Apple's audio playback patent filing

"The invention pertains to improved techniques for modifying a playback rate of an audio item," Apple wrote in the filing. "As a result, the audio item can be played back faster or slower than normal."

The company said its approach to the technology is also more resource efficient than existing techniques.

"Portable media devices, such as media players, are small and highly portable and have limited processing resources," it explained. "Given the resource efficiency of these techniques, the improved techniques are also well suited for use with portable electronic devices having audio playback capabilities, such as portable media devices."

In the filing, Apple says the invention is "well suited for audio items pertaining to speech, such as audiobooks, meeting recordings, and other speech or voice recordings." It also makes reference to "an interface" (shown below) that "can facilitate a user's selection of a desired playback rate."

One of the advantage of the invention, the company said, is that speech-related audio can maintain its intelligibility despite a wide range of timescale modification. It would therefore allow users to speed up playback of pre-recorded meeting dialog or audio books for faster digestion.

The April 1, 2005 filing is credited to Apple employees Aram Lindahl and Joseph Mark Williams.