Microsoft's newly launched Xbox Live Video Marketplace is off to a shaky start, apparently struggling under the weight of all that high-definition content. Some people are reporting extraordinarily long download times, with accounts being docked in some cases for movies and TV shows purchased but not received.

A sampling of user experiences:

Gizmodo: "I Was Mugged by the Xbox 360 Video Store."

Kotaku: "360 Movies Download Sloooooow."

Situation Terminal: "My Xbox Live HD Video Rental Nightmare."

Xbox Live's Larry Hryb, a.k.a. Major Nelson, acknowledged the problems in a post late Thursday night. He wrote that the company was making progress in resolving the situation, and that accounts would be refunded, where appropriate, for content purchased but not delivered. He also offered a customer-service number to call and an Xbox.com help forum to visit if you've experienced this.

The Situation Terminal blogger followed up to say that the company granted a refund for the undelivered movie. As of early this morning, however, that high-def download of "V for Vendetta" still hadn't reached 1 percent complete.

If you've tried the Xbox Live movie and TV download service, what's been your experience so far? Drop me a message or leave a comment below.

Update, Friday evening: I spoke this afternoon with Aaron Greenberg, Xbox Live group marketing manager, who said Microsoft will offer refunds not only to people who were double charged but also to people who experienced slow downloads.

He said users having problems should call the 1-800-4MYXBOX customer service line. For people charged more than once to rent a movie, refunds will be automated, Greenberg said. The service offers television shows to own, not rent, so multiple charges shouldn't have happened in those cases, he said. (The service is set up to let people download a TV episode multiple times but only pay once.)

Greenberg said the company is "optimistic that we will have a good solution in place soon," particularly as the holiday traffic subsides. He said the Xbox Live online multi-player gaming system runs on a separate infrastructure and wasn't slowed by the video-download problems.

Microsoft is looking hard for a silver lining, calling the problems an indication of strong interest in the service among Xbox Live members. The demand was "significantly beyond what anybody ever expected," Greenberg said.

Even so, it's an inauspicious beginning. You can imagine some people getting soured by the situation and not trying the service again. Wrote one of the readers who responded to my original post: "My experience matches those mentioned in various blogs. I've spent the last 48 hours trying to download one movie."

Suddenly that trip to the video store isn't sounding so bad.