Skype finally working on Thinkpad T43p under Ubuntu Jaunty

 

This took me a long time, but I finally got Skype working well on my girl-friend’s laptop under Ubuntu 9.04 Jaunty. So here’s a description of the issues I encountered just in case somebody else is suffering from the same problems.

The audio quality of Skype on this laptop was absolutely abysmal, and ever so often the conversation was interrupted for a couple of seconds — no audio came through, and the video froze. It was just not possible to have a real conversation that way.

The solution I found, after literally months of experimenting, reading through forums, pulling my hair out, is as follows:

  1. Upgrade to the most recent Skype beta, version 2.1.0.47. With this version, Skype supports pulseaudio (the standard Ubuntu sound server) natively for the first time.
  2. Upgrade to pulseaudio 0.9.15 or higher (Ubuntu Jaunty comes with pulseaudio 0.9.14). I used the packages that you get from the following source: deb http://ppa.launchpad.net/themuso/ppa/ubuntu jaunty main. Upgrade all the packages that have “pulse” in their name.
  3. With the new Skype version, it is no longer Skype that selects the input and output devices for sound. You have to configure that in the pulseaudio sound server. The application that lets you do that is called pavucontrol and is not installed in Ubuntu Jaunty by default. You have to download it separately, the package is called pavucontrol-0.9.8-0ubuntu1~ppa1
  4. It may or may not be necessary to give real-time privileges to the pulseaudio daemon process. I can add details about how to do that if requested. But I actually think it even works without that.

With the above steps, I got an acceptable sound quality in principle. However, the sound would still hang, or drop, for several seconds once every couple of minutes. This, it turned out, is due to a completely unrelated problem. As outlined in this bug report, there is an incompatibility between the GNOME network manager and some WiFi drivers. The network manager tries to rescan for available networks even while already connected to an access point. This works for most WiFi drivers, but causes some other drivers to drop their connections whenever this scanning occurs. It turns out that the WiFi driver in this Thinkpad T43p, which has an Atheros WiFi card, is affected by this problem. As I could see in the system logs, the WiFi connection went down for a couple of seconds every two minutes, and was reacquired automatically shortly thereafter. It was exactly during those moments that the Skype conversation froze.

It is not yet clear how this problem will ultimately be resolved between the network manager and the WiFi drivers. Some argue that the network manager should stop scanning while connected, others say that the WiFi drivers should be enhanced to support this type of operation. In the meantime, a workaround is to use a modified network manager package which has the background scanning disabled. Such a package can be found here: https://launchpad.net/~volanin/+archive/ppa/+build/1124266/+files/network-manager_0.7.1~rc4.1.cf199a964-0ubuntu2-volanin1_i386.deb

I assume that the other workarounds that are mentioned in the above bug report would also work. With this change installed, I finally got acceptable audio quality and uninterrupted connections.

Fireballs revisited

I am glad to take back my criticism of organizations that collect reports of fireballs and other heavenly phenomena. In the past two days, I received very kind feedback e-mails from the American Meteor Society (AMS) and from the European Fireballnetwork (DLR). Their responses were probably just delayed by the holiday weekend (we saw the fireball last Friday, May 29th, six days ago).

The American Meteor Society lists our fireball sighting prominently in its 2009 table (entry #320).

No other reports about this fireball have been received by the AMS, but the German DLR got five different accounts of it.

Reporting a Fireball

There is really no shortage of sites where you can report a fireball.

What surprised me a little was

  1. There doesn’t seem to be a global, unified network for this sort of thing. Several different countries and organizations all seem to do their own thing.
  2. Once you’ve reported what you saw, it seems to disappear into a great black hole. I didn’t hear anything back, and I couldn’t check the database online. It would be really exciting to see reports coming in from other people who saw the same as you did. You might even wish to contact them and share experiences. A little bit of web 2.0 in heavenly matters.

But anyway, and nonetheless: thanks to those folks who make possible what we now already have. It’s a great service. And thanks to the folks at #asktronomy on twitter who provided helpful answers.