For consumers the great news is the Blu-ray Disc won a brief format war with its direct competitor, HD-DVD. This has allowed a single high-definition physical media type to be offered for both audio and video releases. Known as BD for short, the Blu-Ray Disc was designed to supersede the DVD format. While BDs are the same size as DVDs and CDs, they contain 25 GB per layer, while dual layer discs used for feature-length video discs can store up to 50 GB. The name Blu-ray Disc refers to the blue laser used to read the disc, which allows information to be stored at a greater density than is possible with the longer-wavelength red laser used for DVDs.
Blu-ray Discs may also come with a digital copy in which users can download the music or movie to a portable device capable of operating with a file in contrast to a DVD. Digital copies may be used on iPods, iPhones, and iPads, as well as other tablet and smartphone devices. Audiophiles will enjoy lossless quality file formats such as WAVE, FLAC, MP4, or MKV when downloading music releases that include digital copies. These can be used on any computer and many portable players. Unfortunately, over the years very few audio releases have included a lossless download offering, leaving consumers with the task of ripping Blu-rays for portable use.
With the large amount of space on a Blu-ray Disc, High-definition video may be stored with up to 1920×1080-pixel resolution at up to 59.94 fields per second, if interlaced. Alternatively, progressive scan can go up to 1920×1080-pixel resolution at 24 frames per second, or up to 1280x720 at up to 59.94 frames per second.
For audio, BD supports the compressed Dolby Digital (AC-3) or DTS codecs. Optionally, publishers may support Dolby Digital Plus and DTS-HD High Resolution Audio as well as multi-channel based lossless formats including Dolby TrueHD, DTS-HD Master Audio, Linear PCM, plus the newest object based codecs Dolby Atmos and DTS-X. It is these lossless formats that are typically sought out and reviewed here on Hi-Res Edition. BD-ROM titles must use one of the mandatory schemes for the primary soundtrack. A secondary audio track, if present, may use any of the mandatory or optional codecs.
Here at Hi-Res Edition, we seek high resolution audio and high-definition video to enjoy releases in the best way possible. While multi-channel audio is available for up to 8 discrete channels (7.1 surround), many titles are still releasing material in 5.1 surround sound. However, now with the onslaught of Dolby Atmos releases, listeners can find themselves immersed in up to a 7.1.6 speaker layout for home theaters.
Here at Hi-Res Edition, we seek out releases that include at least one of the Lossless formats, and most titles include one of these audio streams using 24-bit sample depth and up to a 192 kHz sampling frequency for six channels or more and supported by Dolby TrueHD, DTS-HD Master Audio, LPCM, Dolby Atmos, and DTS-X. While Lossless is preferred, the runner ups can sound very good and typically include 5.1 channels at 24-bit sample depth, with a minimum of a 48kHz sampling frequency. These high-definition audio streams include Dolby Digital, Dolby Digital Plus, DTS Digital Surround, DRA, and DRA Extension.
As a side note, there is a distinct difference between the original and more common Blu-ray disc described above and the newest incarnation called Ultra HD Blu-ray (aka/ 4K Ultra HD, UHD-BD, or 4K Blu-ray). This is a digital optical disc that is an enhanced variant of Blu-ray, and they are incompatible with existing standard Blu-ray players. At present these discs are available for movies where the improved 3840×2160-pixel resolution is beneficial and thus far have not served the music market.
For more information on Blu-ray Disc, please see the Blu-ray Disc Article on Wikipedia.