You might want to peruse this thread , where a number of folks here discussed the subjects of IEEE-1394 (also known as FireWire or i.Link), DVI, and HDMI.

1394 supports digital transmission of DVD-Audio and SACD, which is more convenient than the six analog cables otherwise required for those formats. On the other hand, there is a good chance it will not be included in HD optical disc players to carry the newer audio formats that will be included with those players. The reason it will probably be left off is that those players are slated to use HDMI for both audio and video (FireWire will not be used to handle both audio and video). HDMI audio is still being developed - the current version supports DVD-Audio but not SACD (next version of HDMI will add SACD support), and the audio formats intended for use with HD-DVD/Blu-Ray/whatever we end up with (Dolby Digital Plus and DTS's equivalent format) have not been integrated into HDMI or any other digital interface yet.