Apple Compressor 3 User Manual
Page 140
For example, “3/2 (L, C, R, Ls, Rs)” means three front channels (left, center, right), and
two rear channels (surround). “2/0 (L, R)” is essentially a standard stereo file. The audio
coding mode affects settings such as the available bandwidth and surround channel
preprocessing. If you click the Automatic button (next to the Audio Coding Mode
pop-up menu), Compressor makes its best guess at the intended audio coding mode,
based on available source audio files.
3/1 channels
3/0 channels
2/2 channels
1/0 channels
2/1 channels
2/0 channels
(LFE option not available)
(LFE option not available)
3/2 channels
L
C
LFE
LFE
LFE
LFE
LFE
LFE
LFE
R
Ls
Rs
L
R
Ls
Rs
L
R
L
R
S
L
C
R
S
L
C
C
R
Note: In the Audio Coding Mode pop-up menu, “S” stands for a single rear “Surround”
channel, and in this illustration, “LFE” stands for Low Frequency Effects (also known as
“subwoofer”). For more information, see
Assigning Files to Surround Sound Channels
and
Assigning Files to Surround Sound Channels (Automatic Methods)
• Enable Low Frequency Effects: Select this checkbox to include the LFE channel in the
encoded stream (not available for 1/0 mono or 2/0 stereo).
• Sample Rate: Specifies the sample rate. All files intended for video and audio DVD
authoring must have a 48 kHz sample rate as per the DVD specification. The 32 kHz
and 44.1 kHz sample rates are available only when Generic AC-3 is the target system.
• Data Rate: The choices depend on the coding mode and target system. The higher the
rate, the better the quality. AC-3 streams have a constant data rate. At 448 kbps, which
is the default for 5.1 encoding, one minute of AC-3 audio takes about 3.3 MB of storage
space. For stereo encoding, rates of 192 kbps and 224 kbps are typical and will produce
good results.
• Bit Stream Mode: Defines the purpose of the encoded audio material. The information
is included in the finished stream and can be read by some decoding systems.
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Chapter 10
Creating Dolby Digital Professional Output Files