BDROM

BD-ROM stands for Blu-ray Disc Read-Only Memory. It is a read-only format within the Blu-ray Disc standard that contains pre-recorded data and is produced through replication rather than written by end users. The primary use of BD-ROM is to store video content as BD-Video discs, but the format also accommodates non-video data such as software, games, and large data collections on BD-ROM data discs.

Typical BD-ROM capacities are 25 GB per layer, with common discs offering 25 GB (single-layer) or 50 GB (dual-layer). Extended-capacity formats exist under the BD-XL specification, which can reach 100 GB or 128 GB in triple- or quad-layer configurations; these higher-capacity discs are less common and mainly used for data applications rather than standard cinema releases.

Content on BD-ROM can be structured for video or data. BD-Video discs use the Blu-ray movie format with features such as menus, chapters, subtitles, and interactive content powered by BD-J (Java). Copy protection is commonly employed, including AACS, and BD-Video discs are typically region coded (A, B, or C) to control distribution across regions. BD-ROM data discs follow standard data file systems, commonly ISO 9660/Joliet and UDF, and may present the BDMV and CERT directory structure on movie discs.

Manufacturing and use: BD-ROM discs are produced by replication in glass mastering facilities and are designed for one-way playback on compatible Blu-ray players and drives. They are distinct from recordable BD formats (BD-R and BD-RE), which are writable by end users. BD-ROM remains a cornerstone for licensed movie releases and other pre-recorded content within the Blu-ray ecosystem.