error in gscam

edit

To rosrun gscam gscam, change your GSCAM_CONFIG by: (you got error because /dev/video2 does not exist)

export GSCAM_CONFIG="v4l2src device=/dev/video0 ! video/x-raw-rgb,framerate=30/1 ! ffmpegcolorspace"

To roslaunch gscam v4l.launch, modify your v4l.launch to: (you got error because gscam_config was set again in v4l.launch)

<launch>
  <!-- This launchfile should bring up a node that broadcasts a ros image
       transport on /webcam/image_raw -->

  <arg name="DEVICE" default="/dev/video0"/>
  <!-- The GStreamer framerate needs to be an integral fraction -->
  <arg name="FPS" default="30/1"/>
  <arg name="PUBLISH_FRAME" default="false"/>

  <node ns="v4l" name="gscam_driver_v4l" pkg="gscam" type="gscam" output="screen">
    <param name="camera_name" value="default"/>
    <param name="camera_info_url" value="package://gscam/examples/uncalibrated_parameters.ini"/>
    <!--<param name="gscam_config" value="v4l2src device=$(arg DEVICE) ! video/x-raw-rgb,framerate=$(arg FPS) ! ffmpegcolorspace"/>-->
    <param name="frame_id" value="/v4l_frame"/>
    <param name="sync_sink" value="true"/>
  </node>

  <node if="$(arg PUBLISH_FRAME)" name="v4l_transform" pkg="tf" type="static_transform_publisher" args="1 2 3 0 -3.141 0 /world /v4l_frame 10"/>
</launch>