Lossy compression

Lossy compression is a type of data compression method for reducing the size of digital media files at the expense of quality. Using lossy compression, a user can sacrifice the fidelity of a file in order to achieve a smaller file size. Lossy compression techniques are commonly used in digital audio and video formats, image formats, and the transmission of electronic text.

When a file is compressed using a lossy technique, some of the data is discarded and the file is compressed as a result. This allows for a much larger reduction in file size, but can lead to reduced quality in the file itself. Lossy compression is preferable to lossless compression when a reduction in file size is needed, such as when sharing digital files over the internet or when there is limited storage space.

The most commonly used lossy compression technique is JPEG (Joint Photographic Experts Group), which is used for compressing digital photographs. Instead of compressing the entire image, as is done in lossless methods, JPEG will look for areas of an image that are similar and discard them. This results in a much smaller file size without sacrificing as much of the image quality. Additionally, the degree of compression used in JPEG can be adjusted to bring the file size down even further.

Lossy compressed audio formats such as mp3 (MPEG-1 Audio Layer 3) or AAC (Advanced Audio Coding) are some of the most widely used audio formats available. In a lossily compressed audio file, samples are analyzed in order to determine which frequencies can be eliminated without compromising the quality of the track. The compression algorithm then removes those frequencies, resulting in a much smaller file.

Although lossy compression can drastically reduce file size, it can also introduce artifacts into the data. These artifacts can be audible with audio, visible with images, or noticeable in text files. As the degree of compression increases, the quality of the file decreases. The degree of compression should be customized to the user’s needs in order to achieve an optimal file size without sacrificing too much of the file’s original quality.