Engineering:Blu-ray Disc recordable

A blank rewritable Blu-ray Disc (BD-RE)

Blu-ray Disc Recordable (BD-R) and Blu-ray Disc Recordable Erasable (BD-RE) refer to two direct to disc optical disc recording technologies that can be recorded on to a Blu-ray-based optical disc with an optical disc recorder. BD-R discs can be written to once, whereas BD-RE discs can be erased and re-recorded multiple times, similar to CD-R and CD-RW for a compact disc (CD). 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 quadruple-layer (in BD-R only).

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

Version

(As of November 2022), there are five versions of BD-RE and four versions of BD-R formats. Each version includes three Parts (a.k.a. Books): Basic Format Specifications, File System Specifications, Audio Visual Basic Specifications. Each part has sub-versions (e.g. R2 Format Specification includes Part 3: Audio Visual Basic Specifications Ver.3.02, Part 2: File System Specifications Ver. 1.11, Part 1: Basic Format Specifications Ver. 1.3).

Date	RE Version	R Version	By Parts			Changes
			Part 1	Part 2	Part 3
2002	1.0		RE V1.0	RE V1.0	RE V1.0	BD File System (BDFS), computer-incompatible BD Audio/Visual (BDAV) format BD content protection (BDCP)
2005	2.0	1.0	RE V2.1 R V1.3	RE V2.1 R V1.1	RE V2.1	New UDF 2.5 file system for computer use; UDF 2.6 also available for BD-R Uses AACS Hybrid formats (inapplicable to recordable discs) New BD-R Low To High physical format.
September 2006	3.0	2.0	RE V2.1 R V1.3	RE V2.1 R V1.1	RE V3.0 + ROM V2.4 (BDMV)	New camcorder sized (8 cm) discs "Camcorder" added to product categories BDMV (Blu-ray Disc Movie) application format
June 2010	4.0	3.0	RE V3.0 R V2.0	RE V3.0 R V2.0	RE V4.0 + RE V2.1	New BDXL definition: Multi-layered BDAV rewritable/recordable disc with 2× and 4× speeds 100 GB capacity "Professional Device" added to BD product categories
December 2017	5.0	4.0	RE V3.1 R V2.2	RE V4.0 R V3.0	RE V5.0	BDXL expansions: New 128 GB BD-R capacity Ultra HD broadcast recording support

Speed

(As of December 2017), the following speeds are seen in Blu-Ray specifications for R/RE discs:

Drive speed	Data rate			25GB BD-R(E) write time	50GB BD-R(E) DL (25GB/layer) write time	100GB BD-R(E) XL TL (~33GB/layer) write time
1×	36 Mbit/s	4.5 MB/s	4.29 MiB/s	~95 min.	~190 min.	~380 min.
2×	72 Mbit/s	9 MB/s	8.58 MiB/s	~47 min.	~94 min.	~188 min.
4×	144 Mbit/s	18 MB/s	17.17 MiB/s	~24 min.	~48 min.	~96 min.
6×	216 Mbit/s	27 MB/s	25.75 MiB/s	~16 min.	~32 min.	~64 min.
8×	288 Mbit/s	36 MB/s	~34.32 MiB/s	~11.25 min.	~22.5 min.	~45 min.
10×	360 Mbit/s	45 MB/s	42.898 MiB/s	~9 min.	~18 min.	~36 min.
12×	432 Mbit/s	54 MB/s	~51.48 MiB/s	~7.5 min.	~15 min.	~30 min.
14×	504 Mbit/s	63 MB/s	~60 MiB/s	~6.5 min.	~13 min.	~26 min.
16×	576 Mbit/s	72 MB/s	~68.64 MiB/s	~5.7 min.	~11.5 min.	~23 min.

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

Note: Add extra time for disc verification phase and time for erasing the disc in the case of BD-RE.

Pricing

(As of April 2018) (approximate pricing):

• BD-R/RE drive US$50 and above
• 6× single-layer BD-R disc (25 GB) United States dollar 0.42 each in quantity;
• 10× single-layer BD-R disc (25 GB) CN¥2.04 each in quantity;
• 6× double-layer BD-R disc (50 GB) United States dollar 1.64 in quantity;
• 2× single-layer BD-RE disc (25 GB) United States dollar 0.82 in quantity;
• 2× double-layer BD-RE disc (50 GB) United States dollar 3.15 in quantity;
• 4× BD-R XL disc (100 GB) United States dollar 5 in quantity;
• 4× BD-RE XL disc (100 GB) United States dollar 11 in quantity;

Recording mechanisms

Instead of the pits and lands found on prepressed/prerecorded/replicated discs, BD-R and RE discs contain grooves which contain a wobble frequency that is used to locate the position of the reading or writing laser on the disc. BD-R has an Optimum Power Calibrations (OPC) / Test Zone, which is used to calibrate (finely adjust) the power of the writing laser before and during writing, and it also has a Drive Calibration Zone (DCZ) at the outer edge of the disc, for optional high speed calibration. The calibration is necessary to allow for slight manufacturing defects, greatly reducing or completely eliminating rejected discs and drives, reducing costs and eliminating potential waste. The information below describes the different types of recording layers that may be used on BD-R and BD-RE discs.

HTL (high to low)

"Normal" BD-R discs use a composite (or, in the case of BD-RE, a phase-changing alloy) that decreases its reflectivity on recording, i.e. "High To Low". Sony, for example, uses an inorganic composite that splits into two laminar components with low reflectivity. Composites used may include BiN, Ge₃N₄, and Pd-doped tellurium suboxide. A pair of layers with copper alloy and silicon that combines on recording may alternatively be used. Similar to CD-RW and DVD-RW, a phase transition alloy (often GeSbTe or InAgTeSb; copper silicate (CuSi) or other alloys can also be used, like Verbatim's proprietary MABL) is used for BD-RE discs. Melting the material with a very high power beam turns it into an amorphous state with low reflectivity, while heating at a lower power erases it back to a crystalline state with high reflectivity.

In BD-RE discs, the data layers are surrounded by a pair of dielectric Zinc Sulfur-Silicon Dioxide layers. An adhesive spacer layer and a semi-reflective layer are used for multi-layer discs. The recording and dielectric layers are all deposited using Sputtering. On multi-layer BD-RE discs, each GeSbTe recording layer is progressively thinner. So the first layer (L0) is 10 nm thick, L1 is 7.5 nm thick, L2 is 6 nm thick, and so on. The silver alloy reflective layers that are behind each recording layer also become progressively thinner, so the L0 silver layer is 10 nm thick, the L1 layer is 9 nm thick, the L2 layer is 7 nm thick, and so on. The separation layers that separate the recording layers from one another also progressively become thinner.

BD-R LTH (low to high)

BD-R LTH is a write-once Blu-ray Disc format that features an organic dye recording layer. "Low To High" refers to the reflectivity changing from low to high during the burning process, which is the opposite of normal Blu-rays, whose reflectivity changes from high to low during writing. The advantage of BD-R LTH is it can protect a manufacturer's investment in DVD-R/CD-R manufacturing equipment because it does not require investing in new production lines and manufacturing equipment. Instead, the manufacturer only needs to modify current equipment. This is expected to lower the cost of disc manufacturing.

Old Blu-ray players and recorders cannot utilize BD-R LTH; however, a firmware upgrade can enable devices to access BD-R LTH. 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 LTH BD drives in Spring 2008. Sony upgraded the PlayStation 3 firmware enabling BD-R LTH reading in March, 2008.

In 2011, France's Ministry of Culture and Communication conducted a study on the suitability of data archival of LTH (low to high) discs compared to HTL (high to low) discs. The data they collected indicated that the overall quality of LTH discs is worse than HTL discs.

See also

• Blu-ray
• Optical disc authoring
• List of optical disc manufacturers
• CD-R, DVD±R
• DVD recordable

External links

• Blu-ray Player BD-R Compatibility Chart