how do I improve the steam video speed in ROS

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Thank you very much, its much more smooth by setting it to compressed.

Sorry for asking some stupid questions.

rosrun image_view image_view image:=/usb_cam/image_raw _image_transport:=compressed

Could I know how to modify the usb_cam package to get the compressed image? It's need to modify the .cpp file (add some command about image_transport into usb_cam_node )?Otherwise,command "rosrun image_view image_view image:=/usb_cam/image_raw _image_transport:=compressed" showed no data

It should work out of the box, as image_transport is a separate library. Are you sure you are using the correct topic for image? The default name is image, not image_raw. Are you able to see the raw image?

Thank for your reply. I think usb_cam_node.cpp "advertiseCamera("image_raw" ,1)" ,so it publishes the topic named "image_raw". I can't image_view "/usb_cam/image"

rosrun image_view image_view image:=/usb_cam/image_raw _image_transport:=theora

I can see the image with this command. Thank you ,IvanV

You are right. usb_cam wiki page seems to be wrong, as it states "image" as default topic. However, "it should" work with your first command, as the compressed plugin comes by default in most systems (e.g. Ubuntu). Anyway, if you are streaming video theora should perform betters.