It had all the makings of a self-congratulatory snooze: A road-weary rock band throws itself a going-away party while a big-shot director films the spectacle for, y’know, posterity. Drowsy yet? Amazingly, what Martin Scorsese actually captured turned out to be some of the best musical performances ever caught on film. Neil Young’s fragile whine on ”Helpless.” Bob Dylan’s soulful snarl on ”Forever Young.” And, most of all, the heart-wrenching beauty of The Band, who shine on classics like ”It Makes No Difference” and ”The Night They Drove Old Dixie Down.” Now on DVD, The Last Waltz has been spruced up nicely—its warm colors enriched, its full sound sharpened. The two commentaries (one with The Band chieftain Robbie Robertson and Scorsese, the other a grab bag of musicians and commentators) and a making-of featurette provide some nice behind-the-scenes detail. The only disappointment is the dull bonus footage of a meandering jam session. A new CD boxed set uncovers a trove of songs not included in the movie; apparently, corresponding film outtakes don’t exist. Pity.