# China Blue High-definition Disc

> optical disc format based on HD DVD

**Wikidata**: [Q1022966](https://www.wikidata.org/wiki/Q1022966)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/China_Blue_High-definition_Disc)  
**Source**: https://4ort.xyz/entity/china-blue-high-definition-disc

## Summary
China Blue High-definition Disc (CBHD) is an optical disc format based on HD DVD technology. It is a subclass of optical storage media, designed as a machine-readable medium for physical data distribution. The format is also known by the aliases CH-DVD and China Blue High Definition Disc.

## Key Facts
- **Aliases**: CBHD, China Blue High Definition Disc, CH-DVD.
- **Classification**: Subclass of **optical disc** (flat, circular disc encoding binary data).
- **Core Technology**: Format based on **HD DVD**.
- **Wikidata Description**: Defined as an "optical disc format based on HD DVD."
- **Encyclopedia Coverage**: Has a Wikipedia presence across 13 languages, including English, Chinese, German, Spanish, French, Japanese, Korean, and Russian.
- **Freebase ID**: /m/03bybdj.

## FAQs
### What is China Blue High-definition Disc (CBHD)?
CBHD is an optical disc format derived from HD DVD. It falls under the broader category of optical storage, utilizing flat, circular discs to store binary data.

### What are the other names for CBHD?
The format is also referred to as China Blue High Definition Disc and CH-DVD.

### How is CBHD related to standard optical discs?
CBHD is a specific subclass of the optical disc family. Like standard optical discs, it uses laser-readable technology to encode data, but it specifically builds upon the foundation of the HD DVD format.

## Why It Matters
China Blue High-definition Disc represents a specialized evolution within the optical disc ecosystem, tailoring the HD DVD standard for specific markets. As a variant of optical media, it inherits the benefits of the broader format category—specifically the ability to distribute high-definition physical media without requiring power to retain data. While global high-definition standards largely shifted toward Blu-ray, CBHD serves as a distinct branch of optical technology, illustrating the diversification of storage formats to meet regional or specific technical requirements. Its existence highlights the adaptability of the optical disc platform, which supports various families ranging from CDs and DVDs to archival-grade storage solutions.

## Notable For
- **HD DVD Derivation**: Distinct from the dominant Blu-ray standard, being directly based on the HD DVD format.
- **Global Documentation**: Notable for having encyclopedia entries in 13 different languages, indicating broad international recognition or relevance.
- **Optical Classification**: Recognized formally as a machine-readable medium and removable media within knowledge bases like Wikidata and Freebase.

## Body

### Definition and Lineage
China Blue High-definition Disc (CBHD) is an optical disc format explicitly identified as being based on **HD DVD**. It is categorized hierarchically as a subclass of the **optical disc**, placing it within the family of machine-readable media used for computer storage and data distribution.

### Technical Context and Parent Class
As a subclass of the optical disc, CBHD shares the fundamental characteristics of optical storage media.
- **Physical Structure**: Like all optical discs, it is defined as a flat, usually circular disc.
- **Data Encoding**: It utilizes the standard optical methodology of encoding binary data via microscopic pits and lands that are read by a laser.
- **Material Composition**: While specific material details for CBHD are not provided in the source, optical discs generally consist of a polycarbonate substrate with a reflective layer (typically aluminum or gold) and a protective lacquer coating.

### Standards and Identifiers
The entity is formally recognized in major knowledge graphs and structural databases:
- **Wikidata**: Classified under the description "optical disc format based on HD DVD."
- **Freebase**: Assigned the identifier `/m/03bybdj`.
- **Wikipedia**: The entity maintains a sitelink count of 13, corresponding to its presence across various language editions including German (de), English (en), Spanish (es), French (fr), Italian (it), Japanese (ja), Korean (ko), Dutch (nl), Norwegian (no), Portuguese (pt), Russian (ru), Swedish (sv), and Chinese (zh).

## References

1. Freebase Data Dumps. 2013