Sonnox Fraunhofer Pro-Codec User Manual
Page 36
5.9 HD-AAC
5 THE PRO-CODEC PLUG-IN
Whatiftheinputsignalisnotcorrectlyprepared?
HD-AAC 24 bit with
INCORRECT or NO dither and truncation prior to the Plug-In. HD-AAC 24
bit internal dither is
DISABLED.
HD-AAC 16 bit with
INCORRECT or NO dither and truncation prior to the Plug-In. HD-AAC 16
bit internal dither is
DISABLED.
In these cases, it is clear that the HD-AAC truncation to 16/24 bits is causing truncation
distortion.
Note:
The HD-AAC processing will still be lossless to 16/24 bits, however, the signal that is
losslessly encoded has already been distorted prior to the encoder input, so is not an
accurate representation of the signal prior to the Pro-Codec Plug-In!
In these cases, the bottom bits of the bit meter are filled red. This red fill indicates that
truncation distortion is occurring!