Apple Compressor (4.1.2) User Manual
Page 36
Chapter 4
Advanced adjustments
36
MP3
The built-in MP3 File and MP3 for Audio Podcasting settings use the MP3 transcoding format.
This format encodes MP3 files, which are often used for digital audio players. You can also create
custom settings that use the MP3 transcoding format.
The properties of built-in and custom settings that use this transcoding format are located in the
General inspector and Audio inspector. These properties are described below.
Important:
When you add a setting (or a destination that includes settings) to a job, Compressor
analyzes the source media and then automatically assigns the most appropriate setting
properties (based on the setting’s transcoding format and the characteristics of your source
media file). It’s recommended that you use the automatically assigned setting properties.
Setting summary
Displays the setting name and transcoding format, as well as an estimated output file
size. When you add a setting to a job or change the setting’s properties, this summary
automatically updates.
General properties
•
Name: Displays the name of the setting.
•
Description: Displays the description of the setting.
•
Extension: Displays the extension of the output file (.mp3).
•
Allow job segmenting: Job segmenting is not available for settings that output only an
audio file.
•
Default location: Select an item from the pop-up menu to set the default save location for
transcoded files.
Retiming
This section contains one property:
•
Set duration to: Sets the processing algorithm used to adjust the frame rate during transcoding.
Select either of the following options:
•
[Percentage] of source: Modifies the output clip’s speed by a percentage of the source clip’s
speed. Enter a value in the percentage field or choose a preset value from the adjacent
pop-up menu (with a downward arrow).
•
[Total duration]: Sets the duration of the clip. Enter a timecode duration in the field or click
the arrows to increase or decrease the time.
For more information, see
on page 69.
Audio properties
•
Channel layout: Use the pop-up menu to set the audio channel layout. For more information,
see
on page 65.
•
Sample rate: Use this pop-up menu to set the number of times per second that music
waveforms (samples) are captured digitally. The higher the sample rate, the higher the audio
quality and the larger the file size.
•
Data rate: Use the slider to set the number of kilobits per second (kbps) required to deliver
your audio file. Using a higher rate will produce a higher-quality audio file.
•
Use variable bit rate encoding: Select the checkbox to vary the number of bits used to store the
music depending on the complexity of the music. Variable bit rate encoding can reduce the
size of the output file.
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