Perian, a free open source QuickTime component that adds native support for many popular video formats, has been updated with compressed MKV and WebM/VP8 support.
Perian 1.2.2 Changes
● Added WebM/VP8 support. [r1310, r1315]
● Added support for compressed MKV tracks, as generated by newer versions of mkvtoolnix. [r1317, r1334]
● Added FFv1 lossless video support. [r1363] (#407)
● Added an internal decoder for Theora, fixing compatibility problems with XiphQT. [r1379] (#499)
● The readme and license files are now included in the component bundle. [r1309]
The next planned version will remove support for PowerPC and OS X versions prior to 10.6. Maintenance updates may be provided if necessary.