Sonnox Fraunhofer Pro-Codec User Manual
Page 80
9.3 CodecSpecifications
9 SPECIFICATIONS
doesn’t support the sample rate at any bit rate, the codec will default to AAC-LC at the
closest bit rate.
To illustrate this behaviour, consider a stereo session at 48 kHz with three codecs
selected. If the session configuration is changed to mono at 32 kHz, the plug-in will make
the following codec selections:
SelectedCodecs
SubstitutedCodecs
Reason
Session
Session
Stereo48kHz
Mono32kHz
Codec1
HE-AAC 128 kbps
HE-AAC 56 kbps
HE-AAC 128 kbps not
supported at 32 kHz.
Codec2
HE-AAC v2 56 kbps
AAC-LC 56 kbps
HE-AAC v2 is stereo
only.
Codec3
HD-AAC 160 kbps
AAC-LC 96kbps
HD-AAC
not sup-
ported at 32 kHz.
To avoid these problems after changing the session configuration, it is advisable when
using affected host applications to press
PLAY, then STOP, before instantiating the
plug-in or loading a plug-in Preset. This will ensure that session sample rate and channel
configuration data are flushed through the plug-in correctly.
It is also advisable to save Presets for the plug-in at a variety of session sample rates and
channel configurations.
To illustrate this further, consider the following examples. WaveLab 7 is used in these
examples because it has the powerful ability to easily select and play files with different
sample rates. Several other applications exhibit the same behaviour.
Example1: Differentsessionsampleratesandcompatiblecodecbitrates
WaveLab 7 is an example of an application that only provides session configuration
information to a plug-in when there is an active audio data stream (i.e. the transport is set
to play).
Using WaveLab 7, make three mono 24 bit wav files available via the tabbed windows in
the audio file workspace. One is 32 kHz, and is currently selected and playing. The
unselected tabs have a 44.1 kHz wav file and a 22.05 kHz wav file available.