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Hey, I am trying to transfer video from one laptop to another for real-time analysis.

I followed the instructions given in the following link:

http://wiki.ros.org/ROS/Tutorials/MultipleMachines

I want to transfer video at 720p.

But there is a lot of lag and also the frame rate received is very less.

Is there a problem with video transfer using Wifi? That shouldn't be the case since there are cameras having internal wifi or drones are also used in concerts, matches for live streaming.

Are their other methods to transfer other than ROS or another method in ROS?

I could only get real-time video when I reduced to 200 X 200 (very less).

Edit: I am using usb_cam package to get webcam data and using rviz to view the video feed.

Thanks.


Originally posted by Trishant_Roy_221b on ROS Answers with karma: 1 on 2018-01-09

Post score: 0

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Are you using any compression? Or sending raw, uncompressed, full-frame, full-colour 720p frames over a sensor_msgs/Image topic? In the latter case, that could get up to ~ 3.5MB per frame (megabytes, not bits). For 30fps, that would be ~105MB/s. Your wifi probably can't handle that.


Originally posted by gvdhoorn with karma: 86574 on 2018-01-09

This answer was ACCEPTED on the original site

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Original comments

Comment by Trishant_Roy_221b on 2018-01-14:
I tried the compression topic as well and that too in 480p. Though the output is better, the issue still persists.

Is there any other possible reason other than due to Wifi? Coz some surveillance cameras do use Wifi to send output to PC/mobile.

Comment by gvdhoorn on 2018-01-14:
Can you describe what you have used exactly? Edit your original question with the new info. Packages/nodes used, topics, configuration settings, etc.

Note that sending individual frames over sensor_msgs/Image (even if compressed) is always going to be less efficient than a proper video codec.

Comment by Trishant_Roy_221b on 2018-01-14:
Edited. Yes... that is true...But the video feed should be better like wifi cameras

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