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.