Sdi; Audio Decoding And Output Stage; General; Mpeg Audio - TANDBERG TT1260 Reference Manual

•
Support for Closed Captioning (ATSC, Divicom and TTV proprietary MPEG carriage
protocol)
•
Insertion Test Signal (ITS) insertion (CCIR and FCC/UK)
•
World System Teletext (WST)
•
Inverted Teletext (WST)
•
Vertical Interval Test Signal (VITS) (525 and 625 line)
•
Decode of VBI in Video (4:2:2 only)
•
VBI is simultaneously output on CVBS and SDI outputs
•
North American Basic Teletext (NABTS)

SDI

SDI output supports:
•
Embedded Decoded Audios
•
EDH
•
VBI
B.2

Audio Decoding and Output Stage

B.2.1

General

The IRD is capable of simultaneously decoding two PES streams of audio from the transport
stream. Each of the decoders is identical in operation, but act completely independently of the
other, with the following exceptions:
•
Both decoders must be decoding channels that have the same sampling rate
•
Both decoders are not required to simultaneously decode the same PES stream
Each channel supports extraction of three types of coded audio from the Transport Stream as
follows:
•
MPEG-1, Layer 2 Audio (Musicam): ISO/IEC 13818-3
•
Dolby Digital AC-3 Audio: ATSC document A/52
•
Linear Audio: SMPTE 302M – 2000
Audio component selection is specified from the User Interface or remote interfaces. The
TT1260 automatically detects the audio type of the selected audio component and applies the
appropriate algorithm. Where there are audio components in the selected service of the same
language but different coding types, the preferred component is linear audio, followed by
Dolby Digital AC-3, and followed by MPEG audio.
There is no requirement for specific selection behaviour where a service contains two or more
audio components of the same coding type and language. The TT1260 is not required to
support dynamic changes in the audio coding type once the initial selection has been made.
Provision is made in the User Interface and remote interfaces for user override of default
audio selection by language and audio coding type, or by PID.
There is no support for static default languages.
B.2.2

MPEG Audio

The TT1260 supports decoding of MPEG audio as follows:
•
Compression layers: MPEG-1 layers I and II
Reference Guide: TT1260 Contribution Receiver
ST.RE.E10100.3
Technical Specification
Page B-5