Data Compression

Understanding Data Compression

  • Data Compression is a process that reduces the size of files so that they take up less disk space.
  • The primary aim of this process is to efficiently store and transmit data.
  • The two types of data compression are Lossless compression and Lossy compression.

Lossless Compression

  • Lossless Compression involves reducing the file size without losing any original data.
  • When a file is decompressed after Lossless compression, it is exactly the same as the original before compression.
  • Lossless compression is typically used for text and data files, where loss of words or data could be detrimental.

Lossy Compression

  • Lossy Compression reduces a file by permanently eliminating certain information, especially redundant information.
  • When a file is decompressed after Lossy compression, it isn’t exactly the same as the original. Some data is lost during the process.
  • Lossy compression is commonly used for audio and video files, where a small loss in quality is typically not noticeable.

The Compression Process

  • Compression algorithms replace repeated occurrences of data within a file.
  • RLE (Run Length Encoding) is a simple form of data compression where sequences (runs) of the same data value are stored as a single value and count.
  • Dictionary-based compression, used in formats like ZIP, involves indexing common sequences with a ‘dictionary’.

Benefits and Drawbacks of Data Compression

  • Benefits of data compression include saving disk storage space, reducing the time to transmit files over the internet, and saving bandwidth when streaming.
  • Drawbacks can include the time it takes to compress and decompress data, and the potential loss of data in lossy compression.