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 #if CONFIG_AVSERVER
28 #include <unistd.h>
29 
30 int64_t ffm_read_write_index(int fd)
31 {
32  uint8_t buf[8];
33 
34  lseek(fd, 8, SEEK_SET);
35  if (read(fd, buf, 8) != 8)
36  return AVERROR(EIO);
37  return AV_RB64(buf);
38 }
39 
40 int ffm_write_write_index(int fd, int64_t pos)
41 {
42  uint8_t buf[8];
43  int i;
44 
45  for(i=0;i<8;i++)
46  buf[i] = (pos >> (56 - i * 8)) & 0xff;
47  lseek(fd, 8, SEEK_SET);
48  if (write(fd, buf, 8) != 8)
49  return AVERROR(EIO);
50  return 8;
51 }
52 
53 void ffm_set_write_index(AVFormatContext *s, int64_t pos, int64_t file_size)
54 {
55  FFMContext *ffm = s->priv_data;
56  ffm->write_index = pos;
57  ffm->file_size = file_size;
58 }
59 #endif // CONFIG_AVSERVER
60 
62 {
63  FFMContext *ffm = s->priv_data;
64  int64_t pos, avail_size;
65  int len;
66 
67  len = ffm->packet_end - ffm->packet_ptr;
68  if (size <= len)
69  return 1;
70  pos = avio_tell(s->pb);
71  if (!ffm->write_index) {
72  if (pos == ffm->file_size)
73  return AVERROR_EOF;
74  avail_size = ffm->file_size - pos;
75  } else {
76  if (pos == ffm->write_index) {
77  /* exactly at the end of stream */
78  return AVERROR(EAGAIN);
79  } else if (pos < ffm->write_index) {
80  avail_size = ffm->write_index - pos;
81  } else {
82  avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
83  }
84  }
85  avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
86  if (size <= avail_size)
87  return 1;
88  else
89  return AVERROR(EAGAIN);
90 }
91 
92 static int ffm_resync(AVFormatContext *s, int state)
93 {
94  av_log(s, AV_LOG_ERROR, "resyncing\n");
95  while (state != PACKET_ID) {
96  if (s->pb->eof_reached) {
97  av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");
98  return -1;
99  }
100  state = (state << 8) | avio_r8(s->pb);
101  }
102  return 0;
103 }
104 
105 /* first is true if we read the frame header */
107  uint8_t *buf, int size, int header)
108 {
109  FFMContext *ffm = s->priv_data;
110  AVIOContext *pb = s->pb;
111  int len, fill_size, size1, frame_offset, id;
112 
113  size1 = size;
114  while (size > 0) {
115  redo:
116  len = ffm->packet_end - ffm->packet_ptr;
117  if (len < 0)
118  return -1;
119  if (len > size)
120  len = size;
121  if (len == 0) {
122  if (avio_tell(pb) == ffm->file_size)
123  avio_seek(pb, ffm->packet_size, SEEK_SET);
124  retry_read:
125  id = avio_rb16(pb); /* PACKET_ID */
126  if (id != PACKET_ID)
127  if (ffm_resync(s, id) < 0)
128  return -1;
129  fill_size = avio_rb16(pb);
130  ffm->dts = avio_rb64(pb);
131  frame_offset = avio_rb16(pb);
132  avio_read(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
133  ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
134  if (ffm->packet_end < ffm->packet || frame_offset < 0)
135  return -1;
136  /* if first packet or resynchronization packet, we must
137  handle it specifically */
138  if (ffm->first_packet || (frame_offset & 0x8000)) {
139  if (!frame_offset) {
140  /* This packet has no frame headers in it */
141  if (avio_tell(pb) >= ffm->packet_size * 3) {
142  avio_seek(pb, -ffm->packet_size * 2, SEEK_CUR);
143  goto retry_read;
144  }
145  /* This is bad, we cannot find a valid frame header */
146  return 0;
147  }
148  ffm->first_packet = 0;
149  if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
150  return -1;
151  ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
152  if (!header)
153  break;
154  } else {
155  ffm->packet_ptr = ffm->packet;
156  }
157  goto redo;
158  }
159  memcpy(buf, ffm->packet_ptr, len);
160  buf += len;
161  ffm->packet_ptr += len;
162  size -= len;
163  header = 0;
164  }
165  return size1 - size;
166 }
167 
168 /* ensure that acutal seeking happens between FFM_PACKET_SIZE
169  and file_size - FFM_PACKET_SIZE */
170 static void ffm_seek1(AVFormatContext *s, int64_t pos1)
171 {
172  FFMContext *ffm = s->priv_data;
173  AVIOContext *pb = s->pb;
174  int64_t pos;
175 
176  pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);
177  pos = FFMAX(pos, FFM_PACKET_SIZE);
178  av_dlog(s, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
179  avio_seek(pb, pos, SEEK_SET);
180 }
181 
182 static int64_t get_dts(AVFormatContext *s, int64_t pos)
183 {
184  AVIOContext *pb = s->pb;
185  int64_t dts;
186 
187  ffm_seek1(s, pos);
188  avio_skip(pb, 4);
189  dts = avio_rb64(pb);
190  av_dlog(s, "dts=%0.6f\n", dts / 1000000.0);
191  return dts;
192 }
193 
195 {
196  FFMContext *ffm = s->priv_data;
197  AVIOContext *pb = s->pb;
198  int64_t pts;
199  //int64_t orig_write_index = ffm->write_index;
200  int64_t pos_min, pos_max;
201  int64_t pts_start;
202  int64_t ptr = avio_tell(pb);
203 
204 
205  pos_min = 0;
206  pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
207 
208  pts_start = get_dts(s, pos_min);
209 
210  pts = get_dts(s, pos_max);
211 
212  if (pts - 100000 > pts_start)
213  goto end;
214 
216 
217  pts_start = get_dts(s, pos_min);
218 
219  pts = get_dts(s, pos_max);
220 
221  if (pts - 100000 <= pts_start) {
222  while (1) {
223  int64_t newpos;
224  int64_t newpts;
225 
226  newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
227 
228  if (newpos == pos_min)
229  break;
230 
231  newpts = get_dts(s, newpos);
232 
233  if (newpts - 100000 <= pts) {
234  pos_max = newpos;
235  pts = newpts;
236  } else {
237  pos_min = newpos;
238  }
239  }
240  ffm->write_index += pos_max;
241  }
242 
243  //printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);
244  //printf("pts range %0.6f - %0.6f\n", get_dts(s, 0) / 1000000. , get_dts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );
245 
246  end:
247  avio_seek(pb, ptr, SEEK_SET);
248 }
249 
250 
252 {
253  int i;
254 
255  for (i = 0; i < s->nb_streams; i++)
256  av_freep(&s->streams[i]->codec->rc_eq);
257 
258  return 0;
259 }
260 
261 
263 {
264  FFMContext *ffm = s->priv_data;
265  AVStream *st;
266  AVIOContext *pb = s->pb;
267  AVCodecContext *codec;
268  int i, nb_streams;
269  uint32_t tag;
270 
271  /* header */
272  tag = avio_rl32(pb);
273  if (tag != MKTAG('F', 'F', 'M', '1'))
274  goto fail;
275  ffm->packet_size = avio_rb32(pb);
276  if (ffm->packet_size != FFM_PACKET_SIZE)
277  goto fail;
278  ffm->write_index = avio_rb64(pb);
279  /* get also filesize */
280  if (pb->seekable) {
281  ffm->file_size = avio_size(pb);
282  if (ffm->write_index)
284  } else {
285  ffm->file_size = (UINT64_C(1) << 63) - 1;
286  }
287 
288  nb_streams = avio_rb32(pb);
289  avio_rb32(pb); /* total bitrate */
290  /* read each stream */
291  for(i=0;i<nb_streams;i++) {
292  char rc_eq_buf[128];
293 
294  st = avformat_new_stream(s, NULL);
295  if (!st)
296  goto fail;
297 
298  avpriv_set_pts_info(st, 64, 1, 1000000);
299 
300  codec = st->codec;
301  /* generic info */
302  codec->codec_id = avio_rb32(pb);
303  codec->codec_type = avio_r8(pb); /* codec_type */
304  codec->bit_rate = avio_rb32(pb);
305  codec->flags = avio_rb32(pb);
306  codec->flags2 = avio_rb32(pb);
307  codec->debug = avio_rb32(pb);
308  /* specific info */
309  switch(codec->codec_type) {
310  case AVMEDIA_TYPE_VIDEO:
311  codec->time_base.num = avio_rb32(pb);
312  codec->time_base.den = avio_rb32(pb);
313  codec->width = avio_rb16(pb);
314  codec->height = avio_rb16(pb);
315  codec->gop_size = avio_rb16(pb);
316  codec->pix_fmt = avio_rb32(pb);
317  codec->qmin = avio_r8(pb);
318  codec->qmax = avio_r8(pb);
319  codec->max_qdiff = avio_r8(pb);
320  codec->qcompress = avio_rb16(pb) / 10000.0;
321  codec->qblur = avio_rb16(pb) / 10000.0;
322  codec->bit_rate_tolerance = avio_rb32(pb);
323  avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));
324  codec->rc_eq = av_strdup(rc_eq_buf);
325  codec->rc_max_rate = avio_rb32(pb);
326  codec->rc_min_rate = avio_rb32(pb);
327  codec->rc_buffer_size = avio_rb32(pb);
328  codec->i_quant_factor = av_int2double(avio_rb64(pb));
329  codec->b_quant_factor = av_int2double(avio_rb64(pb));
330  codec->i_quant_offset = av_int2double(avio_rb64(pb));
331  codec->b_quant_offset = av_int2double(avio_rb64(pb));
332  codec->dct_algo = avio_rb32(pb);
333  codec->strict_std_compliance = avio_rb32(pb);
334  codec->max_b_frames = avio_rb32(pb);
335  codec->luma_elim_threshold = avio_rb32(pb);
336  codec->chroma_elim_threshold = avio_rb32(pb);
337  codec->mpeg_quant = avio_rb32(pb);
338  codec->intra_dc_precision = avio_rb32(pb);
339  codec->me_method = avio_rb32(pb);
340  codec->mb_decision = avio_rb32(pb);
341  codec->nsse_weight = avio_rb32(pb);
342  codec->frame_skip_cmp = avio_rb32(pb);
344  codec->codec_tag = avio_rb32(pb);
345  codec->thread_count = avio_r8(pb);
346  codec->coder_type = avio_rb32(pb);
347  codec->me_cmp = avio_rb32(pb);
348  codec->me_subpel_quality = avio_rb32(pb);
349  codec->me_range = avio_rb32(pb);
350  codec->keyint_min = avio_rb32(pb);
351  codec->scenechange_threshold = avio_rb32(pb);
352  codec->b_frame_strategy = avio_rb32(pb);
353  codec->qcompress = av_int2double(avio_rb64(pb));
354  codec->qblur = av_int2double(avio_rb64(pb));
355  codec->max_qdiff = avio_rb32(pb);
356  codec->refs = avio_rb32(pb);
357  break;
358  case AVMEDIA_TYPE_AUDIO:
359  codec->sample_rate = avio_rb32(pb);
360  codec->channels = avio_rl16(pb);
361  codec->frame_size = avio_rl16(pb);
362  codec->sample_fmt = (int16_t) avio_rl16(pb);
363  break;
364  default:
365  goto fail;
366  }
367  if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
368  codec->extradata_size = avio_rb32(pb);
369  codec->extradata = av_malloc(codec->extradata_size);
370  if (!codec->extradata)
371  return AVERROR(ENOMEM);
372  avio_read(pb, codec->extradata, codec->extradata_size);
373  }
374  }
375 
376  /* get until end of block reached */
377  while ((avio_tell(pb) % ffm->packet_size) != 0)
378  avio_r8(pb);
379 
380  /* init packet demux */
381  ffm->packet_ptr = ffm->packet;
382  ffm->packet_end = ffm->packet;
383  ffm->frame_offset = 0;
384  ffm->dts = 0;
385  ffm->read_state = READ_HEADER;
386  ffm->first_packet = 1;
387  return 0;
388  fail:
389  ffm_close(s);
390  return -1;
391 }
392 
393 /* return < 0 if eof */
395 {
396  int size;
397  FFMContext *ffm = s->priv_data;
398  int duration, ret;
399 
400  switch(ffm->read_state) {
401  case READ_HEADER:
402  if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
403  return ret;
404 
405  av_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
406  avio_tell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
407  if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
409  return -1;
410  if (ffm->header[1] & FLAG_DTS)
411  if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
412  return -1;
413  ffm->read_state = READ_DATA;
414  /* fall thru */
415  case READ_DATA:
416  size = AV_RB24(ffm->header + 2);
417  if ((ret = ffm_is_avail_data(s, size)) < 0)
418  return ret;
419 
420  duration = AV_RB24(ffm->header + 5);
421 
422  av_new_packet(pkt, size);
423  pkt->stream_index = ffm->header[0];
424  if ((unsigned)pkt->stream_index >= s->nb_streams) {
425  av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
426  av_free_packet(pkt);
427  ffm->read_state = READ_HEADER;
428  return -1;
429  }
430  pkt->pos = avio_tell(s->pb);
431  if (ffm->header[1] & FLAG_KEY_FRAME)
432  pkt->flags |= AV_PKT_FLAG_KEY;
433 
434  ffm->read_state = READ_HEADER;
435  if (ffm_read_data(s, pkt->data, size, 0) != size) {
436  /* bad case: desynchronized packet. we cancel all the packet loading */
437  av_free_packet(pkt);
438  return -1;
439  }
440  pkt->pts = AV_RB64(ffm->header+8);
441  if (ffm->header[1] & FLAG_DTS)
442  pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
443  else
444  pkt->dts = pkt->pts;
445  pkt->duration = duration;
446  break;
447  }
448  return 0;
449 }
450 
451 /* seek to a given time in the file. The file read pointer is
452  positioned at or before pts. XXX: the following code is quite
453  approximative */
454 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
455 {
456  FFMContext *ffm = s->priv_data;
457  int64_t pos_min, pos_max, pos;
458  int64_t pts_min, pts_max, pts;
459  double pos1;
460 
461  av_dlog(s, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
462  /* find the position using linear interpolation (better than
463  dichotomy in typical cases) */
464  pos_min = FFM_PACKET_SIZE;
465  pos_max = ffm->file_size - FFM_PACKET_SIZE;
466  while (pos_min <= pos_max) {
467  pts_min = get_dts(s, pos_min);
468  pts_max = get_dts(s, pos_max);
469  /* linear interpolation */
470  pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
471  (double)(pts_max - pts_min);
472  pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
473  if (pos <= pos_min)
474  pos = pos_min;
475  else if (pos >= pos_max)
476  pos = pos_max;
477  pts = get_dts(s, pos);
478  /* check if we are lucky */
479  if (pts == wanted_pts) {
480  goto found;
481  } else if (pts > wanted_pts) {
482  pos_max = pos - FFM_PACKET_SIZE;
483  } else {
484  pos_min = pos + FFM_PACKET_SIZE;
485  }
486  }
487  pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
488 
489  found:
490  ffm_seek1(s, pos);
491 
492  /* reset read state */
493  ffm->read_state = READ_HEADER;
494  ffm->packet_ptr = ffm->packet;
495  ffm->packet_end = ffm->packet;
496  ffm->first_packet = 1;
497 
498  return 0;
499 }
500 
501 static int ffm_probe(AVProbeData *p)
502 {
503  if (
504  p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
505  p->buf[3] == '1')
506  return AVPROBE_SCORE_MAX + 1;
507  return 0;
508 }
509 
511  .name = "ffm",
512  .long_name = NULL_IF_CONFIG_SMALL("FFM (AVserver live feed) format"),
513  .priv_data_size = sizeof(FFMContext),
518  .read_seek = ffm_seek,
519 };