data compression

4 Results

Dictionary

data compression

Encoding data to take up less storage space and less bandwidth for transmission. Digital data are compressed by finding repeatable patterns of binary 0s and 1s. The more patterns can be found,...

Dictionary

Definition: data compression

Encoding data to take up less storage space and less bandwidth for transmission. Digital data are compressed by finding repeatable patterns of binary 0s and 1s. The more patterns can be found, the more the data can be compressed. Text can typically be compressed to approximately 40% of its original size, and graphics files from 20% to 90%. Some files compress very little. It depends entirely on the type of file and compression algorithm used. See archive and archive formats.

Compression Sparked a Revolution
Data compression is an important part of the digital world. For example, MPEG compression allowed a two-hour movie to fit on a DVD disc. Compression enables voice and video calls over the Internet. MP3 compression sparked a revolution by enabling people to download a song from the Internet 10 times faster than the original CD format. See codec.

Dictionary and Statistical Methods
Two major ways to compress data are the dictionary and statistical methods. The widely used dictionary method creates a list of repeatable phrases. For example, GIF images and ZIP and JAR archives are compressed with this method (see LZW). The statistical method converts characters into variable length strings of bits based on frequency of use (see Huffman coding).

Lossless Vs. Lossy
When text and financial data are compressed, they must be decompressed back to a perfect original, bit for bit. This is known as "lossless compression." However, audio and video can be compressed down to as little as 5% of its original size using "lossy compression." Some of the data are actually lost, but the loss is not noticeable to the human ear and eye. See lossless compression, codec examples and capacity optimization.


data compression





Sponsored White Papers, Webcasts & Resources

  • Improve the Performance of SAN Storage

    Check out this white paper to learn how to improve and maintain the performance of your SAN by adding defragmentation tools into your computing. Keep reading to learn more.

  • IBM picks up data compression company Storwize

    IBM has acquired Storwize, a privately held company that focuses on data compression.

    Blog posts | July 29, 2010 7:30am PDT

  • IBM's latest DB2 woos Oracle customers

    Big Blue released the latest version of its database management system DB2, version 9.7, with new features that include the ability for the database to run applications written for Oracle and...

    News items | April 23, 2009 9:54am PDT

  • Home data compression you can see

    iTunes has rendered my CD cases obsolete A few weeks ago I realized that I had enough disk space - 1 TB - on my desktop to rip all my CDs as 320 Kb/s MP3s. I had also built a $50 DVD burner so I...

    Blog posts | October 9, 2007 4:42pm PDT

  • Data compression you can see

    Compression even your Mom will love The compression ratio is better than 4:1. Try that with Lempel-Ziv! I'm talking about compressing your CD collection - not electronically, buy physically. I've...

    Blog posts | September 4, 2007 9:49am PDT

Additional Results

ie8 fix

The best of ZDNet, delivered

ZDNet Newsletters

Get the best of ZDNet delivered straight to your inbox

Facebook Activity

ie8 fix