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
VP6
H263I
VP3
HuffYUV and ffvhuff
Indeo 1 & 2
MPEG-1 & 2 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