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

Fri Jun 10 21:10:28 UTC 2011

Thank you for the answer.
It works.

Now i would like to transmit compressed images. How can i subscribe mjpeg
server to topic with compressed or theora images.
What should also i write in browser?

This string:
http://192.168.0.101:8080/stream?topic=/camera/image/compressed?width=320?height=240doesn't
work.

i got in mjpeg_server
--------------------------------
[ WARN] [1307739023.476203425]: [image_transport] It looks like you are
trying to subscribe directly to a transport-specific image topic
'/camera/image/compressed', in which case you will likely get a connection
error. Try subscribing to the base topic '/camera/image' instead with
parameter ~image_transport set to 'compressed' (on the command line,
_image_transport:=compressed). See http://ros.org/wiki/image_transport for
details.
--------------------------------
I am a little bit confused. Should i write my owner publisher instead gscam?

Thank you.

2011/6/10 Benjamin Pitzer <ben.pitzer at gmail.com>

> 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.
>>>
>>>
>>> _______________________________________________
>>> ros-users mailing list
>>>
>>> ros-users at code.ros.org
>>> https://code.ros.org/mailman/listinfo/ros-users
>>>
>>>
>>
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