langleyav: The audio on a DVD is encoded a a bit rate of 48Khz whereas an mp3 or wma is usually encoded at 41Khz.
Most music is originated from CD; this is 16bit 44.1kHz, but music can be encoded up to 24bit 192kHz WMA (and FLAC). This is equal to the maximal capability of a 2 channel DVD Audio format. Note: WMA and FLAC can also be encoded in multichannel formats.
In contrast MP3 is a lossy format, so it always loses information from the original!
It is quite easy to extract the MLP format from a DVDA with "DVD Audio Extractor"; a Windows application.
SACD is another story. Until today there is no way to rip the DSD signal directly from a SACD to a hi-res WMA/FLAC format.