Columbia ISA
Audio – Video


Glossary

HDTV

DVD-intro

DVD-tech

DVD-faq

DVD formats

DVD rec



DVD 

DVD Physical Specifications


The DVD technical specifications are contained in five books A to E published by the DVD Forum.
Book Name Physical File System Appli- cation Ver

A

 DVD-ROM Read-only ISO 9660 + UDF undefined  1.01

B

 DVD-Video Read-only UDF MPEG-2 video 1.1

C

 DVD-Audio
 Read-only UDF high quality audio 1.2

D

 DVD-R
 Write once UDF not defined 2.0

E

 DVD-RAM & DVD-RW
 Re-writable UDF not defined 2.0

Physical Parameters

The table below summarizes the physical parameters of DVD and compares them with those of CD and CD-ROM.

Parameter CD DVD Comments
# layers 1 single dual see Disc Formats
Thickness (mm) 1.2 0.6 2 x 0.6 mm
# sides 1 2 DVD substrates bonded
Track pitch 1.6 0.74 microns
Min pit length 0.83 0.4 0.44 microns
Scan velocity 1.3 3.49 3.84 m/sec
Wavelength (nm) 780 635/650 red laser for DVD
Numerical aperture 0.45 0.6  
Modulation EFM 8 to 16 EFM is 8 to 17
Error protection CIRC RSPC Block protection for DVD
3rd layer ECC CD-ROM No Not needed for DVD
Subcode/Tracks Yes No Not needed for DVD

DVD Sector Structure

The data on a DVD disc are organized as sectors of 2048 bytes plus 12 bytes of header data. 

 
Header User Data
ID IED CPR_MAI
12 bytes 2048 bytes
DVD Sector Structure

The header contains the following information:

 
Field Bytes Content
ID 4

Sector type, data type, layer number and sector number
IED 2

ID error correction code
CPR_MAI 6

Copy protection and region code (for DVD-Video)

Blocks of 16 sectors are error protected using RSPC  (Reed Solomon Product Code), which is block oriented and is more suitable for re-writable discs (with packet writing) than CIRC which does not use a block format. The PI and PO data are parity bytes calculated horizontally and vertically over the data bytes.

In addition DVD uses an 8 to 16 modulation scheme giving pit lengths of 3 to 14 (minimum to maximum length) compared with CD's 3 to 11 with EFM modulation.

Burst Cutting Area

The Burst Cutting Area (BCA) is an annular area within the disc hub where a bar code can be written for additional information such as serial numbers. The BCA can be written during mastering and will be common for all discs from that master or, more usually, will be written using a YAG laser to 'cut' the barcode into the aluminum reflective layer of the finished disc.

The data stored in the BCA can be from 12 bytes to 188 bytes in steps of 16 bytes. The Divx format used BCA to uniquely identify every disc. BCA can be used as a unique, tamper-proof means of identifying individual discs.

  

 

 



Learn about the various video formats:
Video formats
 Learn about DVD features:
features

Columbia ISA Audio Video
Empowering consumers through information.
Information offered only for purposes of education and research.
Contact: columbiaisa@yahoo.com