Inside Macintosh: QuickTime Reference

VBR-Supported Features

The VBR-supported features in QuickTime 4.1 include:

opening and importing of both CBR and VBR encoded MP3 files.
editing of local movies containing MP3 VBR sound tracks, using standard cut, copy, and paste operations.
saving movies containing VBR sound tracks, either as self-contained or non-self-contained QuickTime movie files.
exporting from an MP3 VBR compressed sound track to any sound format for which QuickTime has a compressor. Exported data can be saved to WAV, AIFF, snd, .au, AVI, and any other file type format that supports sound.
fast-starting of MP3 VBR files.

There is also support of MP3 VBR audio for streaming. Features include:

hinting of movies containing VBR sound tracks
streaming of MP3 VBR sound data to VBR aware clients

Note: In the descriptions above, MP3 VBR should be considered to be interchangeable with "a VBR audio format." Initially, MP3 will be the only decompressor that takes advantage of added VBR support. In future releases, additional decompressors/compressors will be provided for other VBR sound formats.

Inside Macintosh: QuickTime Reference