Libav
ffmdec.c
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1 /*
2  * FFM (avserver live feed) demuxer
3  * Copyright (c) 2001 Fabrice Bellard
4  *
5  * This file is part of Libav.
6  *
7  * Libav 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  * Libav 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 Libav; 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 
31 {
32  FFMContext *ffm = s->priv_data;
33  int64_t pos, avail_size;
34  int len;
35 
36  len = ffm->packet_end - ffm->packet_ptr;
37  if (size <= len)
38  return 1;
39  pos = avio_tell(s->pb);
40  if (!ffm->write_index) {
41  if (pos == ffm->file_size)
42  return AVERROR_EOF;
43  avail_size = ffm->file_size - pos;
44  } else {
45  if (pos == ffm->write_index) {
46  /* exactly at the end of stream */
47  return AVERROR(EAGAIN);
48  } else if (pos < ffm->write_index) {
49  avail_size = ffm->write_index - pos;
50  } else {
51  avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
52  }
53  }
54  avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
55  if (size <= avail_size)
56  return 1;
57  else
58  return AVERROR(EAGAIN);
59 }
60 
61 static int ffm_resync(AVFormatContext *s, int state)
62 {
63  av_log(s, AV_LOG_ERROR, "resyncing\n");
64  while (state != PACKET_ID) {
65  if (s->pb->eof_reached) {
66  av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");
67  return -1;
68  }
69  state = (state << 8) | avio_r8(s->pb);
70  }
71  return 0;
72 }
73 
74 /* first is true if we read the frame header */
76  uint8_t *buf, int size, int header)
77 {
78  FFMContext *ffm = s->priv_data;
79  AVIOContext *pb = s->pb;
80  int len, fill_size, size1, frame_offset, id;
81 
82  size1 = size;
83  while (size > 0) {
84  redo:
85  len = ffm->packet_end - ffm->packet_ptr;
86  if (len < 0)
87  return -1;
88  if (len > size)
89  len = size;
90  if (len == 0) {
91  if (avio_tell(pb) == ffm->file_size)
92  avio_seek(pb, ffm->packet_size, SEEK_SET);
93  retry_read:
94  id = avio_rb16(pb); /* PACKET_ID */
95  if (id != PACKET_ID)
96  if (ffm_resync(s, id) < 0)
97  return -1;
98  fill_size = avio_rb16(pb);
99  ffm->dts = avio_rb64(pb);
100  frame_offset = avio_rb16(pb);
101  avio_read(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
102  ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
103  if (ffm->packet_end < ffm->packet || frame_offset < 0)
104  return -1;
105  /* if first packet or resynchronization packet, we must
106  handle it specifically */
107  if (ffm->first_packet || (frame_offset & 0x8000)) {
108  if (!frame_offset) {
109  /* This packet has no frame headers in it */
110  if (avio_tell(pb) >= ffm->packet_size * 3) {
111  avio_seek(pb, -ffm->packet_size * 2, SEEK_CUR);
112  goto retry_read;
113  }
114  /* This is bad, we cannot find a valid frame header */
115  return 0;
116  }
117  ffm->first_packet = 0;
118  if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
119  return -1;
120  ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
121  if (!header)
122  break;
123  } else {
124  ffm->packet_ptr = ffm->packet;
125  }
126  goto redo;
127  }
128  memcpy(buf, ffm->packet_ptr, len);
129  buf += len;
130  ffm->packet_ptr += len;
131  size -= len;
132  header = 0;
133  }
134  return size1 - size;
135 }
136 
137 /* ensure that acutal seeking happens between FFM_PACKET_SIZE
138  and file_size - FFM_PACKET_SIZE */
139 static int64_t ffm_seek1(AVFormatContext *s, int64_t pos1)
140 {
141  FFMContext *ffm = s->priv_data;
142  AVIOContext *pb = s->pb;
143  int64_t pos;
144 
145  pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);
146  pos = FFMAX(pos, FFM_PACKET_SIZE);
147  av_dlog(s, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
148  return avio_seek(pb, pos, SEEK_SET);
149 }
150 
151 static int64_t get_dts(AVFormatContext *s, int64_t pos)
152 {
153  AVIOContext *pb = s->pb;
154  int64_t dts;
155 
156  ffm_seek1(s, pos);
157  avio_skip(pb, 4);
158  dts = avio_rb64(pb);
159  av_dlog(s, "dts=%0.6f\n", dts / 1000000.0);
160  return dts;
161 }
162 
164 {
165  FFMContext *ffm = s->priv_data;
166  AVIOContext *pb = s->pb;
167  int64_t pts;
168  //int64_t orig_write_index = ffm->write_index;
169  int64_t pos_min, pos_max;
170  int64_t pts_start;
171  int64_t ptr = avio_tell(pb);
172 
173 
174  pos_min = 0;
175  pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
176 
177  pts_start = get_dts(s, pos_min);
178 
179  pts = get_dts(s, pos_max);
180 
181  if (pts - 100000 > pts_start)
182  goto end;
183 
185 
186  pts_start = get_dts(s, pos_min);
187 
188  pts = get_dts(s, pos_max);
189 
190  if (pts - 100000 <= pts_start) {
191  while (1) {
192  int64_t newpos;
193  int64_t newpts;
194 
195  newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
196 
197  if (newpos == pos_min)
198  break;
199 
200  newpts = get_dts(s, newpos);
201 
202  if (newpts - 100000 <= pts) {
203  pos_max = newpos;
204  pts = newpts;
205  } else {
206  pos_min = newpos;
207  }
208  }
209  ffm->write_index += pos_max;
210  }
211 
212  end:
213  avio_seek(pb, ptr, SEEK_SET);
214 }
215 
216 
218 {
219  int i;
220 
221  for (i = 0; i < s->nb_streams; i++)
222  av_freep(&s->streams[i]->codec->rc_eq);
223 
224  return 0;
225 }
226 
227 
229 {
230  FFMContext *ffm = s->priv_data;
231  AVStream *st;
232  AVIOContext *pb = s->pb;
233  AVCodecContext *codec;
234  int i, nb_streams;
235  uint32_t tag;
236 
237  /* header */
238  tag = avio_rl32(pb);
239  if (tag != MKTAG('F', 'F', 'M', '1'))
240  goto fail;
241  ffm->packet_size = avio_rb32(pb);
242  if (ffm->packet_size != FFM_PACKET_SIZE)
243  goto fail;
244  ffm->write_index = avio_rb64(pb);
245  /* get also filesize */
246  if (pb->seekable) {
247  ffm->file_size = avio_size(pb);
248  if (ffm->write_index)
250  } else {
251  ffm->file_size = (UINT64_C(1) << 63) - 1;
252  }
253 
254  nb_streams = avio_rb32(pb);
255  avio_rb32(pb); /* total bitrate */
256  /* read each stream */
257  for(i=0;i<nb_streams;i++) {
258  char rc_eq_buf[128];
259 
260  st = avformat_new_stream(s, NULL);
261  if (!st)
262  goto fail;
263 
264  avpriv_set_pts_info(st, 64, 1, 1000000);
265 
266  codec = st->codec;
267  /* generic info */
268  codec->codec_id = avio_rb32(pb);
269  codec->codec_type = avio_r8(pb); /* codec_type */
270  codec->bit_rate = avio_rb32(pb);
271  codec->flags = avio_rb32(pb);
272  codec->flags2 = avio_rb32(pb);
273  codec->debug = avio_rb32(pb);
274  /* specific info */
275  switch(codec->codec_type) {
276  case AVMEDIA_TYPE_VIDEO:
277  codec->time_base.num = avio_rb32(pb);
278  codec->time_base.den = avio_rb32(pb);
279  codec->width = avio_rb16(pb);
280  codec->height = avio_rb16(pb);
281  codec->gop_size = avio_rb16(pb);
282  codec->pix_fmt = avio_rb32(pb);
283  codec->qmin = avio_r8(pb);
284  codec->qmax = avio_r8(pb);
285  codec->max_qdiff = avio_r8(pb);
286  codec->qcompress = avio_rb16(pb) / 10000.0;
287  codec->qblur = avio_rb16(pb) / 10000.0;
288  codec->bit_rate_tolerance = avio_rb32(pb);
289  avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));
290  codec->rc_eq = av_strdup(rc_eq_buf);
291  codec->rc_max_rate = avio_rb32(pb);
292  codec->rc_min_rate = avio_rb32(pb);
293  codec->rc_buffer_size = avio_rb32(pb);
294  codec->i_quant_factor = av_int2double(avio_rb64(pb));
295  codec->b_quant_factor = av_int2double(avio_rb64(pb));
296  codec->i_quant_offset = av_int2double(avio_rb64(pb));
297  codec->b_quant_offset = av_int2double(avio_rb64(pb));
298  codec->dct_algo = avio_rb32(pb);
299  codec->strict_std_compliance = avio_rb32(pb);
300  codec->max_b_frames = avio_rb32(pb);
301  codec->mpeg_quant = avio_rb32(pb);
302  codec->intra_dc_precision = avio_rb32(pb);
303  codec->me_method = avio_rb32(pb);
304  codec->mb_decision = avio_rb32(pb);
305  codec->nsse_weight = avio_rb32(pb);
306  codec->frame_skip_cmp = avio_rb32(pb);
308  codec->codec_tag = avio_rb32(pb);
309  codec->thread_count = avio_r8(pb);
310  codec->coder_type = avio_rb32(pb);
311  codec->me_cmp = avio_rb32(pb);
312  codec->me_subpel_quality = avio_rb32(pb);
313  codec->me_range = avio_rb32(pb);
314  codec->keyint_min = avio_rb32(pb);
315  codec->scenechange_threshold = avio_rb32(pb);
316  codec->b_frame_strategy = avio_rb32(pb);
317  codec->qcompress = av_int2double(avio_rb64(pb));
318  codec->qblur = av_int2double(avio_rb64(pb));
319  codec->max_qdiff = avio_rb32(pb);
320  codec->refs = avio_rb32(pb);
321  break;
322  case AVMEDIA_TYPE_AUDIO:
323  codec->sample_rate = avio_rb32(pb);
324  codec->channels = avio_rl16(pb);
325  codec->frame_size = avio_rl16(pb);
326  break;
327  default:
328  goto fail;
329  }
330  if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
331  codec->extradata_size = avio_rb32(pb);
332  codec->extradata = av_malloc(codec->extradata_size);
333  if (!codec->extradata)
334  return AVERROR(ENOMEM);
335  avio_read(pb, codec->extradata, codec->extradata_size);
336  }
337  }
338 
339  /* get until end of block reached */
340  while ((avio_tell(pb) % ffm->packet_size) != 0)
341  avio_r8(pb);
342 
343  /* init packet demux */
344  ffm->packet_ptr = ffm->packet;
345  ffm->packet_end = ffm->packet;
346  ffm->frame_offset = 0;
347  ffm->dts = 0;
348  ffm->read_state = READ_HEADER;
349  ffm->first_packet = 1;
350  return 0;
351  fail:
352  ffm_close(s);
353  return -1;
354 }
355 
356 /* return < 0 if eof */
358 {
359  int size;
360  FFMContext *ffm = s->priv_data;
361  int duration, ret;
362 
363  switch(ffm->read_state) {
364  case READ_HEADER:
365  if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
366  return ret;
367 
368  av_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
369  avio_tell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
370  if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
372  return -1;
373  if (ffm->header[1] & FLAG_DTS)
374  if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
375  return -1;
376  ffm->read_state = READ_DATA;
377  /* fall thru */
378  case READ_DATA:
379  size = AV_RB24(ffm->header + 2);
380  if ((ret = ffm_is_avail_data(s, size)) < 0)
381  return ret;
382 
383  duration = AV_RB24(ffm->header + 5);
384 
385  av_new_packet(pkt, size);
386  pkt->stream_index = ffm->header[0];
387  if ((unsigned)pkt->stream_index >= s->nb_streams) {
388  av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
389  av_free_packet(pkt);
390  ffm->read_state = READ_HEADER;
391  return -1;
392  }
393  pkt->pos = avio_tell(s->pb);
394  if (ffm->header[1] & FLAG_KEY_FRAME)
395  pkt->flags |= AV_PKT_FLAG_KEY;
396 
397  ffm->read_state = READ_HEADER;
398  if (ffm_read_data(s, pkt->data, size, 0) != size) {
399  /* bad case: desynchronized packet. we cancel all the packet loading */
400  av_free_packet(pkt);
401  return -1;
402  }
403  pkt->pts = AV_RB64(ffm->header+8);
404  if (ffm->header[1] & FLAG_DTS)
405  pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
406  else
407  pkt->dts = pkt->pts;
408  pkt->duration = duration;
409  break;
410  }
411  return 0;
412 }
413 
414 /* seek to a given time in the file. The file read pointer is
415  positioned at or before pts. XXX: the following code is quite
416  approximative */
417 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
418 {
419  FFMContext *ffm = s->priv_data;
420  int64_t pos_min, pos_max, pos;
421  int64_t pts_min, pts_max, pts;
422  double pos1;
423 
424  av_dlog(s, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
425  /* find the position using linear interpolation (better than
426  dichotomy in typical cases) */
427  pos_min = FFM_PACKET_SIZE;
428  pos_max = ffm->file_size - FFM_PACKET_SIZE;
429  while (pos_min <= pos_max) {
430  pts_min = get_dts(s, pos_min);
431  pts_max = get_dts(s, pos_max);
432  /* linear interpolation */
433  pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
434  (double)(pts_max - pts_min);
435  pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
436  if (pos <= pos_min)
437  pos = pos_min;
438  else if (pos >= pos_max)
439  pos = pos_max;
440  pts = get_dts(s, pos);
441  /* check if we are lucky */
442  if (pts == wanted_pts) {
443  goto found;
444  } else if (pts > wanted_pts) {
445  pos_max = pos - FFM_PACKET_SIZE;
446  } else {
447  pos_min = pos + FFM_PACKET_SIZE;
448  }
449  }
450  pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
451 
452  found:
453  if (ffm_seek1(s, pos) < 0)
454  return -1;
455 
456  /* reset read state */
457  ffm->read_state = READ_HEADER;
458  ffm->packet_ptr = ffm->packet;
459  ffm->packet_end = ffm->packet;
460  ffm->first_packet = 1;
461 
462  return 0;
463 }
464 
465 static int ffm_probe(AVProbeData *p)
466 {
467  if (
468  p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
469  p->buf[3] == '1')
470  return AVPROBE_SCORE_MAX + 1;
471  return 0;
472 }
473 
475  .name = "ffm",
476  .long_name = NULL_IF_CONFIG_SMALL("FFM (AVserver live feed)"),
477  .priv_data_size = sizeof(FFMContext),
482  .read_seek = ffm_seek,
483 };