CD

DVD

Disc diameter

120 mm

120 mm

Disc thickness

1.2 mm

1.2 mm

Disc structure

Single substrate

Two bonded
0.6 mm substrates

Laser wavelength

780 nm (infrared)

650 and 635 nm (red)

Numerical aperture

0.45

0.60

Track pitch

1.6 um

0.74 um

Shortest pit/land length

0.83 um

0.4 um

Reference speed

1.2 m/sec. CLV

4.0 m/sec. CLV

Data layers

1

1 or 2

Data capacity

Aprox. 680 megabytes

Single layer: 4.7 gigabytes
Dual layer: 8.5 gigabytes

Reference user data rate

Mode 1: 153.6 kilobytes/sec
Mode 2: 176.4 kilobytes/sec

1,108 kilobytes/sec, nomial

Video CD

DVD-Video

Video data rate

1.44 megabits/sec
(video, audio)

1 to 10 megabits/sec variable
(video, audio, subtitles)

Video compression

MPEG1

MPEG2

Sound tracks

2 Channel-MPEG

Mandatory (NTSC):
2-channel linear PCM;
2-channel/5.1-channel AC-3.
Optional:
up to 8 streams of data available

Subtitles

Open caption only

Up to 32 lanuages