RCA was trying to edge out the pre-existing VHS and LaserDisc formats, but ultimately failed in the long run. The format lasted from 1981 until 1986, and about 1700 titles were released on CED.
Movies came in large plastic caddies, which you inserted, as a whole, into a CED player, which disengaged the disc from the caddy when you pulled it back out (so you wouldn't touch the disc with your bare hands, which could cause disc damage.) A stylus picked up the audio/video data from the disc, which spun at 450 RPM.
To remove the videodisc, you simply push the caddy back into the player, and the disc re-engages itself in the caddy.
Like a CLV laserdisc, CEDs have one hour of content on each side... but you must remove and re-insert the disc upside-down, to continue playing (like with the early laserdisc players.)
If a film ran over two hours by a significant amount of time, it was released on a set of two CEDs. Otherwise, time compression was used to fit the movie onto one disc.
The estimated life of a CED videodisc is 500 playings. Not too bad.