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Backwards Compatibility

The Blu-ray Disc Association recommends that the various PC, player and games console BD drives be backwards compatible in order to read both CDs as well as DVDs.

Content Protection

BD+ was developed by Cryptography Research Inc. and was based on the idea of Self-Protecting Digital Content. In brief, BD+ is a virtual machine embedded in Blu-ray players which allows content providers to include executable programmes on Blu-ray discs. The BD+ virtual machine allows executable programmes to:

• Examine the BD player to check if it has been tampered with.
• Check whether or not the player’s keys remain unchanged.
• Unscramble audio and video files that ought to be unviewable/inaudible without a transformation carried out by the programme embedded on the BD.

Essentially, the protection offered the BD+ technology to BD content providers is the ability of the virtual machine to test and evaluate the integrity of the BD player, check for any abnormalities, and then circumvent the vulnerabilities of the copyrighted content created by player tampering.

The BD-ROM Mark is a set of cryptographic data stored on a Blu-ray disc apart from the audio-visual files. The aim of the Mark is to prevent the illegal replication of copyrighted disc content. A licenced piece of hardware is needed to insert a BD-ROM Mark into the disc during the replication process. The cryptographic data is needed to decode/decrypt the audio-visual information, and a standard BD player will not be able to read the content replicated from a sector by sector copy of the original disc as it will be without the crucial cryptographic information.

The Future of Blu-ray Disc Technology

Although the BD standard has already been defined, engineers nonetheless continue to explore the possibilities and capabilities latent within Blu-ray technology. Quad-layer discs have been proven to work on drives with unaltered optics as well as on drives with modified optics. Before the turn of the decade, TDK had already announced that they created a disc capable of storing 200 GB of information in 6 layers of 33 GB/layer. Ritek successfully developed a HD disc that is able to hold 250 GB of data by creating 10 layers that contain a standard 25 GB per layer. A major obstacle in the process of releasing the disc in the market is that current BD players don’t have the capability of reading 10 layers of information. As early as 2008, Pioneer Corporation revealed that they had produced a 400 GB disc that could be read by standard BD players that had undergone a firmware upgrade. The disc contained 16 layers of data, with each layer capable of storing 25 GB. The writable version of the disc should appear before 2013; the company has further ambitions to release a read only 1 terabyte disc by 2013. Sony, in partnership with Panasonic, has increased the standard 25 GB of storage per layer of a BD to 33 GB per layer.

Blu-ray has also gone 3-D: 3-D video needs to be read in stereoscopic video streams, which can be encoded in the MPEG4-MVC codecs. The Multiview Video Coding (MVC) codec is based on the Advanced Video coding (AVC) codec that standard 2-D Blu-ray discs typically use (in addition to the VC-1 codec), which makes the 3-D BDs backwards compatible with current 2-D players. Sony made significant inroads into the 3-D market via the PS3 console. This is to say that in 2010, Sony released a firmware upgrade that allowed the PS3 to support 3-D gaming, which was closely followed by 3-D movie support.