If you plunked down the $550 for the new Pink Floyd box set, The Early Years 1965-1972, you may have stumbled upon a surprise.

When the 27-disc collection was announced, it was going to include new stereo and 5.1 mixes of the albums Meddle and Obscured by Clouds. But they were replaced by a stereo soundtrack to the concert film Live at Pompeii — or were they? Hidden on the REVERBER/ATION Blu-ray disc are the two mixes of Meddle, but you will need specialized software to access them.

The collection features TV recordings, BBC sessions, unreleased songs, outtakes and demos. In all, it presents 130 tracks that clock in at 12 and a half hours. The set also includes more than 15 hours of video, half of it rare concert footage, along with memorabilia and much