Perian - The swiss-army knife of QuickTime� components: "Perian enables QuickTime application support for additional Media Types:
* AVI, FLV, and MKV file formats
* MS-MPEG4 v1 & v2, DivX, 3ivX, H.264, FLV1, FSV1, VP6, H263I, VP3, HuffYUV, FFVHuff, MPEG1 & MPEG2 Video, Fraps, Windows Media Audio v1 & v2, Flash ADPCM, Xiph Vorbis (in Matroska), MPEG Layer II Audio
* AVI support for: AAC, AC3 Audio, H.264, MPEG4, and VBR MP3
* Subtitle support for SSA and SRT
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