Optimize your mix for
CODEC TOOLBOX is a lite version of the pricier
Sonnox Fraunhofer Pro-Codec, but it’s no
slouch. The Codec Toolbox plug-in lets you
audition, in real time, how different codecs will
make your mix sound before it is rendered (see
Figure 1). This removes the guesswork from
creating different mixes or masters that are
sonically optimized for each data-compressed
release format, such as MP3 or iTunes Plus.
|Fig. 1. Codec Toolbox lets you hear how your
mix will sound when processed by different
codecs before the fact. The included Codec
Toolbox Manager encodes and decodes
audio and edits metadata.
Once your mix is tweaked to perfection,
use the included Codec Toolbox Manager
standalone application to encode your mix
and add metadata such as the song title and
artist’s name. Codec Toolbox Manager can also
perform batch processing and decode data-compressed
files into WAV or AIFF format.
Codec Toolbox and Manager support
32, 44.1, and 48kHz sampling rates and 16-bit audio, and will automatically dither and truncate to 16-bit if necessary. (Pro-Codec can
encode higher-resolution audio, but doesn’t
offer metadata editing or batch processing.)
I tested V1.0.3 of the software bundle using
Digital Performer 8.05 and Mac OS X 10.8.5.
Put it There Codec Toolbox should be placed
on the last insert slot for your master output.
While I mixed or mastered, I could switch
back and forth between hearing the effect
of the plug-in’s requisite 16-bit word-length
reduction (pre-codec input) and post-codec
output for comparison purposes, using buttons
in the plug-in’s GUI.
While my DAW played back, I selected
from the plug-in’s pop-up menu the MP3,
AAC-LC, HE-AAC, HE-AAC V2, and Apple
AAC (iTunes Plus or Mastered for iTunes)
codecs in turn to hear how they made my
mix sound. Where the selected codec offered
alternate settings, I could choose either
constant- or variable-bitrate mode, and the
specific bit rate I wanted to hear (for example,
256kbps for MP3). The HD-AAC codec—which includes both a lossless and lossy
core—is also included solely for the purpose
of auditioning its 16-bit input signal; its actual
lossless core can’t be auditioned, but you can
hear its lossy core by auditioning the AAC-LC
codec in constant-bitrate mode.
Any codec can sometimes cause clipping
when fed a hot signal. Codec Toolbox’s Overs
meter and associated clip LED (both featuring
adjustable peak-hold time) showed the post-decoder
level. This invaluable visual feedback
alerted me that I should lower my master’s
output level 0.8dB to preclude iTunes Plus
encoding causing distortion.
An NMR (Noise to Mask Ratio) meter indicated whether my selected codec was
causing audible artifacts in any of nine
frequency bands. This was most likely to
occur with a very low bit rate selected (which
is unavoidable when using either generation
HE-AAC codec). The only consistent solution
I found was to choose a higher bit rate; in my
experience, you can’t EQ a mix differently to
prevent these artifacts.
Saving Time and My Neck In Codec
Toolbox Manager, I could see how big the
file size would be for the currently selected
codec, mode, and bit rate before rendering
the file—a big time-saver when preparing files
for websites with upload-size restrictions. I
encoded the audio in the compressed-data
format I’d mixed for, adding metadata to
the file before rendering. I could also edit
metadata in pre-existing MP3 and M4A files.
For archived, full-resolution masters
not prepared while using Codec Toolbox,
activating the Manager’s Clip Safe button
automatically applied the correct amount of
gain trim needed during the encode process to
avoid clipping the chosen codec. This is just
one of the many ways in which Codec Toolbox
saves time and prevents heartburn. Costing
only around $58, Codec Toolbox is a steal!
STRENGTHS Realtime auditioning of
multiple codecs. Offline encoding and
decoding. Batch processing. Automatic
level optimization. Writes and edits
LIMITATIONS Doesn’t support sampling
rates above 48kHz. Dithers and truncates
greater bit depths to 16 bits.
£35 (~$58 USD) direct,