Compression -- source

Encoding information using fewer bits than the original representation.

Lossless

• lossless compression reduces bits by identifying and reducing statistical redundancy
  • redundancy measures the fractional difference. It is reduced by compression, or increased for checksums
  • lossless is revertable
  • run length encoding takes advantages of consecutive data elements
  • LZ77 & LZ78 -- TODO

Huffman Coding

Prefix Code is a system which posesses the prefix property, stating that no whole code word in the system is a prefix of any other code word in the system.

• {9, 55} and {5, 95} both satisfy, {5, 59} does not
• prefix codes can be used to send messages without needing markers to delimit words, since the prefix property allows unambiguous decoding

Lossy

• lossy compression reduces bits by removing unnecessary information

Video: Interframe vs. Intraframe

• interframe tracks differences between frames
  • high computation, lots of space optimization
• intraframe compression works on each frame
  • fast to compute final result, more space needed