Specifications

Pro Tools Reference Guide486
Select the “Include RealPlayer 5.0 Compatible
Stream” option to include a backward compati-
ble stream that can be played on older version
5.0 RealPlayers. (This backward compatibility is
only available for SureStream-encoded files.)
If you select Single Rate, you can only select one
connection speed under Target Audience. With
this file type, a single stream is encoded into the
output file. Files encoded with the Single Rate
option can be played back from either a stan-
dard web server or a G2 server.
MP3 (MPEG Layer 3)
The MPEG-1 Layer 3 compression format (MP3)
is used for streaming and downloading audio
over the Internet, and for playback on portable
devices. The MP3 option is required to use this
file type.
On Windows and Mac OS 9, the MP3 encoder
file is stored in a folder named Codecs inside the
DAE folder; on Mac OS X, the MP3 encoder file
is stored in Applications/
Pro Tools/Codecs/MP3/. This version of the en-
coder uses the latest technology from the devel-
oper of the MP3 format, the Fraunhofer Insti-
tute. It features improved processing speed and
quality, and supports both constant and vari-
able bit rate encoding.
The MP3 encoder provided as an install option
with Pro Tools is a fully functional 30-day demo
version. To purchase the full version of the MP3
encoder, visit Digidesign’s Web site
(www.digidesign.com).
When you select this format, the Resolution
pop-up menu in the Pro Tools Output Options
dialog is unavailable. The resolution is set by the
encoder.
The sample rate chosen is given to the codec as
a “base” sample rate for operations. The actual
sample rate of the resulting file is determined in
the MP3 Encoder Options dialog. For example,
if a base sample rate of 48000 Hz is chosen, the
MP3 Encoder Options dialog will allow output
streams in 48, 24, or 12 kHz, depending on en-
coding quality.
When you export or bounce to MP3 format, you
can set the following options:
Encoder Settings
Encoding Quality Determines the audio quality
of the bounced file. The higher the quality, the
longer it will take to process the audio. The three
options, in ascending order of quality, are Fast-
est Encoding, Medium Encoding, and Highest
Quality.
The Highest Quality setting can take up to five
times longer to process audio than the Fastest
Encoding setting, so you should use it only
when the highest fidelity is essential and you
have a considerable amount of time to devote to
the encoding process. You should experiment
with the other encoding quality settings, since
they can provide acceptable quality with a sig-
nificantly shorter encoding time.
Encoding Method Two encoding methods are
available:
MP3 Output Options