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 |
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|
|
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) |
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|
|
|
|
DV25 (miniDV, DVCAM, DVCPRO) | 25000 | 3 min, 44 seconds |
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|
|
Typical DVD | 5000 | 18 min, 40 seconds |
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|
|
VideoCD | 1167 | 80 minutes |
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|
|
Broadband web video | 100‐2000 | 3 hours, 8 minutes at 500 |
|
| Kbps |
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|
|
Modem web video | 18‐48 | 48 hours, 37 minutes at |
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