[ros-users] show video from robot in the web interface (based on rosjs tutoirial)

Benjamin Pitzer ben.pitzer at gmail.com
Fri Jun 10 19:10:18 UTC 2011


Hi Alex,

There is a bug in mjpeg_server which we thought was fixed already. Please
use question marks "?" instead of ampersands "&" to separate the topic,
width, and height parameters. That should fix your resize problem.

For streaming audio over ROS there is a package available:
http://www.ros.org/wiki/compressed_audio_streaming

Cheers,
Ben



On Thu, Jun 9, 2011 at 2:55 PM, Alexander Shavykin <alex at shavykin.ru> wrote:

> Thank you for the answer Sarah.
> It works but not so as i want.
>
> First of all i have problems with the setting params for mjpeg_server as it
> has written in tutorial:
>
> http://localhost:8080/stream?topic=/gscam/image_raw&width=320&height=240
>
> Now i see only 640*480 picture with very big delay in local network.
> Also i tried to set params in gscam (using GSCAM_CONFIG) but it didn't help
> (like *GSCAM_CONFIG*="v4l2src device=/dev/video0 ! videoscale !
> video/x-raw-yuv,width=320,height=240 ! ffmpegcolorspace !
> video/x-raw-rgb")
>
>
> And also i have some other questions
> Is gscam better for publish images then another image_transport modules?
>
> Is combination gscam and mjpeg_server is the best decision for decrease the delays between robot and
>  offboard computer?
>
> Also if you could put up a tutorial for another way to show video from robot to web using rosjs
>
> it will be very good.
>
> And the last question: what is the best way to transmit audio from ROS to offboard computer?
>
> Thank you!
>
>
> 2011/6/9 Osentoski Sarah (CR/RTC1.1-NA) <Sarah.Osentoski at us.bosch.com>
>
>>  Hi Alexander,
>>
>>
>> So, I'm a bit confused about getting the camera to publish topics to ros
>> or getting those topics from ros into the website.  So I'll endeavour to
>> answer both.
>>
>> 1. How to get your camera to be publishing rostopics:
>>
>> The first thing to do is to make sure that you get your camera publishing
>> images to ros.  There are a lot of different drivers/code you can use but
>> since you mentioned gstreammer I'll explain how to use gscam to get the
>> images from your camera into ROS.
>>
>> The documentation for gscam can be found here:
>> http://www.ros.org/wiki/gscam
>>
>> And you can download it using apt-get install
>> ros-diamondback-brown-perception
>>
>> If your camera was attached to /dev/video2 then you coul ddo the vollowing
>> commands
>>
>> roscd gscam
>> cd bin
>> export GSCAM_CONFIG="v4l2src device=/dev/video2 ! video/x-raw-rgb ! ffmpegcolorspace"
>> rosrun gscam gscam
>>
>> Now gscam will be publishing the images on gscam/image_raw topic
>>
>> 2. How to get the rostopics that your camera publishes to be viewed on the
>> website:
>>
>> You can stream the video to the website one of two ways.  The first is
>> how you mentioned where you use rosjs to subscribe to the topic.  If you
>> need help with what to do from here we can put up a tutorial.
>>
>> There is another node, mjpeg_server http://www.ros.org/wiki/mjpeg_server that
>> will let you stream the videos and take advantage of built in optimizations
>> in the browser
>>
>> To use this node you can install it via the following command:
>> apt-get install ros-diamondback-remote-lab
>>
>> then just  rosrun mjpeg_server mjpeg_server
>>
>> To see the image you can just type the address into your web browser:
>>
>>
>> http://localhost:8080/stream?topic=/gscam/image_raw
>>
>>
>> You should see the image in your browser at this point.  The documentation
>> on the mjpeg_server page will tell you parameters you can set to see the
>> images at different quality/sizes.
>>
>> I hope this helps.  Let us know if you have any questions.
>>
>> Sarah Osentoski
>>
>>  ------------------------------
>> *From:* ros-users-bounces at code.ros.org [mailto:
>> ros-users-bounces at code.ros.org] *On Behalf Of *Alexander Shavykin
>> *Sent:* Wednesday, June 08, 2011 1:43 PM
>> *To:* ros-users at code.ros.org
>> *Subject:* [ros-users] show video from robot in the web interface (based
>> on rosjs tutoirial)
>>
>> Hello.
>>
>> I have an Irobot Create and netbook with web camera on it.
>> The system on netbook is Ubuntu 10.04
>> I try to make control the robot with ROS via web interface from offboard
>> computer using wi-fi.
>> So there is very good tutorial with rosjs.
>>
>> All examples work.
>> But i am a little confused how to show video from web camera on the robot
>> in my web interface.
>>
>> So as i understand there are some methods for this task
>>
>> To use service /imagetopic
>> connection.callService('/rosjs/subscribe',json(['/imagetopic',0,'jpeg',128,96,100]),function(rsp)
>> {});
>> or
>> to use gstreamer
>> and also others.
>> I don't understand how to realize these methods.
>> Could you give some examples how to show the video from the robot in the
>> web interface on off board computer?
>>
>>
>> Thank you.
>>
>>
>> _______________________________________________
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>>
>> ros-users at code.ros.org
>> https://code.ros.org/mailman/listinfo/ros-users
>>
>>
>
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