Pro-Codec User Manual

9.3 Codec Specifications 9 SPECIFICATIONS
Selected Codecs Substituted Codecs Reason
Session Session
Stereo 48 kHz Mono 32 kHz
Codec 1 HE-AAC 128 kbps HE-AAC 56 kbps
HE-AAC 128 kbps not
supported at 32 kHz.
Codec 2 HE-AAC v2 56 kbps AAC-LC 56 kbps
HE-AAC v2 is stereo
only.
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.
Example: Different session sample rates and compatible codec bit rates
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.
A Sonnox Fraunhofer Pro-Codec is instantiated and shows the default codec as AAC-LC
192 kpbs. Note the usual default of 256 kbps is not valid for a mono WAV file (see section
9.3.4 for the full table of codec supported sample rates).
If the 22.05 kHz file is selected, and play stopped and re-started, the codec will
automatically select 28 kbps (which is the closest to 192 kbps that the codec supports at
22.05 kHz).
www.sonnox.com 73 Go to contents