I am using ubuntu16.04 and trying to run opencv script.
when i use:
video_capture = cv2.VideoCapture(-1)
it gives me error VIDEOIO ERROR: V4L: can't find camera device
No video window opens
But when i run
video_capture = cv2.VideoCapture('test.jpg')
It opens window shows the picture and close the window.
Please tell me why it is not streaming video directly from camera.
The suggestion api55 gave in his comment
video_capture = cv2.VideoCapture(0)
is what I would try first.
Generally, you can list the available cameras with ls /dev/video* or v4l2-ctl --list-devices. Here sample output:
NZXT-U:rt-trx> v4l2-ctl --list-devices
Microsoft® LifeCam Cinema(TM): (usb-0000:00:14.0-1):
/dev/video1
Microsoft® LifeCam Cinema(TM): (usb-0000:00:1a.0-1.3):
/dev/video0
/dev/video0 corresponds to device id 0, etc.
PS: v4l2-ctl is quite useful for solving camera issues and can do much more than --list-devices. I installed it via packagev4l-utils on a 16.04 machine.
Late, but to get mine working i put in terminal:
-ltrh /dev/video*
To get a list of the video devices that are plugged into my computer. Then for each one I did:
sudo chmod 777 /dev/videox
Where x was one of the video files that were listed, giving everything access to them. Probaly not the most secure solution, but it got my code working.
Related
Hi I have a BBB which is running on Angstrom 2013 image. For display purpose I am using a cape which is connected to gpio extensions. There is a Qt application running on BBB, which use to get displayed on the Cape.
How can I take screenshot of the cape.
I want to take some screen-shot of the running application.
I couldn't find gnome-screenshot on angstrom image, using import command to take screenshot I got an error regarding x11.
How can I get the screenshot?
You can try and install scrot
On Ubuntu based Beagle Bone Black, I installed it as follows:
sudo apt-get install scrot
To Capture a screenshot:
scrot -q 100 /home/debian/Desktop/Desktop.jpg
#-q 100 == best quality
# /home/debian/Desktop/Desktop.jpg is path where to store captured screenshot
For more information, you can read this tutorial here.
I have a physical box with QNX 6.3.0 installed. PS/2 mice and keyboard work fine. I'm trying to see if I can get a USB mouse going. What info I could find seemed to say I should start with:
usb -vvv
However, I get this:
$ usb
/bin/sh: usb: not found
Where's the usb utility supposed to be installed at, and why is it not found? Isn't it supposed to be a default utility?
I think you should try for :
cd /fs/usb0 In my case this usb0 is the desired name . you can change accordingly .
I need to work with asus xtion pro live to detect hand movements and objects. I am an amateur as far as it concerns programming this camera.
My problem is how to connect them and from where to start.
I work on Ubuntu 12.04. I've downloaded Ros fuerte and both Openni2 and OpenCV. When i plug the camera (usb port) and run the lsusb command, i see this:
"Bus 001 Device 003: ID 1d27:0601 "
Even when i run the command $ roslaunch openni_launch openni.launch
i get:
[ INFO] [1415717730.873978521]: No matching device found.... waiting for devices. Reason: openni_wrapper::OpenNIDevice::OpenNIDevice(xn::Context&, const xn::NodeInfo&, const xn::NodeInfo&, const xn::NodeInfo&, const xn::NodeInfo&) # /tmp/buildd/ros-fuerte-openni-camera-1.8.6/debian/ros-fuerte-openni-camera/opt/ros/fuerte/stacks/openni_camera/src/openni_device.cpp # 61 : creating depth generator failed. Reason: USB interface is not supported!
Can anyone please help? Is there a problem with the camera driver?
Thank you in advance.
you must go to a terminal and do
sudo nano /etc/openni/GlobalDefaults.ini
and there find UsbInterface and make sure it is not a comment (without ; at the beginning) and that is equal to 2
UsbInterface=2
I heard that this may give you problems with Kinect hardware (the same error you are getting now). But, if you use the Kinect later on and gives this problem, just comment it and it should work
;UsbInterface=2
You must reboot every time you change this value!!
I hope this works for you ;)
I have an audio stream
cvlc -vvv alsa://hw:1,0 --sout '#transcode{acodec=mp3,ab=128}:standard{access=http,mux=ogg,dst=192.168.0.106:8081}'
and it works if i logged in KDE, but if i see login window (where you need to type password kde login) i cannot open alsa device.
I got
vlc cannot open MRL 'alsa://hw:1,0'.
Is it possible to have access to alsa without login to KDE?
Any suggestions are welcomed.
alsa is KDE independent; before logging in, from a console (ctrl+alt+F1) use this command: aplay -l, it will show all audio devices; I think kde has some script to change the soundcard stack
I have a problem with recording rtsp stream with VLC player. Actually my method works in MacOS X, but doesn't in Windows. Command line:
vlc -vvv rtsp://admin:admin#192.168.0.151/live/h264/ --sout="#transcode{vcodec=mp4v,vfilter=canvas{width=800,height=600}}:std{access=file,mux=mp4,dst=C:\123.mp4}"
On MacOS it works fine, but under Windows it creates unreadable file. MediaInfo output:
General
Complete name : C:\123.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom
File size : 1.08 MiB
Any suggestions?
Seems like your destination URL is not correct. Try this:
vlc -vvv rtsp://admin:admin#192.168.0.151/live/h264/ --sout="#transcode{vcodec=mp4v,vfilter=canvas{width=800,height=600}}:std{access=file,mux=mp4,dst=C:\\123.mp4}"
For Linux users, ffmpeg alone works straight away.
If you want to watch the stream while recording, write to a .mkv instead of a .mp4.
This example will overwrite the file video.mp4 in your home folder without asking due to the -y param, and the original codecs are kept.
ffmpeg -i rtsp://192.168.42.1/live -vcodec copy -acodec copy -y ~/video.mp4
NB: This example url is for an Ambarella Xiaomi Mijia 4K camera, like many wifi ip cameras, you have to activate the stream via telnet first, for this particular model the command to be sent before reading the stream via rtsp://:
echo '{"msg_id":257,"token":0}' | telnet 192.168.42.1 7878