DVD Technical Guide

Review Pages

1. DVD History
2. Concepts and Structure of the DVD Format
3. The Future of DVD
4. Design Concept of the Physical Specification
5. Features of the DVD Physical Specification
6. The DVD Data Format
7. Read-Only Disc File Format
8. Video Format
9. Video Format - Page 2
10. Video Format - Page 3
11. Audio Format
12. Audio Format - Page 2
13. Audio Format - Page 3
14. Audio Format - Page 4
15. Audio Format - Page 5
16. DVD-R and DVD-RW
17. DVD-R and DVD-RW - Page 2
18. DVD-R and DVD-RW - Page 3
19. DVD-R and DVD-RW - Page 4
20. DVD-RAM
21. DVD-RAM - Page 2
22. DVD-RAM - Page 3
23. DVD-RAM - Page 4

4.3 Presentation Data

Within the presentation data, video, audio, and sub-picture data are multiplexed with a portion of the navigation data in conformance with the MPEG-2 program stream specification. The structure of pack and packet comply with this specification, and each pack contains 2048 bytes. The multiplex rate (mux_rate) is 10.08 Mbps.

4.3.1 Video

data compression method	MPEG2, MPEG1
bit rate	9.8 Mbps max. (MPEG-2) 1.856 Mbps max. (MPEG-1)
GOP size	36 fields max.
screen display
TV systems	525/60, 625/50
aspect ratios	4:3, 16:9
modes	pan & scan, letterbox
user data	closed captions

Video data exists as one stream of data compressed according to the MPEG-2 video format. The maximum bit rate is 9.8 Mbps, and the stream supports variable bit rate to provide high-quality video.
DVD-Video is compatible with both NTSC and PAL formats, and supports both 4:3 and 16:9 aspect ratios. The title creator can specify either "pan & scan" (cutting off a portion of the image) or "letterbox" (showing then entire image with black bands at the top and bottom of the screen) format to provide output of 16:9 aspect ratio video content at an aspect ratio of 4:3.

4.3.2 Audio

	Linear PCM	Dolby Digital*	MPEG Audio
Fs	48kHz, 96kHz	48kHz	48kHz
Qb	16 / 20 / 24 bits	Compressed	Compressed
Bit-rate (per 1stream)	MAX 6.144Mbps	MAX 448kbps	MAX 912kbps

* Trademarks of Dolby Laboratories Licensing CorporationThree audio formats are allowed by the DVD specification: linear PCM, Dolby Digital, and MPEG audio. Each title can have up to eight audio streams. The streams are distinguished by attributes such as language. Each stream is comprised of multiple channels. For instance, the Dolby Digital format supports 5.1 channels.When using the linear PCM format, DVD audio can support a sampling rate of up to 96 kHz with up to 24 bits per sample, providing audio quality which far surpasses that of CDs. For Dolby Digital or MPEG audio, the sampling rate is 48 kHz. MPEG audio supports MPEG-2 audio with multi-channel capability.

4.3.3 Sub-picture

data format	run-length encoding, two bits per pixel
data size per picture	52 kB max.
resolution	720X480 (525/60) 720X576 (625/50)
display color	16 colors (specified per PGC)
display control	change pixel contrast and color change display area (move) change display data (scroll up/down) force display

Sub-picture data is a concept peculiar to DVD, and consists of defining data, such as subtitles, menus, and karaoke lyrics, which is overlaid as a bitmap onto the main video content. This data is compressed using run-length encoding. Up to 32 streams of sub-picture data can exist for each title. Sub-picture streams are distinguished by attributes such as language.Sub-picture data can be displayed in up to 16 different colors. For applications such as subtitles, the user controls the display of sub-picture data. DVD also supports the forcing of sub-picture data display, for example if the title creator wants to force a menu to be displayed at a particular point in the content stream.

Source: http://www.pioneer.co.jp/crdl/tech/index-e.html