Apple released QuickTime 7.6 for Mac OS X and Windows Wednesday, an update that addresses seven security issues and includes a number of improvements for both audio and video quality. The update is for both Mac OS X 10.4 and Mac OS X 10.5 users, as well as Windows users.

The security issues are all potential exploits that could result in a hacker being able to take over your Mac or PC if you were to view a maliciously crafted movie file. Most of the errors are buffer or memory overflow errors, with the addition of an issue involving Cinepak encoded files.

The different security issues addressed affect various combinations of Mac OS X 10.4.x and 10.5.x, as well as Windows Vista, XP SP2 and SP3.

On the video side, the company said the update improves single pass H.264 encoding quality and that it increases the playback reliability of Motion JPEG media. Apple also said that the update improves AAC encoding quality, and that audio tracks from MPEG video files will now export consistently.

Lastly, Apple said the update improves compatibility with iChat and Photo Booth in Mac OS X.

For Mac OS X 10.5.6, the update is a 75.1 MB download, and can be downloaded through Software Update. Windows users should use the Apple Software Update application, which can be accessed through iTunes.