FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
v4l2.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2000,2001 Fabrice Bellard
3  * Copyright (c) 2006 Luca Abeni
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 /**
23  * @file
24  * Video4Linux2 grab interface
25  *
26  * Part of this file is based on the V4L2 video capture example
27  * (http://linuxtv.org/downloads/v4l-dvb-apis/capture-example.html)
28  *
29  * Thanks to Michael Niedermayer for providing the mapping between
30  * V4L2_PIX_FMT_* and AV_PIX_FMT_*
31  */
32 
33 #include "v4l2-common.h"
34 #include <dirent.h>
35 
36 #if CONFIG_LIBV4L2
37 #include <libv4l2.h>
38 #endif
39 
40 static const int desired_video_buffers = 256;
41 
42 #define V4L_ALLFORMATS 3
43 #define V4L_RAWFORMATS 1
44 #define V4L_COMPFORMATS 2
45 
46 /**
47  * Return timestamps to the user exactly as returned by the kernel
48  */
49 #define V4L_TS_DEFAULT 0
50 /**
51  * Autodetect the kind of timestamps returned by the kernel and convert to
52  * absolute (wall clock) timestamps.
53  */
54 #define V4L_TS_ABS 1
55 /**
56  * Assume kernel timestamps are from the monotonic clock and convert to
57  * absolute timestamps.
58  */
59 #define V4L_TS_MONO2ABS 2
60 
61 /**
62  * Once the kind of timestamps returned by the kernel have been detected,
63  * the value of the timefilter (NULL or not) determines whether a conversion
64  * takes place.
65  */
66 #define V4L_TS_CONVERT_READY V4L_TS_DEFAULT
67 
68 struct video_data {
69  AVClass *class;
70  int fd;
71  int pixelformat; /* V4L2_PIX_FMT_* */
72  int width, height;
76  int ts_mode;
78  int64_t last_time_m;
79 
80  int buffers;
81  volatile int buffers_queued;
82  void **buf_start;
83  unsigned int *buf_len;
84  char *standard;
85  v4l2_std_id std_id;
86  int channel;
87  char *pixel_format; /**< Set by a private option. */
88  int list_format; /**< Set by a private option. */
89  int list_standard; /**< Set by a private option. */
90  char *framerate; /**< Set by a private option. */
91 
93  int (*open_f)(const char *file, int oflag, ...);
94  int (*close_f)(int fd);
95  int (*dup_f)(int fd);
96  int (*ioctl_f)(int fd, unsigned long int request, ...);
97  ssize_t (*read_f)(int fd, void *buffer, size_t n);
98  void *(*mmap_f)(void *start, size_t length, int prot, int flags, int fd, int64_t offset);
99  int (*munmap_f)(void *_start, size_t length);
100 };
101 
102 struct buff_data {
103  struct video_data *s;
104  int index;
105 };
106 
107 static int device_open(AVFormatContext *ctx)
108 {
109  struct video_data *s = ctx->priv_data;
110  struct v4l2_capability cap;
111  int fd;
112  int err;
113  int flags = O_RDWR;
114 
115 #define SET_WRAPPERS(prefix) do { \
116  s->open_f = prefix ## open; \
117  s->close_f = prefix ## close; \
118  s->dup_f = prefix ## dup; \
119  s->ioctl_f = prefix ## ioctl; \
120  s->read_f = prefix ## read; \
121  s->mmap_f = prefix ## mmap; \
122  s->munmap_f = prefix ## munmap; \
123 } while (0)
124 
125  if (s->use_libv4l2) {
126 #if CONFIG_LIBV4L2
127  SET_WRAPPERS(v4l2_);
128 #else
129  av_log(ctx, AV_LOG_ERROR, "libavdevice is not build with libv4l2 support.\n");
130  return AVERROR(EINVAL);
131 #endif
132  } else {
133  SET_WRAPPERS();
134  }
135 
136 #define v4l2_open s->open_f
137 #define v4l2_close s->close_f
138 #define v4l2_dup s->dup_f
139 #define v4l2_ioctl s->ioctl_f
140 #define v4l2_read s->read_f
141 #define v4l2_mmap s->mmap_f
142 #define v4l2_munmap s->munmap_f
143 
144  if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
145  flags |= O_NONBLOCK;
146  }
147 
148  fd = v4l2_open(ctx->filename, flags, 0);
149  if (fd < 0) {
150  err = AVERROR(errno);
151  av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",
152  ctx->filename, av_err2str(err));
153  return err;
154  }
155 
156  if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
157  err = AVERROR(errno);
158  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
159  av_err2str(err));
160  goto fail;
161  }
162 
163  av_log(ctx, AV_LOG_VERBOSE, "fd:%d capabilities:%x\n",
164  fd, cap.capabilities);
165 
166  if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
167  av_log(ctx, AV_LOG_ERROR, "Not a video capture device.\n");
168  err = AVERROR(ENODEV);
169  goto fail;
170  }
171 
172  if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
173  av_log(ctx, AV_LOG_ERROR,
174  "The device does not support the streaming I/O method.\n");
175  err = AVERROR(ENOSYS);
176  goto fail;
177  }
178 
179  return fd;
180 
181 fail:
182  v4l2_close(fd);
183  return err;
184 }
185 
186 static int device_init(AVFormatContext *ctx, int *width, int *height,
187  uint32_t pixelformat)
188 {
189  struct video_data *s = ctx->priv_data;
190  struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
191  int res = 0;
192 
193  fmt.fmt.pix.width = *width;
194  fmt.fmt.pix.height = *height;
195  fmt.fmt.pix.pixelformat = pixelformat;
196  fmt.fmt.pix.field = V4L2_FIELD_ANY;
197 
198  /* Some drivers will fail and return EINVAL when the pixelformat
199  is not supported (even if type field is valid and supported) */
200  if (v4l2_ioctl(s->fd, VIDIOC_S_FMT, &fmt) < 0)
201  res = AVERROR(errno);
202 
203  if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {
204  av_log(ctx, AV_LOG_INFO,
205  "The V4L2 driver changed the video from %dx%d to %dx%d\n",
206  *width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);
207  *width = fmt.fmt.pix.width;
208  *height = fmt.fmt.pix.height;
209  }
210 
211  if (pixelformat != fmt.fmt.pix.pixelformat) {
212  av_log(ctx, AV_LOG_DEBUG,
213  "The V4L2 driver changed the pixel format "
214  "from 0x%08X to 0x%08X\n",
215  pixelformat, fmt.fmt.pix.pixelformat);
216  res = AVERROR(EINVAL);
217  }
218 
219  if (fmt.fmt.pix.field == V4L2_FIELD_INTERLACED) {
220  av_log(ctx, AV_LOG_DEBUG,
221  "The V4L2 driver is using the interlaced mode\n");
222  s->interlaced = 1;
223  }
224 
225  return res;
226 }
227 
228 static int first_field(const struct video_data *s)
229 {
230  int res;
231  v4l2_std_id std;
232 
233  res = v4l2_ioctl(s->fd, VIDIOC_G_STD, &std);
234  if (res < 0)
235  return 0;
236  if (std & V4L2_STD_NTSC)
237  return 0;
238 
239  return 1;
240 }
241 
242 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
243 static void list_framesizes(AVFormatContext *ctx, uint32_t pixelformat)
244 {
245  const struct video_data *s = ctx->priv_data;
246  struct v4l2_frmsizeenum vfse = { .pixel_format = pixelformat };
247 
248  while(!v4l2_ioctl(s->fd, VIDIOC_ENUM_FRAMESIZES, &vfse)) {
249  switch (vfse.type) {
250  case V4L2_FRMSIZE_TYPE_DISCRETE:
251  av_log(ctx, AV_LOG_INFO, " %ux%u",
252  vfse.discrete.width, vfse.discrete.height);
253  break;
254  case V4L2_FRMSIZE_TYPE_CONTINUOUS:
255  case V4L2_FRMSIZE_TYPE_STEPWISE:
256  av_log(ctx, AV_LOG_INFO, " {%u-%u, %u}x{%u-%u, %u}",
257  vfse.stepwise.min_width,
258  vfse.stepwise.max_width,
259  vfse.stepwise.step_width,
260  vfse.stepwise.min_height,
261  vfse.stepwise.max_height,
262  vfse.stepwise.step_height);
263  }
264  vfse.index++;
265  }
266 }
267 #endif
268 
269 static void list_formats(AVFormatContext *ctx, int type)
270 {
271  const struct video_data *s = ctx->priv_data;
272  struct v4l2_fmtdesc vfd = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
273 
274  while(!v4l2_ioctl(s->fd, VIDIOC_ENUM_FMT, &vfd)) {
275  enum AVCodecID codec_id = ff_fmt_v4l2codec(vfd.pixelformat);
276  enum AVPixelFormat pix_fmt = ff_fmt_v4l2ff(vfd.pixelformat, codec_id);
277 
278  vfd.index++;
279 
280  if (!(vfd.flags & V4L2_FMT_FLAG_COMPRESSED) &&
281  type & V4L_RAWFORMATS) {
282  const char *fmt_name = av_get_pix_fmt_name(pix_fmt);
283  av_log(ctx, AV_LOG_INFO, "Raw : %9s : %20s :",
284  fmt_name ? fmt_name : "Unsupported",
285  vfd.description);
286  } else if (vfd.flags & V4L2_FMT_FLAG_COMPRESSED &&
287  type & V4L_COMPFORMATS) {
288  AVCodec *codec = avcodec_find_decoder(codec_id);
289  av_log(ctx, AV_LOG_INFO, "Compressed: %9s : %20s :",
290  codec ? codec->name : "Unsupported",
291  vfd.description);
292  } else {
293  continue;
294  }
295 
296 #ifdef V4L2_FMT_FLAG_EMULATED
297  if (vfd.flags & V4L2_FMT_FLAG_EMULATED)
298  av_log(ctx, AV_LOG_INFO, " Emulated :");
299 #endif
300 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
301  list_framesizes(ctx, vfd.pixelformat);
302 #endif
303  av_log(ctx, AV_LOG_INFO, "\n");
304  }
305 }
306 
308 {
309  int ret;
310  struct video_data *s = ctx->priv_data;
311  struct v4l2_standard standard;
312 
313  if (s->std_id == 0)
314  return;
315 
316  for (standard.index = 0; ; standard.index++) {
317  if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
318  ret = AVERROR(errno);
319  if (ret == AVERROR(EINVAL)) {
320  break;
321  } else {
322  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
323  return;
324  }
325  }
326  av_log(ctx, AV_LOG_INFO, "%2d, %16"PRIx64", %s\n",
327  standard.index, (uint64_t)standard.id, standard.name);
328  }
329 }
330 
331 static int mmap_init(AVFormatContext *ctx)
332 {
333  int i, res;
334  struct video_data *s = ctx->priv_data;
335  struct v4l2_requestbuffers req = {
336  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
337  .count = desired_video_buffers,
338  .memory = V4L2_MEMORY_MMAP
339  };
340 
341  if (v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req) < 0) {
342  res = AVERROR(errno);
343  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS): %s\n", av_err2str(res));
344  return res;
345  }
346 
347  if (req.count < 2) {
348  av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");
349  return AVERROR(ENOMEM);
350  }
351  s->buffers = req.count;
352  s->buf_start = av_malloc_array(s->buffers, sizeof(void *));
353  if (!s->buf_start) {
354  av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");
355  return AVERROR(ENOMEM);
356  }
357  s->buf_len = av_malloc_array(s->buffers, sizeof(unsigned int));
358  if (!s->buf_len) {
359  av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");
360  av_freep(&s->buf_start);
361  return AVERROR(ENOMEM);
362  }
363 
364  for (i = 0; i < req.count; i++) {
365  struct v4l2_buffer buf = {
366  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
367  .index = i,
368  .memory = V4L2_MEMORY_MMAP
369  };
370  if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {
371  res = AVERROR(errno);
372  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF): %s\n", av_err2str(res));
373  return res;
374  }
375 
376  s->buf_len[i] = buf.length;
377  if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) {
378  av_log(ctx, AV_LOG_ERROR,
379  "buf_len[%d] = %d < expected frame size %d\n",
380  i, s->buf_len[i], s->frame_size);
381  return AVERROR(ENOMEM);
382  }
383  s->buf_start[i] = v4l2_mmap(NULL, buf.length,
384  PROT_READ | PROT_WRITE, MAP_SHARED,
385  s->fd, buf.m.offset);
386 
387  if (s->buf_start[i] == MAP_FAILED) {
388  res = AVERROR(errno);
389  av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", av_err2str(res));
390  return res;
391  }
392  }
393 
394  return 0;
395 }
396 
397 #if FF_API_DESTRUCT_PACKET
398 static void dummy_release_buffer(AVPacket *pkt)
399 {
400  av_assert0(0);
401 }
402 #endif
403 
404 static int enqueue_buffer(struct video_data *s, struct v4l2_buffer *buf)
405 {
406  int res = 0;
407 
408  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, buf) < 0) {
409  res = AVERROR(errno);
410  av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
411  } else {
413  }
414 
415  return res;
416 }
417 
418 static void mmap_release_buffer(void *opaque, uint8_t *data)
419 {
420  struct v4l2_buffer buf = { 0 };
421  struct buff_data *buf_descriptor = opaque;
422  struct video_data *s = buf_descriptor->s;
423 
424  buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
425  buf.memory = V4L2_MEMORY_MMAP;
426  buf.index = buf_descriptor->index;
427  av_free(buf_descriptor);
428 
429  enqueue_buffer(s, &buf);
430 }
431 
432 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
433 static int64_t av_gettime_monotonic(void)
434 {
435  return av_gettime_relative();
436 }
437 #endif
438 
439 static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)
440 {
441  struct video_data *s = ctx->priv_data;
442  int64_t now;
443 
444  now = av_gettime();
445  if (s->ts_mode == V4L_TS_ABS &&
446  ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE) {
447  av_log(ctx, AV_LOG_INFO, "Detected absolute timestamps\n");
449  return 0;
450  }
451 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
452  if (ctx->streams[0]->avg_frame_rate.num) {
453  now = av_gettime_monotonic();
454  if (s->ts_mode == V4L_TS_MONO2ABS ||
455  (ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE)) {
456  AVRational tb = {AV_TIME_BASE, 1};
457  int64_t period = av_rescale_q(1, tb, ctx->streams[0]->avg_frame_rate);
458  av_log(ctx, AV_LOG_INFO, "Detected monotonic timestamps, converting\n");
459  /* microseconds instead of seconds, MHz instead of Hz */
460  s->timefilter = ff_timefilter_new(1, period, 1.0E-6);
461  if (!s->timefilter)
462  return AVERROR(ENOMEM);
464  return 0;
465  }
466  }
467 #endif
468  av_log(ctx, AV_LOG_ERROR, "Unknown timestamps\n");
469  return AVERROR(EIO);
470 }
471 
472 static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)
473 {
474  struct video_data *s = ctx->priv_data;
475 
476  if (s->ts_mode) {
477  int r = init_convert_timestamp(ctx, *ts);
478  if (r < 0)
479  return r;
480  }
481 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
482  if (s->timefilter) {
483  int64_t nowa = av_gettime();
484  int64_t nowm = av_gettime_monotonic();
485  ff_timefilter_update(s->timefilter, nowa, nowm - s->last_time_m);
486  s->last_time_m = nowm;
487  *ts = ff_timefilter_eval(s->timefilter, *ts - nowm);
488  }
489 #endif
490  return 0;
491 }
492 
494 {
495  struct video_data *s = ctx->priv_data;
496  struct v4l2_buffer buf = {
497  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
498  .memory = V4L2_MEMORY_MMAP
499  };
500  int res;
501 
502  /* FIXME: Some special treatment might be needed in case of loss of signal... */
503  while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
504  if (res < 0) {
505  if (errno == EAGAIN) {
506  pkt->size = 0;
507  return AVERROR(EAGAIN);
508  }
509  res = AVERROR(errno);
510  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n",
511  av_err2str(res));
512  return res;
513  }
514 
515  if (buf.index >= s->buffers) {
516  av_log(ctx, AV_LOG_ERROR, "Invalid buffer index received.\n");
517  return AVERROR(EINVAL);
518  }
520  // always keep at least one buffer queued
522 
523  /* CPIA is a compressed format and we don't know the exact number of bytes
524  * used by a frame, so set it here as the driver announces it.
525  */
526  if (ctx->video_codec_id == AV_CODEC_ID_CPIA)
527  s->frame_size = buf.bytesused;
528 
529  if (s->frame_size > 0 && buf.bytesused != s->frame_size) {
530  av_log(ctx, AV_LOG_ERROR,
531  "The v4l2 frame is %d bytes, but %d bytes are expected\n",
532  buf.bytesused, s->frame_size);
533  enqueue_buffer(s, &buf);
534  return AVERROR_INVALIDDATA;
535  }
536 
537  /* Image is at s->buff_start[buf.index] */
538  if (avpriv_atomic_int_get(&s->buffers_queued) == FFMAX(s->buffers / 8, 1)) {
539  /* when we start getting low on queued buffers, fall back on copying data */
540  res = av_new_packet(pkt, buf.bytesused);
541  if (res < 0) {
542  av_log(ctx, AV_LOG_ERROR, "Error allocating a packet.\n");
543  enqueue_buffer(s, &buf);
544  return res;
545  }
546  memcpy(pkt->data, s->buf_start[buf.index], buf.bytesused);
547 
548  res = enqueue_buffer(s, &buf);
549  if (res) {
550  av_free_packet(pkt);
551  return res;
552  }
553  } else {
554  struct buff_data *buf_descriptor;
555 
556  pkt->data = s->buf_start[buf.index];
557  pkt->size = buf.bytesused;
558 #if FF_API_DESTRUCT_PACKET
560  pkt->destruct = dummy_release_buffer;
562 #endif
563 
564  buf_descriptor = av_malloc(sizeof(struct buff_data));
565  if (!buf_descriptor) {
566  /* Something went wrong... Since av_malloc() failed, we cannot even
567  * allocate a buffer for memcpying into it
568  */
569  av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
570  enqueue_buffer(s, &buf);
571 
572  return AVERROR(ENOMEM);
573  }
574  buf_descriptor->index = buf.index;
575  buf_descriptor->s = s;
576 
577  pkt->buf = av_buffer_create(pkt->data, pkt->size, mmap_release_buffer,
578  buf_descriptor, 0);
579  if (!pkt->buf) {
580  av_log(ctx, AV_LOG_ERROR, "Failed to create a buffer\n");
581  enqueue_buffer(s, &buf);
582  av_freep(&buf_descriptor);
583  return AVERROR(ENOMEM);
584  }
585  }
586  pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec;
587  convert_timestamp(ctx, &pkt->pts);
588 
589  return s->buf_len[buf.index];
590 }
591 
592 static int mmap_start(AVFormatContext *ctx)
593 {
594  struct video_data *s = ctx->priv_data;
595  enum v4l2_buf_type type;
596  int i, res;
597 
598  for (i = 0; i < s->buffers; i++) {
599  struct v4l2_buffer buf = {
600  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
601  .index = i,
602  .memory = V4L2_MEMORY_MMAP
603  };
604 
605  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
606  res = AVERROR(errno);
607  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
608  av_err2str(res));
609  return res;
610  }
611  }
612  s->buffers_queued = s->buffers;
613 
614  type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
615  if (v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type) < 0) {
616  res = AVERROR(errno);
617  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n",
618  av_err2str(res));
619  return res;
620  }
621 
622  return 0;
623 }
624 
625 static void mmap_close(struct video_data *s)
626 {
627  enum v4l2_buf_type type;
628  int i;
629 
630  type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
631  /* We do not check for the result, because we could
632  * not do anything about it anyway...
633  */
634  v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
635  for (i = 0; i < s->buffers; i++) {
636  v4l2_munmap(s->buf_start[i], s->buf_len[i]);
637  }
638  av_freep(&s->buf_start);
639  av_freep(&s->buf_len);
640 }
641 
643 {
644  struct video_data *s = ctx->priv_data;
645  struct v4l2_standard standard = { 0 };
646  struct v4l2_streamparm streamparm = { 0 };
647  struct v4l2_fract *tpf;
648  AVRational framerate_q = { 0 };
649  int i, ret;
650 
651  if (s->framerate &&
652  (ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) {
653  av_log(ctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n",
654  s->framerate);
655  return ret;
656  }
657 
658  if (s->standard) {
659  if (s->std_id) {
660  ret = 0;
661  av_log(ctx, AV_LOG_DEBUG, "Setting standard: %s\n", s->standard);
662  /* set tv standard */
663  for (i = 0; ; i++) {
664  standard.index = i;
665  if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
666  ret = AVERROR(errno);
667  break;
668  }
669  if (!av_strcasecmp(standard.name, s->standard))
670  break;
671  }
672  if (ret < 0) {
673  av_log(ctx, AV_LOG_ERROR, "Unknown or unsupported standard '%s'\n", s->standard);
674  return ret;
675  }
676 
677  if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
678  ret = AVERROR(errno);
679  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_STD): %s\n", av_err2str(ret));
680  return ret;
681  }
682  } else {
683  av_log(ctx, AV_LOG_WARNING,
684  "This device does not support any standard\n");
685  }
686  }
687 
688  /* get standard */
689  if (v4l2_ioctl(s->fd, VIDIOC_G_STD, &s->std_id) == 0) {
690  tpf = &standard.frameperiod;
691  for (i = 0; ; i++) {
692  standard.index = i;
693  if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
694  ret = AVERROR(errno);
695  if (ret == AVERROR(EINVAL)
696 #ifdef ENODATA
697  || ret == AVERROR(ENODATA)
698 #endif
699  ) {
700  tpf = &streamparm.parm.capture.timeperframe;
701  break;
702  }
703  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
704  return ret;
705  }
706  if (standard.id == s->std_id) {
707  av_log(ctx, AV_LOG_DEBUG,
708  "Current standard: %s, id: %"PRIx64", frameperiod: %d/%d\n",
709  standard.name, (uint64_t)standard.id, tpf->numerator, tpf->denominator);
710  break;
711  }
712  }
713  } else {
714  tpf = &streamparm.parm.capture.timeperframe;
715  }
716 
717  streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
718  if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) < 0) {
719  ret = AVERROR(errno);
720  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n", av_err2str(ret));
721  return ret;
722  }
723 
724  if (framerate_q.num && framerate_q.den) {
725  if (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) {
726  tpf = &streamparm.parm.capture.timeperframe;
727 
728  av_log(ctx, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
729  framerate_q.den, framerate_q.num);
730  tpf->numerator = framerate_q.den;
731  tpf->denominator = framerate_q.num;
732 
733  if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) < 0) {
734  ret = AVERROR(errno);
735  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_PARM): %s\n",
736  av_err2str(ret));
737  return ret;
738  }
739 
740  if (framerate_q.num != tpf->denominator ||
741  framerate_q.den != tpf->numerator) {
742  av_log(ctx, AV_LOG_INFO,
743  "The driver changed the time per frame from "
744  "%d/%d to %d/%d\n",
745  framerate_q.den, framerate_q.num,
746  tpf->numerator, tpf->denominator);
747  }
748  } else {
749  av_log(ctx, AV_LOG_WARNING,
750  "The driver does not allow to change time per frame\n");
751  }
752  }
753  if (tpf->denominator > 0 && tpf->numerator > 0) {
754  ctx->streams[0]->avg_frame_rate.num = tpf->denominator;
755  ctx->streams[0]->avg_frame_rate.den = tpf->numerator;
756  ctx->streams[0]->r_frame_rate = ctx->streams[0]->avg_frame_rate;
757  } else
758  av_log(ctx, AV_LOG_WARNING, "Time per frame unknown\n");
759 
760  return 0;
761 }
762 
764  enum AVPixelFormat pix_fmt,
765  int *width,
766  int *height,
767  uint32_t *desired_format,
768  enum AVCodecID *codec_id)
769 {
770  int ret, i;
771 
772  *desired_format = ff_fmt_ff2v4l(pix_fmt, ctx->video_codec_id);
773 
774  if (*desired_format) {
775  ret = device_init(ctx, width, height, *desired_format);
776  if (ret < 0) {
777  *desired_format = 0;
778  if (ret != AVERROR(EINVAL))
779  return ret;
780  }
781  }
782 
783  if (!*desired_format) {
784  for (i = 0; ff_fmt_conversion_table[i].codec_id != AV_CODEC_ID_NONE; i++) {
785  if (ctx->video_codec_id == AV_CODEC_ID_NONE ||
787  av_log(ctx, AV_LOG_DEBUG, "Trying to set codec:%s pix_fmt:%s\n",
789  (char *)av_x_if_null(av_get_pix_fmt_name(ff_fmt_conversion_table[i].ff_fmt), "none"));
790 
791  *desired_format = ff_fmt_conversion_table[i].v4l2_fmt;
792  ret = device_init(ctx, width, height, *desired_format);
793  if (ret >= 0)
794  break;
795  else if (ret != AVERROR(EINVAL))
796  return ret;
797  *desired_format = 0;
798  }
799  }
800 
801  if (*desired_format == 0) {
802  av_log(ctx, AV_LOG_ERROR, "Cannot find a proper format for "
803  "codec '%s' (id %d), pixel format '%s' (id %d)\n",
805  (char *)av_x_if_null(av_get_pix_fmt_name(pix_fmt), "none"), pix_fmt);
806  ret = AVERROR(EINVAL);
807  }
808  }
809 
810  *codec_id = ff_fmt_v4l2codec(*desired_format);
811  av_assert0(*codec_id != AV_CODEC_ID_NONE);
812  return ret;
813 }
814 
816 {
817  if (av_strstart(p->filename, "/dev/video", NULL))
818  return AVPROBE_SCORE_MAX - 1;
819  return 0;
820 }
821 
823 {
824  struct video_data *s = ctx->priv_data;
825  AVStream *st;
826  int res = 0;
827  uint32_t desired_format;
830  struct v4l2_input input = { 0 };
831 
832  st = avformat_new_stream(ctx, NULL);
833  if (!st)
834  return AVERROR(ENOMEM);
835 
836 #if CONFIG_LIBV4L2
837  /* silence libv4l2 logging. if fopen() fails v4l2_log_file will be NULL
838  and errors will get sent to stderr */
839  if (s->use_libv4l2)
840  v4l2_log_file = fopen("/dev/null", "w");
841 #endif
842 
843  s->fd = device_open(ctx);
844  if (s->fd < 0)
845  return s->fd;
846 
847  if (s->channel != -1) {
848  /* set video input */
849  av_log(ctx, AV_LOG_DEBUG, "Selecting input_channel: %d\n", s->channel);
850  if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &s->channel) < 0) {
851  res = AVERROR(errno);
852  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_INPUT): %s\n", av_err2str(res));
853  goto fail;
854  }
855  } else {
856  /* get current video input */
857  if (v4l2_ioctl(s->fd, VIDIOC_G_INPUT, &s->channel) < 0) {
858  res = AVERROR(errno);
859  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_INPUT): %s\n", av_err2str(res));
860  goto fail;
861  }
862  }
863 
864  /* enum input */
865  input.index = s->channel;
866  if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
867  res = AVERROR(errno);
868  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMINPUT): %s\n", av_err2str(res));
869  goto fail;
870  }
871  s->std_id = input.std;
872  av_log(ctx, AV_LOG_DEBUG, "Current input_channel: %d, input_name: %s, input_std: %"PRIx64"\n",
873  s->channel, input.name, (uint64_t)input.std);
874 
875  if (s->list_format) {
876  list_formats(ctx, s->list_format);
877  res = AVERROR_EXIT;
878  goto fail;
879  }
880 
881  if (s->list_standard) {
882  list_standards(ctx);
883  res = AVERROR_EXIT;
884  goto fail;
885  }
886 
887  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
888 
889  if (s->pixel_format) {
891 
892  if (codec)
893  ctx->video_codec_id = codec->id;
894 
895  pix_fmt = av_get_pix_fmt(s->pixel_format);
896 
897  if (pix_fmt == AV_PIX_FMT_NONE && !codec) {
898  av_log(ctx, AV_LOG_ERROR, "No such input format: %s.\n",
899  s->pixel_format);
900 
901  res = AVERROR(EINVAL);
902  goto fail;
903  }
904  }
905 
906  if (!s->width && !s->height) {
907  struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
908 
909  av_log(ctx, AV_LOG_VERBOSE,
910  "Querying the device for the current frame size\n");
911  if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
912  res = AVERROR(errno);
913  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n",
914  av_err2str(res));
915  goto fail;
916  }
917 
918  s->width = fmt.fmt.pix.width;
919  s->height = fmt.fmt.pix.height;
920  av_log(ctx, AV_LOG_VERBOSE,
921  "Setting frame size to %dx%d\n", s->width, s->height);
922  }
923 
924  res = device_try_init(ctx, pix_fmt, &s->width, &s->height, &desired_format, &codec_id);
925  if (res < 0)
926  goto fail;
927 
928  /* If no pixel_format was specified, the codec_id was not known up
929  * until now. Set video_codec_id in the context, as codec_id will
930  * not be available outside this function
931  */
932  if (codec_id != AV_CODEC_ID_NONE && ctx->video_codec_id == AV_CODEC_ID_NONE)
933  ctx->video_codec_id = codec_id;
934 
935  if ((res = av_image_check_size(s->width, s->height, 0, ctx)) < 0)
936  goto fail;
937 
938  s->pixelformat = desired_format;
939 
940  if ((res = v4l2_set_parameters(ctx)) < 0)
941  goto fail;
942 
943  st->codec->pix_fmt = ff_fmt_v4l2ff(desired_format, codec_id);
944  s->frame_size =
946 
947  if ((res = mmap_init(ctx)) ||
948  (res = mmap_start(ctx)) < 0)
949  goto fail;
950 
952 
954  st->codec->codec_id = codec_id;
955  if (codec_id == AV_CODEC_ID_RAWVIDEO)
956  st->codec->codec_tag =
958  else if (codec_id == AV_CODEC_ID_H264) {
960  }
961  if (desired_format == V4L2_PIX_FMT_YVU420)
962  st->codec->codec_tag = MKTAG('Y', 'V', '1', '2');
963  else if (desired_format == V4L2_PIX_FMT_YVU410)
964  st->codec->codec_tag = MKTAG('Y', 'V', 'U', '9');
965  st->codec->width = s->width;
966  st->codec->height = s->height;
967  if (st->avg_frame_rate.den)
968  st->codec->bit_rate = s->frame_size * av_q2d(st->avg_frame_rate) * 8;
969 
970  return 0;
971 
972 fail:
973  v4l2_close(s->fd);
974  return res;
975 }
976 
978 {
979  struct video_data *s = ctx->priv_data;
980  AVFrame *frame = ctx->streams[0]->codec->coded_frame;
981  int res;
982 
983  av_init_packet(pkt);
984  if ((res = mmap_read_frame(ctx, pkt)) < 0) {
985  return res;
986  }
987 
988  if (frame && s->interlaced) {
989  frame->interlaced_frame = 1;
990  frame->top_field_first = s->top_field_first;
991  }
992 
993  return pkt->size;
994 }
995 
997 {
998  struct video_data *s = ctx->priv_data;
999 
1001  av_log(ctx, AV_LOG_WARNING, "Some buffers are still owned by the caller on "
1002  "close.\n");
1003 
1004  mmap_close(s);
1005 
1006  v4l2_close(s->fd);
1007  return 0;
1008 }
1009 
1010 static int v4l2_is_v4l_dev(const char *name)
1011 {
1012  return !strncmp(name, "video", 5) ||
1013  !strncmp(name, "radio", 5) ||
1014  !strncmp(name, "vbi", 3) ||
1015  !strncmp(name, "v4l-subdev", 10);
1016 }
1017 
1019 {
1020  struct video_data *s = ctx->priv_data;
1021  DIR *dir;
1022  struct dirent *entry;
1023  AVDeviceInfo *device = NULL;
1024  struct v4l2_capability cap;
1025  int ret = 0;
1026 
1027  if (!device_list)
1028  return AVERROR(EINVAL);
1029 
1030  dir = opendir("/dev");
1031  if (!dir) {
1032  ret = AVERROR(errno);
1033  av_log(ctx, AV_LOG_ERROR, "Couldn't open the directory: %s\n", av_err2str(ret));
1034  return ret;
1035  }
1036  while ((entry = readdir(dir))) {
1037  if (!v4l2_is_v4l_dev(entry->d_name))
1038  continue;
1039 
1040  snprintf(ctx->filename, sizeof(ctx->filename), "/dev/%s", entry->d_name);
1041  if ((s->fd = device_open(ctx)) < 0)
1042  continue;
1043 
1044  if (v4l2_ioctl(s->fd, VIDIOC_QUERYCAP, &cap) < 0) {
1045  ret = AVERROR(errno);
1046  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n", av_err2str(ret));
1047  goto fail;
1048  }
1049 
1050  device = av_mallocz(sizeof(AVDeviceInfo));
1051  if (!device) {
1052  ret = AVERROR(ENOMEM);
1053  goto fail;
1054  }
1055  device->device_name = av_strdup(ctx->filename);
1056  device->device_description = av_strdup(cap.card);
1057  if (!device->device_name || !device->device_description) {
1058  ret = AVERROR(ENOMEM);
1059  goto fail;
1060  }
1061 
1062  if ((ret = av_dynarray_add_nofree(&device_list->devices,
1063  &device_list->nb_devices, device)) < 0)
1064  goto fail;
1065 
1066  v4l2_close(s->fd);
1067  s->fd = -1;
1068  continue;
1069 
1070  fail:
1071  if (device) {
1072  av_freep(&device->device_name);
1073  av_freep(&device->device_description);
1074  av_freep(&device);
1075  }
1076  if (s->fd >= 0)
1077  v4l2_close(s->fd);
1078  s->fd = -1;
1079  break;
1080  }
1081  closedir(dir);
1082  return ret;
1083 }
1084 
1085 #define OFFSET(x) offsetof(struct video_data, x)
1086 #define DEC AV_OPT_FLAG_DECODING_PARAM
1087 
1088 static const AVOption options[] = {
1089  { "standard", "set TV standard, used only by analog frame grabber", OFFSET(standard), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, DEC },
1090  { "channel", "set TV channel, used only by frame grabber", OFFSET(channel), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, INT_MAX, DEC },
1091  { "video_size", "set frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
1092  { "pixel_format", "set preferred pixel format", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1093  { "input_format", "set preferred pixel format (for raw video) or codec name", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1094  { "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1095 
1096  { "list_formats", "list available formats and exit", OFFSET(list_format), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, DEC, "list_formats" },
1097  { "all", "show all available formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_ALLFORMATS }, 0, INT_MAX, DEC, "list_formats" },
1098  { "raw", "show only non-compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_RAWFORMATS }, 0, INT_MAX, DEC, "list_formats" },
1099  { "compressed", "show only compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_COMPFORMATS }, 0, INT_MAX, DEC, "list_formats" },
1100 
1101  { "list_standards", "list supported standards and exit", OFFSET(list_standard), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, DEC, "list_standards" },
1102  { "all", "show all supported standards", OFFSET(list_standard), AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, DEC, "list_standards" },
1103 
1104  { "timestamps", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },
1105  { "ts", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },
1106  { "default", "use timestamps from the kernel", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_DEFAULT }, 0, 2, DEC, "timestamps" },
1107  { "abs", "use absolute timestamps (wall clock)", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_ABS }, 0, 2, DEC, "timestamps" },
1108  { "mono2abs", "force conversion from monotonic to absolute timestamps", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, "timestamps" },
1109  { "use_libv4l2", "use libv4l2 (v4l-utils) conversion functions", OFFSET(use_libv4l2), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
1110  { NULL },
1111 };
1112 
1113 static const AVClass v4l2_class = {
1114  .class_name = "V4L2 indev",
1115  .item_name = av_default_item_name,
1116  .option = options,
1117  .version = LIBAVUTIL_VERSION_INT,
1119 };
1120 
1122  .name = "video4linux2,v4l2",
1123  .long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),
1124  .priv_data_size = sizeof(struct video_data),
1125  .read_probe = v4l2_read_probe,
1126  .read_header = v4l2_read_header,
1127  .read_packet = v4l2_read_packet,
1128  .read_close = v4l2_read_close,
1129  .get_device_list = v4l2_get_device_list,
1130  .flags = AVFMT_NOFILE,
1131  .priv_class = &v4l2_class,
1132 };