Though technically feasible, broadband speeds hamper online movie services.

Even using Apple's H.264 compression, full-length movies consume vast amounts of bandwidth because they are large files. This means customers would have to wait for hours for their purchased movies to download, a report explains.

Apple's director of QuickTime Product Marketing, Frank Casanova, told Technology Review that this is "one of the reasons why there's no activity taking place in movie downloads".

With a 1.5GB movie file "you could request a movie from Netflix [which delivers DVDs by mail] before this download gets to you," he explains.

The report points out that high-speed broadband is relatively expensive to run, and that this extra expense can easily contribute to the cost of a handful of DVDs.

TV shows are a different matter, the report explains, adding that the QuickTime movie trailers that are accessible through iTunes take up in excess of 100MB.

However, portable video encoded as a small file for use with iPods is a possibility. Casanova did mention the one full-length movie that is available through iTunes, High School Musical, which has been "selling well", he said. "I travel a lot, and see people watching movies on their [Sony] PSPs," he added,

Michael Gartenberg, vice president and research director for Jupiter Research, said: "The remaining technical issues have to do with details. It's attention to details that made it work for Apple and the iPod."

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