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Chapter 6 Audio Modules
Table 6–5: AHC-RAC Audio Bit Rates continued
AHC-RAC Feature
MPEG AAC
compression
a.
These rates are not compliant with A/53.
b.
These rates are valid for 1.0 coding only.
c.
AHC-561 supports 48 kHz sampling rate only.
d.
Above 56 kbps (1.0), 112 kbps )2.0) or 192 kbps (5.1), the system automatically configures
compressions for AAC-LC even if HE AAC is selected.
Note the following limitations:
ATSC Standard A/53 specifies that only 48 kHz sampling may be used, and that ES bit
n
rates must be less than or equal to 384 Kbps for a complete service. It also specifies that
a two-channel dialog-only service must be less than or equal to 192 Kbps. Total ES rates
for all services must be less than or equal to 51 2 Kbps.
Embedded audio must be 48 kHz sampling and synchronous with the video. See SMPTE
n
272M for definitions.
MPEG AAC and HE AAC can be placed into the output Transport Stream encapsulated in
either of two methods
ADTS
n
ADTS is an acronym for "Audio Data Transport Stream. " This is the default used if the user
selects MPEG-2 AAC/HE AAC. ADTS is assigned a stream type of 0x0F.
LATM/LOAS
n
LATM is an acronym for "Low Overhead Audio Transport Multiplex. " LOAS is an acronym
for "Low Overhead Audio Stream," and furnishes an outer wrapper for LATM's inner
wrapper of the raw audio Elementary Stream syntax. MPEG-4 AAC and HE AAC
bitstreams are encapsulated as LATM/LOAS and assigned a stream type value of
0x1 1.Encapsulation mode is controlled by selecting "MPEG-2" or "MPEG-4" as required.
© 2015 Harmonic Inc. All rights reserved.
Coding Mode
Single channel (1.0)
n
Dual channel (1+1)
n
Stereo channel (2.0)
n
Joint stereo channel
n
Multi-channel (5.1)
58
Sampling
ES Bit Rates
Frequency
Supported (Kbps)
32 kHz
32, 48, 56, 64, 96, 1 1 2,
44.1 kHz
1 28, 182, 192
48 kHz
32 kHz
64, 96, 1 1 2, 1 28, 1 44, 182,
44.1 kHz
192, 224, 256, 320, 384
48 kHz
32 kHz
224, 256, 288, 320, 352,
44.1 kHz
384, 448, 51 2, 576, 640
48 kHz
AHC-RAC Module
Electra 9200, Rev O
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