Compression

Why do we need to compress files in the first place?

Uncompressed video files are too large and the data rates are too high to transport effectively over a local area network or the Internet, so you need to compress them.

Video Compression

Below is a table showing data rates and storage requirements for different DV media types:

BITSTREAM TYPE

DATA RATE

TIME ON 1 700MB CD‐ROM

 

 

 

Uncompressed high definition (1920 x

745750

7.5 seconds

1080 29.97 fps)

 

 

 

 

 

Uncompressed standard definition

167794

33 seconds

(720 x 486 29.97 fps)

 

 

 

 

 

DV25 (miniDV, DVCAM, DVCPRO)

25000

3 min, 44 seconds

 

 

 

Typical DVD

5000

18 min, 40 seconds

 

 

 

VideoCD

1167

80 minutes

 

 

 

Broadband web video

100‐2000

3 hours, 8 minutes at 500

 

 

Kbps

 

 

 

Modem web video

18‐48

48 hours, 37 minutes at

 

 

 

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Canon XL1 3CCD manual Video Compression