Transparency (data compression): Difference between revisions

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In [[data compression]] and [[psychoacoustics]], '''transparency''' is the result of [[lossy data compression]] accurate enough that the compressed result is [[perception|perceptually]] indistinguishable from the uncompressed input. In other words, transparent compression has no or imperceptibleperceptible [[compression artifact]]s.

A '''transparency threshold''' is a given value at which transparency is reached. It is commonly used to describe compressed data bitrates. For example, the transparency threshold for MP3 to Linear PCM audio is said to be between 175 and 245&nbsp;kbit/s, at [[44.1 kHz|44.1&nbsp;kHz]], when encoded as [[Variable_bitrate|VBR]] MP3 (corresponding to the -V3 and -V0 settings of the highly popular [[LAME]] MP3 encoder).<ref name="LAME Recommended Encoder Settings">{{citation

| title = LAME Recommended Encoder Settings | date =

| publisher = hydrogenaudio | format =

| url = http://wiki.hydrogenaud.io/index.php?title=LAME | accessdate = }}</ref> This means that when an MP3 that was encoded at those bitrates is being played back, it is indistinguishable from the original PCM, and the compression is transparent to compressionthe listener.

Transparency, like sound or video quality, is subjective. It depends most on the listener's familiarity with digital artifacts, their awareness that artifacts may in fact be present, and to a lesser extent, the compression method, [[bit-rate]] used, input characteristics, and the listening/viewing conditions and equipment. Despite this, sometimes general consensus is formed for what compression options "should" provide transparent results for most people on most equipment. Due to the subjectivity and the changing nature of compression, recording, and playback technology, such opinions should be considered only as rough estimates rather than established fact.