Apple has quietly introduced a new feature that improves how people stream their stored music files to their iPhones, iPod Touches and iPads, MP3Tunes founder and CEO Michael Robertson explains on his blog. A new addition to Apple’s MobileMe iDisk software has this item in the list of features: “Play audio from your iDisk while using another app.” This allows the user to play stored AAC or MP3 files on a connected Apple device while using other applications (so the music streams in the background).

The streaming function has been available in the past, but the new ability to stream music in the background makes this a more viable music streaming service. And that could be a controversy waiting to happen. Major labels are not pushing music services to acquire a license to simply store a music file. But to offer a feature-rich cloud-based music service would indeed require a license and the payment of royalties. In offering this feature, Apple is pushing against the demands of labels.

But, as Robertson explains, the service is not a celestial jukebox but appears to be a step in that direction.

This is not "iTunes in the cloud" but it is definitely moving the Cupertino company in that direction. First off there is no automated way to get all your iTunes music to your iDisk account. To load files to iDisk you have to select individual files and upload them from your browser. (Apple does let you sync Calendars, Contacts, Bookmarks, etc directly from OSX but excludes music files.) Secondly there's no support for playlists so your iTunes playlist do not work in iDisk. There seems to be no way to play a list of files. Cover art is not supported as well. And while iDisk will cache other files, it will not cache music files. Still it's not hard to see how Apple is adding features to enable it to support audio in it's cloud storage business.

This new feature comes just as news broke that Apple appears to be working on a video streaming service rather than a music streaming one. As Billboard reported on Tuesday, any cloud-based music service Apple launches in 2010 is likely to be a modest one without big innovations or many bells and whistles. Apple has reportedly put Lala engineers (it acquired music service Lala in late 2009) to work on a video-focused project rather than a music-focused one.