Vertical blanking signals, Audio decoding and output stage, General – TANDBERG TT1260 User Manual

Page 97: B.2 audio decoding and output stage, B.2.1 general

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Technical Specification

Instruction Manual: TT1260 Standard Definition Professional Receiver/Decoder

Page B-5

ST.TM.E10100.1

Vertical Blanking Signals

The TT1260 range of Receivers and Decoders support the following VBI

reinsertion and signalling:

·

VBI streams

·

VPS data and pass through

·

WSS data and pass through

·

525 VITC and 625 VITC

·

Vertical Interval Test Signal (VITS)

·

Video Index data

·

AMOL pass through

·

Closed Captioning (525-line sub-titling system)

·

Insertion Test Signal (ITS) Insertion

B.2

Audio Decoding and Output Stage

B.2.1

General

The TT1260 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-2 Audio (Musicam): ISO/IEC 13818-3

·

Dolby Digital AC-3 Audio: ATSC document A/52

·

Linear Audio: SMPTE 302M – 2000 with system limitations as specified

in following section below

·

The Receiver does not support MPEG-2 AAC Audio (ISO/IEC 13818-7)

at this release.

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 apply the appropriate decoding. 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.

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