Both Blockbuster and Best Buy's services will see the benefit.
Now that we've got the basics of internet delivery down, it's time to do some upgrading, and that's exactly what Sonic's doing. If the name's not familiar, they're the people behind CinemaNow, now known as RoxioNow, the service that both Best Buy and Blockbuster use for online video sales and rentals.
Later this year, Sonic will be enabling DTS 5.1 sound on their service, allowing customers to take advantage of their home theater systems. From the sound of things, that'll be right around the same time that Netflix will be debuting 5.1 on for its customers.
5.1 channel audio is a great step, but there's been no information from Sonic about how this will affect the size of video files. If adding 5.1 slows downloads too much, it may be a problem for some customers.