A few statements to start:
DVD audio has a better bit/sample rate than CD audio..CD is 16 bit/44.1 khz, while DVD audio is 24 bit/96 khz,if I recall correctly. That would give a better base to create high quality audio off of.
Sound quality from 44.1 to 48khz is sooooo slight, that a human would not notice.
and now...
In theory yes..it would sound better... however(at this time)..
the compression of data for mp3 format seems to take a bit out of the audio as compared to a CD, and the weak link in the ENTIRE chain is the DAC.
DAC is short for Digital to Audio Converter. It is what changes the 0s and 1s on your CD/DVD to sound. At this point in time, no mp3 playback software can compete with the ones used in CD/DVD players. The DACs in CD/DVD playback devices are specialized for that one task, and therefore are better at sound reproduction. I have tested this out in a studio setting..and no mp3(even at a VERY high encoding rate) can match a CD. However...give the programmers time..and it will be better than a CD.