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 "libavutil/intreadwrite.h"
23 #include "libavutil/intfloat.h"
24 #include "avformat.h"
25 #include "internal.h"
26 #include "ffm.h"
27 
29 {
30  FFMContext *ffm = s->priv_data;
31  int64_t pos, avail_size;
32  int len;
33 
34  len = ffm->packet_end - ffm->packet_ptr;
35  if (size <= len)
36  return 1;
37  pos = avio_tell(s->pb);
38  if (!ffm->write_index) {
39  if (pos == ffm->file_size)
40  return AVERROR_EOF;
41  avail_size = ffm->file_size - pos;
42  } else {
43  if (pos == ffm->write_index) {
44  /* exactly at the end of stream */
45  return AVERROR(EAGAIN);
46  } else if (pos < ffm->write_index) {
47  avail_size = ffm->write_index - pos;
48  } else {
49  avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
50  }
51  }
52  avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
53  if (size <= avail_size)
54  return 1;
55  else
56  return AVERROR(EAGAIN);
57 }
58 
59 static int ffm_resync(AVFormatContext *s, int state)
60 {
61  av_log(s, AV_LOG_ERROR, "resyncing\n");
62  while (state != PACKET_ID) {
63  if (s->pb->eof_reached) {
64  av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");
65  return -1;
66  }
67  state = (state << 8) | avio_r8(s->pb);
68  }
69  return 0;
70 }
71 
72 /* first is true if we read the frame header */
74  uint8_t *buf, int size, int header)
75 {
76  FFMContext *ffm = s->priv_data;
77  AVIOContext *pb = s->pb;
78  int len, fill_size, size1, frame_offset, id;
79 
80  size1 = size;
81  while (size > 0) {
82  redo:
83  len = ffm->packet_end - ffm->packet_ptr;
84  if (len < 0)
85  return -1;
86  if (len > size)
87  len = size;
88  if (len == 0) {
89  if (avio_tell(pb) == ffm->file_size)
90  avio_seek(pb, ffm->packet_size, SEEK_SET);
91  retry_read:
92  id = avio_rb16(pb); /* PACKET_ID */
93  if (id != PACKET_ID)
94  if (ffm_resync(s, id) < 0)
95  return -1;
96  fill_size = avio_rb16(pb);
97  ffm->dts = avio_rb64(pb);
98  frame_offset = avio_rb16(pb);
99  avio_read(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
100  ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
101  if (ffm->packet_end < ffm->packet || frame_offset < 0)
102  return -1;
103  /* if first packet or resynchronization packet, we must
104  handle it specifically */
105  if (ffm->first_packet || (frame_offset & 0x8000)) {
106  if (!frame_offset) {
107  /* This packet has no frame headers in it */
108  if (avio_tell(pb) >= ffm->packet_size * 3) {
109  avio_seek(pb, -ffm->packet_size * 2, SEEK_CUR);
110  goto retry_read;
111  }
112  /* This is bad, we cannot find a valid frame header */
113  return 0;
114  }
115  ffm->first_packet = 0;
116  if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
117  return -1;
118  ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
119  if (!header)
120  break;
121  } else {
122  ffm->packet_ptr = ffm->packet;
123  }
124  goto redo;
125  }
126  memcpy(buf, ffm->packet_ptr, len);
127  buf += len;
128  ffm->packet_ptr += len;
129  size -= len;
130  header = 0;
131  }
132  return size1 - size;
133 }
134 
135 /* ensure that acutal seeking happens between FFM_PACKET_SIZE
136  and file_size - FFM_PACKET_SIZE */
137 static int64_t ffm_seek1(AVFormatContext *s, int64_t pos1)
138 {
139  FFMContext *ffm = s->priv_data;
140  AVIOContext *pb = s->pb;
141  int64_t pos;
142 
143  pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);
144  pos = FFMAX(pos, FFM_PACKET_SIZE);
145  av_dlog(s, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
146  return avio_seek(pb, pos, SEEK_SET);
147 }
148 
149 static int64_t get_dts(AVFormatContext *s, int64_t pos)
150 {
151  AVIOContext *pb = s->pb;
152  int64_t dts;
153 
154  ffm_seek1(s, pos);
155  avio_skip(pb, 4);
156  dts = avio_rb64(pb);
157  av_dlog(s, "dts=%0.6f\n", dts / 1000000.0);
158  return dts;
159 }
160 
162 {
163  FFMContext *ffm = s->priv_data;
164  AVIOContext *pb = s->pb;
165  int64_t pts;
166  //int64_t orig_write_index = ffm->write_index;
167  int64_t pos_min, pos_max;
168  int64_t pts_start;
169  int64_t ptr = avio_tell(pb);
170 
171 
172  pos_min = 0;
173  pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
174 
175  pts_start = get_dts(s, pos_min);
176 
177  pts = get_dts(s, pos_max);
178 
179  if (pts - 100000 > pts_start)
180  goto end;
181 
183 
184  pts_start = get_dts(s, pos_min);
185 
186  pts = get_dts(s, pos_max);
187 
188  if (pts - 100000 <= pts_start) {
189  while (1) {
190  int64_t newpos;
191  int64_t newpts;
192 
193  newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
194 
195  if (newpos == pos_min)
196  break;
197 
198  newpts = get_dts(s, newpos);
199 
200  if (newpts - 100000 <= pts) {
201  pos_max = newpos;
202  pts = newpts;
203  } else {
204  pos_min = newpos;
205  }
206  }
207  ffm->write_index += pos_max;
208  }
209 
210  end:
211  avio_seek(pb, ptr, SEEK_SET);
212 }
213 
214 
216 {
217  int i;
218 
219  for (i = 0; i < s->nb_streams; i++)
220  av_freep(&s->streams[i]->codec->rc_eq);
221 
222  return 0;
223 }
224 
225 
227 {
228  FFMContext *ffm = s->priv_data;
229  AVStream *st;
230  AVIOContext *pb = s->pb;
231  AVCodecContext *codec;
232  int i, nb_streams;
233  uint32_t tag;
234 
235  /* header */
236  tag = avio_rl32(pb);
237  if (tag != MKTAG('F', 'F', 'M', '1'))
238  goto fail;
239  ffm->packet_size = avio_rb32(pb);
240  if (ffm->packet_size != FFM_PACKET_SIZE)
241  goto fail;
242  ffm->write_index = avio_rb64(pb);
243  /* get also filesize */
244  if (pb->seekable) {
245  ffm->file_size = avio_size(pb);
246  if (ffm->write_index)
248  } else {
249  ffm->file_size = (UINT64_C(1) << 63) - 1;
250  }
251 
252  nb_streams = avio_rb32(pb);
253  avio_rb32(pb); /* total bitrate */
254  /* read each stream */
255  for(i=0;i<nb_streams;i++) {
256  char rc_eq_buf[128];
257 
258  st = avformat_new_stream(s, NULL);
259  if (!st)
260  goto fail;
261 
262  avpriv_set_pts_info(st, 64, 1, 1000000);
263 
264  codec = st->codec;
265  /* generic info */
266  codec->codec_id = avio_rb32(pb);
267  codec->codec_type = avio_r8(pb); /* codec_type */
268  codec->bit_rate = avio_rb32(pb);
269  codec->flags = avio_rb32(pb);
270  codec->flags2 = avio_rb32(pb);
271  codec->debug = avio_rb32(pb);
272  /* specific info */
273  switch(codec->codec_type) {
274  case AVMEDIA_TYPE_VIDEO:
275  codec->time_base.num = avio_rb32(pb);
276  codec->time_base.den = avio_rb32(pb);
277  codec->width = avio_rb16(pb);
278  codec->height = avio_rb16(pb);
279  codec->gop_size = avio_rb16(pb);
280  codec->pix_fmt = avio_rb32(pb);
281  codec->qmin = avio_r8(pb);
282  codec->qmax = avio_r8(pb);
283  codec->max_qdiff = avio_r8(pb);
284  codec->qcompress = avio_rb16(pb) / 10000.0;
285  codec->qblur = avio_rb16(pb) / 10000.0;
286  codec->bit_rate_tolerance = avio_rb32(pb);
287  avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));
288  codec->rc_eq = av_strdup(rc_eq_buf);
289  codec->rc_max_rate = avio_rb32(pb);
290  codec->rc_min_rate = avio_rb32(pb);
291  codec->rc_buffer_size = avio_rb32(pb);
292  codec->i_quant_factor = av_int2double(avio_rb64(pb));
293  codec->b_quant_factor = av_int2double(avio_rb64(pb));
294  codec->i_quant_offset = av_int2double(avio_rb64(pb));
295  codec->b_quant_offset = av_int2double(avio_rb64(pb));
296  codec->dct_algo = avio_rb32(pb);
297  codec->strict_std_compliance = avio_rb32(pb);
298  codec->max_b_frames = avio_rb32(pb);
299  codec->mpeg_quant = avio_rb32(pb);
300  codec->intra_dc_precision = avio_rb32(pb);
301  codec->me_method = avio_rb32(pb);
302  codec->mb_decision = avio_rb32(pb);
303  codec->nsse_weight = avio_rb32(pb);
304  codec->frame_skip_cmp = avio_rb32(pb);
306  codec->codec_tag = avio_rb32(pb);
307  codec->thread_count = avio_r8(pb);
308  codec->coder_type = avio_rb32(pb);
309  codec->me_cmp = avio_rb32(pb);
310  codec->me_subpel_quality = avio_rb32(pb);
311  codec->me_range = avio_rb32(pb);
312  codec->keyint_min = avio_rb32(pb);
313  codec->scenechange_threshold = avio_rb32(pb);
314  codec->b_frame_strategy = avio_rb32(pb);
315  codec->qcompress = av_int2double(avio_rb64(pb));
316  codec->qblur = av_int2double(avio_rb64(pb));
317  codec->max_qdiff = avio_rb32(pb);
318  codec->refs = avio_rb32(pb);
319  break;
320  case AVMEDIA_TYPE_AUDIO:
321  codec->sample_rate = avio_rb32(pb);
322  codec->channels = avio_rl16(pb);
323  codec->frame_size = avio_rl16(pb);
324  break;
325  default:
326  goto fail;
327  }
328  if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
329  codec->extradata_size = avio_rb32(pb);
330  codec->extradata = av_malloc(codec->extradata_size);
331  if (!codec->extradata)
332  return AVERROR(ENOMEM);
333  avio_read(pb, codec->extradata, codec->extradata_size);
334  }
335  }
336 
337  /* get until end of block reached */
338  while ((avio_tell(pb) % ffm->packet_size) != 0)
339  avio_r8(pb);
340 
341  /* init packet demux */
342  ffm->packet_ptr = ffm->packet;
343  ffm->packet_end = ffm->packet;
344  ffm->frame_offset = 0;
345  ffm->dts = 0;
346  ffm->read_state = READ_HEADER;
347  ffm->first_packet = 1;
348  return 0;
349  fail:
350  ffm_close(s);
351  return -1;
352 }
353 
354 /* return < 0 if eof */
356 {
357  int size;
358  FFMContext *ffm = s->priv_data;
359  int duration, ret;
360 
361  switch(ffm->read_state) {
362  case READ_HEADER:
363  if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
364  return ret;
365 
366  av_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
367  avio_tell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
368  if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
370  return -1;
371  if (ffm->header[1] & FLAG_DTS)
372  if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
373  return -1;
374  ffm->read_state = READ_DATA;
375  /* fall thru */
376  case READ_DATA:
377  size = AV_RB24(ffm->header + 2);
378  if ((ret = ffm_is_avail_data(s, size)) < 0)
379  return ret;
380 
381  duration = AV_RB24(ffm->header + 5);
382 
383  av_new_packet(pkt, size);
384  pkt->stream_index = ffm->header[0];
385  if ((unsigned)pkt->stream_index >= s->nb_streams) {
386  av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
387  av_free_packet(pkt);
388  ffm->read_state = READ_HEADER;
389  return -1;
390  }
391  pkt->pos = avio_tell(s->pb);
392  if (ffm->header[1] & FLAG_KEY_FRAME)
393  pkt->flags |= AV_PKT_FLAG_KEY;
394 
395  ffm->read_state = READ_HEADER;
396  if (ffm_read_data(s, pkt->data, size, 0) != size) {
397  /* bad case: desynchronized packet. we cancel all the packet loading */
398  av_free_packet(pkt);
399  return -1;
400  }
401  pkt->pts = AV_RB64(ffm->header+8);
402  if (ffm->header[1] & FLAG_DTS)
403  pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
404  else
405  pkt->dts = pkt->pts;
406  pkt->duration = duration;
407  break;
408  }
409  return 0;
410 }
411 
412 /* seek to a given time in the file. The file read pointer is
413  positioned at or before pts. XXX: the following code is quite
414  approximative */
415 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
416 {
417  FFMContext *ffm = s->priv_data;
418  int64_t pos_min, pos_max, pos;
419  int64_t pts_min, pts_max, pts;
420  double pos1;
421 
422  av_dlog(s, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
423  /* find the position using linear interpolation (better than
424  dichotomy in typical cases) */
425  pos_min = FFM_PACKET_SIZE;
426  pos_max = ffm->file_size - FFM_PACKET_SIZE;
427  while (pos_min <= pos_max) {
428  pts_min = get_dts(s, pos_min);
429  pts_max = get_dts(s, pos_max);
430  /* linear interpolation */
431  pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
432  (double)(pts_max - pts_min);
433  pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
434  if (pos <= pos_min)
435  pos = pos_min;
436  else if (pos >= pos_max)
437  pos = pos_max;
438  pts = get_dts(s, pos);
439  /* check if we are lucky */
440  if (pts == wanted_pts) {
441  goto found;
442  } else if (pts > wanted_pts) {
443  pos_max = pos - FFM_PACKET_SIZE;
444  } else {
445  pos_min = pos + FFM_PACKET_SIZE;
446  }
447  }
448  pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
449 
450  found:
451  if (ffm_seek1(s, pos) < 0)
452  return -1;
453 
454  /* reset read state */
455  ffm->read_state = READ_HEADER;
456  ffm->packet_ptr = ffm->packet;
457  ffm->packet_end = ffm->packet;
458  ffm->first_packet = 1;
459 
460  return 0;
461 }
462 
463 static int ffm_probe(AVProbeData *p)
464 {
465  if (
466  p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
467  p->buf[3] == '1')
468  return AVPROBE_SCORE_MAX + 1;
469  return 0;
470 }
471 
473  .name = "ffm",
474  .long_name = NULL_IF_CONFIG_SMALL("FFM (AVserver live feed)"),
475  .priv_data_size = sizeof(FFMContext),
480  .read_seek = ffm_seek,
481 };