Archive for the ‘Linux’ Category

Ubuntu Jaunty, EeePC and Wireless

August 8, 2009 Leave a comment

Ubuntu Jaunty runs well on my EeePC 901. The main problem was that it would not connect to some encrypted. wireless networks. It seems that the problem is related to the device driver in the Linux kernel for the rta2860 wireless chip. The device driver is flagged as “staging” which means it is “not ready to be merged into the main portion of the Linux kernel tree at this point in time for various technical reasons”.

As it turns out, the driver is beingĀ  worked on and there is a patch that could fix the problem i am seeing. I did not want to compile the kernel and try to integrate it with the Ubuntu installation, but this is not necessary: The Ubuntu kernel team provides deb packages for current kernel releases and pre-releases. After downloading and installing the latest package (linux-image-2.6.31-020631rc5-generic_2.6.31-020631rc5_i386.deb as of the time of writing this) and booting into the new kernel, i can now connect to the wireless network i want to use.

Now i am happily wring this on the EeePC while being connected on the wireless network. The next release of Ubuntu (Karmic) will use the 2.6.31 version of the Linux kernel, which already has the wireless fix included.

Update: As it turns out, the mainline kernel packages for Ubuntu do not include the uvc webcam driver. So my plan B is to use the linux-image-generic package from karmic. Only this requires adding the kernel option nomodeset to the kopt= line in /boot/grub/menu.lst and running sudo /sbin/update-grub to get the change in the correct place in menu.lst. But now, both wireless and the webcam are working, i am hoping that no more tweaking is required.

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Testing audio and video with gstreamer

January 2, 2009 Leave a comment

The gstreamer framework provides a plethora of ways to process audio and video. I just figured out that the command gst-launch allows testing audio and video on the command line:


First, to check the available ALSA audio devices:

cat /proc/asound/pcm

Now, to read from a microphone and immediately playback on a sound device (adjust the hw ids as necessary):

gst-launch alsasrc device=hw:1,0 ! alsasink device=hw:0,0


Show the live video from a webcam on the monitor:

gst-launch v4l2src ! video/x-raw-rgb,width=800,height=600,framerate=30/1 ! xvimagesink

These are just the very basics. Mixing audio and video and recording is more involved, but gst-launch is a good term to start googling for.

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