"So theoretically, the Star wars episode I dvd at 448 should be better than the lasers 384, but it's not the case."
Because, again, the difference between the SW LD and DVD isn't just the bitrate. The LD is a different mix as well.
And your SPD LD comparison makes perfect sense.
[EDIT]
This gentleman states that the Episode I dvd and LD same mix is essentially the same.
http://www.videophile.info/Graphs/TPM/TPM_01.htm
"Apart from the difference in overall volume, the mix on both is basically the same. While a lower recording level could also be called a different 'mix' already, it usually isn't. A different mix suggests that either the frequency response of the track is altered (roll-off of the ultra low sub 30hz bass for example, see JP DVDs), or the impact and design of single effects is changed (see beginning of T2 UE). Neither of which happened on TPM.
The only 're-mix' that happened here, is that the level difference between the 2 versions is not constant (lets say 8db), but differs from one part of the movie to the other. The 'Podrace' for example is recorded 7db lower than on the LD, while the 'Invasion' and the 'Bigger Fish' scene in the beginning are recorded 9db lower. So Lucasfilm chose a different balance between the scenes. Whether the new balance on the DVD or the old on the LD is closer to the theatrical presentation is anyone's guess. But considering that the mix on the DVD was prepared by the same people that created this fabulous soundtrack in the first place, implies that the balance on the DVD is either correct or at least prefered by those involved. "
And can you elaborate on your statement that the SPD LD comparison makes perfect sense? Not sure what doesn't make sense. The Dolby digital DVD was recorded at a bitrate of 448kbps, the DTS DVD at 754kbps, and the Dolby digital LD at 384kbps. My point was to say that bitrate isn't the end all factor as is a common conception. the LD is the reference soundtrack for this film, and it's the one at the lowest bitrate.