目录

1. 安装v4l-utils

2. 查找连接的摄像头列表

3. 查看各相机支持的分辨率、帧率、像素格式等参数

4. 注意事项

5. OpenCV(C++)调用摄像头代码

本博文描述了在Ubuntu系统下如何使用v4l-utils工具来查看所连接摄像头（包含USB摄像头及树莓派摄像头）信息，主要内容如下：
1. 获取摄像头列表；
2. 获取各摄像头支持的分辨率、帧率、像素格式；
3. 基于OpenCV抓取摄像头图像。

1. 安装v4l-utils

sudo apt-get install v4l-utils

如果有以下报错：

Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package v4l-utils is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another sourceE: Package 'v4l-utils' has no installation candidate

则先更新源，再安装即可。

sudo apt-get update

2. 查找连接的摄像头列表

ls /dev/video*

输出

/dev/video0  /dev/video1

或

v4l2-ctl --list-devices

输出

vi-output, imx219 7-0010 (platform:54080000.vi:0):/dev/video0USB Camera (usb-70090000.xusb-2.3):/dev/video1

3. 查看各相机支持的分辨率、帧率、像素格式等参数

v4l2-ctl -d /dev/video0 --list-formats-ext

ioctl: VIDIOC_ENUM_FMTIndex       : 0Type        : Video CapturePixel Format: 'RG10'Name        : 10-bit Bayer RGRG/GBGBSize: Discrete 3264x2464Interval: Discrete 0.048s (21.000 fps)Size: Discrete 3264x1848Interval: Discrete 0.036s (28.000 fps)Size: Discrete 1920x1080Interval: Discrete 0.033s (30.000 fps)Size: Discrete 1640x1232Interval: Discrete 0.033s (30.000 fps)Size: Discrete 1280x720Interval: Discrete 0.017s (60.000 fps)

v4l2-ctl -d /dev/video1 --list-formats-ext

ioctl: VIDIOC_ENUM_FMTIndex       : 0Type        : Video CapturePixel Format: 'MJPG' (compressed)Name        : Motion-JPEGSize: Discrete 1920x1080Interval: Discrete 0.033s (30.000 fps)Size: Discrete 1280x720Interval: Discrete 0.033s (30.000 fps)Size: Discrete 640x480Interval: Discrete 0.033s (30.000 fps)Index       : 1Type        : Video CapturePixel Format: 'YUYV'Name        : YUYV 4:2:2Size: Discrete 1920x1080Interval: Discrete 0.200s (5.000 fps)Size: Discrete 1280x720Interval: Discrete 0.100s (10.000 fps)Size: Discrete 640x480Interval: Discrete 0.033s (30.000 fps)

4. 注意事项

（1）如上所示的/dev/video1 USB摄像头支持 MJPG 和 YUYV 两种像素格式，每种格式支持多种分辨率及帧率。如果需要实时抓取1080p的图像，则需要采用MJPG格式，默认的YUYV格式不能满足实时抓取需求。

（2）另外，调用摄像头时传入的摄像头设备、图像帧宽、帧高、帧率，应与v4l2-ctl 打印的参数一致。调用代码如下。

5. OpenCV(C++)调用摄像头代码

#include 
#include int main()
{cv::VideoCapture capture;capture.open("/dev/video1", cv::CAP_V4L2);capture.set(cv::CAP_PROP_FOURCC, cv::VideoWriter::fourcc('M','J','P','G'));capture.set(cv::CAP_PROP_FRAME_WIDTH, 1920);capture.set(cv::CAP_PROP_FRAME_HEIGHT, 1080);capture.set(cv::CAP_PROP_FPS, 30);cv::Mat frame;while (1){capture >> frame;if (!frame.empty()){cv::imshow("frame", frame);}if (cv::waitKey(1) == 27)break;}return 0;
}