A lossy data compression method is one where compressing a file and then decompressing it retrieves a file that may well be different to the original, but is "close enough" to be useful in some way. Used a lot on the Internet and especially in Streaming_Media applications
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.
Lossy methods are most often used for compressing sound or images.
In these cases, the retrieved file can be quite different to 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 anatomy, taking into account, for example, that the human eye can see only certain frequencies of light. The
psychoacoustic model describes how sound can be highly compressed without degrading the quality of the sound.
Lossy methods for still image compression:
Lossy methods for moving image compression:
- MNG (supports JPEG sprites)
- Flash (also supports JPEG sprites)
Lossy methods for general music:
- Ogg Vorbis (noted for its lack of patent restrictions)
Lossy methods for speech:
Lossy methods for geometry data:
Lossy methods for other types of data:
/Talk