The brief release notes:
This update adds the following video codecs for use by QuickTime-based applications:
- Apple Intermediate Codec
- Apple ProRes
- AVC-Intra
- DVCPRO HD
- HDV
- XDCAM HD / EX / HD422
- MPEG IMX
- Uncompressed 4:2:2
The software can be downloaded through Software Update if you have any of the above-mentioned apps installed. It’s a 992KB download. You can download a standalone installer from Apple’s support site as a 1.1MB file.