Generation loss refers to the loss of quality between subsequent copies of data. Anything that reduces the quality of the representation when copying, and would cause further reduction in quality on making a copy of the copy, can be considered a form of generation loss. Look up Copy in Wiktionary, the free dictionary Copy may mean: Copy (written) refers to written content in a large number of contexts including magazines and advertising, in contrast to photographs or other elements of layout. ... Quality refers to the inherent or distinctive characteristics or properties of a person, object, process or other thing. ...

Analog generation loss

In analogue systems (including systems that use digital recording but make the copy over an analog connection), generation loss is mostly due to noise and bandwidth issues in cables, amplifiers, mixers, recording equipment and anything else between the source and the destination. Repeated conversion between analog and digital can also cause loss. An analog or analogue signal is any variable signal continuous in both time and amplitude. ... In science, and especially in physics and telecommunication, noise is fluctuations in and the addition of external factors to the stream of target information (signal) being received at a detector. ... Bandwidth is a measure of frequency range, measured in hertz, of a function of a frequency variable. ... A cable is two or more wires bound together which may be bare, covered or insulated. ... An amplifier can be considered to be any device that uses a small amount of energy to control a larger amount, although the term today usually refers to an electronic amplifier. ... In telecommunications a mixer is a frequency mixer. ...

Digital generation loss

Digital technology was invented to minimize generation loss. Copying a digital file gives an exact copy if the equipment is operating properly. This trait of digital technology has given rise to awareness of the risk of unauthorised copying; before digital technology was widespread, a record label, for example, could rest easy in knowing that unauthorised copies of their music tracks were never as good as the originals. A record label is a brand created by companies that specialize in producing, manufacturing, distributing and promoting audio and sometimes video recordings (especially music videos), on various formats including compact discs, LPs, DVD-Audio, SACDs, and cassettes. ...

Techniques that bring back generation loss in digital systems

In digital systems, several techniques, used because of other advantages, may reintroduce generation loss and must be used with caution. Digital circuits are electric circuits based on a number of discrete voltage levels. ...

• "Compression" (more accurately "recoding with a technique that uses fewer bits" ) is often used to minimize storage or communications time used. Lossless compression is, by definition, fully reversible. Lossy compression throws away some of the information which cannot be restored. Ideally, when its use is appropriate, it would only be done once, at a carefully planned spot. Repeated applications of lossy compression and decompression can cause generation loss. Some lossy compression algorithms are much worse than others in this regard. Generation loss caused by lossy compression can be made worse if the parameters used are not consistent across generations. For example, with JPEG, changing the quality setting will cause different quantisation constants to be used, causing a lot of extra loss. Shifting the image by a number of pixels that is not a multiple of the block size will also cause a lot of extra loss. However, copying a digital file as-is, without decompression and recompression, even if it is in a lossy format, incurs no generation loss — the copied file is identical to the original.
• Digital resampling, picture scaling, and other DSP techniques can also introduce artifacts each time they are used. Often, particular implementations fall short of theoretical ideals.

Careful planning of an audio or imaging signal chain from beginning to end and rearranging to minimize multiple conversions is important. Often, arbitrary choices of numbers of pixels and sampling rates for source, destination, and intermediates can seriously degrade digital signals in spite of the potential of digital technology for eliminating generation loss completely. A lossy data 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. ... Flowcharts are often used to represent algorithms. ... A photo of a flower compressed with successively lossier compression ratios from left to right. ... A pixel (pix, 1932 abbreviation of pictures, coined by Variety headline writers + element) is one of the many tiny dots that make up the representation of a picture in a computers memory. ... The term DSP, when used by itself, can refer to: The sterilisation process Dry Sterilisation Process for the cold and fast sterilisation of surfaces. ... Audio can mean: Sound that can be heard. ... Imaging refers to the science of obtaining pictures or more complicated spatial representations, such as animations or 3-D computer graphics models, from physical things. ...

See also

• Editing digital images