ros读取硬件网络摄像头/USB摄像头/本地文件

参考：
wiki教程
https://github.com/ros-drivers/video_stream_opencv.git

0 . 查看摄像头是否挂载及挂载的USB端口号

• 两个USB摄像头同时使用 hub连接电脑，会报:
• [ERROR] [1652284172.828043630]: VIDIOC_S_FMT error 22, Invalid argument.

1.介绍 接受的视频输入，例如：

1 . USB摄像头
2 . rtsp
3 . 视频文件

video_stream_provider: A number for the /dev/videoX device;
e.g.: 0 for /dev/video0. A string for a path for a video file;
e.g.: /home/user/Videos/myvideo.avi or a url of a video stream;
e.g.: rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov and http://10.68.0.6/mjpg/video.mjpg.

2.读取rtsp视频

修改rtsp_stream.launch文件

<?xml version="1.0"?>
<launch>
   <!-- launch video stream -->
   <include file="$(find video_stream_opencv)/launch/camera.launch" >
   		<!-- node name and ros graph name -->
	  	<arg name="camera_name" value="rtsp2" />
	  	<!-- url of the video stream -->
	  	<!--<arg name="video_stream_provider" value="rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov" />-->
	  	 
        <arg name="video_stream_provider" value="rtsp://admin:@192.168.1.112:554/ch0" />
      
	  	<!-- set camera fps to (does nothing on a stream)-->
	  	<!-- <arg name="set_camera_fps" value="30"/> -->
      	<!-- set buffer queue size of frame capturing to -->
      	<arg name="buffer_queue_size" value="1000" />
	  	<!-- throttling the querying of frames to -->
	  	<arg name="fps" value="30" />
	  	<!-- setting frame_id -->
	  	<arg name="frame_id" value="rtsp_frame" />
	  	<!-- camera info loading, take care as it needs the "file:///" at the start , e.g.:
	  	"file:///$(find your_camera_package)/config/your_camera.yaml" -->
	  	<arg name="camera_info_url" value="" />
	  	<!-- flip the image horizontally (mirror it) -->
	  	<arg name="flip_horizontal" value="false" />
	  	<!-- flip the image vertically -->
	  	<arg name="flip_vertical" value="false" />
	  	<!-- visualize on an image_view window the stream generated -->
	  	<arg name="visualize" value="true" />
   </include>
</launch>

3.读取usb摄像头

使用这个包读取usb摄像头在agx上有问题，换个包读取。
参考：ros驱动：http://wiki.ros.org/usb_cam
打开launch文件

<launch>
  <node name="usb_cam" pkg="usb_cam" type="usb_cam_node" output="screen" >
    <param name="video_device" value="/dev/video0" />
    <param name="image_width" value="640" />
    <param name="image_height" value="480" />
    <param name="pixel_format" value="yuyv" />
    <param name="camera_frame_id" value="usb_cam" />
    <param name="io_method" value="mmap"/>
  </node>
  <node name="image_view" pkg="image_view" type="image_view" respawn="false" output="screen">
    <remap from="image" to="/usb_cam/image_raw"/>
    <param name="autosize" value="true" />
  </node>
</launch>

查看摄像头是否挂载及挂载的USB端口号 可以查看usb摄像头的信息，修改对应的参数

启动摄像头launch

roslaunch usb_cam usb_cam-test.launch

打开rviz查看视频流