VLC (initially VideoLAN Client) is a highly portable multimedia player for various audio and video formats (3GP, MP4, FLV, AVI, WAV, MKV, ASF, VOB, AAC, WMA, MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg...) as well as DVDs, VCDs, and various streaming protocols.
QuickTime Alternative 2.3.0 uses codecs taken from QuickTime 7. As such, many question its legitimacy as the codec package is not a licensed Apple product, nor is the specific version of QuickTime that the codec is taken from available free of charge.
VLC Media Player 0.8.6d is freeware to play multimedia files. This multimedia player supports a large number of multimedia formats, without the need for additional codecs.