/* * Video4Linux2 grab interface * Copyright (c) 2000,2001 Fabrice Bellard * Copyright (c) 2006 Luca Abeni * * Part of this file is based on the V4L2 video capture example * (http://v4l2spec.bytesex.org/v4l2spec/capture.c) * * Thanks to Michael Niedermayer for providing the mapping between * V4L2_PIX_FMT_* and PIX_FMT_* * * * This file is part of Libav. * * Libav is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * Libav is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #undef __STRICT_ANSI__ //workaround due to broken kernel headers #include "config.h" #include "libavformat/avformat.h" #include <unistd.h> #include <fcntl.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <sys/time.h> #if HAVE_SYS_VIDEOIO_H #include <sys/videoio.h> #else #include <asm/types.h> #include <linux/videodev2.h> #endif #include <time.h> #include <strings.h> #include "libavutil/imgutils.h" #include "libavutil/log.h" #include "libavutil/opt.h" #include "libavutil/parseutils.h" #include "libavutil/pixdesc.h" static const int desired_video_buffers = 256; enum io_method { io_read, io_mmap, io_userptr }; struct video_data { AVClass *class; int fd; int frame_format; /* V4L2_PIX_FMT_* */ enum io_method io_method; int width, height; int frame_size; int top_field_first; int buffers; void **buf_start; unsigned int *buf_len; char *standard; int channel; char *video_size; /**< String describing video size, set by a private option. */ char *pixel_format; /**< Set by a private option. */ char *framerate; /**< Set by a private option. */ }; struct buff_data { int index; int fd; }; struct fmt_map { enum PixelFormat ff_fmt; enum CodecID codec_id; uint32_t v4l2_fmt; }; static struct fmt_map fmt_conversion_table[] = { //ff_fmt codec_id v4l2_fmt { PIX_FMT_YUV420P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV420 }, { PIX_FMT_YUV422P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV422P }, { PIX_FMT_YUYV422, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUYV }, { PIX_FMT_UYVY422, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_UYVY }, { PIX_FMT_YUV411P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV411P }, { PIX_FMT_YUV410P, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_YUV410 }, { PIX_FMT_RGB555, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB555 }, { PIX_FMT_RGB565, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB565 }, { PIX_FMT_BGR24, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR24 }, { PIX_FMT_RGB24, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_RGB24 }, { PIX_FMT_BGRA, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_BGR32 }, { PIX_FMT_GRAY8, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_GREY }, { PIX_FMT_NV12, CODEC_ID_RAWVIDEO, V4L2_PIX_FMT_NV12 }, { PIX_FMT_NONE, CODEC_ID_MJPEG, V4L2_PIX_FMT_MJPEG }, { PIX_FMT_NONE, CODEC_ID_MJPEG, V4L2_PIX_FMT_JPEG }, }; static int device_open(AVFormatContext *ctx, uint32_t *capabilities) { struct v4l2_capability cap; int fd; int res, err; int flags = O_RDWR; if (ctx->flags & AVFMT_FLAG_NONBLOCK) { flags |= O_NONBLOCK; } fd = open(ctx->filename, flags, 0); if (fd < 0) { av_log(ctx, AV_LOG_ERROR, "Cannot open video device %s : %s\n", ctx->filename, strerror(errno)); return AVERROR(errno); } res = ioctl(fd, VIDIOC_QUERYCAP, &cap); // ENOIOCTLCMD definition only availble on __KERNEL__ if (res < 0 && ((err = errno) == 515)) { av_log(ctx, AV_LOG_ERROR, "QUERYCAP not implemented, probably V4L device but not supporting V4L2\n"); close(fd); return AVERROR(515); } if (res < 0) { av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYCAP): %s\n", strerror(errno)); close(fd); return AVERROR(err); } if ((cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) == 0) { av_log(ctx, AV_LOG_ERROR, "Not a video capture device\n"); close(fd); return AVERROR(ENODEV); } *capabilities = cap.capabilities; return fd; } static int device_init(AVFormatContext *ctx, int *width, int *height, uint32_t pix_fmt) { struct video_data *s = ctx->priv_data; int fd = s->fd; struct v4l2_format fmt; int res; memset(&fmt, 0, sizeof(struct v4l2_format)); fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; fmt.fmt.pix.width = *width; fmt.fmt.pix.height = *height; fmt.fmt.pix.pixelformat = pix_fmt; fmt.fmt.pix.field = V4L2_FIELD_INTERLACED; res = ioctl(fd, VIDIOC_S_FMT, &fmt); if ((*width != fmt.fmt.pix.width) || (*height != fmt.fmt.pix.height)) { 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); *width = fmt.fmt.pix.width; *height = fmt.fmt.pix.height; } if (pix_fmt != fmt.fmt.pix.pixelformat) { 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); res = -1; } return res; } static int first_field(int fd) { int res; v4l2_std_id std; res = ioctl(fd, VIDIOC_G_STD, &std); if (res < 0) { return 0; } if (std & V4L2_STD_NTSC) { return 0; } return 1; } static uint32_t fmt_ff2v4l(enum PixelFormat pix_fmt, enum CodecID codec_id) { int i; for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) { if ((codec_id == CODEC_ID_NONE || fmt_conversion_table[i].codec_id == codec_id) && (pix_fmt == PIX_FMT_NONE || fmt_conversion_table[i].ff_fmt == pix_fmt)) { return fmt_conversion_table[i].v4l2_fmt; } } return 0; } static enum PixelFormat fmt_v4l2ff(uint32_t v4l2_fmt, enum CodecID codec_id) { int i; for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) { if (fmt_conversion_table[i].v4l2_fmt == v4l2_fmt && fmt_conversion_table[i].codec_id == codec_id) { return fmt_conversion_table[i].ff_fmt; } } return PIX_FMT_NONE; } static enum CodecID fmt_v4l2codec(uint32_t v4l2_fmt) { int i; for (i = 0; i < FF_ARRAY_ELEMS(fmt_conversion_table); i++) { if (fmt_conversion_table[i].v4l2_fmt == v4l2_fmt) { return fmt_conversion_table[i].codec_id; } } return CODEC_ID_NONE; } static int mmap_init(AVFormatContext *ctx) { struct video_data *s = ctx->priv_data; struct v4l2_requestbuffers req; int i, res; memset(&req, 0, sizeof(struct v4l2_requestbuffers)); req.count = desired_video_buffers; req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; req.memory = V4L2_MEMORY_MMAP; res = ioctl(s->fd, VIDIOC_REQBUFS, &req); if (res < 0) { if (errno == EINVAL) { av_log(ctx, AV_LOG_ERROR, "Device does not support mmap\n"); } else { av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_REQBUFS)\n"); } return AVERROR(errno); } if (req.count < 2) { av_log(ctx, AV_LOG_ERROR, "Insufficient buffer memory\n"); return AVERROR(ENOMEM); } s->buffers = req.count; s->buf_start = av_malloc(sizeof(void *) * s->buffers); if (s->buf_start == NULL) { av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer pointers\n"); return AVERROR(ENOMEM); } s->buf_len = av_malloc(sizeof(unsigned int) * s->buffers); if (s->buf_len == NULL) { av_log(ctx, AV_LOG_ERROR, "Cannot allocate buffer sizes\n"); av_free(s->buf_start); return AVERROR(ENOMEM); } for (i = 0; i < req.count; i++) { struct v4l2_buffer buf; memset(&buf, 0, sizeof(struct v4l2_buffer)); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; buf.index = i; res = ioctl(s->fd, VIDIOC_QUERYBUF, &buf); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QUERYBUF)\n"); return AVERROR(errno); } s->buf_len[i] = buf.length; if (s->frame_size > 0 && s->buf_len[i] < s->frame_size) { av_log(ctx, AV_LOG_ERROR, "Buffer len [%d] = %d != %d\n", i, s->buf_len[i], s->frame_size); return -1; } s->buf_start[i] = mmap (NULL, buf.length, PROT_READ | PROT_WRITE, MAP_SHARED, s->fd, buf.m.offset); if (s->buf_start[i] == MAP_FAILED) { av_log(ctx, AV_LOG_ERROR, "mmap: %s\n", strerror(errno)); return AVERROR(errno); } } return 0; } static int read_init(AVFormatContext *ctx) { return -1; } static void mmap_release_buffer(AVPacket *pkt) { struct v4l2_buffer buf; int res, fd; struct buff_data *buf_descriptor = pkt->priv; if (pkt->data == NULL) { return; } memset(&buf, 0, sizeof(struct v4l2_buffer)); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; buf.index = buf_descriptor->index; fd = buf_descriptor->fd; av_free(buf_descriptor); res = ioctl(fd, VIDIOC_QBUF, &buf); if (res < 0) { av_log(NULL, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno)); } pkt->data = NULL; pkt->size = 0; } static int mmap_read_frame(AVFormatContext *ctx, AVPacket *pkt) { struct video_data *s = ctx->priv_data; struct v4l2_buffer buf; struct buff_data *buf_descriptor; int res; memset(&buf, 0, sizeof(struct v4l2_buffer)); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; /* FIXME: Some special treatment might be needed in case of loss of signal... */ while ((res = ioctl(s->fd, VIDIOC_DQBUF, &buf)) < 0 && (errno == EINTR)); if (res < 0) { if (errno == EAGAIN) { pkt->size = 0; return AVERROR(EAGAIN); } av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_DQBUF): %s\n", strerror(errno)); return AVERROR(errno); } assert (buf.index < s->buffers); if (s->frame_size > 0 && buf.bytesused != s->frame_size) { av_log(ctx, AV_LOG_ERROR, "The v4l2 frame is %d bytes, but %d bytes are expected\n", buf.bytesused, s->frame_size); return AVERROR_INVALIDDATA; } /* Image is at s->buff_start[buf.index] */ pkt->data= s->buf_start[buf.index]; pkt->size = buf.bytesused; pkt->pts = buf.timestamp.tv_sec * INT64_C(1000000) + buf.timestamp.tv_usec; pkt->destruct = mmap_release_buffer; buf_descriptor = av_malloc(sizeof(struct buff_data)); if (buf_descriptor == NULL) { /* Something went wrong... Since av_malloc() failed, we cannot even * allocate a buffer for memcopying into it */ av_log(ctx, AV_LOG_ERROR, "Failed to allocate a buffer descriptor\n"); res = ioctl(s->fd, VIDIOC_QBUF, &buf); return AVERROR(ENOMEM); } buf_descriptor->fd = s->fd; buf_descriptor->index = buf.index; pkt->priv = buf_descriptor; return s->buf_len[buf.index]; } static int read_frame(AVFormatContext *ctx, AVPacket *pkt) { return -1; } static int mmap_start(AVFormatContext *ctx) { struct video_data *s = ctx->priv_data; enum v4l2_buf_type type; int i, res; for (i = 0; i < s->buffers; i++) { struct v4l2_buffer buf; memset(&buf, 0, sizeof(struct v4l2_buffer)); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; buf.index = i; res = ioctl(s->fd, VIDIOC_QBUF, &buf); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_QBUF): %s\n", strerror(errno)); return AVERROR(errno); } } type = V4L2_BUF_TYPE_VIDEO_CAPTURE; res = ioctl(s->fd, VIDIOC_STREAMON, &type); if (res < 0) { av_log(ctx, AV_LOG_ERROR, "ioctl(VIDIOC_STREAMON): %s\n", strerror(errno)); return AVERROR(errno); } return 0; } static void mmap_close(struct video_data *s) { enum v4l2_buf_type type; int i; type = V4L2_BUF_TYPE_VIDEO_CAPTURE; /* We do not check for the result, because we could * not do anything about it anyway... */ ioctl(s->fd, VIDIOC_STREAMOFF, &type); for (i = 0; i < s->buffers; i++) { munmap(s->buf_start[i], s->buf_len[i]); } av_free(s->buf_start); av_free(s->buf_len); } static int v4l2_set_parameters(AVFormatContext *s1, AVFormatParameters *ap) { struct video_data *s = s1->priv_data; struct v4l2_input input; struct v4l2_standard standard; struct v4l2_streamparm streamparm = { 0 }; struct v4l2_fract *tpf = &streamparm.parm.capture.timeperframe; int i, ret; AVRational framerate_q; streamparm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (s->framerate && (ret = av_parse_video_rate(&framerate_q, s->framerate)) < 0) { av_log(s1, AV_LOG_ERROR, "Could not parse framerate '%s'.\n", s->framerate); return ret; } /* set tv video input */ memset (&input, 0, sizeof (input)); input.index = s->channel; if (ioctl(s->fd, VIDIOC_ENUMINPUT, &input) < 0) { av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl enum input failed:\n"); return AVERROR(EIO); } av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set input_id: %d, input: %s\n", s->channel, input.name); if (ioctl(s->fd, VIDIOC_S_INPUT, &input.index) < 0) { av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set input(%d) failed\n", s->channel); return AVERROR(EIO); } if (s->standard) { av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s\n", s->standard); /* set tv standard */ memset (&standard, 0, sizeof (standard)); for(i=0;;i++) { standard.index = i; if (ioctl(s->fd, VIDIOC_ENUMSTD, &standard) < 0) { av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n", s->standard); return AVERROR(EIO); } if (!strcasecmp(standard.name, s->standard)) { break; } } av_log(s1, AV_LOG_DEBUG, "The V4L2 driver set standard: %s, id: %"PRIu64"\n", s->standard, (uint64_t)standard.id); if (ioctl(s->fd, VIDIOC_S_STD, &standard.id) < 0) { av_log(s1, AV_LOG_ERROR, "The V4L2 driver ioctl set standard(%s) failed\n", s->standard); return AVERROR(EIO); } } if (framerate_q.num && framerate_q.den) { av_log(s1, AV_LOG_DEBUG, "Setting time per frame to %d/%d\n", framerate_q.den, framerate_q.num); tpf->numerator = framerate_q.den; tpf->denominator = framerate_q.num; if (ioctl(s->fd, VIDIOC_S_PARM, &streamparm) != 0) { av_log(s1, AV_LOG_ERROR, "ioctl set time per frame(%d/%d) failed\n", framerate_q.den, framerate_q.num); return AVERROR(EIO); } if (framerate_q.num != tpf->denominator || framerate_q.den != tpf->numerator) { av_log(s1, AV_LOG_INFO, "The driver changed the time per frame from %d/%d to %d/%d\n", framerate_q.den, framerate_q.num, tpf->numerator, tpf->denominator); } } else { /* if timebase value is not set, read the timebase value from the driver */ if (ioctl(s->fd, VIDIOC_G_PARM, &streamparm) != 0) { av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_PARM): %s\n", strerror(errno)); return AVERROR(errno); } } s1->streams[0]->codec->time_base.den = tpf->denominator; s1->streams[0]->codec->time_base.num = tpf->numerator; return 0; } static uint32_t device_try_init(AVFormatContext *s1, enum PixelFormat pix_fmt, int *width, int *height, enum CodecID *codec_id) { uint32_t desired_format = fmt_ff2v4l(pix_fmt, s1->video_codec_id); if (desired_format == 0 || device_init(s1, width, height, desired_format) < 0) { int i; desired_format = 0; for (i = 0; i<FF_ARRAY_ELEMS(fmt_conversion_table); i++) { if (s1->video_codec_id == CODEC_ID_NONE || fmt_conversion_table[i].codec_id == s1->video_codec_id) { desired_format = fmt_conversion_table[i].v4l2_fmt; if (device_init(s1, width, height, desired_format) >= 0) { break; } desired_format = 0; } } } if (desired_format != 0) { *codec_id = fmt_v4l2codec(desired_format); assert(*codec_id != CODEC_ID_NONE); } return desired_format; } static int v4l2_read_header(AVFormatContext *s1, AVFormatParameters *ap) { struct video_data *s = s1->priv_data; AVStream *st; int res = 0; uint32_t desired_format, capabilities; enum CodecID codec_id; enum PixelFormat pix_fmt = PIX_FMT_NONE; st = av_new_stream(s1, 0); if (!st) { res = AVERROR(ENOMEM); goto out; } av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */ if (s->video_size && (res = av_parse_video_size(&s->width, &s->height, s->video_size)) < 0) { av_log(s1, AV_LOG_ERROR, "Could not parse video size '%s'.\n", s->video_size); goto out; } if (s->pixel_format && (pix_fmt = av_get_pix_fmt(s->pixel_format)) == PIX_FMT_NONE) { av_log(s1, AV_LOG_ERROR, "No such pixel format: %s.\n", s->pixel_format); res = AVERROR(EINVAL); goto out; } capabilities = 0; s->fd = device_open(s1, &capabilities); if (s->fd < 0) { res = AVERROR(EIO); goto out; } av_log(s1, AV_LOG_VERBOSE, "[%d]Capabilities: %x\n", s->fd, capabilities); if (!s->width && !s->height) { struct v4l2_format fmt; av_log(s1, AV_LOG_VERBOSE, "Querying the device for the current frame size\n"); fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) { av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", strerror(errno)); res = AVERROR(errno); goto out; } s->width = fmt.fmt.pix.width; s->height = fmt.fmt.pix.height; av_log(s1, AV_LOG_VERBOSE, "Setting frame size to %dx%d\n", s->width, s->height); } desired_format = device_try_init(s1, pix_fmt, &s->width, &s->height, &codec_id); if (desired_format == 0) { av_log(s1, AV_LOG_ERROR, "Cannot find a proper format for " "codec_id %d, pix_fmt %d.\n", s1->video_codec_id, pix_fmt); close(s->fd); res = AVERROR(EIO); goto out; } if ((res = av_image_check_size(s->width, s->height, 0, s1) < 0)) goto out; s->frame_format = desired_format; if ((res = v4l2_set_parameters(s1, ap) < 0)) goto out; st->codec->pix_fmt = fmt_v4l2ff(desired_format, codec_id); s->frame_size = avpicture_get_size(st->codec->pix_fmt, s->width, s->height); if (capabilities & V4L2_CAP_STREAMING) { s->io_method = io_mmap; res = mmap_init(s1); if (res == 0) { res = mmap_start(s1); } } else { s->io_method = io_read; res = read_init(s1); } if (res < 0) { close(s->fd); res = AVERROR(EIO); goto out; } s->top_field_first = first_field(s->fd); st->codec->codec_type = AVMEDIA_TYPE_VIDEO; st->codec->codec_id = codec_id; st->codec->width = s->width; st->codec->height = s->height; st->codec->bit_rate = s->frame_size * 1/av_q2d(st->codec->time_base) * 8; out: return res; } static int v4l2_read_packet(AVFormatContext *s1, AVPacket *pkt) { struct video_data *s = s1->priv_data; int res; if (s->io_method == io_mmap) { av_init_packet(pkt); res = mmap_read_frame(s1, pkt); } else if (s->io_method == io_read) { if (av_new_packet(pkt, s->frame_size) < 0) return AVERROR(EIO); res = read_frame(s1, pkt); } else { return AVERROR(EIO); } if (res < 0) { return res; } if (s1->streams[0]->codec->coded_frame) { s1->streams[0]->codec->coded_frame->interlaced_frame = 1; s1->streams[0]->codec->coded_frame->top_field_first = s->top_field_first; } return pkt->size; } static int v4l2_read_close(AVFormatContext *s1) { struct video_data *s = s1->priv_data; if (s->io_method == io_mmap) { mmap_close(s); } close(s->fd); return 0; } #define OFFSET(x) offsetof(struct video_data, x) #define DEC AV_OPT_FLAG_DECODING_PARAM static const AVOption options[] = { { "standard", "", offsetof(struct video_data, standard), FF_OPT_TYPE_STRING, {.str = NULL }, 0, 0, AV_OPT_FLAG_DECODING_PARAM }, { "channel", "", offsetof(struct video_data, channel), FF_OPT_TYPE_INT, {.dbl = 0 }, 0, INT_MAX, AV_OPT_FLAG_DECODING_PARAM }, { "video_size", "A string describing frame size, such as 640x480 or hd720.", OFFSET(video_size), FF_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC }, { "pixel_format", "", OFFSET(pixel_format), FF_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC }, { "framerate", "", OFFSET(framerate), FF_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC }, { NULL }, }; static const AVClass v4l2_class = { .class_name = "V4L2 indev", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT, }; AVInputFormat ff_v4l2_demuxer = { .name = "video4linux2", .long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 device grab"), .priv_data_size = sizeof(struct video_data), .read_header = v4l2_read_header, .read_packet = v4l2_read_packet, .read_close = v4l2_read_close, .flags = AVFMT_NOFILE, .priv_class = &v4l2_class, };