1.win+r打开运行。
2.在运行中键入services.msc回车,打开服务。
3.右边下拉找到VMware Authorization Service。
4.双击打开属性,启动类型->自动,点击驱动,点击应用,点击确定。这个时候已经授权虚拟机能访问到摄像头了。
5.打开虚拟机,点击"虚拟机"->可移动设备,找到摄像头camera,点击链接。此时虚拟机完成对摄像头的接管。
6.查看在/dev/下有video的文件。
安装cheese,打开摄像头:
sudo apt-get install cheese
在终端输入cheese回车->此时可以看到打开的摄像头。
查看设备类型
ffmpeg -devices
可以看到有video4linux2,v4l2这个选项
“ v4l2”可以用作“ video4linux2”的别名。
alsa是音频类型,见另一篇:虚拟机使用pc麦克风声卡
根据设备类型查看具体设备名
ffmpeg -sources video4linux2
或
ffmpeg -sources v4l2
可以看到有这两个设备,这两个设备对应pc的摄像头
/dev/video1 [Integrated Camera: Integrated I] /dev/video0 [Integrated Camera: Integrated C]
用命令打开摄像头,另一个不能用来打开
ffplay -f video4linux2 -video_size 640x480 -pixel_format yuyv422 -framerate 30 -i /dev/video0
查看设备输入输出参数
ffmpeg -h demuxer=v4l2
如查看都支持哪些像素格式
ffplay -f video4linux2 -list_formats all /dev/video0
这些选项也可以用代码设置,"video_size"等名称与ffmpeg -h demuxer=v4l2 命令列举的名称一样。
AVDictionary *options = NULL;
av_dict_set(&options, “video_size”, “1920x1080”, 0);
av_dict_set(&options, “framerate”, “30”, 0);
//以上参数如果不设置的话,ffmpeg就会用默认值,但默认值摄像头不一定支持
int re = avformat_open_input(&ic, “/dev/video0”, ifmt, &options);
其次对于显示在/dev/video中的摄像头其实都是支持UVC协议的摄像头,一般说摄像头免驱动也是基于UVC开发的,我们可以用luvcview这款软件查看所有基于UVC的摄像头的信息,对于ubuntu12,可以直接执行下列命令安装,因为当时是为ubuntu12设计的:
sudo apt-get install luvcview
对于其他版本,可以到官网下载deb包安装,连接:
luvcview_0.2.6-5_amd64.deb (52.3 KiB)
安装好后
打开摄像头
luvcview -l
打开摄像头
luvcview -d /dev/video1 -f yuv -s 640x480
查看设备支持的像素格式和帧率
luvcview -d /dev/video0 -L
可以看到支持的像素格式:MJPG YUYV RGB3 BGR3 YU12 YV12
Time interval between frame: 1/30 也就是帧间的时间间隔,也就是帧率了。
luvcview 0.2.6 SDL information: Video driver: x11 A window manager is available Device information: Device path: /dev/video0 { pixelformat = 'MJPG', description = 'Motion-JPEG' } { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, { discrete: width = 320, height = 180 } Time interval between frame: 1/30, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, { discrete: width = 424, height = 240 } Time interval between frame: 1/30, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, { discrete: width = 640, height = 480 } Time interval between frame: 1/30, { discrete: width = 848, height = 480 } Time interval between frame: 1/30, { discrete: width = 960, height = 540 } Time interval between frame: 1/30, { pixelformat = 'YUYV', description = 'YUYV 4:2:2' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, { discrete: width = 320, height = 180 } Time interval between frame: 1/30, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, { discrete: width = 424, height = 240 } Time interval between frame: 1/30, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, { discrete: width = 848, height = 480 } Time interval between frame: 1/20, { discrete: width = 960, height = 540 } Time interval between frame: 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 1/10, { pixelformat = 'RGB3', description = 'RGB3' } { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, { discrete: width = 320, height = 180 } Time interval between frame: 1/30, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, { discrete: width = 424, height = 240 } Time interval between frame: 1/30, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, { discrete: width = 640, height = 480 } Time interval between frame: 1/30, { discrete: width = 848, height = 480 } Time interval between frame: 1/20, { discrete: width = 960, height = 540 } Time interval between frame: 1/30, { pixelformat = 'BGR3', description = 'BGR3' } { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, { discrete: width = 320, height = 180 } Time interval between frame: 1/30, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, { discrete: width = 424, height = 240 } Time interval between frame: 1/30, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, { discrete: width = 640, height = 480 } Time interval between frame: 1/30, { discrete: width = 848, height = 480 } Time interval between frame: 1/20, { discrete: width = 960, height = 540 } Time interval between frame: 1/30, { pixelformat = 'YU12', description = 'YU12' } { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, { discrete: width = 320, height = 180 } Time interval between frame: 1/30, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, { discrete: width = 424, height = 240 } Time interval between frame: 1/30, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, { discrete: width = 640, height = 480 } Time interval between frame: 1/30, { discrete: width = 848, height = 480 } Time interval between frame: 1/20, { discrete: width = 960, height = 540 } Time interval between frame: 1/30, { pixelformat = 'YV12', description = 'YV12' } { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, { discrete: width = 320, height = 180 } Time interval between frame: 1/30, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, { discrete: width = 424, height = 240 } Time interval between frame: 1/30, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, { discrete: width = 640, height = 480 } Time interval between frame: 1/30, { discrete: width = 848, height = 480 } Time interval between frame: 1/20, { discrete: width = 960, height = 540 } Time interval between frame: 1/30,
ffplay -f video4linux2 -framerate 60 -video_size 1920x1080 -pixel_format mjpeg -i /dev/video4
用mjpeg的方式播放,并设置帧率。
如果你想把其他的raw流放入/dev/video设备中,也是可以用ffmpeg推流的:
ffmpeg -f x11grab -r 15 -s 1280x720 -i :0.0+0,0 -vcodec rawvideo -pix_fmt yuv420p -threads 0 -f v4l2 /dev/video0
以上把屏幕推流到/dev/video0上,但video0是必须是虚拟设备,不对应实际device
如何设置虚拟/dev/video参考:https://www.cnblogs.com/xl2432/p/13501145.html
同时一个device可以对应多个输入源,比如/dev/video0可以对应两个输入源通道,也就是它在硬件上可以对应两个usb输入口,用下面代码切换通道,-d 2代表指定/dev/video2
v4l2-ctl -d 2 -i 4
查看驱动各种信息,如色域等,色域一般为Rec. 709,这个在笔者其他博客有介绍,-d 2指定usb设备
v4l2-ctl -DVI --get-parm -d 2
Driver Info: Driver name : uvcvideo Card type : USB Video: USB Video Bus info : usb-0000:00:14.0-3.1 Driver version : 5.19.0 Capabilities : 0x84a00001 Video Capture Metadata Capture Streaming Extended Pix Format Device Capabilities Device Caps : 0x04200001 Video Capture Streaming Extended Pix Format Media Driver Info: Driver name : uvcvideo Model : USB Video: USB Video Serial : Bus info : usb-0000:00:14.0-3.1 Media version : 5.19.0 Hardware revision: 0x00002100 (8448) Driver version : 5.19.0 Interface Info: ID : 0x03000002 Type : V4L Video Entity Info: ID : 0x00000001 (1) Name : USB Video: USB Video Function : V4L2 I/O Flags : default Pad 0x01000007 : 0: Sink Link 0x0200000d: from remote pad 0x100000a of entity 'Processing 2' (Video Pixel Formatter): Data, Enabled, Immutable Video input : 0 (Camera 1: ok) Format Video Capture: Width/Height : 1920/1080 Pixel Format : 'MJPG' (Motion-JPEG) Field : None Bytes per Line : 0 Size Image : 4147200 Colorspace : sRGB Transfer Function : Rec. 709 YCbCr/HSV Encoding: ITU-R 601 Quantization : Default (maps to Full Range) Flags : Streaming Parameters Video Capture: Capabilities : timeperframe Frames per second: 30.000 (30/1) Read buffers : 0
补充:
ffmpeg的libavdevice模块支持的计算机中常用的音视频捕获或输出设备:ALSA、AUDIO_BEOS 、JACK、OSS、1394、VFW等。
sudo fuser /dev/video0 sudo lsof /dev/video0