Transcode

From Free net encyclopedia

Transcoding is the direct digital-to-digital conversion from one (usually lossy) codec to another. It involves decoding/decompressing the original data to a raw intermediate format (i.e. PCM for audio or YUV for video), in a way that mimics standard playback of the lossy content, and then re-encoding this into the target format.

Transcoding can also refer to recompressing files to a lower bitrate without changing formats.

Compression artifacts are cumulative, therefore transcoding between lossy codecs causes a progressive loss of quality with each successive generation. For this reason, it is generally discouraged unless unavoidable. For instance, if an individual owns a digital audio player that does not support a particular format (i.e. Apple iPod and Ogg Vorbis), then the only way for the owner to use content encoded in that format is to transcode it to a supported format. It is better to retain a copy in a lossless format (such as TTA, FLAC or WavPack), then encode directly from the lossless source file to the lossy formats required.

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Software

Transcode is also a free tool for video conversion released under the GNU General Public License. It can be used to convert between many different video and audio codecs and packaging formats.

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