Sonnox Fraunhofer Pro-Codec - Manual (Page 24)

5.5 Data
Compression
Factor
(COMP Tab) 5 THE PRO-CODEC PLUG-IN
unrepeatable maximum values. The discrepancies in both cases should be minor, and not
all source audio and not all codecs will be affected. So, it is not always possible to trim
exactly while auditioning, because a subsequent pass might have a slightly different
maximum value.
There is a technical reason for this, stemming from the difficulty of synchronizing the start
point of the buffer that is used to input data to the codecs.
Note:
In some situations this will be important and, for those occasions, we recommend
encoding the file offline using the Manager application. Offline encoding is exactly
repeatable however many times the file is encoded.
5.5 Data
Compression
Factor
(COMP Tab)
The COMP tab shows the data compression
ratio for each of the selected codecs.
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). HD-AAC, in contrast, is 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.
A yellow asterisk (if present) indicates that the figure is approximate. This will be the case
for HD-AAC and variable bit rate (VBR) encoders.
Note:
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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