Codec, Whats a Codec A Technophobes Guide to Digital Video

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Codec, Whats a Codec? A Technophobes Guide to
Digital Video

• Joann Flick
• Agency for Instructional Technology

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A Very Brief Overview of Digital Video
Transmission Technologies

• What the heck
• Why you need to know
• How to use this information and explain it to
  others

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• Kbps
• Mbps
• Modem
• Codec
• MPEG
• ISDN
• DSL
• LAN
• WAN
• T-1
• POTS

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POTS Plain Old Telephone Service

• AKA dial-up connection
• What most people use from home to access the
  Internet (really)
• Size soda straw 28-56 Kbps

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ISDN/DSL

• ISDN Integrated Systems Digital Network (64
  Kbps)
• DSL Digital Subscriber Line (512 Kbps)
• Both use regular phone lines to bring
  higher-speed connectivity
• Size garden hose (at least 3 times to 10 times
  as big as the soda straw)

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T-1

• A long-distance, point-to-point, dedicated line
  that usually connects a computer network to the
  Internet
• 1.544 Mbps
• Size a drainage pipe (3-10 times the size of the
  garden hose)

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LAN/WAN Ethernet

• Using copper wire(twisted pair) or coaxial cable,
  the most popular way of networking a bunch of
  computers within a building or campus
• Fast, broad pipeline 10-100 Mbps
• Size a drainage culvert (6-60 times the size of
  the T-1 line)

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Wireless LAN

• Everything a LAN/WAN is, except the wires
• Uses transmitters and receivers to move data
  around a network
• 802.11

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Cable Broadband

• Using a digital device, access to the Internet
  across existing cable TV service lines
• Hefty bandwidth capacity up to 500 Mbps
• Size A big drainage culvert (twice to 5 times
  the size of Ethernet)

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Datacasting

• Uses a digital TV signal to send data to a
  receiving device connected to a computer
• Its a DOWNSTREAM delivery system
• Lots of capacity (10-15 MBPS)
• Size drainage Culvert

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Codec
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Video Codec

• Codec Compression-Decompression or
  Coder-Decodera program for compressing all the
  millions of pixels in a video file so that it can
  be transmitted, decoded, and viewed. Not every
  single pixel of every single frame is
  transmitted, the Codec uses a kind of short hand
  to transmit enough info to construct the moving
  image.

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Types of Codecs

• MPEG (1, 2, 4, 7and more)
• Quicktime
• MP3 (for audio)

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Codecs how do they look?
48k
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Codecs How do they look?
1.5M
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48K
1.5 M
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Why?
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Why?
Less information transmitted less bandwidth
consumed