Rotate the output of a webcam with Skype and other software!

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NicCo
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Rotate the output of a webcam with Skype and other software!

Post by NicCo »

Sometimes we have our webcam's image vertical flipped and also installing Video 4 Linux user control panel (v4l2ucp) we do not find the option “vertical flip”, so we can not turn upside down our image and so we could not use our webcam to do videocalls or simply recorder a video, what we can do?

I was in this situation too and after lots of hours and headcache, thanks to Moreno we have find a way “fast & painless” to solve the problem.

First step, you need to have v4l package and the library libv4l-wrapper installed (to let your OS to use the webcam) plus other packages necessary, to do this we give into a terminal this command line:

Mandriva 32 bit

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urpmi v4l-utils libv4l-wrappers
Mandriva 64 bit

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urpmi v4l-utils libv4l0 libv4l-wrappers lib64v4l0 lib64v4l-wrappers
Optionals but usefull to have (both architectures 32 & 64)

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urpmi v4l2ucp v4l-utils-qt4
ATTENTION: Skype is only 32 bit version so if you use a 64 bit OS you need to enable 32 bit sources to install all properly.

Once you have the packages you only need to launch your application with this string (the example is referred to Skype, but you just need to change the command with the one of your application):

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export LIBV4LCONTROL_FLAGS=3 skype
For some webcams (expecially Logitech) those parameters are not sufficient, you need to give other parameters to load the module v4l before the program, we need to use this string:

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export LIBV4LCONTROL_FLAGS=3 && LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
If you don't need rotate the Skype output but only activate video with certain wecam, it could be sufficient use only

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LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
At last, when finally you have the right command string working nice for your webcam
  • you can edit the mandriva menu of your user, adding the needed string before the word skype
  • otherwise you could edit by root, so it'll work for all users, the mandriva-skype.desktop file
To do that, open a terminal and logging in by root, then type:

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# vi /usr/share/applications/mandriva-skype.desktop
Modify this:

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[Desktop Entry]
Name=Skype
Comment=Skype Internet Telephony
Exec=export LIBV4LCONTROL_FLAGS=3 && LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
Icon=skype.png
Terminal=false
Type=Application
Categories=Network;X-MandrivaLinux-Internet-InstantMessaging;
X-Desktop-File-Install-Version=0.15
The string you need to change is only this, from this:

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Exec=skype
to this:

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Exec=export LIBV4LCONTROL_FLAGS=3 skype
or this, in case your webcam still not working:

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Exec=export LIBV4LCONTROL_FLAGS=3 && LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so skype
This example is referred to Skype application, for others programs you need to edit the right file.




Image Italiano

Capita alle volte di trovarsi con l'immagine della webcam ribaltata e anche installando il pannello di controllo di Video 4 Linux (v4l2ucp) non troviamo l'opzione "vertical flip" quindi, ci troviamo nella situazione di non poter capovolgere l'immagine e di conseguenza di non poter utilizzare la webcam per effettuare videochiamate o semplicemente registrare video; che fare quindi?

Leggi tutto (Guida in Italiano)



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promeneur
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Re: Rotate the output of a webcam with Skype and other softw

Post by promeneur »

is there similar solution for the following pb ?

kopete adjusts dynamically light,exposure,contrast,colour

skype has this feature but it does not work then if there is not enough light or too much light then image is bad
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