2 * Video4Linux2 grab interface
3 * Copyright (c) 2000,2001 Fabrice Bellard
4 * Copyright (c) 2006 Luca Abeni
6 * Part of this file is based on the V4L2 video capture example
7 * (http://v4l2spec.bytesex.org/v4l2spec/capture.c)
9 * Thanks to Michael Niedermayer for providing the mapping between
10 * V4L2_PIX_FMT_* and PIX_FMT_*
13 * This file is part of Libav.
15 * Libav is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU Lesser General Public
17 * License as published by the Free Software Foundation; either
18 * version 2.1 of the License, or (at your option) any later version.
20 * Libav is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 * Lesser General Public License for more details.
25 * You should have received a copy of the GNU Lesser General Public
26 * License along with Libav; if not, write to the Free Software
27 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 #undef __STRICT_ANSI__ //workaround due to broken kernel headers
32 #include "libavformat/avformat.h"
35 #include <sys/ioctl.h>
38 #if HAVE_SYS_VIDEOIO_H
39 #include <sys/videoio.h>
41 #include <asm/types.h>
42 #include <linux/videodev2.h>
46 #include "libavutil/imgutils.h"
47 #include "libavutil/log.h"
48 #include "libavutil/opt.h"
49 #include "libavutil/parseutils.h"
50 #include "libavutil/pixdesc.h"
52 static const int desired_video_buffers = 256;
63 int frame_format; /* V4L2_PIX_FMT_* */
64 enum io_method io_method;
71 unsigned int *buf_len;
74 char *video_size; /**< String describing video size, set by a private option. */
75 char *pixel_format; /**< Set by a private option. */
84 enum PixelFormat ff_fmt;
85 enum CodecID codec_id;
89 static struct fmt_map fmt_conversion_table[] = {
90 //ff_fmt codec_id v4l2_fmt
91 { PIX_FMT_YUV420P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV420 },
92 { PIX_FMT_YUV422P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV422P },
93 { PIX_FMT_YUYV422, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUYV },
94 { PIX_FMT_UYVY422, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_UYVY },
95 { PIX_FMT_YUV411P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV411P },
96 { PIX_FMT_YUV410P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV410 },
97 { PIX_FMT_RGB555, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB555 },
98 { PIX_FMT_RGB565, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB565 },
99 { PIX_FMT_BGR24, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR24 },
100 { PIX_FMT_RGB24, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB24 },
101 { PIX_FMT_BGRA, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR32 },
102 { PIX_FMT_GRAY8, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_GREY },
103 { PIX_FMT_NV12, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_NV12 },
104 { PIX_FMT_NONE, CODEC_ID_MJPEG, V4L2_PIX_FMT_MJPEG },
105 { PIX_FMT_NONE, CODEC_ID_MJPEG, V4L2_PIX_FMT_JPEG },
108 static int device_open(AVFormatContext *ctx, uint32_t *capabilities)
110 struct v4l2_capability cap;
115 if (ctx->flags & AVFMT_FLAG_NONBLOCK) {
118 fd = open(ctx->filename, flags, 0);
120 av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s : %s\n",
121 ctx->filename, strerror(errno));
123 return AVERROR(errno);
126 res = ioctl(fd, VIDIOC_QUERYCAP, &cap);
127 // ENOIOCTLCMD definition only availble on __KERNEL__
128 if (res < 0 && ((err = errno) == 515)) {
129 av_log(ctx, AV_LOG_ERROR, "QUERYCAP not implemented, probably V4L device but not supporting V4L2\n");
135 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n",
141 if ((cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) == 0) {
142 av_log(ctx, AV_LOG_ERROR, "Not a video capture device\n");
145 return AVERROR(ENODEV);
147 *capabilities = cap.capabilities;
152 static int device_init(AVFormatContext *ctx, int *width, int *height, uint32_t pix_fmt)
154 struct video_data *s = ctx->priv_data;
156 struct v4l2_format fmt;
159 memset(&fmt, 0, sizeof(struct v4l2_format));
160 fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
161 fmt.fmt.pix.width = *width;
162 fmt.fmt.pix.height = *height;
163 fmt.fmt.pix.pixelformat = pix_fmt;
164 fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
165 res = ioctl(fd, VIDIOC_S_FMT, &fmt);
166 if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) {
167 av_log(ctx, AV_LOG_INFO, "The V4L2 driver changed the video from %dx%d to %dx%d\n", *width, *height, fmt.fmt.pix.width, fmt.fmt.pix.height);
168 *width = fmt.fmt.pix.width;
169 *height = fmt.fmt.pix.height;
172 if (pix_fmt != fmt.fmt.pix.pixelformat) {
173 av_log(ctx, AV_LOG_DEBUG, "The V4L2 driver changed the pixel format from 0x%08X to 0x%08X\n", pix_fmt, fmt.fmt.pix.pixelformat);
180 static int first_field(int fd)
185 res = ioctl(fd, VIDIOC_G_STD, &std);
189 if (std & V4L2_STD_NTSC) {
196 static uint32_t fmt_ff2v4l(enum PixelFormat pix_fmt, enum CodecID codec_id)
200 for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
201 if ((codec_id == CODEC_ID_NONE ||
202 fmt_conversion_table[i].codec_id == codec_id) &&
203 (pix_fmt == PIX_FMT_NONE ||
204 fmt_conversion_table[i].ff_fmt == pix_fmt)) {
205 return fmt_conversion_table[i].v4l2_fmt;
212 static enum PixelFormat fmt_v4l2ff(uint32_t v4l2_fmt, enum CodecID codec_id)
216 for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
217 if (fmt_conversion_table[i].v4l2_fmt == v4l2_fmt &&
218 fmt_conversion_table[i].codec_id == codec_id) {
219 return fmt_conversion_table[i].ff_fmt;
226 static enum CodecID fmt_v4l2codec(uint32_t v4l2_fmt)
230 for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
231 if (fmt_conversion_table[i].v4l2_fmt == v4l2_fmt) {
232 return fmt_conversion_table[i].codec_id;
236 return CODEC_ID_NONE;
239 static int mmap_init(AVFormatContext *ctx)
241 struct video_data *s = ctx->priv_data;
242 struct v4l2_requestbuffers req;
245 memset(&req, 0, sizeof(struct v4l2_requestbuffers));
246 req.count = desired_video_buffers;
247 req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
248 req.memory = V4L2_MEMORY_MMAP;
249 res = ioctl(s->fd, VIDIOC_REQBUFS, &req);
251 if (errno == EINVAL) {
252 av_log(ctx, AV_LOG_ERROR, "Device does not support mmap\n");
254 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS)\n");
257 return AVERROR(errno);
261 av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n");
263 return AVERROR(ENOMEM);
265 s->buffers = req.count;
266 s->buf_start = av_malloc(sizeof(void *) * s->buffers);
267 if (s->buf_start == NULL) {
268 av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n");
270 return AVERROR(ENOMEM);
272 s->buf_len = av_malloc(sizeof(unsigned int) * s->buffers);
273 if (s->buf_len == NULL) {
274 av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n");
275 av_free(s->buf_start);
277 return AVERROR(ENOMEM);
280 for (i = 0; i < req.count; i++) {
281 struct v4l2_buffer buf;
283 memset(&buf, 0, sizeof(struct v4l2_buffer));
284 buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
285 buf.memory = V4L2_MEMORY_MMAP;
287 res = ioctl(s->fd, VIDIOC_QUERYBUF, &buf);
289 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n");
291 return AVERROR(errno);
294 s->buf_len[i] = buf.length;
295 if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) {
296 av_log(ctx, AV_LOG_ERROR, "Buffer len [%d] = %d != %d\n", i, s->buf_len[i], s->frame_size);
300 s->buf_start[i] = mmap (NULL, buf.length,
301 PROT_READ | PROT_WRITE, MAP_SHARED, s->fd, buf.m.offset);
302 if (s->buf_start[i] == MAP_FAILED) {
303 av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", strerror(errno));
305 return AVERROR(errno);
312 static int read_init(AVFormatContext *ctx)
317 static void mmap_release_buffer(AVPacket *pkt)
319 struct v4l2_buffer buf;
321 struct buff_data *buf_descriptor = pkt->priv;
323 if (pkt->data == NULL) {
327 memset(&buf, 0, sizeof(struct v4l2_buffer));
328 buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
329 buf.memory = V4L2_MEMORY_MMAP;
330 buf.index = buf_descriptor->index;
331 fd = buf_descriptor->fd;
332 av_free(buf_descriptor);
334 res = ioctl(fd, VIDIOC_QBUF, &buf);
336 av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno));
342 static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt)
344 struct video_data *s = ctx->priv_data;
345 struct v4l2_buffer buf;
346 struct buff_data *buf_descriptor;
349 memset(&buf, 0, sizeof(struct v4l2_buffer));
350 buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
351 buf.memory = V4L2_MEMORY_MMAP;
353 /* FIXME: Some special treatment might be needed in case of loss of signal... */
354 while ((res = ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR));
356 if (errno == EAGAIN) {
359 return AVERROR(EAGAIN);
361 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n", strerror(errno));
363 return AVERROR(errno);
365 assert (buf.index < s->buffers);
366 if (s->frame_size > 0 && buf.bytesused != s->frame_size) {
367 av_log(ctx, AV_LOG_ERROR, "The v4l2 frame is %d bytes, but %d bytes are expected\n", buf.bytesused, s->frame_size);
369 return AVERROR_INVALIDDATA;
372 /* Image is at s->buff_start[buf.index] */
373 pkt->data= s->buf_start[buf.index];
374 pkt->size = buf.bytesused;
375 pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec;
376 pkt->destruct = mmap_release_buffer;
377 buf_descriptor = av_malloc(sizeof(struct buff_data));
378 if (buf_descriptor == NULL) {
379 /* Something went wrong... Since av_malloc() failed, we cannot even
380 * allocate a buffer for memcopying into it
382 av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n");
383 res = ioctl(s->fd, VIDIOC_QBUF, &buf);
385 return AVERROR(ENOMEM);
387 buf_descriptor->fd = s->fd;
388 buf_descriptor->index = buf.index;
389 pkt->priv = buf_descriptor;
391 return s->buf_len[buf.index];
394 static int read_frame(AVFormatContext *ctx, AVPacket *pkt)
399 static int mmap_start(AVFormatContext *ctx)
401 struct video_data *s = ctx->priv_data;
402 enum v4l2_buf_type type;
405 for (i = 0; i < s->buffers; i++) {
406 struct v4l2_buffer buf;
408 memset(&buf, 0, sizeof(struct v4l2_buffer));
409 buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
410 buf.memory = V4L2_MEMORY_MMAP;
413 res = ioctl(s->fd, VIDIOC_QBUF, &buf);
415 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno));
417 return AVERROR(errno);
421 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
422 res = ioctl(s->fd, VIDIOC_STREAMON, &type);
424 av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n", strerror(errno));
426 return AVERROR(errno);
432 static void mmap_close(struct video_data *s)
434 enum v4l2_buf_type type;
437 type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
438 /* We do not check for the result, because we could
439 * not do anything about it anyway...
441 ioctl(s->fd, VIDIOC_STREAMOFF, &type);
442 for (i = 0; i < s->buffers; i++) {
443 munmap(s->buf_start[i], s->buf_len[i]);
445 av_free(s->buf_start);
449 static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap)
451 struct video_data *s = s1->priv_data;
452 struct v4l2_input input;
453 struct v4l2_standard standard;
454 struct v4l2_streamparm streamparm = { 0 };
455 struct v4l2_fract *tpf = &streamparm.parm.capture.timeperframe;
458 streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
460 #if FF_API_FORMAT_PARAMETERS
462 s->channel = ap->channel;
465 /* set tv video input */
466 memset (&input, 0, sizeof (input));
467 input.index = s->channel;
468 if (ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) {
469 av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n");
473 av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set input_id: %d, input: %s\n",
474 s->channel, input.name);
475 if (ioctl(s->fd, VIDIOC_S_INPUT, &input.index) < 0) {
476 av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set input(%d) failed\n",
481 #if FF_API_FORMAT_PARAMETERS
483 av_freep(&s->standard);
484 s->standard = av_strdup(ap->standard);
489 av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s\n",
491 /* set tv standard */
492 memset (&standard, 0, sizeof (standard));
495 if (ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) {
496 av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n",
501 if (!strcasecmp(standard.name, s->standard)) {
506 av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s, id: %"PRIu64"\n",
507 s->standard, (uint64_t)standard.id);
508 if (ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) {
509 av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n",
515 if (ap->time_base.num && ap->time_base.den) {
516 av_log(s1, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n",
517 ap->time_base.num, ap->time_base.den);
518 tpf->numerator = ap->time_base.num;
519 tpf->denominator = ap->time_base.den;
520 if (ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) {
521 av_log(s1, AV_LOG_ERROR,
522 "ioctl set time per frame(%d/%d) failed\n",
523 ap->time_base.num, ap->time_base.den);
527 if (ap->time_base.den != tpf->denominator ||
528 ap->time_base.num != tpf->numerator) {
529 av_log(s1, AV_LOG_INFO,
530 "The driver changed the time per frame from %d/%d to %d/%d\n",
531 ap->time_base.num, ap->time_base.den,
532 tpf->numerator, tpf->denominator);
535 /* if timebase value is not set in ap, read the timebase value from the driver */
536 if (ioctl(s->fd, VIDIOC_G_PARM, &streamparm) != 0) {
537 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n", strerror(errno));
538 return AVERROR(errno);
541 ap->time_base.num = tpf->numerator;
542 ap->time_base.den = tpf->denominator;
547 static uint32_t device_try_init(AVFormatContext *s1,
548 enum PixelFormat pix_fmt,
551 enum CodecID *codec_id)
553 uint32_t desired_format = fmt_ff2v4l(pix_fmt, s1->video_codec_id);
555 if (desired_format == 0 ||
556 device_init(s1, width, height, desired_format) < 0) {
560 for (i = 0; i<FF_ARRAY_ELEMS(fmt_conversion_table); i++) {
561 if (s1->video_codec_id == CODEC_ID_NONE ||
562 fmt_conversion_table[i].codec_id == s1->video_codec_id) {
563 desired_format = fmt_conversion_table[i].v4l2_fmt;
564 if (device_init(s1, width, height, desired_format) >= 0) {
571 if (desired_format != 0) {
572 *codec_id = fmt_v4l2codec(desired_format);
573 assert(*codec_id != CODEC_ID_NONE);
576 return desired_format;
579 static int v4l2_read_header(AVFormatContext *s1, AVFormatParameters *ap)
581 struct video_data *s = s1->priv_data;
584 uint32_t desired_format, capabilities;
585 enum CodecID codec_id;
586 enum PixelFormat pix_fmt = PIX_FMT_NONE;
588 st = av_new_stream(s1, 0);
590 res = AVERROR(ENOMEM);
593 av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */
595 if (s->video_size && (res = av_parse_video_size(&s->width, &s->height, s->video_size)) < 0) {
596 av_log(s1, AV_LOG_ERROR, "Couldn't parse video size.\n");
599 if (s->pixel_format && (pix_fmt = av_get_pix_fmt(s->pixel_format)) == PIX_FMT_NONE) {
600 av_log(s1, AV_LOG_ERROR, "No such pixel format: %s.\n", s->pixel_format);
601 res = AVERROR(EINVAL);
604 #if FF_API_FORMAT_PARAMETERS
606 s->width = ap->width;
608 s->height = ap->height;
610 pix_fmt = ap->pix_fmt;
614 s->fd = device_open(s1, &capabilities);
619 av_log(s1, AV_LOG_VERBOSE, "[%d]Capabilities: %x\n", s->fd, capabilities);
621 if (!s->width && !s->height) {
622 struct v4l2_format fmt;
624 av_log(s1, AV_LOG_VERBOSE, "Querying the device for the current frame size\n");
625 fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
626 if (ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
627 av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", strerror(errno));
628 res = AVERROR(errno);
631 s->width = fmt.fmt.pix.width;
632 s->height = fmt.fmt.pix.height;
633 av_log(s1, AV_LOG_VERBOSE, "Setting frame size to %dx%d\n", s->width, s->height);
636 desired_format = device_try_init(s1, pix_fmt, &s->width, &s->height, &codec_id);
637 if (desired_format == 0) {
638 av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for "
639 "codec_id %d, pix_fmt %d.\n", s1->video_codec_id, ap->pix_fmt);
645 if ((res = av_image_check_size(s->width, s->height, 0, s1) < 0))
647 s->frame_format = desired_format;
649 if ((res = v4l2_set_parameters(s1, ap) < 0))
652 st->codec->pix_fmt = fmt_v4l2ff(desired_format, codec_id);
653 s->frame_size = avpicture_get_size(st->codec->pix_fmt, s->width, s->height);
654 if (capabilities & V4L2_CAP_STREAMING) {
655 s->io_method = io_mmap;
658 res = mmap_start(s1);
661 s->io_method = io_read;
670 s->top_field_first = first_field(s->fd);
672 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
673 st->codec->codec_id = codec_id;
674 st->codec->width = s->width;
675 st->codec->height = s->height;
676 st->codec->time_base.den = ap->time_base.den;
677 st->codec->time_base.num = ap->time_base.num;
678 st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8;
681 av_freep(&s->video_size);
682 av_freep(&s->pixel_format);
683 av_freep(&s->standard);
687 static int v4l2_read_packet(AVFormatContext *s1, AVPacket *pkt)
689 struct video_data *s = s1->priv_data;
692 if (s->io_method == io_mmap) {
694 res = mmap_read_frame(s1, pkt);
695 } else if (s->io_method == io_read) {
696 if (av_new_packet(pkt, s->frame_size) < 0)
699 res = read_frame(s1, pkt);
707 if (s1->streams[0]->codec->coded_frame) {
708 s1->streams[0]->codec->coded_frame->interlaced_frame = 1;
709 s1->streams[0]->codec->coded_frame->top_field_first = s->top_field_first;
715 static int v4l2_read_close(AVFormatContext *s1)
717 struct video_data *s = s1->priv_data;
719 if (s->io_method == io_mmap) {
727 #define OFFSET(x) offsetof(struct video_data, x)
728 #define DEC AV_OPT_FLAG_DECODING_PARAM
729 static const AVOption options[] = {
730 { "standard", "", offsetof(struct video_data, standard), FF_OPT_TYPE_STRING, {.str = "NTSC" }, 0, 0, AV_OPT_FLAG_DECODING_PARAM },
731 { "channel", "", offsetof(struct video_data, channel), FF_OPT_TYPE_INT, {.dbl = 0 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM },
732 { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), FF_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
733 { "pixel_format", "", OFFSET(pixel_format), FF_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },
737 static const AVClass v4l2_class = {
738 .class_name = "V4L2 indev",
739 .item_name = av_default_item_name,
741 .version = LIBAVUTIL_VERSION_INT,
744 AVInputFormat ff_v4l2_demuxer = {
746 NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"),
747 sizeof(struct video_data),
752 .flags = AVFMT_NOFILE,
753 .priv_class = &v4l2_class,