Geoffrey Long
Tip of the Quill: Archives
On syncing AirPort Expresses.

So there's a new app called Airfoil that lets you stream any audio feed to an AirPort Express station. Seems like a good idea to me. What bugs me about it, though, are these passages from their FAQ:

Why does the audio lag?
   Because of the way the AirPort Express works, there's a delay from the time audio is played locally to the time it is heard remotely. This is problematic for movie playback, and tough to solve as the issue is with the hardware itself.

Can I use this while watching movies?
   The above-mentioned delay can be overcome with alternate media players such as VLC and MPlayer, which allow the user to manually de-sync the audio from the video. In this way, you can play the audio a second or so ahead of the video, and sync the two. A perfect solution? No. Workable? Definitely.

Can I use this with multiple AirPort Express units?
   Sending audio to multiple AirPort Express units simultaneously won't be possible in version 1.0, but it may be available in the future.

Would one of the programmers in the audience (Nick, Matt, Tom?) tell me why a utility couldn't be created that sends a four-note pattern to each set of AirPort Express boxes in turn, hooks into the microphone on the machine and autolags the signals until the four beat patterns match up, then automatically caches the video or plays the audio a second or two ahead of the video, as they mention above? It feels a little hackish, so there has to be a reason why this wouldn't work, but can anybody enlighten me as to why not?


Matt posted an excellent follow-up to this post over at his weblog, How Do You Compile?, which brought up an interesting idea -- streaming audio over HTTP or some other open standard. Hmmm.

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