Apple Compressor 2 User Manual
Page 96
96
Chapter 7
Creating Dolby Digital Professional Output Files
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 choose Automatic, Compressor makes its best guess at the
intended Audio Coding Mode, based on available source audio files.
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”). In subsequent sections of this manual, the Low Frequency Effects
channel is referred to as “the LFE channel” and its channel identifier code is “.S” (for
“subwoofer”). The single rear “Surround” channel is referred to as “Center surround”
(and its channel identifier code is “Cs”). For more information, see “
Surround Sound Channels (Manual Method)
Surround Sound Channels (Automatic Methods)
 Sample Rate: Specifies the sample rate. All files intended for DVD authoring must
have a 48 kHz sample rate as per the DVD specification.
 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.
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
R
Ls
Rs
L
R
Ls
Rs
L
R
L
R
S
L
C
LFE
R
S
L
C
C
LFE
R