Pass Through Modes
Describes the supported audio pass through options.
Audio Test Tone
Encoding Stereo
The VCMs audio module codes up to eight channel pairs of the following listed coding standards.
MPEG-1 Layer II Coding Modes
Supported Modes
The VCMs support the following coding modes for MPEG-1 Layer II:
Mono [1/0 (L - input) or 1/0 (R - input)]
This mode has a single audio channel that is encoded independently. It is seldom used in broadcast as most viewing devices now
have stereo speakers or headphones.
Dual Mono [1 + 1 (L/ch1, R/ch2)]
This was introduced to allow two mono channels to be carried in the same bandwidth as stereo signal. The main use for this mode is
for multi-lingual transmission where the decoder selects which language to decode on left or right.
Joint Stereo [2/0 joint]
Coding
Standard
Maximum
Number
Description
Comments
Dolby Digital
2
Dolby Digital Stereo Encoding
Only available when /SWO/DOLBY/AC3 has
been purchased - 1 license required per
channel pair.
MPEG Layer 2
8
MPEG -1 Layer II / Musicam Encode
Stream type MPEG-1 or MPEG-2 (user
selectable), more than two channels are only
available with additional /SWO/M1L2 licenses
- 1 license required per channel pair.
Coding
Mode
Implementation
Comments
Mono (left)
1/0 (L – input)
Mono (right)
1/0 (R – input)
Dual mono
1 + 1 (L/ch1, R/ch2) Left and right are coded separately, referenced as two services/languages
Stereo
2/0
Coded as two mono signals, only referenced as one language/service in SI,
output as stereo at the receiver
Joint Stereo
2/0 joint
Coded as a stereo pair, coding takes advantage of them being stereo, only
referenced as one language/service in SI, output as stereo at the receiver
© Ericsson AB 2011. All rights reserved
© Ericsson AB 2011. All rights reserved
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