Linear Acoustic LA-5269 User manual

Dolby®Digital/Plus Transcoder
Model LA-5269
User Guide

Dolby®Digital/Plus Transcoder
Model LA-5269
User Guide
Release Date: March, 2011
Software Version: V0.0.15 and later
Linear Acoustic Inc.
Phone: [phone]
FAX: [phone]
Web: www.LinearAcoustic.com

Warranty Information
DISCLAIMER OF WARRANTIES: Products manufactured by Linear Acoustic Inc. are warranted
against defects in material and workmanship
purchase of date the from
warranty 5-year Alliance Telos standard the under
.THERE ARE NO OTHER IMPLIED OR EXPRESS
WARRANTIES AND NO WAR- RANTY FOR MERCHANTABILITY OR FITNESS
FOR A PARTICULAR PURPOSE.
During the warranty period Linear Acoustic Inc. will repair, or at our discretion replace, components
which prove to be defective, provided the unit is returned, shipped pre-paid to us directly with a return
authorization (RA) number clearly marked on the packaging. Please note, this RA number must be
present or package will be refused and returned to sender.
All requests for repairs MUST include the unit serial number to ensure quick and accurate service.
DEFECTS CAUSED BY UNAUTHORIZED MODIFICATIONS, MISUSE OR ACCI-
DENTS, UNAUTHORIZED CUSTOMER REPAIRS, OR ANY FURTHER DAMAGE
CAUSED BY INADEQUATE PACKAGING FOR SERVICE RETURN ARE NOT COV-
ERED BY THIS WARRANTY.
PLEASE SAVE THE SHIPPING CARTON AND ALL PACKING MATERIALS. FAILURE
TO RETURN UNIT IN ORIGINAL SHIPPING CARTON AND PACKING MATERIALS
WILL RESULT IN A CHARGE FOR NEW SHIPPING MATERIALS.
LIMITATION OF PERIOD OF ACTION ON CONTRACT: No action, regardless of form,
arising out of the transactions under this agreement may be brought by buyer, its successors, agents
and/or assigns, more than three years from date of purchase.
LIMITATION OF LIABILITY: It is understood and agreed that Linear Acoustic’s liability whether
in contract, in tort, under any warranty, in negligence or otherwise shall not exceed the cost of repair
or replacement of the defective components and under no circumstances shall Linear Acoustic be liable
for incidental, special, direct, indirect or consequential damages, or loss of use, revenue or profit even
if Linear Acoustic or its agents have been advised, orally or in writing, of the possibility of such damages.
This product optionally contains Dolby Digital (AC-3) encoding and is manufactured under license
from Dolby Laboratories, Inc. The encoder contains confidential unpublished works and is protected
by US and foreign patents and is copyright 2007 Dolby Laboratories, Inc.
LA-5269, Linear Acoustic and the “LA” symbol are trademarks or registered trademarks of Linear
Acoustic Inc., all other trademarks remain the property of their respective owners.

Linear Acoustic LA-5269 Transcoder User Guide
v
List of Figures
1-1 Audio Block Diagram .........................................................................................................................6
2-1 Rear Panel ...........................................................................................................................................10
3-1 LA-5269 Connection Example ........................................................................................................13
3-2 A/V Sync Timing ..............................................................................................................................14

Linear Acoustic LA-5269 Transcoder User Guide
vi

Linear Acoustic LA-5269 Transcoder User Guide
vii
Table of Contents
List of Figures............................................................................................................................................v
Chapter 1: Introduction...................................................................................................................5
1.1 Principles of Operation..........................................................................................5
1.2 Location of LA-5269..............................................................................................6
1.3 Reference Levels .....................................................................................................6
1.4 Reset and Upgrades................................................................................................6
1.5 Warranty and Feedback .........................................................................................7
Chapter 2: Connections and Quick Setup.......................................................................9
2.1 Unpacking and Inspection ....................................................................................9
2.2 Installation ...............................................................................................................9
2.3 Rear Panel ..............................................................................................................10
2.3.1 Connection Ports .................................................................................10
2.4 Quick Setup Notes ...............................................................................................11
Chapter 3: Applications................................................................................................................13
3.1 Example .................................................................................................................13
3.2 Latency ...................................................................................................................14
3.3 SNMP (option)......................................................................................................15
Chapter 4: Detailed Operation.................................................................................................23
4.1 Menu Navigation ..................................................................................................23
4.2 Statistics Menu ......................................................................................................23
4.3 I/O Menu ..............................................................................................................24
4.3.1 Master Bypass .......................................................................................24
4.3.2 Reference Setup....................................................................................24
4.3.3 Audio Input Sources (Channels 1-8).................................................25
4.3.4 SDI Embed ...........................................................................................25
4.3.5 SDI Out Destination (Channels 1-16) ..............................................25

Linear Acoustic LA-5269 Transcoder User Guide
viii
4.3.6 Metadata Setup .....................................................................................25
4.4 AC-3 Encoder Menu............................................................................................26
4.4.1 AES Channel Status Bits.....................................................................26
4.4.2 Transcoder.............................................................................................26
4.4.3 Encoder Mode & Metadata ................................................................26
4.5 Communication Menu .........................................................................................29
4.5.1 IP Address & Subnet ...........................................................................29
4.5.2 SNMP Trap Addresses........................................................................29
4.6 System Menu .........................................................................................................30
4.7 SDI Status Menu...................................................................................................30
Chapter 5: Troubleshooting.......................................................................................................33
5.1 Problems and Possible Causes............................................................................33
5.1.1 Unit won’t power on............................................................................33
5.1.2 The Ref LED is red .............................................................................33
5.1.3 Output Audio Clicks and Pops ..........................................................34
5.1.4 Received Audio Has Dropouts ..........................................................34
5.1.5 Audio Pumps and Breathes ................................................................34
5.1.6 Nielsen Watermark Issues...................................................................34
5.1.7 Problems with EAS decoding ............................................................34
Chapter 6: Specifications............................................................................................................35

Linear Acoustic LA-5269 Transcoder User Guide
5
Chapter 1: Introduction
The Linear Acoustic LA-5269 is a Dolby decoder, encoder, and transcoder enabling inputs
of PCM, Dolby E, and Dolby Digital (AC-3) to be output as Dolby Digital (AC-3), Dolby
Digital Plus (E-AC-3) and in the future Dolby Pulse (AAC and HE AAC).
Below are some features of the LA-5269:
• AES and HD/SD-SDI inputs and outputs standard
• Support for serial (RS-485) and VANC (SMPTE 2020) metadata
• Dual power supplies
• SNMP reporting (option)
• Encode:
• PCM to Dolby Digital (AC-3), Dolby Digital Plus (E-AC-3)
• PCM to Dolby Pulse (AAC and HE AAC) - future option
• Transcode:
• Dolby Digital (AC-3) to Dolby Digital Plus (E-AC-3)
• Dolby E to Dolby Digital (AC-3), Dolby Digital Plus (E-AC-3) - Option
• Smooth splicing and switching of transcode and main audio
• Framesync of transcode input
• Metadata translation between codecs
1.1 Principles of Operation
Figure 1-1 shows the internal audio path of the LA-5269. It should be noted that this dia-
gram is a general representation of signal flow. Please consult the appropriate section of
this manual for specific functionality.

Linear Acoustic LA-5269 Transcoder User Guide Introduction
6
Figure 1-1 Audio Block Diagram
1.2 Location of LA-5269
In the signal flow of a modern television station, audio processors can be placed in a variety
of locations depending on how the transmission path is designed. Our suggestion is to try
to keep LA-5269 near the MPEG video encoder and/or multiplexer as the units work
closely together and will benefit from short cable runs and common clocking.
1.3 Reference Levels
The LA-5269 is designed to support a standard reference level of -20dBFS via its digital
inputs.
1.4 Reset and Upgrades
A soft re-boot of the unit can be accomplished by briefly and simultaneously pressing the
Left, Up, and Right arrow keys.
3/4 C/LFE
CPU
(FPUI, I/O, PSU Mon,
System Control) ETHERNET
5/6 Ls/Rs
1/2 LfRf
HD/SD-SDI
Demux
SDI In
(HD/SD)
1/2
PSU 1
90-264V
50/60Hz
3/4
5/6
7/8
LA-5269 Dolby Digital/Plus Transcoder
24-bit
SRC
SRC
SRC
SRC
RS485 MD
PSU 2
90-264V
50/60Hz
HD-SDI
Mux HD/SD-SDI
48k
Int.
Enc A Out
REF
Dolby Digital
(AC-3)
Dolby Digital +
(E-AC-3)
Enc. A
Dolby Digital
(AC-3)
Dolby Digital +
(E-AC-3)
Enc. B
DD+
&
DE
T
R
A
N
S
C
O
D
E
9/10
Enc. A Byp/
Transcode In
7/8
Enc B Out
VANC MD
(SMPTE 2020)
Out Ref
Input
7/8
C/Sw
Ls/Rs
LfRf
Input:
SDI/AES
Bypass

Linear Acoustic LA-5269 Transcoder User Guide Introduction
7
Upgrades are performed via the rear-panel Ethernet connector. The USB connector is un-
used, however please do not insert any device into this connector.
1.5 Warranty and Feedback
Please take a moment to fill out and return the warranty card included with the unit. This
will enable us to contact you if there are any software or documentation issues. Also, we
are very interested in your feedback. This unit was designed based on input gathered from
many broadcast engineers and it will evolve further thanks to ongoing suggestions and
comments from users. We look forward to hearing from you.

Linear Acoustic LA-5269 Transcoder User Guide Introduction
8

Linear Acoustic LA-5269 Transcoder User Guide
9
Chapter 2: Connections and Quick Setup
This chapter covers all required connections for the LA-5269.
2.1 Unpacking and Inspection
Before unpacking the unit, inspect the outer carton for shipping damage. If the carton
shows damage, inspect the unit in those areas. Please save the carefully designed shipping
carton and packing materials. In the unlikely event that the unit needs to be returned to the
factory, alternate cartons or packing materials may not be adequate and can cause damage
not covered by warranty.
The following essential items are provided with the unit:
• Bag containing:
• Two IEC power cords (style matches country of order);
• this manual, and a handy black pen.
• Warranty information: Please fill out and return the warranty card to Linear Acoustic
to ensure your software and documentation are kept up to date.
2.2 Installation
LA-5269 installation requires:
• One standard rack space unit with ADEQUATE VENTILATION (the unit relies on
convection cooling from side-panel vents);
• standard 75-Ohm BNC cables for digital signal connections;
To connect to digital equipment with 110-Ohm XLR connectors, use impedance-
matching transformers (available from Canare, Neutrik and other manufacturers).
• Proper reference. The unit will default to internal 48kHz with no signals applied, how-
ever correct reference is of critical importance especially with encoded audio. Different
MPEG multiplexers may have different requirements, however best success has typi-
cally been achieved with SDI connections as there is embedded clock information.
Note that if embedding is enabled, reference will be forced to SDI.

Linear Acoustic LA-5269 Transcoder User Guide Connections and Quick Setup
10
2.3 Rear Panel
The rear panel of the LA-5269 contains its electrical I/O.
2.3.1 Connection Ports
All of the connections for LA-5269 are on the rear panel and are described in detail below.
See Chapter 5: Specifications for specific pinouts.
Figure 2-1 Rear Panel
•Metadata I/O: RS-485 connection accepts the metadata output of any Dolby equip-
ment (DP572, DP570, etc...) or any Dolby-compatible metadata source. Used to con-
trol upmixing and other functions.
•SDI Input/SDI Output: Option allows for de-embedding and re-embedding any of
the 16 available channels in an applied HD or SD-SDI signal. VANC metadata extrac-
tion per SMPTE 2020 methods A and B is also supported.
•GPI/O: Output of unit status, GPI currently not used.
•ETHERNET: Used for firmware upgrades and SNMP reporting (see chapter 3)
•Main Audio Input: Connect the 48kHz PCM signals to these inputs. The input chan-
nels are arranged as follows: 1/2 = Left front/Right front, 3/4 = Center/LFE, 5/6 =
Left surround/Right surround. 7/8 is for the +2 program.
•Enc. A Bypass: Bypass input for Dolby Digital (AC-3) encoder A. Accepts output of
external encoder for fail-safe operation. Connector is also the input for the transcoder.
Apply Dolby E encoded audio here for decode then re-encode to Dolby Digital (AC-
3) or Dolby Digital Plus (E-AC-3), or apply Dolby Digital (AC-3) for transcode to Dol-
by Digital Plus (E-AC-3).
•AES REf Input: Apply 48kHz DARS (Digital Audio Reference Signal) here and
choose AES Ref as clock source in Setup->I/O menu. Note that this is useful with
some MPEG video encoders which provide an AES reference output.
NOTE: Appropriate reference must be applied and selected for proper operation.

Linear Acoustic LA-5269 Transcoder User Guide Connections and Quick Setup
11
•Main Audio Outputs: 48kHz discrete audio inputs selected for encoding. If input is
SDI, these outputs are the de-embedded audio channels. For 5.1+2 operation, 1/2 =
Left Front/Right Front, 3/4 = Center/LFE, 5/6 = Left Surround/Right Surround, 7/
8 = Alternate program.
• Encoder A Output: AC-3 output of the 5.1 channel Dolby Digital encoder option
• Encoder B Output: AC-3 output of the 2.0 channel Dolby Digital encoder option
2.4 Quick Setup Notes
The Linear Acoustic LA-5269 is configured at the factory and is ready to go on the air after
making the proper input and output connections.
• Apply audio to Main Input 1/2
• Set Clock Reference = AES 1
• The front panel Reference indicator should be green.
• The main menu will default to showing input and output meters, and there should be
activity on some or all of the first six meters.
• Audio will be available on the main outputs 1-6 and encoded audio will be present on
the Enc A and Enc B outputs.
The best way to learn the menus is to explore the different settings with audio applied and
monitored.

Linear Acoustic LA-5269 Transcoder User Guide Connections and Quick Setup
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Linear Acoustic LA-5269 Transcoder User Guide
13
Chapter 3: Applications
The LA-5269 is essentially a modern updated version of the classic Dolby DP569. Features
such as dual power supply, HD/SD-SDI I/O, and SNMP have been added to a Dolby-
manufactured encoder card. Support for encoding from PCM inputs is provided along
with several space and cost saving transcode functions that allow inputs to be PCM, Dolby
E, or Dolby Digital (AC-3) and outputs to be Dolby Digital, Dolby Digital Plus, or option-
ally Dolby Pulse.
3.1 Example
Below is a simple connection scenario to highlight some possible applications for the LA-
6269.It should be noted that both SDI and AES connections are shown, but likely both
will not be used in every case.
Figure 3-1 LA-5269 Connection Example
MPEG Mux
Transmitter
Network Feed
Network IRD
1/2 3/4 5/6
PCM Out
LA-5269
SNMP
DD or DD+
via SDI DD or DD+
via AES
7/8
DE or DD
via AES
DE or DD
via SDI
5.1+2 PCM Audio In
1/2 3/4 5/6 7/8
9/10
Transcode In

Linear Acoustic LA-5269 Transcoder User Guide Applications
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3.2 Latency
Audio coding takes time. Luckily, so does video, and in all modern multiplexers there is far
more video delay than audio delay and so adjustable compensation is added to the audio
inputs. When installing an external audio encoder such as the LA-5269, the latency im-
posed by the audio coding process can be “tuned out” of the MPEG multiplexer by re-
moving some of the compensating delay. This adjustment is sometimes called “External
Coding Delay” or simply “External Delay” and when set to the latency of the external en-
coder, this value is actually removed from the audio path thereby lining up audio and video
properly in time.
The simple block diagram below illustrates the internal signal flow inside a typical MPEG
encoder and multiplexer.
Figure 3-2 A/V Sync Timing
This is an elegant method for maintaining proper lip sync. External delays could be em-
ployed, but it seems somewhat counterintuitive to introduce additional delay when delay
can actually be removed to achieve the same result.
MUX
MPEG-2/4
Video Encode
(1-4 seconds delay)
2-channel Internal
AC-3 Encoder
187 msec Delay Fixed Delay=
MPEG-2
minus AC-3
Adjustable Delay=
MPEG-2 minus
ext Dly
HD
Video
Stereo
PCM
Audio
AC-3
Transport
Stream
Data
(PMT, PSIP, etc..)
LA-5269:
137msec (DD/DD+)
236/257msec (DE to
DD/DD+ NTSC/PAL)
0-Time
Plus Total
Latency
Timing
5.1 Ch
PCM
Audio
0-Time
© 2011 Linear Acoustic

Linear Acoustic LA-5269 Transcoder User Guide Applications
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3.3 SNMP (option)
The LA-5269 supports error reporting via the Simple Network Management Protocol. Sta-
tus of critical functions such as the health of each power supply, encoder function, unit
bypass, metadata reversion, audio presence and others are reported.
The current LA-5269 MIB file is copied below. Note that this data can be copied and past-
ed to a text file that can be re-named LINEAR-ACOUSTIC-LA5269.mib and used by an
SNMP manager.
---------------------------------
LINEAR-ACOUSTIC-LA5269-MIB DEFINITIONS ::= BEGIN
-- MIB for Linear Acoustic la5269 devices
IMPORTS
enterprises FROM RFC1155-SMI
TRAP-TYPE FROM RFC-1215
OBJECT-TYPE FROM RFC-1212;
linearAcoustic OBJECT IDENTIFIER ::= { enterprises 28660 }
la5269 OBJECT IDENTIFIER ::= { linearAcoustic 5269 }
la5269-system OBJECT IDENTIFIER ::= { la5269 1 }
la5269-status OBJECT IDENTIFIER ::= { la5269 2 }
--
-- la5269-system
--
-- model
la-model OBJECT-TYPE

Linear Acoustic LA-5269 Transcoder User Guide Applications
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SYNTAX OCTET STRING (SIZE (0..40))
ACCESS read-only
STATUS mandatory
DESCRIPTION
"Linear Acoustic Model."
::= { la5269-system 1 }
-- software version
software-version OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..40))
ACCESS read-only
STATUS optional
DESCRIPTION
"Device's software version."
::= { la5269-system 2 }
-- firmware version
firmware-version OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (0..40))
ACCESS read-only
STATUS optional
DESCRIPTION
"Devices's firmware version."
::= { la5269-system 3 }
--
-- la5269-status