Yes, I have QuickTime Player v. 7.6.6 installed as well as a third-party application called
PERIAN:

Perian aims to provide a single package for all your playback needs. It is a collection of QuickTime components incorporating several libraries:
• libavcodec, from the ffmpeg project, along with code from the old FFusion component:
• MS-MPEG4 v1 & v2
• DivX
• 3ivx
• H.264
• Flash Video
• Flash Screen Video
• On2 VP3, VP6, VP8
• H263I
• HuffYUV and ffvhuff
• Indeo 2, 3 & 5
• MPEG-1, 2 & 4 Video (in supported formats)
• Fraps (up to v4)
• Windows Media Audio v1 & v2
• Flash ADPCM
• Xiph Vorbis (in Matroska)
• MPEG Layer I and II audio
• DTS Coherent Acoustics audio
• Snow wavelet video
• DosBox video
• Nellymoser ASAO audio
• libavformat, from the ffmpeg project. along with AVIImporter.component:
• AVI file format
• FLV file format
• NUV file format
• libmatroska, along with matroska-qt.component:
• MKV file format
• Subtitles:
• (Advanced) SubStation Alpha
• SRT
• SAMI
• VobSub
• liba52, via A52Codec:
• AC3 audio

The code is available under the LGPL. The development site is located at <http://trac.perian.org/> and the project’s Subversion repository is located at <http://svn.perian.org/>.
The code for A52Codec is available under the GPL. The project site is located at <http://trac.cod3r.com/a52codec/> and the project Subversion repository is located at <http://svn.cod3r.com/a52codec/>. »