Compression
Compression refers to a wide variety of processes designed to reduce digital storage requirements and improve data transmission speeds. Compression refers to the difference in size between the uncompressed raw image and the compressed image that is recorded to storage.
- Uncompressed 8-bit digital video stored on 650 MB CD-ROM
- 31 seconds of video
- Recorded 30 fps in 720 x 480 NTSC video
- 8-bit sampling
- 4:2:2: sampling
- Luminance data generated at 10.4 Mbps
- Colour data generated at 10.4 Mbps
- Data rate of 20.8 Mbps
Source
H.R. Wu and K.R. Rao. Digital video image quality and perceptual coding. CRC Press (2005): 3-4.
Statistical redundancy...
Comparison of compression ratios
| Format | Compression ratio |
|---|---|
| Digital Betacam | 2:1 |
| DV | 5:1 |
| Analog Hi8 | 7:1 |
| VHS | 15:1 |
Further reading
H.R. Wu and K.R. Rao. Digital video image quality and perceptual coding. “There is considerable statistical redundancy in the signal.”