Apple has released QuickTime 6.5.1 for Mac OS X 10.2.6 or higher. The company also this morning released new QuickTime software for users of older operating systems.

QuickTime 6.5.1 offers a series of improvements, Apple reveals, including:

Apple Lossless Encoder, a new lossless audio codec that retains the full quality of uncompressed CD audio while requiring only about half the storage space.

Significant improvements to AAC encoding, resulting in high-quality sound over a full range of audio frequencies.

Enhanced support for iTunes and other QuickTime-based applications.

QuickTime 6 already supports MPEG-4, 3GPP and 3GPP2 and multiple other formats. The software also offers Instant On streaming, providing immediate access to media with no buffer delays.

QuickTime 6 also includes an instrument sound set licensed from Roland Corporation that makes a complete General MIDI compatible sound set.