BD-R

BD-R (Blu-Ray Recordable) refers to two direct-to-disc recording technologies that can be recorded on a Blu-ray with a recorder of the aforementioned format.

BD-R discs can be written once, while BD-RE (Blu-ray Rewritable, for its acronym in English Blu-ray Disc Recordable Erasable) can be erased and re-recorded multiple times. The disc capacities are 25 GB for single layer discs, 50 GB for double layer discs, 100 GB ("XL") for triple layer and 128 GB for quad layer (the latter only on a BD -R).

The minimum speed at which a Blu-ray disc can be written is 36 megabits (4.5 megabytes) per second.

Versions

There are five versions of BD Rewritable (BD-RE) and four versions of BD Recordable (BD-R). Each version includes three Parts (also known as Books): Basic Format Specifications, File System Specifications, Basic Audio Visual Specifications. Each part has sub-versions (for example, the R2 format specification includes Part 3: Basic Audiovisual Specifications Ver.3.02, Part 2: File System Specifications Ver. 1.11, Part 1: Basic Format Specifications Ver 1.3).

Burn Speed

As of December 2017, the following speeds are seen in the Blu-Ray specifications for Recordable and Rewritable discs:

2× speeds are required for all formats, with 4× and 6× optional for non-XL BD-R media. From BD-RE 5.0 to BD-R 4.0, a read speed of 4× is mandatory for UHD media.

Note: You have to add an additional time for the disc verification phase and time to erase the disc in the case of BD-RE.

Price

As of April 2018 (approximate price):

• BD-R and BD-RE management $50 and higher prices.
• Disco BD-R 6× (25 GB) $0.42, each in quantity.
• Disco BD-R 10× (25 GB) 2.04 yuan, each of them.
• Disco BD-R DL 6× (50 GB) $1.64 in quantity.
• Disco BD-RE 2× (25 GB) $0.82 in quantity.
• Disco BD-RE DL 2× (50 GB) $3.15 in amount.
• Disco BD-R XL 4× (100 GB) $5 in quantity.
• Disco BD-RE XL 4× (100 GB) $11 in quantity.

Recording Mechanisms

Instead of the pits and grounds found on pre-printed, pre-recorded, and replicated discs, BD-R and BD-RE discs contain grooves that contain an oscillation frequency that is used to locate the position of the reading laser or writing to the disc. BD-R has a Power Optimum Calibration (OPC) or Test Zone, which is used to calibrate (finely tune) the power of the writing laser before and during writing, and also has a Zone Calibration Unit (ZCU) on the outer edge of the disk, for optional high-speed calibration. Calibration is necessary to allow for slight manufacturing defects, reducing or completely eliminating rejected drives and drives, lowering costs and eliminating potential waste. The following information describes the different types of recording layers that can be used on BD-R and BD-RE discs.

BD-R AaB (High to Low)

BD-R "regular" they use a composite (or, in the case of BD-REs, a phase shift alloy) that lowers their reflectivity in the recording, i.e. "High to Low". Sony, for example, uses an inorganic compound that splits into two lamellar components with low reflectivity. Compounds used may include bismuth nitride (NBi), germanium nitride (Ge₃N₄) doped palladium, and suboxide tellurium. Alternatively, a pair of copper-silicon alloy layers can be used that are combined in recording. Similar to CD-RW and DVD-RW, a transition alloy of phase (often GeSbTe or InAgTeSb, they are Copper Silicide (SiCu) or other alloys can also be used, such as Verbatim's proprietary MABL) is used for BD-RE discs. Melting the material with a high power beam converts it to an amorphous state with low reflectivity, while heating at a lower power erases it back to a crystalline state with high reflectivity.

On BD-RE discs, the data layers are surrounded by a pair of Zinc/Sulphur/Silicon dioxide dielectric layers. An adhesive spacer layer and a semi-reflective layer are used for multi-layer discs. Recording and dielectric layers are deposited using sputtering. On multilayer BD-RE discs, each GeSbTe recording layer is progressively thinner. So, the first layer (C0) is 10 nm thick, C1 is 7.5 nm thick, C2 is 6 nm thick, and so on. The reflective silver alloy layers behind each recording layer also become progressively thinner, so the C0 silver layer is 100 nm thick, the C1 layer is 9 nm thick, the of C2 is 7 nm thick, and so on. The separation layers that separate the recording layers from each other also become progressively thinner.

BD-R BaA (Low to High)

BD-R BaA is a Blu-ray disc recording format that features a recording layer of organic dyes from CD-Rs. "Low to High" refers to the reflectivity that changes from low to high during the burning process, which is the opposite of regular Blu-rays, whose reflectivity changes from high to low during writing. The advantage of BD-R BaA is that it can protect a manufacturer's investment in DVD-R/CD-R manufacturing equipment because it does not require investment in new production lines and manufacturing equipment. Instead, the manufacturer only needs to modify the current equipment. This is expected to reduce the cost of manufacturing discs.

Old Blu-ray players and recorders can't use BD-R BaA; however, a firmware update may allow devices to access the BD-R BaA. Panasonic released such a firmware update in November 2007 for its DMR-BW200, DMR-BR100, and MR-BW900/BW800/BW700 models. Pioneer was expected to ship the first BD-R BaA drives in spring 2008. Sony updated the PlayStation 3 firmware allowing the reading of BD-R BaAs in March 2008.

In 2011, the French Ministry of Culture and Communication conducted a study on the data archiving suitability of BaA (Low to High) discs compared to AaB (High to Low) discs. The data they collected indicated that the overall quality of BaA discs is worse than AaB discs.