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Blu-Ray Discs also known as Blu-Ray, (BD) is the name of a next-generation optical disc format jointly developed by the Blu-ray Disc Association (BDA), a group of leading consumer electronics and PC companies (Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson). This new format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. A single-layer Blu-Ray Disc can hold 25GB, which can be used to record over 2 hours of HDTV or more than 13 hours of standard-definition TV. There are also dual-layer versions of the discs now that can hold 50GB. While current optical disc technologies such as CD and DVD use a red laser to read and write data, the new format uses a thinner blue-violet laser, hence the name Blu-ray. Despite the fact this is different type of laser, Blu-Ray products can easily be made backwards compatible through the use of a BD/DVD/CD compatible optical pickup and allow playback of both CDs and DVDs. The benefit of using a blue-violet laser (405nm) is that it has a shorter wavelength than a red laser (650nm), which makes it possible to focus the laser beam with even greater precision. This allows data to be packed more tightly and stored in less space, so it's possible to fit more data on the disc even though it's the same size as a CD and DVD. This together with the change of numerical aperture to 0.85 is what enables Blu-ray Discs to hold 25GB/50GB. With the rapid growth of HDTV, the consumer demand for recording HD programming is quickly rising. Blu-Ray was designed with this application in mind and supports direct recording of the MPEG-2 TS (Transport Stream) used by digital broadcasts, which makes it highly compatible with global standards for digital TV. This means that HDTV broadcasts can be recorded directly to the disc without any quality loss or extra processing. To handle the increased amount of data required for HD, Blu-ray employs a 36Mbps data transfer rate, which is more than enough to record and playback HDTV while maintaining the original picture quality. By fully utilizing an optical disc's random accessing features, it's possible to playback video on a disc while simultaneously recording HD video. Blu-ray is expected to replace VCRs and DVD recorders over the coming years with the transition to HDTV. The format is also likely to become a standard for PC data storage and HD movies in the future.
Super Audio CD - SACD is a new high-resolution digital audio format that has vast sonic improvements over the audio CD format which has dominated digital audio for over 20 years. Unlike any digital audio format to date (all based on Pulse Code Modulation), Super Audio CD uses an entirely new method of encoding audio, called Direct Stream Digital (DSD). DSD digitally encodes the audio information as 1-bit data words sampled at 2,822,400 times per second! Among other benefits, DSD has better sonic performance because the encoded bitstream resembles the analog characteristics of the original analog signal. Super Audio CD can support high-resolution stereo recordings as well as up to six high-resolution multi-channels. The multi-channel Super Audio CD format is capable of reproducing an immersive sonic experience that is best described as "virtual reality for sound". Super Audio CD discs can be played back on Super Audio CD players or on combination SACD/DVD players. SACD Hybrids are proving to be the format of choice as they feature a conventional audio CD top layer (which can be played back on any CD player or computer) and an SACD layer underneath, readable by an SACD player or combination SACD/DVD player.
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