Manual

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17
3.5 Data Compression Factor (COMP tab)
All of the available codecs compress an audio data bitstream. Different codecs compress
using different algorithms, and will compress to very different degrees.
HE-AAC is optimized for the best quality at very low bit-rates, and will produce very small
files (potentially around one hundredth of the input file size). Lossless encoders, in contrast,
are not so effective at compressing data, and will produce files that are around half the size of
the input. The familiar mp3 codecs produce compression factors of typically around 12.
Selecting the COMP tab (see below) gives a visual indication of the compression ratios
pertinent to the selected codecs:
A yellow asterisk (if present) indicates that the figure is approximate. This will be the case
for lossless encoders and variable bitrate (VBR) encoders.
Remember that using perceptual coding is always a trade-off between more accurate
reproduction of the original on the one hand, against a higher compression ratio and smaller
files on the other hand.
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