Sony managed to obtain the rights to the HD-footage that was broadcast at Japanese national TV at the time. It was sourced from different cameras so it's basically a different representation of the same show.
It had been sitting in Japan at NHK. Japan was an early adopter in HD and they had HD cameras at the event. What you're seeing now is their cut of the show, which nobody had ever seen before. Getting the full rights was very complicated because of bankruptcies. A Sony lawyer who was a passionate music fan sorted it all out.
C'était probablement de la HD analogique (système HDVS de Sony) ;
A part Dylan qui joue quelques morceaux, c'est surtout un concert hommage réunissant pas mal d'artistes (Neil Young, Eric Clapton, George Harrison, Johnny Cash, Lou Reed, 2 gars de Pearl Jam, Willie Nelson, Tom Petty, Stevie Wonder, Sinead O'Connor ... rien que ça ) ;
Apparemment le morceau avec George Harrison ne serait pas sur le Blu-ray, et pourtant je viens de le voir sur la RTBF.