TANDBERG E5714 DSNG Voyager, Справочное руководство

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Introduction to the Basic Encoder
Reference Guide: E57xx DSNG and DENG Voyager Encoder Page 1-11
ST.RE.E10076.3
Dolby Digital (AC-3)
Dolby Digital (AC-3) audio encoding incorporates digital normalisation,
preprocessing (filtering), dynamic range compression and the addition of
bit-stream information.
Dolby Pro Logic audio can be carried as stereo audio through the Encoder
as long as a suitably high bit-rate is selected (see Annex B, Technical
Specification).
1.3.3 Vertical Blanking Interval (VBI) Line Processing
Modes
Introduction
The Encoder has three modes for processing VBI lines.
NOTE…
A maximum of eight VBI lines per field may be extracted. This limit does not apply to Teletext.
VBI in Picture
By selecting the VBI in Picture extended active picture format available in
the MPEG 4:2:2 specification the Encoder compresses and transmits the
VBI data as part of the active picture. This mode requires up to 3 Mbit/s of
extra bit-rate, depending on the amount and complexity of the VBI
present.
NOTES…
1.
VBI in Picture transmits the VBI waveform as part of the picture and as such will be subject to
some distortion. Most analogue VBI types are robust against this type of distortion but others,
e.g. video index, are intended for SDI transmission and will not survive MPEG coding/decoding
in VBI in Picture mode. VITS test signal and ghost cancellation signal will become corrupted.
2. VBI in Picture is not supported when 3:2 Pulldown is active.
VBI User Data
Closed Caption data, together with other formats such as VITC and AFD,
can be transmitted in the user data field of the video or relevant part of
the video stream.
VBI in PID
The Encoder has the ability to extract and transmit a wide variety of VBI
line formats. Circuitry on the front end of the equipment incorporates a
number of general purpose line grabbers so that known formats of VBI
data can be extracted.
The following VBI data formats are supported:
•
Line 21 (field 1 and field 2) data Services EIA-608 (Closed Caption and
V-chip)
•
Neilson AMOL 1, Neilson AMOL 11