TANDBERG E5780, Справочное руководство

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Introduction to the Basic Encoder
Reference Guide: evolution 5000 E5780 and E5782 Encoder Page 1-7
ST.RE.E10135.4
1.2.2 Audio Encoding
General
Audio can be encoded to:
•
MPEG-1 Audio (layer 2) standard (sampling rate 32 kHz or 48 kHz).
•
Dolby Digital (sampling rate 32 kHz or 48 kHz).
Output bitrate is selectable in the range 32 kbit/s - 384 kbit/s (dependent on
configuration) for MPEG-1 Audio (layer 2) and 56 kbit/s - 640 kbit/s (dependent on
configuration) for Dolby Digital coding mode selectable between 1/0 and 2/0.
•
Dolby Digital pre-encoded audio (IEC 61937 specification) in pass-through mode is also
available (it only operates at 48 kHz). This is where an audio stream has already been
encoded externally, prior to entering the Encoder.
•
Linear PCM (Direct) [SMPTE 302M].
•
Linear PCM (Via SRC) [sample rate converter]
•
Dolby E Pass-through.
•
DTS Pass-through.
NOTES…
1. See
Annex F, Audio Modes for details of setting up the audio.
2. MPEG-1 audio sampling rate is fixed at 48 kHz when controlled from the front panel.
Audio Inputs
The standard audio input is:
•
AUDIO IN – 15-way male D-type - software selectable balanced analogue or digital
AES/EBU, with AES/EBU on left only. A break-out cable is supplied which plugs into this
connector and provides a more convenient means of connecting the audio inputs via five
connectors. There are four XLR female connectors, with the fifth cable being a BNC
which provides an AES/EBU 75
Ω
digital reference output.
•
Alternatively, audio can be input embedded as AES/EBU on the serial digital interface
(
SDI – HD or SD). In this mode a maximum of four stereo pairs can be extracted from any
two Data Identifiers (DIDs). Audio may be converted to either of the standard output
sampling frequencies, 32 kHz or 48 kHz, by use of the built-in asynchronous sample rate
converters. This applies only to audio which is not pre-encoded.
Audio Channels
The Encoder Base Board is capable of processing two stereo pairs, from any of the following
6
:
•
SDI Embedded source (HD or SD)
•
Digital source AES/EBU
•
Analogue source, termination impedance 600
Ω
or 20 k
Ω
These signals may be processed using the encoding modes in the following section.
6
See Annex F, Audio Modes for details of setting up the audio.