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v4l2.c
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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 
35 #if CONFIG_LIBV4L2
36 #include <libv4l2.h>
37 #endif
38 
39 static const int desired_video_buffers = 256;
40 
41 #define V4L_ALLFORMATS 3
42 #define V4L_RAWFORMATS 1
43 #define V4L_COMPFORMATS 2
44 
45 /**
46  * Return timestamps to the user exactly as returned by the kernel
47  */
48 #define V4L_TS_DEFAULT 0
49 /**
50  * Autodetect the kind of timestamps returned by the kernel and convert to
51  * absolute (wall clock) timestamps.
52  */
53 #define V4L_TS_ABS 1
54 /**
55  * Assume kernel timestamps are from the monotonic clock and convert to
56  * absolute timestamps.
57  */
58 #define V4L_TS_MONO2ABS 2
59 
60 /**
61  * Once the kind of timestamps returned by the kernel have been detected,
62  * the value of the timefilter (NULL or not) determines whether a conversion
63  * takes place.
64  */
65 #define V4L_TS_CONVERT_READY V4L_TS_DEFAULT
66 
67 struct video_data {
68  AVClass *class;
69  int fd;
70  int frame_format; /* V4L2_PIX_FMT_* */
71  int width, height;
75  int ts_mode;
77  int64_t last_time_m;
78 
79  int buffers;
80  volatile int buffers_queued;
81  void **buf_start;
82  unsigned int *buf_len;
83  char *standard;
84  v4l2_std_id std_id;
85  int channel;
86  char *pixel_format; /**< Set by a private option. */
87  int list_format; /**< Set by a private option. */
88  int list_standard; /**< Set by a private option. */
89  char *framerate; /**< Set by a private option. */
90 
92  int (*open_f)(const char *file, int oflag, ...);
93  int (*close_f)(int fd);
94  int (*dup_f)(int fd);
95  int (*ioctl_f)(int fd, unsigned long int request, ...);
96  ssize_t (*read_f)(int fd, void *buffer, size_t n);
97  void *(*mmap_f)(void *start, size_t length, int prot, int flags, int fd, int64_t offset);
98  int (*munmap_f)(void *_start, size_t length);
99 };
100 
101 struct buff_data {
102  struct video_data *s;
103  int index;
104 };
105 
106 static int device_open(AVFormatContext *ctx)
107 {
108  struct video_data *s = ctx->priv_data;
109  struct v4l2_capability cap;
110  int fd;
111  int ret;
112  int flags = O_RDWR;
113 
114 #define SET_WRAPPERS(prefix) do { \
115  s->open_f = prefix ## open; \
116  s->close_f = prefix ## close; \
117  s->dup_f = prefix ## dup; \
118  s->ioctl_f = prefix ## ioctl; \
119  s->read_f = prefix ## read; \
120  s->mmap_f = prefix ## mmap; \
121  s->munmap_f = prefix ## munmap; \
122 } while (0)
123 
124  if (s->use_libv4l2) {
125 #if CONFIG_LIBV4L2
126  SET_WRAPPERS(v4l2_);
127 #else
128  av_log(ctx, AV_LOG_ERROR, "libavdevice is not build with libv4l2 support.\n");
129  return AVERROR(EINVAL);
130 #endif
131  } else {
132  SET_WRAPPERS();
133  }
134 
135 #define v4l2_open s->open_f
136 #define v4l2_close s->close_f
137 #define v4l2_dup s->dup_f
138 #define v4l2_ioctl s->ioctl_f
139 #define v4l2_read s->read_f
140 #define v4l2_mmap s->mmap_f
141 #define v4l2_munmap s->munmap_f
142 
143  if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
144  flags |= O_NONBLOCK;
145  }
146 
147  fd = v4l2_open(ctx->filename, flags, 0);
148  if (fd < 0) {
149  ret = AVERROR(errno);
150  av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",
151  ctx->filename, av_err2str(ret));
152  return ret;
153  }
154 
155  if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
156  ret = AVERROR(errno);
157  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
158  av_err2str(ret));
159  goto fail;
160  }
161 
162  av_log(ctx, AV_LOG_VERBOSE, "fd:%d capabilities:%x\n",
163  fd, cap.capabilities);
164 
165  if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
166  av_log(ctx, AV_LOG_ERROR, "Not a video capture device.\n");
167  ret = AVERROR(ENODEV);
168  goto fail;
169  }
170 
171  if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
172  av_log(ctx, AV_LOG_ERROR,
173  "The device does not support the streaming I/O method.\n");
174  ret = AVERROR(ENOSYS);
175  goto fail;
176  }
177 
178  return fd;
179 
180 fail:
181  v4l2_close(fd);
182  return ret;
183 }
184 
185 static int device_init(AVFormatContext *ctx, int *width, int *height,
186  uint32_t pix_fmt)
187 {
188  struct video_data *s = ctx->priv_data;
189  int fd = s->fd;
190  struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
191  struct v4l2_pix_format *pix = &fmt.fmt.pix;
192 
193  int res = 0;
194 
195  pix->width = *width;
196  pix->height = *height;
197  pix->pixelformat = pix_fmt;
198  pix->field = V4L2_FIELD_ANY;
199 
200  if (v4l2_ioctl(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 (pix_fmt != 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  pix_fmt, 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, int fd)
229 {
230  int res;
231  v4l2_std_id std;
232 
233  res = v4l2_ioctl(fd, VIDIOC_G_STD, &std);
234  if (res < 0) {
235  return 0;
236  }
237  if (std & V4L2_STD_NTSC) {
238  return 0;
239  }
240 
241  return 1;
242 }
243 
244 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
245 static void list_framesizes(AVFormatContext *ctx, int fd, uint32_t pixelformat)
246 {
247  const struct video_data *s = ctx->priv_data;
248  struct v4l2_frmsizeenum vfse = { .pixel_format = pixelformat };
249 
250  while(!v4l2_ioctl(fd, VIDIOC_ENUM_FRAMESIZES, &vfse)) {
251  switch (vfse.type) {
252  case V4L2_FRMSIZE_TYPE_DISCRETE:
253  av_log(ctx, AV_LOG_INFO, " %ux%u",
254  vfse.discrete.width, vfse.discrete.height);
255  break;
256  case V4L2_FRMSIZE_TYPE_CONTINUOUS:
257  case V4L2_FRMSIZE_TYPE_STEPWISE:
258  av_log(ctx, AV_LOG_INFO, " {%u-%u, %u}x{%u-%u, %u}",
259  vfse.stepwise.min_width,
260  vfse.stepwise.max_width,
261  vfse.stepwise.step_width,
262  vfse.stepwise.min_height,
263  vfse.stepwise.max_height,
264  vfse.stepwise.step_height);
265  }
266  vfse.index++;
267  }
268 }
269 #endif
270 
271 static void list_formats(AVFormatContext *ctx, int fd, int type)
272 {
273  const struct video_data *s = ctx->priv_data;
274  struct v4l2_fmtdesc vfd = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
275 
276  while(!v4l2_ioctl(fd, VIDIOC_ENUM_FMT, &vfd)) {
277  enum AVCodecID codec_id = avpriv_fmt_v4l2codec(vfd.pixelformat);
278  enum AVPixelFormat pix_fmt = avpriv_fmt_v4l2ff(vfd.pixelformat, codec_id);
279 
280  vfd.index++;
281 
282  if (!(vfd.flags & V4L2_FMT_FLAG_COMPRESSED) &&
283  type & V4L_RAWFORMATS) {
284  const char *fmt_name = av_get_pix_fmt_name(pix_fmt);
285  av_log(ctx, AV_LOG_INFO, "Raw : %9s : %20s :",
286  fmt_name ? fmt_name : "Unsupported",
287  vfd.description);
288  } else if (vfd.flags & V4L2_FMT_FLAG_COMPRESSED &&
289  type & V4L_COMPFORMATS) {
290  AVCodec *codec = avcodec_find_decoder(codec_id);
291  av_log(ctx, AV_LOG_INFO, "Compressed: %9s : %20s :",
292  codec ? codec->name : "Unsupported",
293  vfd.description);
294  } else {
295  continue;
296  }
297 
298 #ifdef V4L2_FMT_FLAG_EMULATED
299  if (vfd.flags & V4L2_FMT_FLAG_EMULATED)
300  av_log(ctx, AV_LOG_INFO, " Emulated :");
301 #endif
302 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
303  list_framesizes(ctx, fd, vfd.pixelformat);
304 #endif
305  av_log(ctx, AV_LOG_INFO, "\n");
306  }
307 }
308 
310 {
311  int ret;
312  struct video_data *s = ctx->priv_data;
313  struct v4l2_standard standard;
314 
315  if (s->std_id == 0)
316  return;
317 
318  for (standard.index = 0; ; standard.index++) {
319  if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
320  ret = AVERROR(errno);
321  if (ret == AVERROR(EINVAL)) {
322  break;
323  } else {
324  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
325  return;
326  }
327  }
328  av_log(ctx, AV_LOG_INFO, "%2d, %16"PRIx64", %s\n",
329  standard.index, (uint64_t)standard.id, standard.name);
330  }
331 }
332 
333 static int mmap_init(AVFormatContext *ctx)
334 {
335  int i, res;
336  struct video_data *s = ctx->priv_data;
337  struct v4l2_requestbuffers req = {
338  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
339  .count = desired_video_buffers,
340  .memory = V4L2_MEMORY_MMAP
341  };
342 
343  if (v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req) < 0) {
344  res = AVERROR(errno);
345  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS): %s\n", av_err2str(res));
346  return res;
347  }
348 
349  if (req.count < 2) {
350  av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");
351  return AVERROR(ENOMEM);
352  }
353  s->buffers = req.count;
354  s->buf_start = av_malloc_array(s->buffers, sizeof(void *));
355  if (!s->buf_start) {
356  av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");
357  return AVERROR(ENOMEM);
358  }
359  s->buf_len = av_malloc_array(s->buffers, sizeof(unsigned int));
360  if (!s->buf_len) {
361  av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");
362  av_free(s->buf_start);
363  return AVERROR(ENOMEM);
364  }
365 
366  for (i = 0; i < req.count; i++) {
367  struct v4l2_buffer buf = {
368  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
369  .index = i,
370  .memory = V4L2_MEMORY_MMAP
371  };
372  if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {
373  res = AVERROR(errno);
374  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF): %s\n", av_err2str(res));
375  return res;
376  }
377 
378  s->buf_len[i] = buf.length;
379  if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) {
380  av_log(ctx, AV_LOG_ERROR,
381  "buf_len[%d] = %d < expected frame size %d\n",
382  i, s->buf_len[i], s->frame_size);
383  return AVERROR(ENOMEM);
384  }
385  s->buf_start[i] = v4l2_mmap(NULL, buf.length,
386  PROT_READ | PROT_WRITE, MAP_SHARED,
387  s->fd, buf.m.offset);
388 
389  if (s->buf_start[i] == MAP_FAILED) {
390  res = AVERROR(errno);
391  av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", av_err2str(res));
392  return res;
393  }
394  }
395 
396  return 0;
397 }
398 
399 #if FF_API_DESTRUCT_PACKET
400 static void dummy_release_buffer(AVPacket *pkt)
401 {
402  av_assert0(0);
403 }
404 #endif
405 
406 static void mmap_release_buffer(void *opaque, uint8_t *data)
407 {
408  struct v4l2_buffer buf = { 0 };
409  int res;
410  struct buff_data *buf_descriptor = opaque;
411  struct video_data *s = buf_descriptor->s;
412 
413  buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
414  buf.memory = V4L2_MEMORY_MMAP;
415  buf.index = buf_descriptor->index;
416  av_free(buf_descriptor);
417 
418  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
419  res = AVERROR(errno);
420  av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
421  av_err2str(res));
422  }
423 
425 }
426 
427 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
428 static int64_t av_gettime_monotonic(void)
429 {
430  return av_gettime_relative();
431 }
432 #endif
433 
434 static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)
435 {
436  struct video_data *s = ctx->priv_data;
437  int64_t now;
438 
439  now = av_gettime();
440  if (s->ts_mode == V4L_TS_ABS &&
441  ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE) {
442  av_log(ctx, AV_LOG_INFO, "Detected absolute timestamps\n");
444  return 0;
445  }
446 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
447  if (ctx->streams[0]->avg_frame_rate.num) {
448  now = av_gettime_monotonic();
449  if (s->ts_mode == V4L_TS_MONO2ABS ||
450  (ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE)) {
451  AVRational tb = {AV_TIME_BASE, 1};
452  int64_t period = av_rescale_q(1, tb, ctx->streams[0]->avg_frame_rate);
453  av_log(ctx, AV_LOG_INFO, "Detected monotonic timestamps, converting\n");
454  /* microseconds instead of seconds, MHz instead of Hz */
455  s->timefilter = ff_timefilter_new(1, period, 1.0E-6);
456  if (!s->timefilter)
457  return AVERROR(ENOMEM);
459  return 0;
460  }
461  }
462 #endif
463  av_log(ctx, AV_LOG_ERROR, "Unknown timestamps\n");
464  return AVERROR(EIO);
465 }
466 
467 static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)
468 {
469  struct video_data *s = ctx->priv_data;
470 
471  if (s->ts_mode) {
472  int r = init_convert_timestamp(ctx, *ts);
473  if (r < 0)
474  return r;
475  }
476 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
477  if (s->timefilter) {
478  int64_t nowa = av_gettime();
479  int64_t nowm = av_gettime_monotonic();
480  ff_timefilter_update(s->timefilter, nowa, nowm - s->last_time_m);
481  s->last_time_m = nowm;
482  *ts = ff_timefilter_eval(s->timefilter, *ts - nowm);
483  }
484 #endif
485  return 0;
486 }
487 
489 {
490  struct video_data *s = ctx->priv_data;
491  struct v4l2_buffer buf = {
492  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
493  .memory = V4L2_MEMORY_MMAP
494  };
495  int res;
496 
497  /* FIXME: Some special treatment might be needed in case of loss of signal... */
498  while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
499  if (res < 0) {
500  if (errno == EAGAIN) {
501  pkt->size = 0;
502  return AVERROR(EAGAIN);
503  }
504  res = AVERROR(errno);
505  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n", av_err2str(res));
506  return res;
507  }
508 
509  if (buf.index >= s->buffers) {
510  av_log(ctx, AV_LOG_ERROR, "Invalid buffer index received.\n");
511  return AVERROR(EINVAL);
512  }
514  // always keep at least one buffer queued
516 
517  /* CPIA is a compressed format and we don't know the exact number of bytes
518  * used by a frame, so set it here as the driver announces it.
519  */
520  if (ctx->video_codec_id == AV_CODEC_ID_CPIA)
521  s->frame_size = buf.bytesused;
522 
523  if (s->frame_size > 0 && buf.bytesused != s->frame_size) {
524  av_log(ctx, AV_LOG_ERROR,
525  "The v4l2 frame is %d bytes, but %d bytes are expected\n",
526  buf.bytesused, s->frame_size);
527  return AVERROR_INVALIDDATA;
528  }
529 
530  /* Image is at s->buff_start[buf.index] */
531  if (avpriv_atomic_int_get(&s->buffers_queued) == FFMAX(s->buffers / 8, 1)) {
532  /* when we start getting low on queued buffers, fall back on copying data */
533  res = av_new_packet(pkt, buf.bytesused);
534  if (res < 0) {
535  av_log(ctx, AV_LOG_ERROR, "Error allocating a packet.\n");
536  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) == 0)
538  return res;
539  }
540  memcpy(pkt->data, s->buf_start[buf.index], buf.bytesused);
541 
542  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
543  res = AVERROR(errno);
544  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
545  av_free_packet(pkt);
546  return res;
547  }
549  } else {
550  struct buff_data *buf_descriptor;
551 
552  pkt->data = s->buf_start[buf.index];
553  pkt->size = buf.bytesused;
554 #if FF_API_DESTRUCT_PACKET
556  pkt->destruct = dummy_release_buffer;
558 #endif
559 
560  buf_descriptor = av_malloc(sizeof(struct buff_data));
561  if (!buf_descriptor) {
562  /* Something went wrong... Since av_malloc() failed, we cannot even
563  * allocate a buffer for memcpying into it
564  */
565  av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
566  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) == 0)
568 
569  return AVERROR(ENOMEM);
570  }
571  buf_descriptor->index = buf.index;
572  buf_descriptor->s = s;
573 
574  pkt->buf = av_buffer_create(pkt->data, pkt->size, mmap_release_buffer,
575  buf_descriptor, 0);
576  if (!pkt->buf) {
577  av_log(ctx, AV_LOG_ERROR, "Failed to create a buffer\n");
578  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) == 0)
580  av_freep(&buf_descriptor);
581  return AVERROR(ENOMEM);
582  }
583  }
584  pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec;
585  convert_timestamp(ctx, &pkt->pts);
586 
587  return s->buf_len[buf.index];
588 }
589 
590 static int mmap_start(AVFormatContext *ctx)
591 {
592  struct video_data *s = ctx->priv_data;
593  enum v4l2_buf_type type;
594  int i, res;
595 
596  for (i = 0; i < s->buffers; i++) {
597  struct v4l2_buffer buf = {
598  .type = V4L2_BUF_TYPE_VIDEO_CAPTURE,
599  .index = i,
600  .memory = V4L2_MEMORY_MMAP
601  };
602 
603  if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
604  res = AVERROR(errno);
605  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
606  return res;
607  }
608  }
609  s->buffers_queued = s->buffers;
610 
611  type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
612  if (v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type) < 0) {
613  res = AVERROR(errno);
614  av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n", av_err2str(res));
615  return res;
616  }
617 
618  return 0;
619 }
620 
621 static void mmap_close(struct video_data *s)
622 {
623  enum v4l2_buf_type type;
624  int i;
625 
626  type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
627  /* We do not check for the result, because we could
628  * not do anything about it anyway...
629  */
630  v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
631  for (i = 0; i < s->buffers; i++) {
632  v4l2_munmap(s->buf_start[i], s->buf_len[i]);
633  }
634  av_free(s->buf_start);
635  av_free(s->buf_len);
636 }
637 
639 {
640  struct video_data *s = s1->priv_data;
641  struct v4l2_standard standard = { 0 };
642  struct v4l2_streamparm streamparm = { 0 };
643  struct v4l2_fract *tpf;
644  AVRational framerate_q = { 0 };
645  int i, ret;
646 
647  if (s->framerate &&
648  (ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) {
649  av_log(s1, AV_LOG_ERROR, "Could not parse framerate '%s'.\n",
650  s->framerate);
651  return ret;
652  }
653 
654  if (s->standard) {
655  if (s->std_id) {
656  ret = 0;
657  av_log(s1, AV_LOG_DEBUG, "Setting standard: %s\n", s->standard);
658  /* set tv standard */
659  for (i = 0; ; i++) {
660  standard.index = i;
661  if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
662  ret = AVERROR(errno);
663  break;
664  }
665  if (!av_strcasecmp(standard.name, s->standard))
666  break;
667  }
668  if (ret < 0) {
669  av_log(s1, AV_LOG_ERROR, "Unknown or unsupported standard '%s'\n", s->standard);
670  return ret;
671  }
672 
673  if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
674  ret = AVERROR(errno);
675  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_STD): %s\n", av_err2str(ret));
676  return ret;
677  }
678  } else {
680  "This device does not support any standard\n");
681  }
682  }
683 
684  /* get standard */
685  if (v4l2_ioctl(s->fd, VIDIOC_G_STD, &s->std_id) == 0) {
686  tpf = &standard.frameperiod;
687  for (i = 0; ; i++) {
688  standard.index = i;
689  if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
690  ret = AVERROR(errno);
691  if (ret == AVERROR(EINVAL)
692 #ifdef ENODATA
693  || ret == AVERROR(ENODATA)
694 #endif
695  ) {
696  tpf = &streamparm.parm.capture.timeperframe;
697  break;
698  }
699  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
700  return ret;
701  }
702  if (standard.id == s->std_id) {
703  av_log(s1, AV_LOG_DEBUG,
704  "Current standard: %s, id: %"PRIx64", frameperiod: %d/%d\n",
705  standard.name, (uint64_t)standard.id, tpf->numerator, tpf->denominator);
706  break;
707  }
708  }
709  } else {
710  tpf = &streamparm.parm.capture.timeperframe;
711  }
712 
713  streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
714  if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) < 0) {
715  ret = AVERROR(errno);
716  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n", av_err2str(ret));
717  return ret;
718  }
719 
720  if (framerate_q.num && framerate_q.den) {
721  if (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) {
722  tpf = &streamparm.parm.capture.timeperframe;
723 
724  av_log(s1, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
725  framerate_q.den, framerate_q.num);
726  tpf->numerator = framerate_q.den;
727  tpf->denominator = framerate_q.num;
728 
729  if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) < 0) {
730  ret = AVERROR(errno);
731  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_PARM): %s\n", av_err2str(ret));
732  return ret;
733  }
734 
735  if (framerate_q.num != tpf->denominator ||
736  framerate_q.den != tpf->numerator) {
737  av_log(s1, AV_LOG_INFO,
738  "The driver changed the time per frame from "
739  "%d/%d to %d/%d\n",
740  framerate_q.den, framerate_q.num,
741  tpf->numerator, tpf->denominator);
742  }
743  } else {
745  "The driver does not allow to change time per frame\n");
746  }
747  }
748  if (tpf->denominator > 0 && tpf->numerator > 0) {
749  s1->streams[0]->avg_frame_rate.num = tpf->denominator;
750  s1->streams[0]->avg_frame_rate.den = tpf->numerator;
751  s1->streams[0]->r_frame_rate = s1->streams[0]->avg_frame_rate;
752  } else
753  av_log(s1, AV_LOG_WARNING, "Time per frame unknown\n");
754 
755  return 0;
756 }
757 
759  enum AVPixelFormat pix_fmt,
760  int *width,
761  int *height,
762  uint32_t *desired_format,
763  enum AVCodecID *codec_id)
764 {
765  int ret, i;
766 
767  *desired_format = avpriv_fmt_ff2v4l(pix_fmt, s1->video_codec_id);
768 
769  if (*desired_format) {
770  ret = device_init(s1, width, height, *desired_format);
771  if (ret < 0) {
772  *desired_format = 0;
773  if (ret != AVERROR(EINVAL))
774  return ret;
775  }
776  }
777 
778  if (!*desired_format) {
779  for (i = 0; avpriv_fmt_conversion_table[i].codec_id != AV_CODEC_ID_NONE; i++) {
780  if (s1->video_codec_id == AV_CODEC_ID_NONE ||
782  av_log(s1, AV_LOG_DEBUG, "Trying to set codec:%s pix_fmt:%s\n",
784  (char *)av_x_if_null(av_get_pix_fmt_name(avpriv_fmt_conversion_table[i].ff_fmt), "none"));
785 
786  *desired_format = avpriv_fmt_conversion_table[i].v4l2_fmt;
787  ret = device_init(s1, width, height, *desired_format);
788  if (ret >= 0)
789  break;
790  else if (ret != AVERROR(EINVAL))
791  return ret;
792  *desired_format = 0;
793  }
794  }
795 
796  if (*desired_format == 0) {
797  av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for "
798  "codec '%s' (id %d), pixel format '%s' (id %d)\n",
800  (char *)av_x_if_null(av_get_pix_fmt_name(pix_fmt), "none"), pix_fmt);
801  ret = AVERROR(EINVAL);
802  }
803  }
804 
805  *codec_id = avpriv_fmt_v4l2codec(*desired_format);
806  av_assert0(*codec_id != AV_CODEC_ID_NONE);
807  return ret;
808 }
809 
811 {
812  struct video_data *s = s1->priv_data;
813  AVStream *st;
814  int res = 0;
815  uint32_t desired_format;
818  struct v4l2_input input = { 0 };
819 
820  st = avformat_new_stream(s1, NULL);
821  if (!st)
822  return AVERROR(ENOMEM);
823 
824 #if CONFIG_LIBV4L2
825  /* silence libv4l2 logging. if fopen() fails v4l2_log_file will be NULL
826  and errors will get sent to stderr */
827  if (s->use_libv4l2)
828  v4l2_log_file = fopen("/dev/null", "w");
829 #endif
830 
831  s->fd = device_open(s1);
832  if (s->fd < 0)
833  return s->fd;
834 
835  if (s->channel != -1) {
836  /* set video input */
837  av_log(s1, AV_LOG_DEBUG, "Selecting input_channel: %d\n", s->channel);
838  if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &s->channel) < 0) {
839  res = AVERROR(errno);
840  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_INPUT): %s\n", av_err2str(res));
841  return res;
842  }
843  } else {
844  /* get current video input */
845  if (v4l2_ioctl(s->fd, VIDIOC_G_INPUT, &s->channel) < 0) {
846  res = AVERROR(errno);
847  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_INPUT): %s\n", av_err2str(res));
848  return res;
849  }
850  }
851 
852  /* enum input */
853  input.index = s->channel;
854  if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
855  res = AVERROR(errno);
856  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMINPUT): %s\n", av_err2str(res));
857  return res;
858  }
859  s->std_id = input.std;
860  av_log(s1, AV_LOG_DEBUG, "Current input_channel: %d, input_name: %s, input_std: %"PRIx64"\n",
861  s->channel, input.name, (uint64_t)input.std);
862 
863  if (s->list_format) {
864  list_formats(s1, s->fd, s->list_format);
865  return AVERROR_EXIT;
866  }
867 
868  if (s->list_standard) {
869  list_standards(s1);
870  return AVERROR_EXIT;
871  }
872 
873  avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
874 
875  if ((res = v4l2_set_parameters(s1)) < 0)
876  return res;
877 
878  if (s->pixel_format) {
880 
881  if (codec)
882  s1->video_codec_id = codec->id;
883 
884  pix_fmt = av_get_pix_fmt(s->pixel_format);
885 
886  if (pix_fmt == AV_PIX_FMT_NONE && !codec) {
887  av_log(s1, AV_LOG_ERROR, "No such input format: %s.\n",
888  s->pixel_format);
889 
890  return AVERROR(EINVAL);
891  }
892  }
893 
894  if (!s->width && !s->height) {
895  struct v4l2_format fmt = { .type = V4L2_BUF_TYPE_VIDEO_CAPTURE };
896 
898  "Querying the device for the current frame size\n");
899  if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
900  res = AVERROR(errno);
901  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", av_err2str(res));
902  return res;
903  }
904 
905  s->width = fmt.fmt.pix.width;
906  s->height = fmt.fmt.pix.height;
908  "Setting frame size to %dx%d\n", s->width, s->height);
909  }
910 
911  res = device_try_init(s1, pix_fmt, &s->width, &s->height, &desired_format, &codec_id);
912  if (res < 0) {
913  v4l2_close(s->fd);
914  return res;
915  }
916 
917  /* If no pixel_format was specified, the codec_id was not known up
918  * until now. Set video_codec_id in the context, as codec_id will
919  * not be available outside this function
920  */
921  if (codec_id != AV_CODEC_ID_NONE && s1->video_codec_id == AV_CODEC_ID_NONE)
922  s1->video_codec_id = codec_id;
923 
924  if ((res = av_image_check_size(s->width, s->height, 0, s1)) < 0)
925  return res;
926 
927  s->frame_format = desired_format;
928 
929  st->codec->pix_fmt = avpriv_fmt_v4l2ff(desired_format, codec_id);
930  s->frame_size =
932 
933  if ((res = mmap_init(s1)) ||
934  (res = mmap_start(s1)) < 0) {
935  v4l2_close(s->fd);
936  return res;
937  }
938 
939  s->top_field_first = first_field(s, s->fd);
940 
942  st->codec->codec_id = codec_id;
943  if (codec_id == AV_CODEC_ID_RAWVIDEO)
944  st->codec->codec_tag =
946  else if (codec_id == AV_CODEC_ID_H264) {
948  }
949  if (desired_format == V4L2_PIX_FMT_YVU420)
950  st->codec->codec_tag = MKTAG('Y', 'V', '1', '2');
951  else if (desired_format == V4L2_PIX_FMT_YVU410)
952  st->codec->codec_tag = MKTAG('Y', 'V', 'U', '9');
953  st->codec->width = s->width;
954  st->codec->height = s->height;
955  if (st->avg_frame_rate.den)
956  st->codec->bit_rate = s->frame_size * av_q2d(st->avg_frame_rate) * 8;
957 
958  return 0;
959 }
960 
962 {
963  struct video_data *s = s1->priv_data;
964  AVFrame *frame = s1->streams[0]->codec->coded_frame;
965  int res;
966 
967  av_init_packet(pkt);
968  if ((res = mmap_read_frame(s1, pkt)) < 0) {
969  return res;
970  }
971 
972  if (frame && s->interlaced) {
973  frame->interlaced_frame = 1;
974  frame->top_field_first = s->top_field_first;
975  }
976 
977  return pkt->size;
978 }
979 
981 {
982  struct video_data *s = s1->priv_data;
983 
985  av_log(s1, AV_LOG_WARNING, "Some buffers are still owned by the caller on "
986  "close.\n");
987 
988  mmap_close(s);
989 
990  v4l2_close(s->fd);
991  return 0;
992 }
993 
994 #define OFFSET(x) offsetof(struct video_data, x)
995 #define DEC AV_OPT_FLAG_DECODING_PARAM
996 
997 static const AVOption options[] = {
998  { "standard", "set TV standard, used only by analog frame grabber", OFFSET(standard), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, DEC },
999  { "channel", "set TV channel, used only by frame grabber", OFFSET(channel), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, INT_MAX, DEC },
1000  { "video_size", "set frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
1001  { "pixel_format", "set preferred pixel format", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1002  { "input_format", "set preferred pixel format (for raw video) or codec name", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1003  { "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1004 
1005  { "list_formats", "list available formats and exit", OFFSET(list_format), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, DEC, "list_formats" },
1006  { "all", "show all available formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_ALLFORMATS }, 0, INT_MAX, DEC, "list_formats" },
1007  { "raw", "show only non-compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_RAWFORMATS }, 0, INT_MAX, DEC, "list_formats" },
1008  { "compressed", "show only compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_COMPFORMATS }, 0, INT_MAX, DEC, "list_formats" },
1009 
1010  { "list_standards", "list supported standards and exit", OFFSET(list_standard), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, DEC, "list_standards" },
1011  { "all", "show all supported standards", OFFSET(list_standard), AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, DEC, "list_standards" },
1012 
1013  { "timestamps", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },
1014  { "ts", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, "timestamps" },
1015  { "default", "use timestamps from the kernel", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_DEFAULT }, 0, 2, DEC, "timestamps" },
1016  { "abs", "use absolute timestamps (wall clock)", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_ABS }, 0, 2, DEC, "timestamps" },
1017  { "mono2abs", "force conversion from monotonic to absolute timestamps", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, "timestamps" },
1018  { "use_libv4l2", "use libv4l2 (v4l-utils) conversion functions", OFFSET(use_libv4l2), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC },
1019  { NULL },
1020 };
1021 
1022 static const AVClass v4l2_class = {
1023  .class_name = "V4L2 indev",
1024  .item_name = av_default_item_name,
1025  .option = options,
1026  .version = LIBAVUTIL_VERSION_INT,
1028 };
1029 
1031  .name = "video4linux2,v4l2",
1032  .long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),
1033  .priv_data_size = sizeof(struct video_data),
1034  .read_header = v4l2_read_header,
1035  .read_packet = v4l2_read_packet,
1036  .read_close = v4l2_read_close,
1037  .flags = AVFMT_NOFILE,
1038  .priv_class = &v4l2_class,
1039 };