DigiDesign Pro Tools Reference Manual page 654

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
Encoder Speed Determines the audio quality of
the bounced file. There are two options: Highest
Quality and Fastest Encoding Time.
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.
Constant Bit Rate (CBR) Encodes the file at a
single bit rate that you choose from the CBR
pop-up menu. Because the bit rate is fixed, the
quality of the encoded audio will vary depend-
ing on the nature of the material being com-
pressed. This option is best for streaming over
the Internet, since it has predictable bandwidth
requirements.
ID3 Tag Info Settings
ID3 Tag Type The ID3 tag stores data about the
encoded audio file that is used by MP3 players to
display information about the file. Pro Tools
supports three versions of this tag, in order to
provide backward compatibility with older MP3
players:
• ID3 v1.0: Appears at the end of a streaming
MP3 file, so that tag information is only dis-
played after software streaming is finished.
642 Pro Tools Reference Guide
• ID3 v1.1: Same as version 1.0, but adds track
number information to the tag.
• ID3 v2.3: Appears at the front of a streaming
MP3 file, so that tag information is displayed
when streaming begins.
While ID3 v2.3 is becoming the standard
MP3 format, not all MP3 players currently
support ID3 v2.3. Contact the developer of
your player software for compatibility infor-
mation.
Title/Artist/Album/Comment Type the title, art-
ist, and other information for the MP3 file. This
information is displayed by many MP3 players.
Genre Choose a genre for the file. This informa-
tion is displayed by many MP3 players, and can
appear in searchable catalogs and databases.
Track Number If you select ID3 tag type v1.1 or
v2.3, you can enter a CD track number for the
file. This information is displayed by many MP3
players.
Year Enter a year for the file. This information is
displayed by many MP3 players.
Mac File Settings
Mac File Type and Creator If you expect your file
to be used on a Mac, you can enter the Mac file
type and creator. This will allow users to double-
click the file to open their MP3 player.
Default Button
To restore all settings in this dialog to their de-
fault values, click Defaults.