BeagleBone Black 连接USB摄像头，并实现采集、存储及传输

1.硬件准备

1.1 BBB

1.2 UVC cameras

(支持UVC协议的就好，我手里只有个几年前很老的，但是也可以用)

2.软件准备

2.1 BBB刷的ubuntu系统

2.2 v4l2,没有可如下安装

sudo apt-get install v4l-utils

2.3 python

2.4 opencv

3.步骤

3.1 v4l2-ctl

几个查询命令及返回：

ubuntu@arm:~$ v4l2-ctl --info
Driver Info (not using libv4l2):
        Driver name   : uvcvideo
        Card type     : USB2.0 Camera
        Bus info      : usb-musb-hdrc.1.auto-1.3
        Driver version: 3.8.13
        Capabilities  : 0x84000001
                Video Capture
                Streaming
                Device Capabilities
        Device Caps   : 0x04000001
                Video Capture
                Streaming

ubuntu@arm:~$ v4l2-ctl --all
Driver Info (not using libv4l2):
        Driver name   : uvcvideo
        Card type     : USB2.0 Camera
        Bus info      : usb-musb-hdrc.1.auto-1.3
        Driver version: 3.8.13
        Capabilities  : 0x84000001
                Video Capture
                Streaming
                Device Capabilities
        Device Caps   : 0x04000001
                Video Capture
                Streaming
Priority: 2
Video input : 0 (Camera 1: ok)
Format Video Capture:
        Width/Height  : 640/480
        Pixel Format  : 'YUYV'
        Field         : None
        Bytes per Line: 1280
        Size Image    : 614400
        Colorspace    : SRGB
Crop Capability Video Capture:
        Bounds      : Left 0, Top 0, Width 640, Height 480
        Default     : Left 0, Top 0, Width 640, Height 480
        Pixel Aspect: 1/1
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 15.000 (15/1)
        Read buffers     : 0
                     brightness (int)    : min=0 max=100 step=1 default=15 value=15
                       contrast (int)    : min=0 max=100 step=1 default=57 value=57
                     saturation (int)    : min=0 max=4 step=1 default=2 value=2
                          gamma (int)    : min=1 max=8 step=1 default=3 value=3
           power_line_frequency (menu)   : min=0 max=2 default=1 value=1
                      sharpness (int)    : min=0 max=100 step=1 default=10 value=10

 v4l2-ctl --list-ctrls
                     brightness (int)    : min=0 max=100 step=1 default=15 value=15
                       contrast (int)    : min=0 max=100 step=1 default=57 value=57
                     saturation (int)    : min=0 max=4 step=1 default=2 value=2
                          gamma (int)    : min=1 max=8 step=1 default=3 value=3
           power_line_frequency (menu)   : min=0 max=2 default=1 value=1
                      sharpness (int)    : min=0 max=100 step=1 default=10 value=10