HD DVD BD9 formats. HD Rec is an extension of the HD DVD format for recording HD content on regular red laser DVD-Rs/DVD-RWs using H.264/MPEG-4 AVC compression. It was approved by the DVD Forum on September 12, 2007 It is comparable to Blu-ray Disc's AVCREC. The China Blue High-definition Disc (CBHD), a high-definition optical disc format, was based upon the HD DVD format. Like the HD DVD, CBHD discs have a capacity of 15 GB single-layer and 30 GB dual-layer and can use existing DVD production lines. Unlike the HD DVD format, industry support for this format has grown steadily. HD DVD
Compressed audio optical disc case and disc drive exposes the disc to dust, and also makes the disc liable to be damaged permanently. Also note that some CD and DVD discs also have defective aluminum layers that can flake, and damage the disc naturally. Repeated insertion and removal of optical discs can occur when somebody has to deal with multi-gigabyte collections which can span across as many as 10 CD-Rs (or 5 DVD-Rs) or even more when lots more gigabytes were to be used. Sometimes when somebody is looking for a specific MP3 or similar; it can result in insertion and removal if more