 Original Image ( lossless PNG, 60.1 KiB size) - uncompressed is 108.5 KiB
 Low Compression (84% less information than uncompressed PNG, 9.37 KiB)
 Medium Compression (92% less information than uncompressed PNG, 4.82 KiB)
 High Compression (98% less information than uncompressed PNG, 1.14 KiB) 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 and internet telephony. On the other hand lossless compression is preferred for text and data files, such as bank records, text articles, etc. Image File history File links No higher resolution available. ...
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. ...
PNG (Portable Network Graphics), sometimes pronounced as ping, is a relatively new bitmap image format that is becoming popular on the World Wide Web and elsewhere. ...
A kibibyte (a contraction of kilo binary byte) is a unit of information or computer storage, commonly abbreviated KiB (never kiB). 1 kibibyte = 210 bytes = 1,024 bytes The kibibyte is closely related to the kilobyte, which can be used either as a synonym for kibibyte or to refer to...
Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
Source coding redirects here. ...
Look up Multimedia in Wiktionary, the free dictionary. ...
Audio can mean: Sounding that can be heard. ...
For other uses, see Video (disambiguation). ...
Image of the Wikimedia Commons logo. ...
Streaming media is multimedia that is continuously received by, and normally displayed to, the end-user while it is being delivered by the provider. ...
IP Telephony, also called Internet telephony, is the technology that makes it possible to have a telephone conversation over the Internet or a dedicated Internet Protocol (IP) network instead of dedicated voice transmission lines. ...
Lossless data compression is a class of data compression algorithms that allow the original data to be reconstructed exactly from the compressed data. ...
Most 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. Generation loss refers to the loss of quality between subsequent copies of data. ...
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. ...
Types There are two basic lossy compression schemes: - In lossy transform codecs, samples of picture or sound are taken, chopped into small segments, transformed into a new basis space, and quantized. The resulting quantized values are then entropy coded.
- In lossy predictive codecs, previous and/or subsequent decoded data is used to predict the current sound sample or image frame. The error between the predicted data and the real data, together with any extra information needed to reproduce the prediction, is then quantized and coded.
In some systems the two techniques are combined, with transform codecs being used to compress the error signals generated by the predictive stage. A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. ...
Quantized signal Digital signal In digital signal processing, quantization is the process of approximating a continuous range of values (or a very large set of possible discrete values) by a relatively-small set of discrete symbols or integer values. ...
In information theory an entropy encoding is a data compression scheme that assigns codes to symbols so as to match code lengths with the probabilities of the symbols. ...
Quantized signal Digital signal In digital signal processing, quantization is the process of approximating a continuous range of values (or a very large set of possible discrete values) by a relatively-small set of discrete symbols or integer values. ...
Lossy vs. lossless The advantage of lossy methods over lossless methods is that in some cases a lossy method can produce a much smaller compressed file than any known lossless method, while still meeting the requirements of the application. It is important to note all media storage methods are lossy when a live event has been recorded. Recording methods can only capture a small fraction of the total performance. Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. ...
Lossy methods are most often used for compressing sound, images or videos. This is because these types of data are intended for human interpretation where the brain can easily "fill in the blanks" or see past very minor errors or inconsistencies. The compression ratio (that is, the size of the compressed file compared to that of the uncompressed file) of lossy video codecs is nearly always far superior to that of the audio and still-image equivalents. Audio can often be compressed at 10:1 with imperceptible loss of quality, and video can be compressed immensely (e.g. 300:1) with little visible quality loss. Lossily compressed still images are often compressed to 1/10th their original size, as with audio, but the quality loss is more noticeable, especially on closer inspection.
When a user acquires a lossily-compressed file, (for example, to reduce download-time) the retrieved file can be quite different from the original at the bit level while being indistinguishable to the human ear or eye for most practical purposes. Many methods focus on the idiosyncrasies of the human physiology, taking into account, for example, that the human eye can see only certain wavelengths of light. The psychoacoustic model describes how sound can be highly compressed without degrading the perceived quality of the sound. Flaws caused by lossy compression that are noticeable to the human eye or ear are known as compression artifacts. This article is about the unit of information. ...
Human Physiology is the science of the mechanical, physical, and biochemical functions of humans in good health, their organs, and the cells of which they are composed. ...
Psychoacoustics is the study of subjective human perception of sounds. ...
A compression artifact (or artefact) is the result of an aggressive data compression scheme applied to an image, audio, or video that discards some data which is determined by an algorithm to be of lesser importance to the overall content but which is nonetheless discernible and objectionable to the user. ...
Methods
Graphics
Image Cartesian Perceptual Compression (abbreviated CPC) is a file format specifically designed for the compression of black-and-white raster images in document image storage and transmission systems. ...
DjVu (pronounced déjà vu) is a computer file format designed primarily to store scanned images, especially those containing text and line drawings. ...
Fractal compression is a lossy compression method used to compress images using fractals. ...
Hold-and-Modify (more commonly known as HAM) is a screenmode of the Amiga micro computer. ...
This article is about the family of home computers. ...
ICER is a wavelet-based image compression file format used by the NASA Mars Rovers. ...
JPEG 2000 is a wavelet-based image compression standard. ...
JPG redirects here. ...
JPEG 2000 is a wavelet-based image compression standard. ...
JBIG2 is an image compression standard for bi-level images, developed by the Joint Bi-level Image Experts Group. ...
PGF (Progressive Graphics File) is a wavelet-based bitmapped image format that employs lossless and lossy data compression. ...
Wavelet compression is a form of data compression well suited for image compression (sometimes also video compression and audio compression). ...
Video H.261 is an 1990 ITU video coding standard originally designed for transmission over ISDN lines on which data rates are multiples of 64 kbit/s. ...
H.263 is a video codec designed by the ITU-T as a low-bitrate encoding solution for videoconferencing. ...
H.264 is a standard for video compression. ...
MNG (pronounced in IPA) is a public file format for animated images. ...
Motion JPEG, also known as M-JPEG, is a video file format consisting of a sequence of individual JPEG images; unlike other video compression algorithms, each frame is an image unto itself. ...
MPEG-1 defines a group of Audio and Video (AV) coding and compression standards agreed upon by MPEG (Moving Picture Experts Group). ...
MPEG-2 is a standard for the generic coding of moving pictures and associated audio information [1]. It is widely used around the world to specify the format of the digital television signals that are broadcast by terrestrial (over-the-air), cable, and direct broadcast satellite TV systems. ...
MPEG-4 is a standard used primarily to compress audio and visual (AV) digital data. ...
Ogg is an open standard for a free container format for digital multimedia, unrestricted by software patents and designed for efficient streaming and manipulation. ...
Theora is a video codec being developed by the Xiph. ...
The Sorenson codec (also known as Sorenson Video Codec 3 or SVQ3) is a digital video codec devised by the company Sorenson Media and used by Apples QuickTime and the newest version of Macromedia Flash, a special version called Sorenson Spark. ...
VC-1 is the informal name of the SMPTE 421M video codec standard initially developed by Microsoft. ...
Audio
Music MPEG-4 AAC DRM encoding as used in the iTunes Store Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. ...
Apple Inc. ...
Pulse-code modulation (PCM) is a modulation technique. ...
ATRAC (Adaptive TRansform Acoustic Coding) is a family of proprietary audio compression algorithms used to store information on MiniDiscs and other Sony-branded audio players. ...
Description Dolby Digital is the trademark for Dolby Laboratories AC-3 audio coding system. ...
MP2 can refer to: MP2 (format) audio files This is a disambiguation page, a list of pages that otherwise might share the same title. ...
For other uses, see MP3 (disambiguation). ...
Musepack or MPC is an open source lossy audio codec, specifically optimized for transparent compression of stereo audio at bitrates of 160-180 kbit/s. ...
Ogg is an open standard for a free container format for digital multimedia, unrestricted by software patents and designed for efficient streaming and manipulation. ...
Vorbis is an open source, lossy audio codec project headed by the Xiph. ...
Windows Media Audio (WMA) is an audio data compression technology developed by Microsoft. ...
Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ...
Speech CELP stands for Code Excited Linear Prediction and is a speech coding algorithm described by the US Federal Standard FIPS 1016. ...
G.711 is an ITU-T standard for audio companding. ...
G.726 is ITU-T speech codec operating at bit rates of 16-40 kbit/s. ...
Harmonic and Individual Lines and Noise (HILN) is a parametric codec for audio. ...
Adaptive Multi-Rate (AMR) is a Audio data compression scheme optimized for speech coding. ...
Speex is a free software speech codec that may be used on VoIP applications and podcasts. ...
Other data Technically, reducing text size by removing all vowels can be considered a lossy compression as well. The text is usually still readable from the context given by the consonants. Researchers have also (half-jokingly) performed lossy compression on text by either using a thesaurus to substitute short words for long ones, or generative text techniques [1], although these sometimes fall into the related category of lossy data conversion. ng Note: This page contains IPA phonetic symbols in Unicode. ...
In articulatory phonetics, a consonant is a sound in spoken language that is characterized by a closure or stricture of the vocal tract sufficient to cause audible turbulence. ...
A lossy data conversion method is one where converting data between one storage format and another displays data in a form that is close enough to be useful, but may differ in some ways from the original. ...
See also Source coding redirects here. ...
Image of Lena Söderberg famously used in many image processing experiments. ...
Lossless data compression is a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data. ...
A compression artifact (or artefact) is the result of an aggressive data compression scheme applied to an image, audio, or video that discards some data which is determined by an algorithm to be of lesser importance to the overall content but which is nonetheless discernible and objectionable to the user. ...
The following is a list of codecs. ...
Notes - ^ I. H. WITTEN, et al.. Semantic and Generative Models for Lossy Text Compression (PDF). The Computer Journal. Retrieved on 2007-10-13.
Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ...
is the 286th day of the year (287th in leap years) in the Gregorian calendar. ...
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