Editing Transcoding (section)

==Drawbacks==
The key drawback of transcoding in lossy formats is decreased quality. [[Compression artifact]]s are cumulative, so transcoding causes a progressive loss of quality with each successive generation, known as [[digital generation loss]]. For this reason, transcoding (in lossy formats) is generally discouraged unless unavoidable.

For users wanting to be able to re-encode audio into any format, and for [[digital audio editing]], it is best to retain a master copy in a [[data compression#Audio|lossless format]] (such as [[FLAC]], [[Apple Lossless|ALAC]], TTA, [[WavPack]], and others) that take around half the storage space needed when compared to original uncompressed [[PCM]] formats (such as [[WAV]], and [[Audio Interchange File Format|AIFF]]), as lossless formats usually have the added benefit of having [[meta data]] options, which are either completely missing or very limited in PCM formats. These lossless formats can be transcoded to PCM formats or transcoded directly from one lossless format to another lossless format, without any loss in quality. They can be transcoded into a lossy format, but these copies will then not be able to be transcoded into another format of any kind (PCM, lossless, or lossy) without a subsequent loss of quality.

For [[image editing]] users are advised to capture or save images in a [[raw image format|raw]] or uncompressed format, and then edit a copy of that master version, only converting to lossy formats if smaller file sized images are needed for final distribution. As with audio, transcoding from lossy format to another format of any type will result in a loss of quality.

For [[video editing]], (for video converting), images are normally compressed directly during the recording process due to the huge [[file size]]s that would be created if they were not, and because the huge storage demands being too cumbersome for the user otherwise. However, the amount of compression used at the recording stage can be highly variable, and is dependent on a number of factors, including the quality of images being recorded (e.g. analog or digital, standard def. or high def., etc.), and type of equipment available to the user, which is often related to budget constraints – as highest quality digital video equipment, and storage space, may be expensive. Effectively this means that any transcoding will involve some cumulative image loss, and hence the most practical solution insofar as minimizing loss of quality is for the original recording to be deemed the master copy, and for desired subsequent transcoded versions, which will often be in a different format and smaller file size, to be transcoded only from that master copy.<!--non expert here, this needs expanding/explaining better. --><!--(after edit) still non expert, but perhaps clearer now?-->