Apple Compressor 2 - Manual (Page 93)

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93
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Creating Dolby Digital
Professional
Output Files
Compressor provides the tools you need to encode, and
batch-encode, Dolby Digital Professional (AC-3) audio files.
Dolby Digital Professional format (also known as AC-3) is a very common compressed
audio format for DVD-Video discs. Compressor 2 accepts multichannel sound files in a
variety of formats and gives you complete control over the AC-3 encoding process.
Dolby Digital programs can deliver 5.1-channel surround sound with five discrete full-
range channels (left, center, right, left surround, and right surround) plus a sixth channel
for low-frequency effects (LFE), sometimes known as “the subwoofer.” Another surround
option is Dolby Surround, with four channels (left, center, right, surround). But not all
AC-3 audio is 5.1 surround sound. Dolby Digital Professional is commonly used to
encode stereo files to greatly reduce their file size.
This chapter covers the following:
 About the Dolby Digital Professional Encoder Pane (p. 94)
 Converting Audio Files to Dolby Digital Professional Format (p. 100)
 Creating Surround Files (p. 101)
 Options for Spatial Mixing (p. 106)
Note: Dolby Digital Professional encoding with Compressor is available only on
computers that also have DVD Studio Pro 4 or Final Cut Studio installed. If you are
using Compressor with distributed processing, DVD Studio Pro must be installed on
each node that will be doing Dolby Digital Professional encoding.
If you are planning to make DVDs using DVD Studio Pro, see the DVD Studio Pro User
Manual for more information about the DVD authoring workflow.
Note: It’s important to understand that Compressor cannot take stereo audio files and
create 5.1 surround sound from them. If you want to create a 5.1 surround sound AC-3
audio file, you must first create the six channels of audio it requires. This must be done
using other applications outside Compressor.