
434  codec->b_quant_factor = av_int2double(avio_rb64(pb));
435  codec->i_quant_offset = av_int2double(avio_rb64(pb));
436  codec->b_quant_offset = av_int2double(avio_rb64(pb));
437  codec->dct_algo = avio_rb32(pb);
438  codec->strict_std_compliance = avio_rb32(pb);
439  codec->max_b_frames = avio_rb32(pb);
440  codec->mpeg_quant = avio_rb32(pb);
441  codec->intra_dc_precision = avio_rb32(pb);
442  codec->me_method = avio_rb32(pb);
443  codec->mb_decision = avio_rb32(pb);
444  codec->nsse_weight = avio_rb32(pb);
445  codec->frame_skip_cmp = avio_rb32(pb);
447  codec->codec_tag = avio_rb32(pb);
448  codec->thread_count = avio_r8(pb);
449  codec->coder_type = avio_rb32(pb);
450  codec->me_cmp = avio_rb32(pb);
451  codec->me_subpel_quality = avio_rb32(pb);
452  codec->me_range = avio_rb32(pb);
453  codec->keyint_min = avio_rb32(pb);
454  codec->scenechange_threshold = avio_rb32(pb);
455  codec->b_frame_strategy = avio_rb32(pb);
456  codec->qcompress = av_int2double(avio_rb64(pb));
457  codec->qblur = av_int2double(avio_rb64(pb));
458  codec->max_qdiff = avio_rb32(pb);
459  codec->refs = avio_rb32(pb);
460  break;
461  case AVMEDIA_TYPE_AUDIO:
462  codec->sample_rate = avio_rb32(pb);
463  codec->channels = avio_rl16(pb);
464  codec->frame_size = avio_rl16(pb);
465  break;
466  default:
467  goto fail;
468  }
469  if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
470  if (ff_get_extradata(codec, pb, avio_rb32(pb)) < 0)
471  return AVERROR(ENOMEM);
472  }
473  }
474 
475  /* get until end of block reached */
476  while ((avio_tell(pb) % ffm->packet_size) != 0)
477  avio_r8(pb);
478 
479  /* init packet demux */
480  ffm->packet_ptr = ffm->packet;
481  ffm->packet_end = ffm->packet;
482  ffm->frame_offset = 0;
483  ffm->dts = 0;
484  ffm->read_state = READ_HEADER;
485  ffm->first_packet = 1;
486  return 0;
487  fail:
488  ffm_close(s);
489  return -1;
490 }
491 
492 /* return < 0 if eof */
494 {
495  int size;
496  FFMContext *ffm = s->priv_data;
497  int duration, ret;
498 
499  switch(ffm->read_state) {
500  case READ_HEADER:
501  if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
502  return ret;
503 
504  av_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
505  avio_tell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
506  if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
508  return -1;
509  if (ffm->header[1] & FLAG_DTS)
510  if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
511  return -1;
512  ffm->read_state = READ_DATA;
513  /* fall through */
514  case READ_DATA:
515  size = AV_RB24(ffm->header + 2);
516  if ((ret = ffm_is_avail_data(s, size)) < 0)
517  return ret;
518 
519  duration = AV_RB24(ffm->header + 5);
520 
521  if (av_new_packet(pkt, size) < 0) {
522  return AVERROR(ENOMEM);
523  }
524  pkt->stream_index = ffm->header[0];
525  if ((unsigned)pkt->stream_index >= s->nb_streams) {
526  av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
527  av_free_packet(pkt);
528  ffm->read_state = READ_HEADER;
529  return -1;
530  }
531  pkt->pos = avio_tell(s->pb);
532  if (ffm->header[1] & FLAG_KEY_FRAME)
533  pkt->flags |= AV_PKT_FLAG_KEY;
534 
535  ffm->read_state = READ_HEADER;
536  if (ffm_read_data(s, pkt->data, size, 0) != size) {
537  /* bad case: desynchronized packet. we cancel all the packet loading */
538  av_free_packet(pkt);
539  return -1;
540  }
541  pkt->pts = AV_RB64(ffm->header+8);
542  if (ffm->header[1] & FLAG_DTS)
543  pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
544  else
545  pkt->dts = pkt->pts;
546  pkt->duration = duration;
547  break;
548  }
549  return 0;
550 }
551 
552 /* seek to a given time in the file. The file read pointer is
553  positioned at or before pts. XXX: the following code is quite
554  approximative */
555 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
556 {
557  FFMContext *ffm = s->priv_data;
558  int64_t pos_min, pos_max, pos;
559  int64_t pts_min, pts_max, pts;
560  double pos1;
561 
562  av_dlog(s, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
563  /* find the position using linear interpolation (better than
564  dichotomy in typical cases) */
565  if (ffm->write_index && ffm->write_index < ffm->file_size) {
566  if (get_dts(s, FFM_PACKET_SIZE) < wanted_pts) {
567  pos_min = FFM_PACKET_SIZE;
568  pos_max = ffm->write_index - FFM_PACKET_SIZE;
569  } else {
570  pos_min = ffm->write_index;
571  pos_max = ffm->file_size - FFM_PACKET_SIZE;
572  }
573  } else {
574  pos_min = FFM_PACKET_SIZE;
575  pos_max = ffm->file_size - FFM_PACKET_SIZE;
576  }
577  while (pos_min <= pos_max) {
578  pts_min = get_dts(s, pos_min);
579  pts_max = get_dts(s, pos_max);
580  if (pts_min > wanted_pts || pts_max <= wanted_pts) {
581  pos = pts_min > wanted_pts ? pos_min : pos_max;
582  goto found;
583  }
584  /* linear interpolation */
585  pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
586  (double)(pts_max - pts_min);
587  pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
588  if (pos <= pos_min)
589  pos = pos_min;
590  else if (pos >= pos_max)
591  pos = pos_max;
592  pts = get_dts(s, pos);
593  /* check if we are lucky */
594  if (pts == wanted_pts) {
595  goto found;
596  } else if (pts > wanted_pts) {
597  pos_max = pos - FFM_PACKET_SIZE;
598  } else {
599  pos_min = pos + FFM_PACKET_SIZE;
600  }
601  }
602  pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
603 
604  found:
605  if (ffm_seek1(s, pos) < 0)
606  return -1;
607 
608  /* reset read state */
609  ffm->read_state = READ_HEADER;
610  ffm->packet_ptr = ffm->packet;
611  ffm->packet_end = ffm->packet;
612  ffm->first_packet = 1;
613 
614  return 0;
615 }
616 
617 static int ffm_probe(AVProbeData *p)
618 {
619  if (
620  p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
621  (p->buf[3] == '1' || p->buf[3] == '2'))
622  return AVPROBE_SCORE_MAX + 1;
623  return 0;
624 }
625 
627  .name = "ffm",
628  .long_name = NULL_IF_CONFIG_SMALL("FFM (FFserver live feed)"),
629  .priv_data_size = sizeof(FFMContext),
634  .read_seek = ffm_seek,
635 };