What is data compression?
Data compression is the process of encoding large files in order to make them smaller and take up less space.
What is a data compression ratio?
Data compression ration (also known as compression power), is a computer-science term used to reduce the amount of data representation size produced by a data compression algorithm.
Why is data compression an important technique for the online world?
It reduces the amount of data stored on a hard disk or transmission of bandwidth.
What is the difference between Lossy and Lossless data compression?
In Lossy data compression, the decompressed data does not have to be exactly the same as the original data. Instead, some amount of distortion is tolerated.
When the compression is Lossless there is no distortion. It is exactly the same as the original.
Which method offers the greatest compression ratio?
Lossy data compression video codes generally provide the greatest compression ratio.
The video can be compressed at 100:1 ratio while audio and still images can often be compressed at 10:1.
The compression rate of lossy is about 5-6% while Lossless compression is about 50-60%
Why is human psychology and perception an important factor in methods of Lossy compression?
Because very little of the original file is still there. The human eye simply “fills in the blanks” if parts of audio or imagery is lost. Without the perception of the human eye we would see how much of a difference there is from the original. If we were able to see how much information is being distorted we would see the errors in a Lossy compression.
Name Lossy file formats for audio, still image and video format.
Audio:
MP3 - .mp3
MPEG-1 - .mp2
WMA - .wma
Still Image:
CPC - .cpc
DjVu - .djvu .djv
JPEG - .jpg .jpeg
Video:
DV - .dv .dif
MPEG-1 - .mpg .mpeg .mp2 .mp3 .mpa
MPEG-2 - .mpg .mpeg .mp2 .mp3 .m2v
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