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Hd sdi, Audio decoding and output stage, General – TANDBERG High Definition Professional Recevier/Decoder TT1280 User Manual

Page 96: Mpeg audio, Dolby digital ac-3 audio, B.1.4, B.2.1, B.2.2, B.2.3, B.2 audio decoding and output stage

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Technical Specification

Page B-4

Reference Guide: TT128x High Definition Professional Receiver/Decoder

ST.RE.E10141.5

B.1.4 HD

SDI

HD SDI output supports:

Embedded Decoded Audios

Closed Captioning (EIA 708B)

VITC

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 four 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

DTS Audio pass-through

Audio component selection is automatic or may be specified from the User

Interface or remote interfaces. The IRD automatically detects the audio

type of the selected audio component and applies the appropriate

algorithm. Audio component selection is based on the position of the

component descriptor in the PMT. Audio 1 takes the first component,

Audio 2 the second. These may be overridden by selecting User-specified

component PIDs.

B.2.2 MPEG

Audio

The IRD supports decoding of MPEG audio as follows:

Compression layers: MPEG-1 layers I and II

Sampling rates (kHz): 32, 44.1, 48

Maximum compressed data rate: 384 kbit/s (layer II)

B.2.3

Dolby Digital AC-3 Audio

The IRD is able to decode and output the primary stereo pair of a Dolby

Digital AC-3 encoded audio stream. When there is data encoded on the

audio surround channels, the Decoder applies downmixing, so that either a

surround encoded stereo pair (LtRt downmix) or a conventional stereo pair

(LoRo downmix) is available at the output.
The IRD is not able to decode and output all 5.1 channels individually as

separate channels.

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