Hello, I'm using the usb_cam package and I'm trying to launch my 2 cameras at the same time. I'm using the following launch file:
<launch><group ns="camera1"><node name="usb_cam1" pkg="usb_cam" type="usb_cam_node" output="screen" ><param name="video_device" value="/dev/video1" /><param name="image_width" value="640" /><param name="image_height" value="480" /><param name="pixel_format" value="mjpeg" /><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></group><group ns="camera2"><node name="usb_cam2" pkg="usb_cam" type="usb_cam_node" output="screen" ><param name="video_device" value="/dev/video2" /><param name="image_width" value="640" /><param name="image_height" value="480" /><param name="pixel_format" value="mjpeg" /><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></group></launch>
$ roslaunch 2cams_test.launch
... logging to /home/davicho/.ros/log/3a1f0a6e-6889-11e5-8461-0071cc3abcf5/roslaunch-davicho-3304.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.
started roslaunch server http://davicho:51904/
SUMMARY
========
PARAMETERS
* /camera1/image_view/autosize: True
* /camera1/usb_cam1/camera_frame_id: usb_cam
* /camera1/usb_cam1/image_height: 480
* /camera1/usb_cam1/image_width: 640
* /camera1/usb_cam1/io_method: mmap
* /camera1/usb_cam1/pixel_format: mjpeg
* /camera1/usb_cam1/video_device: /dev/video1
* /camera2/image_view/autosize: True
* /camera2/usb_cam2/camera_frame_id: usb_cam
* /camera2/usb_cam2/image_height: 480
* /camera2/usb_cam2/image_width: 640
* /camera2/usb_cam2/io_method: mmap
* /camera2/usb_cam2/pixel_format: mjpeg
* /camera2/usb_cam2/video_device: /dev/video2
* /rosdistro: indigo
* /rosversion: 1.11.13
NODES
/camera2/
image_view (image_view/image_view)
usb_cam2 (usb_cam/usb_cam_node)
/camera1/
image_view (image_view/image_view)
usb_cam1 (usb_cam/usb_cam_node)
auto-starting new master
process[master]: started with pid [3316]
ROS_MASTER_URI=http://localhost:11311
setting /run_id to 3a1f0a6e-6889-11e5-8461-0071cc3abcf5
process[rosout-1]: started with pid [3329]
started core service [/rosout]
process[camera1/usb_cam1-2]: started with pid [3346]
process[camera1/image_view-3]: started with pid [3356]
process[camera2/usb_cam2-4]: started with pid [3357]
process[camera2/image_view-5]: started with pid [3376]
[ INFO] [1443737430.656950901]: Using transport "raw"
(image_raw:3356): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",
[ INFO] [1443737430.778414332]: Using transport "raw"
(image_raw:3376): Gtk-WARNING **: Unable to locate theme engine in module_path: "adwaita",
[ INFO] [1443737431.047213737]: using default calibration URL
[ INFO] [1443737431.047358391]: camera calibration URL: file:///home/davicho/.ros/camera_info/head_camera.yaml
[ INFO] [1443737431.047471646]: Unable to open camera calibration file [/home/davicho/.ros/camera_info/head_camera.yaml]
[ WARN] [1443737431.047526261]: Camera calibration file /home/davicho/.ros/camera_info/head_camera.yaml not found.
[ INFO] [1443737431.047583711]: Starting 'head_camera' (/dev/video1) at 640x480 via mmap (mjpeg) at 30 FPS
[ WARN] [1443737431.075626997]: unknown control 'focus_auto'
[ERROR] [1443737431.076149773]: Webcam: expected picture but didn't get it...
[ INFO] [1443737431.082241865]: using default calibration URL
[ INFO] [1443737431.082405128]: camera calibration URL: file:///home/davicho/.ros/camera_info/head_camera.yaml
[ INFO] [1443737431.082533707]: Unable to open camera calibration file [/home/davicho/.ros/camera_info/head_camera.yaml]
[ WARN] [1443737431.082587458]: Camera calibration file /home/davicho/.ros/camera_info/head_camera.yaml not found.
[ INFO] [1443737431.082646527]: Starting 'head_camera' (/dev/video2) at 640x480 via mmap (mjpeg) at 30 FPS
[ WARN] [1443737431.111333288]: unknown control 'focus_auto'
[ERROR] [1443737431.111752759]: Webcam: expected picture but didn't get it...