A lossy compression method is one where compressing data and then decompressing it retrieves data that may well be different from the original, but is close enough to be useful in some way. Lossy compression is most commonly used to compress multimedia data (audio, video, still images), especially in applications such as streaming media. By contrast, lossless compression is required for text and data files, such as bank records, text articles, etc.
Lossy compression formats suffer from generation loss: repeatedly compressing and decompressing the file will cause it to progressively lose quality. This is in contrast with lossless data compression.
Examples of Lossy video files include MNG, MPEG-1, MPEG-2, MPEG-4 and VC-1. Examples Of Lossy Video Files Next Slide
Lossless compression is used when it is important that the original and the decompressed data be identical, or when no assumption can be made on whether certain deviation is uncritical.
Typical examples are executable programs and source code. Some image file formats, like PNG, GIF, WMV and MP4 use only lossless compression, while others like TIFF and MNG may use either lossless or lossy methods.
It can also be used as
It is important to distinguish between a file format and a codec. A codec performs the encoding and decoding of the raw audio data while the data itself is stored in a file with a specific audio file format. Though most audio file formats support only one audio codec, a file format may support multiple codec's, as AVI does. There are three major groups of audio file formats: Uncompressed audio formats, such as WAV, AIFF and AU; formats with lossless compression, such as FLAC, Monkey’s Audio (filename extension APE), WavPack (filename extension WV), Shorten, Tom's lossless Audio Kompressor (TAK), TTA, ATRAC Advanced Lossless, Apple Lossless and lossless Window Media Audio (WMA). formats with lossy compression, such as MP3, Vorbis, Musepack, ATRAC, lossy Windows Media Audio( WMA) and AAC.
Is an extension of the popular Microsoft WAVE audio format and is the recording format of most file-based non-linear digital recorders used for motion picture and television production.
The purpose of this file format is the addition of metadata to facilitate the seamless exchange of sound data between different computer platforms and applications. It specifies the format of metadata, allowing audio processing elements to identify themselves, document their activities, and permit synchronization with other recordings. This metadata is stored as extension chunks in a standard digital audio WAV file.
WAV Waveform audio format Standard audio file container format used mainly in Windows PCs The WAV format is limited to files that are less than 4 GB in size Uncompressed WAV files are quite large in size, so, as file sharing over the Internet has become popular, the WAV format has declined in popularity.
JPEG stands for ‘Joint Photographic Experts Group’ this file is a lossy format, nearly every digital camera can save images in the JPEG format, which supports 8 bits per colour (red, green, blue) for a 24-bit total, producing relatively small files. When not too great, the compression does not noticeably detract from the image's quality, but JPEG files suffer generational degradation when repeatedly edited and saved
GIF stands for ‘Graphics Interchange Format’ is limited to an 8-bit palette, or 256 colours. This makes the GIF format suitable for storing graphics with relatively few colours such as simple diagrams, shapes, logos and cartoon style images. The GIF format supports animation and is still widely used to provide image animation effects. It also uses a lossless compression that is more effective when large areas have a single colour, and ineffective for detailed images or dithered images .
PNG stands for Portable Network Graphics file format was created as the free, open-source successor to the GIF. The PNG file format supports truecolor (16 million colours) while the GIF supports only 256 colours. The PNG file excels when the image has large, uniformly coloured areas. The lossless PNG format is best suited for editing pictures, and the lossy formats, like JPG, are best for the final distribution of photographic images, because JPG files are smaller than PNG files
The BMP file format (Windows bitmap) handles graphics files within the Microsft Windows OS. Typically, BMP files are uncompressed, hence they are large; the advantage is their simplicity, wide acceptance, and use in Windows programs