FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavdevice/v4l2.c
Date: 2026-04-30 18:27:06
Exec Total Coverage
Lines: 3 570 0.5%
Functions: 1 24 4.2%
Branches: 1 319 0.3%

Line Branch Exec Source
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 <stdatomic.h>
34
35 #include "libavutil/avassert.h"
36 #include "libavutil/avstring.h"
37 #include "libavutil/imgutils.h"
38 #include "libavutil/mem.h"
39 #include "libavutil/parseutils.h"
40 #include "libavutil/pixdesc.h"
41 #include "libavutil/time.h"
42 #include "libavcodec/avcodec.h"
43 #include "libavcodec/codec_desc.h"
44 #include "libavformat/demux.h"
45 #include "libavformat/internal.h"
46 #include "avdevice.h"
47 #include "timefilter.h"
48 #include "v4l2-common.h"
49 #include <dirent.h>
50
51 #if CONFIG_LIBV4L2
52 #include <libv4l2.h>
53 #endif
54
55 static const int desired_video_buffers = 256;
56
57 #define V4L_ALLFORMATS 3
58 #define V4L_RAWFORMATS 1
59 #define V4L_COMPFORMATS 2
60
61 /**
62 * Return timestamps to the user exactly as returned by the kernel
63 */
64 #define V4L_TS_DEFAULT 0
65 /**
66 * Autodetect the kind of timestamps returned by the kernel and convert to
67 * absolute (wall clock) timestamps.
68 */
69 #define V4L_TS_ABS 1
70 /**
71 * Assume kernel timestamps are from the monotonic clock and convert to
72 * absolute timestamps.
73 */
74 #define V4L_TS_MONO2ABS 2
75
76 /**
77 * Once the kind of timestamps returned by the kernel have been detected,
78 * the value of the timefilter (NULL or not) determines whether a conversion
79 * takes place.
80 */
81 #define V4L_TS_CONVERT_READY V4L_TS_DEFAULT
82
83 struct buf_data {
84 void *start;
85 unsigned int len;
86 };
87
88 struct video_data {
89 AVClass *class;
90 int fd;
91 int pixelformat; /* V4L2_PIX_FMT_* */
92 int width, height;
93 int frame_size;
94 int interlaced;
95 int top_field_first;
96 int ts_mode;
97 TimeFilter *timefilter;
98 int64_t last_time_m;
99
100 int multiplanar;
101 enum v4l2_buf_type buf_type;
102
103 int buffers;
104 atomic_int buffers_queued;
105 struct buf_data *buf_data;
106 char *standard;
107 v4l2_std_id std_id;
108 int channel;
109 char *pixel_format; /**< Set by a private option. */
110 int list_format; /**< Set by a private option. */
111 int list_standard; /**< Set by a private option. */
112 char *framerate; /**< Set by a private option. */
113
114 int use_libv4l2;
115 int (*open_f)(const char *file, int oflag, ...);
116 int (*close_f)(int fd);
117 int (*dup_f)(int fd);
118 #if HAVE_IOCTL_POSIX
119 int (*ioctl_f)(int fd, int request, ...);
120 #else
121 int (*ioctl_f)(int fd, unsigned long int request, ...);
122 #endif
123 ssize_t (*read_f)(int fd, void *buffer, size_t n);
124 void *(*mmap_f)(void *start, size_t length, int prot, int flags, int fd, int64_t offset);
125 int (*munmap_f)(void *_start, size_t length);
126 };
127
128 struct buf_desc {
129 struct video_data *s;
130 int index;
131 };
132
133 static int device_open(AVFormatContext *ctx, const char* device_path)
134 {
135 struct video_data *s = ctx->priv_data;
136 struct v4l2_capability cap;
137 int fd;
138 int err;
139 int flags = O_RDWR;
140
141 #define SET_WRAPPERS(prefix) do { \
142 s->open_f = prefix ## open; \
143 s->close_f = prefix ## close; \
144 s->dup_f = prefix ## dup; \
145 s->ioctl_f = prefix ## ioctl; \
146 s->read_f = prefix ## read; \
147 s->mmap_f = prefix ## mmap; \
148 s->munmap_f = prefix ## munmap; \
149 } while (0)
150
151 if (s->use_libv4l2) {
152 #if CONFIG_LIBV4L2
153 SET_WRAPPERS(v4l2_);
154 #else
155 av_log(ctx, AV_LOG_ERROR, "libavdevice is not built with libv4l2 support.\n");
156 return AVERROR(EINVAL);
157 #endif
158 } else {
159 SET_WRAPPERS();
160 }
161
162 #define v4l2_open s->open_f
163 #define v4l2_close s->close_f
164 #define v4l2_dup s->dup_f
165 #define v4l2_ioctl s->ioctl_f
166 #define v4l2_read s->read_f
167 #define v4l2_mmap s->mmap_f
168 #define v4l2_munmap s->munmap_f
169
170 if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
171 flags |= O_NONBLOCK;
172 }
173
174 fd = v4l2_open(device_path, flags, 0);
175 if (fd < 0) {
176 err = AVERROR(errno);
177 av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s: %s\n",
178 device_path, av_err2str(err));
179 return err;
180 }
181
182 if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
183 err = AVERROR(errno);
184 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
185 av_err2str(err));
186 goto fail;
187 }
188
189 av_log(ctx, AV_LOG_VERBOSE, "fd:%d capabilities:%x\n",
190 fd, cap.capabilities);
191
192 if (cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) {
193 s->multiplanar = 0;
194 s->buf_type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
195 } else if (cap.capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE) {
196 s->multiplanar = 1;
197 s->buf_type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
198 } else {
199 av_log(ctx, AV_LOG_ERROR, "Not a video capture device.\n");
200 err = AVERROR(ENODEV);
201 goto fail;
202 }
203
204 if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
205 av_log(ctx, AV_LOG_ERROR,
206 "The device does not support the streaming I/O method.\n");
207 err = AVERROR(ENOSYS);
208 goto fail;
209 }
210
211 return fd;
212
213 fail:
214 v4l2_close(fd);
215 return err;
216 }
217
218 static int device_init(AVFormatContext *ctx, int *width, int *height,
219 uint32_t pixelformat)
220 {
221 struct video_data *s = ctx->priv_data;
222 struct v4l2_format fmt = { .type = s->buf_type };
223 int res = 0;
224
225 fmt.fmt.pix.width = *width;
226 fmt.fmt.pix.height = *height;
227 fmt.fmt.pix.pixelformat = pixelformat;
228 fmt.fmt.pix.field = V4L2_FIELD_ANY;
229
230 /* Some drivers will fail and return EINVAL when the pixelformat
231 is not supported (even if type field is valid and supported) */
232 if (v4l2_ioctl(s->fd, VIDIOC_S_FMT, &fmt) < 0)
233 res = AVERROR(errno);
234
235 if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {
236 av_log(ctx, AV_LOG_INFO,
237 "The V4L2 driver changed the video from %dx%d to %dx%d\n",
238 *width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);
239 *width = fmt.fmt.pix.width;
240 *height = fmt.fmt.pix.height;
241 }
242
243 if (pixelformat != fmt.fmt.pix.pixelformat) {
244 av_log(ctx, AV_LOG_DEBUG,
245 "The V4L2 driver changed the pixel format "
246 "from 0x%08X to 0x%08X\n",
247 pixelformat, fmt.fmt.pix.pixelformat);
248 res = AVERROR(EINVAL);
249 }
250
251 if (fmt.fmt.pix.field == V4L2_FIELD_INTERLACED) {
252 av_log(ctx, AV_LOG_DEBUG,
253 "The V4L2 driver is using the interlaced mode\n");
254 s->interlaced = 1;
255 }
256
257 return res;
258 }
259
260 static int first_field(const struct video_data *s)
261 {
262 int res;
263 v4l2_std_id std;
264
265 res = v4l2_ioctl(s->fd, VIDIOC_G_STD, &std);
266 if (res < 0)
267 return 0;
268 if (std & V4L2_STD_NTSC)
269 return 0;
270
271 return 1;
272 }
273
274 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
275 static void list_framesizes(AVFormatContext *ctx, uint32_t pixelformat)
276 {
277 const struct video_data *s = ctx->priv_data;
278 struct v4l2_frmsizeenum vfse = { .pixel_format = pixelformat };
279
280 while(!v4l2_ioctl(s->fd, VIDIOC_ENUM_FRAMESIZES, &vfse)) {
281 switch (vfse.type) {
282 case V4L2_FRMSIZE_TYPE_DISCRETE:
283 av_log(ctx, AV_LOG_INFO, " %ux%u",
284 vfse.discrete.width, vfse.discrete.height);
285 break;
286 case V4L2_FRMSIZE_TYPE_CONTINUOUS:
287 case V4L2_FRMSIZE_TYPE_STEPWISE:
288 av_log(ctx, AV_LOG_INFO, " {%u-%u, %u}x{%u-%u, %u}",
289 vfse.stepwise.min_width,
290 vfse.stepwise.max_width,
291 vfse.stepwise.step_width,
292 vfse.stepwise.min_height,
293 vfse.stepwise.max_height,
294 vfse.stepwise.step_height);
295 }
296 vfse.index++;
297 }
298 }
299 #endif
300
301 static void list_formats(AVFormatContext *ctx, int type)
302 {
303 const struct video_data *s = ctx->priv_data;
304 struct v4l2_fmtdesc vfd = { .type = s->buf_type };
305
306 while(!v4l2_ioctl(s->fd, VIDIOC_ENUM_FMT, &vfd)) {
307 enum AVCodecID codec_id = ff_fmt_v4l2codec(vfd.pixelformat);
308 enum AVPixelFormat pix_fmt = ff_fmt_v4l2ff(vfd.pixelformat, codec_id);
309
310 vfd.index++;
311
312 if (!(vfd.flags & V4L2_FMT_FLAG_COMPRESSED) &&
313 type & V4L_RAWFORMATS) {
314 const char *fmt_name = av_get_pix_fmt_name(pix_fmt);
315 av_log(ctx, AV_LOG_INFO, "Raw : %11s : %20s :",
316 fmt_name ? fmt_name : "Unsupported",
317 vfd.description);
318 } else if (vfd.flags & V4L2_FMT_FLAG_COMPRESSED &&
319 type & V4L_COMPFORMATS) {
320 const AVCodecDescriptor *desc = avcodec_descriptor_get(codec_id);
321 av_log(ctx, AV_LOG_INFO, "Compressed: %11s : %20s :",
322 desc ? desc->name : "Unsupported",
323 vfd.description);
324 } else {
325 continue;
326 }
327
328 #ifdef V4L2_FMT_FLAG_EMULATED
329 if (vfd.flags & V4L2_FMT_FLAG_EMULATED)
330 av_log(ctx, AV_LOG_INFO, " Emulated :");
331 #endif
332 #if HAVE_STRUCT_V4L2_FRMIVALENUM_DISCRETE
333 list_framesizes(ctx, vfd.pixelformat);
334 #endif
335 av_log(ctx, AV_LOG_INFO, "\n");
336 }
337 }
338
339 static void list_standards(AVFormatContext *ctx)
340 {
341 int ret;
342 struct video_data *s = ctx->priv_data;
343 struct v4l2_standard standard;
344
345 if (s->std_id == 0)
346 return;
347
348 for (standard.index = 0; ; standard.index++) {
349 if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
350 ret = AVERROR(errno);
351 if (ret == AVERROR(EINVAL)) {
352 break;
353 } else {
354 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
355 return;
356 }
357 }
358 av_log(ctx, AV_LOG_INFO, "%2d, %16"PRIx64", %s\n",
359 standard.index, (uint64_t)standard.id, standard.name);
360 }
361 }
362
363 static void mmap_free(struct video_data *s, int n)
364 {
365 for (int i = 0; i < n; i++)
366 v4l2_munmap(s->buf_data[i].start, s->buf_data[i].len);
367 av_freep(&s->buf_data);
368 }
369
370 static int mmap_init(AVFormatContext *ctx)
371 {
372 int i, res;
373 struct video_data *s = ctx->priv_data;
374 struct v4l2_requestbuffers req = {
375 .type = s->buf_type,
376 .count = desired_video_buffers,
377 .memory = V4L2_MEMORY_MMAP
378 };
379
380 if (v4l2_ioctl(s->fd, VIDIOC_REQBUFS, &req) < 0) {
381 res = AVERROR(errno);
382 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS): %s\n", av_err2str(res));
383 return res;
384 }
385
386 if (req.count < 2) {
387 av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");
388 return AVERROR(ENOMEM);
389 }
390 s->buffers = req.count;
391 s->buf_data = av_malloc_array(s->buffers, sizeof(struct buf_data));
392 if (!s->buf_data) {
393 av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer data\n");
394 return AVERROR(ENOMEM);
395 }
396
397 for (i = 0; i < req.count; i++) {
398 unsigned int buf_length, buf_offset;
399 struct v4l2_plane planes[VIDEO_MAX_PLANES];
400 struct v4l2_buffer buf = {
401 .type = s->buf_type,
402 .index = i,
403 .memory = V4L2_MEMORY_MMAP,
404 .m.planes = s->multiplanar ? planes : NULL,
405 .length = s->multiplanar ? VIDEO_MAX_PLANES : 0,
406 };
407 if (v4l2_ioctl(s->fd, VIDIOC_QUERYBUF, &buf) < 0) {
408 res = AVERROR(errno);
409 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF): %s\n", av_err2str(res));
410 goto fail;
411 }
412
413 if (s->multiplanar) {
414 if (buf.length != 1) {
415 av_log(ctx, AV_LOG_ERROR, "multiplanar only supported when buf.length == 1\n");
416 res = AVERROR_PATCHWELCOME;
417 goto fail;
418 }
419 buf_length = buf.m.planes[0].length;
420 buf_offset = buf.m.planes[0].m.mem_offset;
421 } else {
422 buf_length = buf.length;
423 buf_offset = buf.m.offset;
424 }
425
426 s->buf_data[i].len = buf_length;
427 if (s->frame_size > 0 && s->buf_data[i].len < s->frame_size) {
428 av_log(ctx, AV_LOG_ERROR,
429 "buf_data[%d].len = %d < expected frame size %d\n",
430 i, buf_length, s->frame_size);
431 res = AVERROR(ENOMEM);
432 goto fail;
433 }
434 s->buf_data[i].start = v4l2_mmap(NULL, buf_length,
435 PROT_READ | PROT_WRITE, MAP_SHARED,
436 s->fd, buf_offset);
437
438 if (s->buf_data[i].start == MAP_FAILED) {
439 res = AVERROR(errno);
440 av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", av_err2str(res));
441 goto fail;
442 }
443 }
444
445 return 0;
446
447 fail:
448 mmap_free(s, i);
449 return res;
450 }
451
452 static int enqueue_buffer(struct video_data *s, struct v4l2_buffer *buf)
453 {
454 int res = 0;
455
456 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, buf) < 0) {
457 res = AVERROR(errno);
458 av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", av_err2str(res));
459 } else {
460 atomic_fetch_add(&s->buffers_queued, 1);
461 }
462
463 return res;
464 }
465
466 static void mmap_release_buffer(void *opaque, uint8_t *data)
467 {
468 struct v4l2_plane planes[VIDEO_MAX_PLANES];
469 struct v4l2_buffer buf = { 0 };
470 struct buf_desc *buf_descriptor = opaque;
471 struct video_data *s = buf_descriptor->s;
472
473 buf.type = s->buf_type;
474 buf.memory = V4L2_MEMORY_MMAP;
475 buf.index = buf_descriptor->index;
476 buf.m.planes = s->multiplanar ? planes : NULL;
477 buf.length = s->multiplanar ? VIDEO_MAX_PLANES : 0;
478 av_free(buf_descriptor);
479
480 enqueue_buffer(s, &buf);
481 }
482
483 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
484 static int64_t av_gettime_monotonic(void)
485 {
486 return av_gettime_relative();
487 }
488 #endif
489
490 static int init_convert_timestamp(AVFormatContext *ctx, int64_t ts)
491 {
492 struct video_data *s = ctx->priv_data;
493 int64_t now;
494
495 now = av_gettime();
496 if (s->ts_mode == V4L_TS_ABS &&
497 ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE) {
498 av_log(ctx, AV_LOG_INFO, "Detected absolute timestamps\n");
499 s->ts_mode = V4L_TS_CONVERT_READY;
500 return 0;
501 }
502 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
503 if (ctx->streams[0]->avg_frame_rate.num) {
504 now = av_gettime_monotonic();
505 if (s->ts_mode == V4L_TS_MONO2ABS ||
506 (ts <= now + 1 * AV_TIME_BASE && ts >= now - 10 * AV_TIME_BASE)) {
507 AVRational tb = {AV_TIME_BASE, 1};
508 int64_t period = av_rescale_q(1, tb, ctx->streams[0]->avg_frame_rate);
509 av_log(ctx, AV_LOG_INFO, "Detected monotonic timestamps, converting\n");
510 /* microseconds instead of seconds, MHz instead of Hz */
511 s->timefilter = ff_timefilter_new(1, period, 1.0E-6);
512 if (!s->timefilter)
513 return AVERROR(ENOMEM);
514 s->ts_mode = V4L_TS_CONVERT_READY;
515 return 0;
516 }
517 }
518 #endif
519 av_log(ctx, AV_LOG_ERROR, "Unknown timestamps\n");
520 return AVERROR(EIO);
521 }
522
523 static int convert_timestamp(AVFormatContext *ctx, int64_t *ts)
524 {
525 struct video_data *s = ctx->priv_data;
526
527 if (s->ts_mode) {
528 int r = init_convert_timestamp(ctx, *ts);
529 if (r < 0)
530 return r;
531 }
532 #if HAVE_CLOCK_GETTIME && defined(CLOCK_MONOTONIC)
533 if (s->timefilter) {
534 int64_t nowa = av_gettime();
535 int64_t nowm = av_gettime_monotonic();
536 ff_timefilter_update(s->timefilter, nowa, nowm - s->last_time_m);
537 s->last_time_m = nowm;
538 *ts = ff_timefilter_eval(s->timefilter, *ts - nowm);
539 }
540 #endif
541 return 0;
542 }
543
544 static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
545 {
546 struct video_data *s = ctx->priv_data;
547 struct v4l2_plane planes[VIDEO_MAX_PLANES];
548 struct v4l2_buffer buf = {
549 .type = s->buf_type,
550 .memory = V4L2_MEMORY_MMAP,
551 .m.planes = s->multiplanar ? planes : NULL,
552 .length = s->multiplanar ? VIDEO_MAX_PLANES : 0,
553 };
554 struct timeval buf_ts;
555 unsigned int bytesused;
556 int res;
557
558 pkt->size = 0;
559
560 /* FIXME: Some special treatment might be needed in case of loss of signal... */
561 while ((res = v4l2_ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
562 if (res < 0) {
563 if (errno == EAGAIN)
564 return AVERROR(EAGAIN);
565
566 res = AVERROR(errno);
567 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n",
568 av_err2str(res));
569 return res;
570 }
571
572 buf_ts = buf.timestamp;
573
574 if (buf.index >= s->buffers) {
575 av_log(ctx, AV_LOG_ERROR, "Invalid buffer index received.\n");
576 return AVERROR(EINVAL);
577 }
578 atomic_fetch_add(&s->buffers_queued, -1);
579 // always keep at least one buffer queued
580 av_assert0(atomic_load(&s->buffers_queued) >= 1);
581
582 bytesused = s->multiplanar ? buf.m.planes[0].bytesused : buf.bytesused;
583
584 #ifdef V4L2_BUF_FLAG_ERROR
585 if (buf.flags & V4L2_BUF_FLAG_ERROR) {
586 av_log(ctx, AV_LOG_WARNING,
587 "Dequeued v4l2 buffer contains corrupted data (%d bytes).\n",
588 bytesused);
589 bytesused = 0;
590 } else
591 #endif
592 {
593 /* CPIA is a compressed format and we don't know the exact number of bytes
594 * used by a frame, so set it here as the driver announces it. */
595 if (ctx->video_codec_id == AV_CODEC_ID_CPIA)
596 s->frame_size = bytesused;
597
598 if (s->frame_size > 0 && bytesused != s->frame_size) {
599 av_log(ctx, AV_LOG_WARNING,
600 "Dequeued v4l2 buffer contains %d bytes, but %d were expected. Flags: 0x%08X.\n",
601 bytesused, s->frame_size, buf.flags);
602 bytesused = 0;
603 }
604 }
605
606 /* Image is at s->buf_data[buf.index].start */
607 if (atomic_load(&s->buffers_queued) == FFMAX(s->buffers / 8, 1)) {
608 /* when we start getting low on queued buffers, fall back on copying data */
609 res = av_new_packet(pkt, bytesused);
610 if (res < 0) {
611 av_log(ctx, AV_LOG_ERROR, "Error allocating a packet.\n");
612 enqueue_buffer(s, &buf);
613 return res;
614 }
615 memcpy(pkt->data, s->buf_data[buf.index].start, bytesused);
616
617 res = enqueue_buffer(s, &buf);
618 if (res) {
619 av_packet_unref(pkt);
620 return res;
621 }
622 } else {
623 struct buf_desc *buf_descriptor;
624
625 pkt->data = s->buf_data[buf.index].start;
626 pkt->size = bytesused;
627
628 buf_descriptor = av_malloc(sizeof(struct buf_desc));
629 if (!buf_descriptor) {
630 /* Something went wrong... Since av_malloc() failed, we cannot even
631 * allocate a buffer for memcpying into it
632 */
633 av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
634 enqueue_buffer(s, &buf);
635
636 return AVERROR(ENOMEM);
637 }
638 buf_descriptor->index = buf.index;
639 buf_descriptor->s = s;
640
641 pkt->buf = av_buffer_create(pkt->data, pkt->size, mmap_release_buffer,
642 buf_descriptor, 0);
643 if (!pkt->buf) {
644 av_log(ctx, AV_LOG_ERROR, "Failed to create a buffer\n");
645 enqueue_buffer(s, &buf);
646 av_freep(&buf_descriptor);
647 return AVERROR(ENOMEM);
648 }
649 }
650 pkt->pts = buf_ts.tv_sec * INT64_C(1000000) + buf_ts.tv_usec;
651 convert_timestamp(ctx, &pkt->pts);
652
653 return pkt->size;
654 }
655
656 static int mmap_start(AVFormatContext *ctx)
657 {
658 struct video_data *s = ctx->priv_data;
659 enum v4l2_buf_type type;
660 int i, res;
661
662 for (i = 0; i < s->buffers; i++) {
663 struct v4l2_plane planes[VIDEO_MAX_PLANES];
664 struct v4l2_buffer buf = {
665 .type = s->buf_type,
666 .index = i,
667 .memory = V4L2_MEMORY_MMAP,
668 .m.planes = s->multiplanar ? planes : NULL,
669 .length = s->multiplanar ? VIDEO_MAX_PLANES : 0,
670 };
671
672 if (v4l2_ioctl(s->fd, VIDIOC_QBUF, &buf) < 0) {
673 res = AVERROR(errno);
674 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n",
675 av_err2str(res));
676 return res;
677 }
678 }
679 atomic_store(&s->buffers_queued, s->buffers);
680
681 type = s->buf_type;
682 if (v4l2_ioctl(s->fd, VIDIOC_STREAMON, &type) < 0) {
683 res = AVERROR(errno);
684 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n",
685 av_err2str(res));
686 return res;
687 }
688
689 return 0;
690 }
691
692 static void mmap_close(struct video_data *s)
693 {
694 enum v4l2_buf_type type;
695
696 type = s->buf_type;
697 /* We do not check for the result, because we could
698 * not do anything about it anyway...
699 */
700 v4l2_ioctl(s->fd, VIDIOC_STREAMOFF, &type);
701 mmap_free(s, s->buffers);
702 }
703
704 static int v4l2_set_parameters(AVFormatContext *ctx)
705 {
706 struct video_data *s = ctx->priv_data;
707 struct v4l2_standard standard = { 0 };
708 struct v4l2_streamparm streamparm = { 0 };
709 struct v4l2_fract *tpf;
710 AVRational framerate_q = { 0 };
711 int i, ret;
712
713 if (s->framerate &&
714 (ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) {
715 av_log(ctx, AV_LOG_ERROR, "Could not parse framerate '%s'.\n",
716 s->framerate);
717 return ret;
718 }
719
720 if (s->standard) {
721 if (s->std_id) {
722 ret = 0;
723 av_log(ctx, AV_LOG_DEBUG, "Setting standard: %s\n", s->standard);
724 /* set tv standard */
725 for (i = 0; ; i++) {
726 standard.index = i;
727 if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
728 ret = AVERROR(errno);
729 break;
730 }
731 if (!av_strcasecmp(standard.name, s->standard))
732 break;
733 }
734 if (ret < 0) {
735 av_log(ctx, AV_LOG_ERROR, "Unknown or unsupported standard '%s'\n", s->standard);
736 return ret;
737 }
738
739 if (v4l2_ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
740 ret = AVERROR(errno);
741 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_STD): %s\n", av_err2str(ret));
742 return ret;
743 }
744 } else {
745 av_log(ctx, AV_LOG_WARNING,
746 "This device does not support any standard\n");
747 }
748 }
749
750 /* get standard */
751 if (v4l2_ioctl(s->fd, VIDIOC_G_STD, &s->std_id) == 0) {
752 tpf = &standard.frameperiod;
753 for (i = 0; ; i++) {
754 standard.index = i;
755 if (v4l2_ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
756 ret = AVERROR(errno);
757 if (ret == AVERROR(EINVAL)
758 #ifdef ENODATA
759 || ret == AVERROR(ENODATA)
760 #endif
761 ) {
762 tpf = &streamparm.parm.capture.timeperframe;
763 break;
764 }
765 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMSTD): %s\n", av_err2str(ret));
766 return ret;
767 }
768 if (standard.id == s->std_id) {
769 av_log(ctx, AV_LOG_DEBUG,
770 "Current standard: %s, id: %"PRIx64", frameperiod: %d/%d\n",
771 standard.name, (uint64_t)standard.id, tpf->numerator, tpf->denominator);
772 break;
773 }
774 }
775 } else {
776 tpf = &streamparm.parm.capture.timeperframe;
777 }
778
779 streamparm.type = s->buf_type;
780 if (v4l2_ioctl(s->fd, VIDIOC_G_PARM, &streamparm) < 0) {
781 ret = AVERROR(errno);
782 av_log(ctx, AV_LOG_WARNING, "ioctl(VIDIOC_G_PARM): %s\n", av_err2str(ret));
783 } else if (framerate_q.num && framerate_q.den) {
784 if (streamparm.parm.capture.capability & V4L2_CAP_TIMEPERFRAME) {
785 tpf = &streamparm.parm.capture.timeperframe;
786
787 av_log(ctx, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
788 framerate_q.den, framerate_q.num);
789 tpf->numerator = framerate_q.den;
790 tpf->denominator = framerate_q.num;
791
792 if (v4l2_ioctl(s->fd, VIDIOC_S_PARM, &streamparm) < 0) {
793 ret = AVERROR(errno);
794 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_PARM): %s\n",
795 av_err2str(ret));
796 return ret;
797 }
798
799 if (framerate_q.num != tpf->denominator ||
800 framerate_q.den != tpf->numerator) {
801 av_log(ctx, AV_LOG_INFO,
802 "The driver changed the time per frame from "
803 "%d/%d to %d/%d\n",
804 framerate_q.den, framerate_q.num,
805 tpf->numerator, tpf->denominator);
806 }
807 } else {
808 av_log(ctx, AV_LOG_WARNING,
809 "The driver does not permit changing the time per frame\n");
810 }
811 }
812 if (tpf->denominator > 0 && tpf->numerator > 0) {
813 ctx->streams[0]->avg_frame_rate.num = tpf->denominator;
814 ctx->streams[0]->avg_frame_rate.den = tpf->numerator;
815 ctx->streams[0]->r_frame_rate = ctx->streams[0]->avg_frame_rate;
816 } else
817 av_log(ctx, AV_LOG_WARNING, "Time per frame unknown\n");
818
819 return 0;
820 }
821
822 static int device_try_init(AVFormatContext *ctx,
823 enum AVPixelFormat pix_fmt,
824 int *width,
825 int *height,
826 uint32_t *desired_format,
827 enum AVCodecID *codec_id)
828 {
829 int ret, i;
830
831 *desired_format = ff_fmt_ff2v4l(pix_fmt, ctx->video_codec_id);
832
833 if (*desired_format) {
834 ret = device_init(ctx, width, height, *desired_format);
835 if (ret < 0) {
836 *desired_format = 0;
837 if (ret != AVERROR(EINVAL))
838 return ret;
839 }
840 }
841
842 if (!*desired_format) {
843 for (i = 0; ff_fmt_conversion_table[i].codec_id != AV_CODEC_ID_NONE; i++) {
844 if (ctx->video_codec_id == AV_CODEC_ID_NONE ||
845 ff_fmt_conversion_table[i].codec_id == ctx->video_codec_id) {
846 av_log(ctx, AV_LOG_DEBUG, "Trying to set codec:%s pix_fmt:%s\n",
847 avcodec_get_name(ff_fmt_conversion_table[i].codec_id),
848 (char *)av_x_if_null(av_get_pix_fmt_name(ff_fmt_conversion_table[i].ff_fmt), "none"));
849
850 *desired_format = ff_fmt_conversion_table[i].v4l2_fmt;
851 ret = device_init(ctx, width, height, *desired_format);
852 if (ret >= 0)
853 break;
854 else if (ret != AVERROR(EINVAL))
855 return ret;
856 *desired_format = 0;
857 }
858 }
859
860 if (*desired_format == 0) {
861 av_log(ctx, AV_LOG_ERROR, "Cannot find a proper format for "
862 "codec '%s' (id %d), pixel format '%s' (id %d)\n",
863 avcodec_get_name(ctx->video_codec_id), ctx->video_codec_id,
864 (char *)av_x_if_null(av_get_pix_fmt_name(pix_fmt), "none"), pix_fmt);
865 ret = AVERROR(EINVAL);
866 }
867 }
868
869 *codec_id = ff_fmt_v4l2codec(*desired_format);
870 if (*codec_id == AV_CODEC_ID_NONE)
871 av_assert0(ret == AVERROR(EINVAL));
872 return ret;
873 }
874
875 3845 static int v4l2_read_probe(const AVProbeData *p)
876 {
877
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3845 if (av_strstart(p->filename, "/dev/video", NULL))
878 return AVPROBE_SCORE_MAX - 1;
879 3845 return 0;
880 }
881
882 static int v4l2_read_header(AVFormatContext *ctx)
883 {
884 struct video_data *s = ctx->priv_data;
885 AVStream *st;
886 int res = 0;
887 uint32_t desired_format;
888 enum AVCodecID codec_id = AV_CODEC_ID_NONE;
889 enum AVPixelFormat pix_fmt = AV_PIX_FMT_NONE;
890 struct v4l2_input input = { 0 };
891
892 st = avformat_new_stream(ctx, NULL);
893 if (!st)
894 return AVERROR(ENOMEM);
895
896 #if CONFIG_LIBV4L2
897 /* silence libv4l2 logging. if fopen() fails v4l2_log_file will be NULL
898 and errors will get sent to stderr */
899 if (s->use_libv4l2)
900 v4l2_log_file = fopen("/dev/null", "w");
901 #endif
902
903 s->fd = device_open(ctx, ctx->url);
904 if (s->fd < 0)
905 return s->fd;
906
907 if (s->channel != -1) {
908 /* set video input */
909 av_log(ctx, AV_LOG_DEBUG, "Selecting input_channel: %d\n", s->channel);
910 if (v4l2_ioctl(s->fd, VIDIOC_S_INPUT, &s->channel) < 0) {
911 res = AVERROR(errno);
912 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_S_INPUT): %s\n", av_err2str(res));
913 goto fail;
914 }
915 } else {
916 /* get current video input */
917 if (v4l2_ioctl(s->fd, VIDIOC_G_INPUT, &s->channel) < 0) {
918 res = AVERROR(errno);
919 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_INPUT): %s\n", av_err2str(res));
920 goto fail;
921 }
922 }
923
924 /* enum input */
925 input.index = s->channel;
926 if (v4l2_ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
927 res = AVERROR(errno);
928 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_ENUMINPUT): %s\n", av_err2str(res));
929 goto fail;
930 }
931 s->std_id = input.std;
932 av_log(ctx, AV_LOG_DEBUG, "Current input_channel: %d, input_name: %s, input_std: %"PRIx64"\n",
933 s->channel, input.name, (uint64_t)input.std);
934
935 if (s->list_format) {
936 list_formats(ctx, s->list_format);
937 res = AVERROR_EXIT;
938 goto fail;
939 }
940
941 if (s->list_standard) {
942 list_standards(ctx);
943 res = AVERROR_EXIT;
944 goto fail;
945 }
946
947 avpriv_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
948
949 if (s->pixel_format) {
950 const AVCodecDescriptor *desc = avcodec_descriptor_get_by_name(s->pixel_format);
951
952 if (desc)
953 ctx->video_codec_id = desc->id;
954
955 pix_fmt = av_get_pix_fmt(s->pixel_format);
956
957 if (pix_fmt == AV_PIX_FMT_NONE && !desc) {
958 av_log(ctx, AV_LOG_ERROR, "No such input format: %s.\n",
959 s->pixel_format);
960
961 res = AVERROR(EINVAL);
962 goto fail;
963 }
964 }
965
966 if (!s->width && !s->height) {
967 struct v4l2_format fmt = { .type = s->buf_type };
968
969 av_log(ctx, AV_LOG_VERBOSE,
970 "Querying the device for the current frame size\n");
971 if (v4l2_ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
972 res = AVERROR(errno);
973 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n",
974 av_err2str(res));
975 goto fail;
976 }
977
978 s->width = fmt.fmt.pix.width;
979 s->height = fmt.fmt.pix.height;
980 av_log(ctx, AV_LOG_VERBOSE,
981 "Setting frame size to %dx%d\n", s->width, s->height);
982 }
983
984 res = device_try_init(ctx, pix_fmt, &s->width, &s->height, &desired_format, &codec_id);
985 if (res < 0)
986 goto fail;
987
988 /* If no pixel_format was specified, the codec_id was not known up
989 * until now. Set video_codec_id in the context, as codec_id will
990 * not be available outside this function
991 */
992 if (codec_id != AV_CODEC_ID_NONE && ctx->video_codec_id == AV_CODEC_ID_NONE)
993 ctx->video_codec_id = codec_id;
994
995 if ((res = av_image_check_size(s->width, s->height, 0, ctx)) < 0)
996 goto fail;
997
998 s->pixelformat = desired_format;
999
1000 if ((res = v4l2_set_parameters(ctx)) < 0)
1001 goto fail;
1002
1003 st->codecpar->format = ff_fmt_v4l2ff(desired_format, codec_id);
1004 if (st->codecpar->format != AV_PIX_FMT_NONE)
1005 s->frame_size = av_image_get_buffer_size(st->codecpar->format,
1006 s->width, s->height, 1);
1007
1008 if ((res = mmap_init(ctx)) ||
1009 (res = mmap_start(ctx)) < 0)
1010 goto fail;
1011
1012 s->top_field_first = first_field(s);
1013
1014 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
1015 st->codecpar->codec_id = codec_id;
1016 if (codec_id == AV_CODEC_ID_RAWVIDEO)
1017 st->codecpar->codec_tag =
1018 avcodec_pix_fmt_to_codec_tag(st->codecpar->format);
1019 else if (codec_id == AV_CODEC_ID_H264) {
1020 avpriv_stream_set_need_parsing(st, AVSTREAM_PARSE_FULL_ONCE);
1021 }
1022 if (desired_format == V4L2_PIX_FMT_YVU420)
1023 st->codecpar->codec_tag = MKTAG('Y', 'V', '1', '2');
1024 else if (desired_format == V4L2_PIX_FMT_YVU410)
1025 st->codecpar->codec_tag = MKTAG('Y', 'V', 'U', '9');
1026 st->codecpar->width = s->width;
1027 st->codecpar->height = s->height;
1028 if (st->avg_frame_rate.den)
1029 st->codecpar->bit_rate = s->frame_size * av_q2d(st->avg_frame_rate) * 8;
1030
1031 return 0;
1032
1033 fail:
1034 v4l2_close(s->fd);
1035 return res;
1036 }
1037
1038 static int v4l2_read_packet(AVFormatContext *ctx, AVPacket *pkt)
1039 {
1040 int res;
1041
1042 if ((res = mmap_read_frame(ctx, pkt)) < 0) {
1043 return res;
1044 }
1045
1046 return pkt->size;
1047 }
1048
1049 static int v4l2_read_close(AVFormatContext *ctx)
1050 {
1051 struct video_data *s = ctx->priv_data;
1052
1053 if (atomic_load(&s->buffers_queued) != s->buffers)
1054 av_log(ctx, AV_LOG_WARNING, "Some buffers are still owned by the caller on "
1055 "close.\n");
1056
1057 mmap_close(s);
1058
1059 ff_timefilter_destroy(s->timefilter);
1060 v4l2_close(s->fd);
1061 return 0;
1062 }
1063
1064 static int v4l2_is_v4l_dev(const char *name)
1065 {
1066 return !strncmp(name, "video", 5) ||
1067 !strncmp(name, "radio", 5) ||
1068 !strncmp(name, "vbi", 3) ||
1069 !strncmp(name, "v4l-subdev", 10);
1070 }
1071
1072 static int v4l2_get_device_list(AVFormatContext *ctx, AVDeviceInfoList *device_list)
1073 {
1074 struct video_data *s = ctx->priv_data;
1075 DIR *dir;
1076 struct dirent *entry;
1077 int ret = 0;
1078
1079 if (!device_list)
1080 return AVERROR(EINVAL);
1081
1082 dir = opendir("/dev");
1083 if (!dir) {
1084 ret = AVERROR(errno);
1085 av_log(ctx, AV_LOG_ERROR, "Couldn't open the directory: %s\n", av_err2str(ret));
1086 return ret;
1087 }
1088 while ((entry = readdir(dir))) {
1089 AVDeviceInfo *device = NULL;
1090 struct v4l2_capability cap;
1091 int fd = -1, size;
1092 char device_name[256];
1093
1094 if (!v4l2_is_v4l_dev(entry->d_name))
1095 continue;
1096
1097 size = snprintf(device_name, sizeof(device_name), "/dev/%s", entry->d_name);
1098 if (size >= sizeof(device_name)) {
1099 av_log(ctx, AV_LOG_ERROR, "Device name too long.\n");
1100 ret = AVERROR(ENOSYS);
1101 break;
1102 }
1103
1104 if ((fd = device_open(ctx, device_name)) < 0)
1105 continue;
1106
1107 if (v4l2_ioctl(fd, VIDIOC_QUERYCAP, &cap) < 0) {
1108 ret = AVERROR(errno);
1109 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n", av_err2str(ret));
1110 goto fail;
1111 }
1112
1113 device = av_mallocz(sizeof(AVDeviceInfo));
1114 if (!device) {
1115 ret = AVERROR(ENOMEM);
1116 goto fail;
1117 }
1118 device->device_name = av_strdup(device_name);
1119 device->device_description = av_strdup(cap.card);
1120 if (!device->device_name || !device->device_description) {
1121 ret = AVERROR(ENOMEM);
1122 goto fail;
1123 }
1124
1125 if ((ret = av_dynarray_add_nofree(&device_list->devices,
1126 &device_list->nb_devices, device)) < 0)
1127 goto fail;
1128
1129 v4l2_close(fd);
1130 continue;
1131
1132 fail:
1133 if (device) {
1134 av_freep(&device->device_name);
1135 av_freep(&device->device_description);
1136 av_freep(&device);
1137 }
1138 v4l2_close(fd);
1139 break;
1140 }
1141 closedir(dir);
1142 return ret;
1143 }
1144
1145 #define OFFSET(x) offsetof(struct video_data, x)
1146 #define DEC AV_OPT_FLAG_DECODING_PARAM
1147
1148 static const AVOption options[] = {
1149 { "standard", "set TV standard, used only by analog frame grabber", OFFSET(standard), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, DEC },
1150 { "channel", "set TV channel, used only by frame grabber", OFFSET(channel), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, INT_MAX, DEC },
1151 { "video_size", "set frame size", OFFSET(width), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, DEC },
1152 { "pixel_format", "set preferred pixel format", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1153 { "input_format", "set preferred pixel format (for raw video) or codec name", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1154 { "framerate", "set frame rate", OFFSET(framerate), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
1155
1156 { "list_formats", "list available formats and exit", OFFSET(list_format), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, INT_MAX, DEC, .unit = "list_formats" },
1157 { "all", "show all available formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_ALLFORMATS }, 0, INT_MAX, DEC, .unit = "list_formats" },
1158 { "raw", "show only non-compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_RAWFORMATS }, 0, INT_MAX, DEC, .unit = "list_formats" },
1159 { "compressed", "show only compressed formats", OFFSET(list_format), AV_OPT_TYPE_CONST, {.i64 = V4L_COMPFORMATS }, 0, INT_MAX, DEC, .unit = "list_formats" },
1160
1161 { "list_standards", "list supported standards and exit", OFFSET(list_standard), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, DEC, .unit = "list_standards" },
1162 { "all", "show all supported standards", OFFSET(list_standard), AV_OPT_TYPE_CONST, {.i64 = 1 }, 0, 0, DEC, .unit = "list_standards" },
1163
1164 { "timestamps", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, .unit = "timestamps" },
1165 { "ts", "set type of timestamps for grabbed frames", OFFSET(ts_mode), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 2, DEC, .unit = "timestamps" },
1166 { "default", "use timestamps from the kernel", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_DEFAULT }, 0, 2, DEC, .unit = "timestamps" },
1167 { "abs", "use absolute timestamps (wall clock)", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_ABS }, 0, 2, DEC, .unit = "timestamps" },
1168 { "mono2abs", "force conversion from monotonic to absolute timestamps", OFFSET(ts_mode), AV_OPT_TYPE_CONST, {.i64 = V4L_TS_MONO2ABS }, 0, 2, DEC, .unit = "timestamps" },
1169 { "use_libv4l2", "use libv4l2 (v4l-utils) conversion functions", OFFSET(use_libv4l2), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, DEC },
1170 { NULL },
1171 };
1172
1173 static const AVClass v4l2_class = {
1174 .class_name = "V4L2 indev",
1175 .item_name = av_default_item_name,
1176 .option = options,
1177 .version = LIBAVUTIL_VERSION_INT,
1178 .category = AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT,
1179 };
1180
1181 const FFInputFormat ff_v4l2_demuxer = {
1182 .p.name = "video4linux2,v4l2",
1183 .p.long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),
1184 .p.flags = AVFMT_NOFILE,
1185 .p.priv_class = &v4l2_class,
1186 .priv_data_size = sizeof(struct video_data),
1187 .read_probe = v4l2_read_probe,
1188 .read_header = v4l2_read_header,
1189 .read_packet = v4l2_read_packet,
1190 .read_close = v4l2_read_close,
1191 .get_device_list = v4l2_get_device_list,
1192 };
1193