Sound+Vision Plus CD Four
The original release of the Sound+Vision boxed set included a 5" CDV
(CD-Visual) which bundled three live tracks from 1972 with a video of
Ashes To Ashes. While the audio tracks are playable in standard CD
players, the video portion is a different format to that used in CD-ROMs or
DVD players today. Instead the video is playable only on laserdisc players
(which are becoming a rarer and rarer breed these days).
A subsequent rerelease in the 90s changed the fourth CD to a more
standard CD-ROM with the Ashes To Ashes video on it (albeit in a lower
quality format than that available on a laserdisc).
Finally, a third release omitted the fourth CD completely.