I was initially confused. XM Radio and Digital Fountain, the makers of innovative compression and broadcast encoding technology, had a deal in place in April 2004 in which XM would license key technology from Digital Fountain for broadcasting digital content. XM gushed in a press release. Today, Digital Fountain announced a deal with Sirius in which they said they expect eventually that all Sirius receivers would incorporate their technology.

Via email, Digital Fountain’s CEO confirmed today that the XM deal—happened at the same time that Honda signed a deal and made an investment—is still in place. I’ll have more information about this in the near future.

XM recently said they would work with On2 for video, but that deal didn’t seem to preclude the Digital Fountain arrangement—On2 was licensing a codec (a compression/decompression algorithm) while Digital Fountain has a delivery technology that works with any codecs or any data whatsoever.

Digital Fountain’s technology defies simple explanation (see illustration above), but one manifestation is that it’s a way to broadcast data continuously with a kind of complicated error correction. Instead of sending, say, a 30-minute video program over and over again to devices that might be in and out of range by just sending the program’s packets in order, Digital Fountain’s technology divides up the data stream and recombines it so that no two packets are the same. Once a sufficient number of packets are received in any order at any time during the transmission window, the original media file can be reconstructed. Clever, but hard to picture.