What's a dual-layer disc? Will it work in all players?

harrika · Frequent GEARhead Joined: 03 Apr 2010 Posts: 39

jainekaif · Frequent GEARhead Joined: 20 Mar 2010 Posts: 39

A dual-layer disc has two layers of data, one of them semi-transparent so that the laser can focus through it and read the second layer. Since both layers are read from the same side, a dual-layer disc can hold almost twice as much as a single-layer disc, typically 4 hours of video (see 3.3 for more details). Many discs use dual layers. Initially only a few replication plants could make dual-layer discs, but most plants now have the capability. The second layer can use either a PTP (parallel track path) layout where both tracks run in parallel (for independent data or special switching effects), or an OTP (opposite track path) layout where the second track runs in an opposite spiral; that is, the pickup head reads out from the center on the first track then in from the outside on the second track. The OTP layout, also called RSDL (reverse-spiral dual layer), is designed to provide continuous video across both layers.

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stefani88 · Joined: 03 Jan 2012 Posts: 1