October 9, 2009

Telepathic Reverberations

Filed under: collabora, facebook — Tags: , , , , , , , , , , , , — alsuren @ 4:05 pm

If you have ever had a call with someone where something wasn’t working, and you’ve wondered whether it was your computer or your contact’s that was broken, I have the answer for you. It takes the form of a user that you can add to your contact list, and call to test your setup. If your contact does the same, then it should be very simple to narrow down where the problem lies.

If you are using XMPP (or Google Talk or Jabber if you hate acronyms), then is the user you want. You can add it to your contact list and it will add you back. You can send it a message and it will send it back to you. If you call it, it will send your audio/video straight back to you. It might be a good idea to put headphones in before you do this though, to avoid feedback loops.

The bot is written in Python, and source can be found at It uses telepathy-gabble to connect to the server and Farsight for the streaming. This means that it has all of the same capabilities and limitations as Empathy on Linux. This makes it good for testing interoperability. If you try it out and have problems, feel free to leave a comment here, or join us in #telepathy on freenode and I (alsuren) will be happy to help you out.

A few things to note if you are having problems:

Users of the Google Mail interface are currently limited to audio only, because Google only uses the h.264 video codec, which cannot legally be distributed with Empathy. If enough people report this problem to them, then maybe they will include Theora as a fallback. There are ways that I could work around this problem for the echo service, but then it wouldn’t be a very good tool for testing whether you’re capable of calling Empathy users ;-).

If you are using Ubuntu Jaunty and pulseaudio, you may notice high CPU usage and a really long lag in your audio. This is a known issue and is fixed in the pulseaudio that ships with Karmic.

Watch this space for an MSN echo service (since telepathy-butterfly now supports voice/video for MSN). Also, if you are interested in writing multi-protocol chat bots, I’m planning to re-factor the code and distribute it as part of telepathy-python. If you want a say in the new API, speak now.

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