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SUBTITLEPLUS DVB SERVER USER

MANUAL (Version: 2.0, August 2013)

This guide explains how to use the basic functionalities of the SubtitlePlus DVB Server v 1.4.

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Legal Notice The information in this manual is furnished for informational use only. No part of this manual may be reproduced or transmitted in any form or by any

means, electronic or mechanical, for any purpose, without the prior written permission of DMT Ltd.

The software, described in this manual, is owned by DMT Ltd. It is protected by Bulgarian Copyright Law, as well as by international copyright treaties,

and may be used or copied only in accordance with the license agreement.

DMT Ltd. provides this manual “as is” without any warranty, either express, or implied.

This publication may contain typographical errors or technical inaccuracies. While every precaution has been taken in the preparation of this document,

DMT Ltd. assumes no responsibility for errors or omissions. Nor is any liability assumed for damages, resulting from the use of the information,

contained herein. Changes are periodically made to the information herein. They will be incorporated in new versions of the manual. Please, check the

PlayBox website regularly for User Manual updates.

DMT Ltd. may introduce changes or improvements in the products, described in this manual at any time, without any special notice.

Please, address your comments or questions to:

Digital Media Technologies Ltd.

7 Iskarsko shose Blvd.

Building 15, 5th Floor

1528 Sofia, Bulgaria

Tel.: +359 2 9703050

Fax: +359 2 9717700

playbox@playbox.tv

www.playbox.tv

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Table of Contents LEGAL NOTICE ........................................................................................... 2 TABLE OF CONTENTS ............................................................................... 3 INTRODUCTION ........................................................................................ 4 STYLE CONVENTIONS............................................................................... 5 GETTING STARTED .................................................................................... 6 INSTALLATION........................................................................................................................ 6

Minimum system requirements ............................................................................................................................................................................... 6 Software License ............................................................................................................................................................................................................ 6

INTRODUCTION TO DVB SUBTITLING ................................................... 7 INTEGRATION OF THE SUBTITLEPLUS DVB SERVER ........................... 9 MULTIPLEXER SETUP .............................................................................. 10 USER INTERFACE ..................................................................................... 12 CHANNEL DESCRIPTION FIELDS........................................................................................ 12 SUBTITLE STREAM DESCRIPTION FIELDS .......................................................................... 13 MENU SETUP ...................................................................................................................... 13 HOW TO .................................................................................................... 16 ADDING SUBTITLE STREAMS ............................................................................................. 16 DELETING CHANNELS ........................................................................................................ 16 ASSIGNING THE INPUT CHANNEL ..................................................................................... 16 ASSIGNING THE SUBTITLE STREAM PID ........................................................................... 16 CHANGING THE CHANNEL NAME .................................................................................... 16 ASSIGNING A PROGRAM NUMBER OR PCR PID ........................................................... 16 SETTING THE PTS ADVANCE VALUE ................................................................................. 17 GLOSSARY ................................................................................................ 18

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Introduction Dear customer, thank you for purchasing SubtitlePlus DVB Server! We believe it will prove to be an efficient solution to your current and future

technological needs.

The SubtitlePlus DVB Server is a subtitling product for generation of different subtitle languages intended for Digital Video Broadcasting (DVB). We

believe it will fit equally well in both small and large subtitling facilities.

It is an official DMT policy to stay close to the customer and his needs and as a result of this, SubtitlePlus DVB Server is extremely well suited to real

DVB subtitling workflow. We are eagerly waiting to receive your future thoughts and recommendations about SubtitlePlus DVB Server functionality and

features. They are a valuable source of information for us and are vital for SubtitlePlus DVB Server’s market success and future development.

This User’s Manual is divided into several logically sequential sections, each dedicated to teach you how to install, use and maintain SubtitlePlus DVB

Server software as efficiently as possible. We believe you will find learning and using SubtitlePlus DVB Server to be a pleasure, and we expect your

feedback at:

e-mail: subtitleplus@playbox.tv

fax: +359-2-971 77 00

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Style Conventions Here are some text style conventions, which will be maintained throughout this manual. These conventions will make the manual easily understandable

and help you better navigate through it:

File names, software, documents or terms are written in italics

Direct quotations from the computer screen are presented as follows:

Menu Items and commands

Field names, check boxes

Buttons

Screen readings are written in [square brackets]

The keyboard keys are enclosed in < > signs

The arrows, used in setting procedures mean as follows:

A menu item follows;

A field name, a check box name or a value name follows.

Except for arrows, you can distinguish between the relevant menu categories also by the stiles, listed above.

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Getting Started

INSTALLATION

In order to install SubtitlePlus DVB Server you should have install the required Microsoft Windows operating system. Then you can go on with

SubtitlePlus DVB Server installation. Just insert the SubtitlePlus DVB Server installation CD and double-click on the Subtitle Plus DVB Server.EXE icon.

It is a routine procedure, which presents you with a License Agreement and a Read Me information.

Minimum system requirements

The minimum system requirements below are estimated for up to 20 subtitle streams.

CPU: Pentium 4 at 2.4 GHz

RAM: 500 MB

OS: Windows 2000 or later, XP Preferred

NOTE: If you are going to use ASI In/Out, hyper-threading is mandatory!

For more than 20 subtitle streams, a Dual Xeon processor is a must.

Software License

THE SubtitlePlus DVB Server LICENSE IS PROVIDED BY THE WIBU USB KEY. IT WILL NOT RUN WITHOUT THE KEY INSTALLED ON YOUR USB PORT.

Prior to initiating any operations with the SubtitlePlus DVB Server, read carefully the following section containing a short introduction to DVB subtitling

principles.

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Introduction to DVB Subtitling DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an

industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards

Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU). The standards can be

obtained for free at the ETSI website after registration (http://www.etsi.org/services_products/freestandard/home.htm).

Later on, the DVB group has specified the standard for subtitle streams accompanying any or all video services within a multiplexed Transport stream.

This standard is known as ETSI 300 743 (1997-09) and was later amended by ETSI 300 743 V1.3.1 (2006-11).

According to this standard, there are two methods of transmitting subtitles – bitmap and code-based.

In the bitmap method, each subtitle row is converted into a graphics image and then transmitted as a bitmap object. The color of each pixel in the

image is determined by a color reference table that can contain up to 256 color definitions. A single language bitmap subtitle stream requires a

bandwidth of between 50 to 100 kbps depending on the size and color density of the subtitles.

In the code-based method, each character within a subtitle is transmitted using a unique character code. This method relies on using character code

reference tables that are shared between encoding systems and the font processor of the receiving device. Besides, there should be at least one subtitle

font available in the receiver. Despite that it requires less transmission bandwidth than the bit-map method, the code-based method is considered

inflexible and is used rarely.

The SubtitlePlus DVB Server provides possibilities for broadcasting subtitles in both methods (check how to setup on page 17).

In order to understand correctly the setup procedure for the SubtitlePlus DVB Server, one should be aware of the structure of a transport stream

(DVB multiplexed stream).

A transport steam carries several separate program channels, the relevant audio for them, and a number of service mapping tables and EPG (Electronic

Program Guide) information. Each of these reference components is enclosed in a transport packet stream within the multiplexed stream and has a

unique packed ID (PID).

For each service in the multiplex, the PAT (program Association Table) indicates the location (the Packet Identifier (PID) values of the Transport Stream

(TS) packets) of the corresponding Program Map Table (PMT) - see Figure 1. It also gives the location of the Network Information Table (NIT). The PAT

is always identified by PID=0.

The PMT on its side identifies and indicates the locations of the steams that make up each service, and the location of the Program Clock Reference

fields for a service.

Figure 1

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The Program Stream could also contain NIT (Network Information Table) and CAT (Conditional Access Table). The CAT (PID=1) holds information about

encrypted programs. As there are no pre-specified MPEG standards for encryption, this table usually contains the encryption algorithm.

Each program could have its own PCR (Program Clock Reference) or many programs could share a common PCR. This is a timing reference used to

synchronize the elementary streams within the program stream.

A Subtitle Service is a single stream of subtitles that has an associated language; purposes (ex. for hearing impaired people); display attributes (ex.

aspect ratio).

The DVB subtitle data is carried within a private data stream. A program could have several associated subtitle services. They can be carried in the

transport stream in two ways:

All subtitles services in a single PID. They are distinguished from each-other through their composition pages.

Each subtitle service in a separate PID. Each PID has only one composition page.

In SubtitlePlus DVB Server, each subtitle stream is carried in an individual stream and hence has its own PID. It is important to remember that there are

several key components within each stream that form the subtitle service:

The PID of a subtitle transport packet stream is described in the PMT which, on its side, “tells” the DVB decoders which PID streams carry subtitles for

each video stream in the multiplex.

Each subtitle has an associated Presentation Time Stamp (PTS). It indicates to the DVB decoder at which point in time (relative to the main PCR) the

object should be displayed on the screen. This optimizes the bandwidth and simplifies multi-language subtitling by allowing subtitles to be pre-delivered

to the decoder.

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Integration of the SubtitlePlus DVB Server Figure 2 represents the principles of DVB subtitles broadcasting. Encoders provide the elementary Audio and Video streams of each program to the

Multiplexer. Each elementary stream has its native PID.

Subtitle streams (each having its own PID) are also fed to the Multiplexer.

Inside the Multiplexer, all PIDs undergo a process of remapping. It is needed for grouping all elementary streams in a single program and describing

these PIDs in the PMT. Remapping PIDs guarantees that there will be no doubling PIDs in the Transport stream as it might happen that some PIDs on the

inputs had identical values.

Further on, all remapped PIDs are fed to the multiplexing engine inside the Multiplexer. Another routine generates a PAT and PMTs and feeds them to

the multiplexing engine as well.

As a result, a transport stream is produced, containing all the elements described above. Usually this transport stream is passed to a kind of signal

“multiplier” that outputs several (depending on the Multiplexer model) identical streams out of the multiplexer.

Figure 2

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Multiplexer SetUp Remapping – Create remapping if the input subtitle PIDs are different from those contained in a program.

In the PMT of the relevant program, create streams of type Private Data 1 for each subtitle stream and assign to it an appropriate PID.

For each such stream create and assign a subtitling prescriptor in which specify:

Language – select the appropriate language

Subtitling type – choose the type of subtitling (aspect ratio, hearing impaired) –see the Specification for Service Information (SI) in DVB systems - ETSI EN

300 468 V1.6.1 (2004-11) for further details.

Composition Page ID = 0

Ancillary Page ID = 0

One of the multiplexer’s outputs must be connected to the SubtitlePlus DVB Server input. It provides the PCR timing needed for correct assignment of

PTSes to the subtitles (See Figure 3).

If there is an encoder in the system setup, it usually has a delay. This is the interval between the video input in the encoder and the output of the

encoded video from the encoder.

The playout application is DMT’s AirBox or any other capable of providing TC and tape ID data. Audio and Video streams are processed in an encoder

and then sent to the multiplexer. Usually there is a decoder delay of 3 to 80 frames (depending on the encoder model). The SubtitlePlus DVB Server must

be “informed” about this delay, so that it could pass the subtitles correctly to the multiplexer. The Delay Buffer must be equal to the encoder delay.

Check how to set the encoder delay on page 16.

The timecode of the playback device (ex. AirBox) is being sent to the SubtitlePlus DVB Server and arrives there with some delay (usually not more than

1-2 frames). This delay should be entered in the Clip Timecode Pre-delay spin box (described in page 161 below).

When receiving the PCR, the SubtitlePlus DVB Server needs some time to decode it. Besides, there is some PCR transport time, and the multiplexer also

accumulates some processing delay. Therefore, when assigning the PTS, the DVB Server should take into account all these delays (called Multiplex delay

in Figure 3). This overall delay is set in the PTS Advance spin box (see page 16).

The idea is that:

the subtitles should be passed simultaneously with the relevant video stream (therefore we need to know the encoder delay);

the assigned PTS should be later than the currently received PCR, as the moment in the PCR has actually past (due to PCR Transport and Decoding delay,

we receive it a little later than it appears). Besides, the multiplexer needs some time before outputting the streams. If we take the received PCR and

assign the PTS based on it, without any delay corrections, the subtitles will not be displayed at all – they will arrive at the multiplexer after the moment

assigned in the PTS.

Figure 3 contains an example of AirBox and SubtitlePlus DVB Server integration. In it, the playout application AirBox passes Time Code and Tape ID

to the SubtitlePlus DVB Server.

The Tape ID is used to detect the relevant subtitle file. The subtitle file, together with the timecode is used for rendering of graphics or text subtitles. The

rendered graphics/text subtitles are passed for Time Stamp Assigning.

Figure 3

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The received PCR from the Transport stream is extracted and also passed to the Time Stamp assigning unit. If there is no PCR input, the SubtitlePlus

DVB Server can generate PCRs internally. In this case the subtitles’ times are not synchronized to any external video stream and can be used for test

purposes only.

After assigning the Presentation Time Stamp, the elementary stream is passed to the Multiplexer which finally outputs the multiplexed transport stream.

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User Interface Now that we are acquainted to the Principles of the transport stream multiplexing process, let us have a look on the SubtitlePlus DVB Server interface

and settings.

The major part of the interface provides Channel description and buttons for the most common settings needed in daily DVB subtitle broadcasting. In

the main menu above are situated the more general setting options, that concern the setup of the multiplexing system.

CHANNEL DESCRIPTION FIELDS

There are two types of rows in the window: channel rows and subtitles rows. You can change the position of a channel using the red arrows in the far

left of its row. Each channel row contains the following buttons and fields:

Each channel should be connected to a TC source. Push the Received Time Code address button to specify this source (it comes from an IP address

– for example from the AirBox PC (DMT proprietary protocol) or from another TC-generating device.

Each Subtitles Channel should also receive PCR, as it is used for PTS assignment. Click on the PCR/Prog.

Button. A dialog will open to assign the program number or the PCR PID. If you want to view these in

hexadecimal values, check the Hex box below.

NOTE: The program number must correspond to the number of the program that goes out of the multiplexer.

The Channel name is displayed next to the PCR/Prog. button (Channel # by default). You can change it by double-

clicking in this field and typing the new name in the dialog.

Fields 4, 5, and 6 contain the timing information and the Video source reference (Tape ID) needed for the correct

identification and presentation of the subtitles.

The Clip Timecode field displays the incoming TC. It is used to render the correct subtitles.

As it was explained already, the PCR is also crucial for the correct subtitle presentation. The PCR could either come from the Transport Stream output,

from another external PCR generator, or from the SubtitlePlus DVB Server internal generator (for test purposes only). Depending on your DVB

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broadcasting system setup, you have to “tell” the SubtitlePlus DVB Server where the PCR comes from. This is done in the Run menu – select among

UDP Receive, Deltacast ASI Receive, or DVB Master Receive.

The Tape ID is used in Subtitle Server to recognize the relevant subtitles file (see Figure 4.). The Tape ID is displayed in case the TC comes from an IP

address.

In the right of the Channel row there are three spin-boxes providing possibilities for subtitles “fine-tuning”. They are related to the correct PTS assigning

(see figure 3).

Clip Timecode Pre-delay – enter the difference between the current timecode (sent out from the playout application) and the received timecode (at

the input of the SubtitlePlus DVB Server). The delay between the actual TC and the received TC (accumulated from the read system, playout system,

etc.)

Encoder Delay – set it according to the specifications of the encoder you use (it is usually described in the encoder’s documentation).

PTS Advance – set it according to the Multiplex delay (see Figure 3.). Here, you should enter the total delay resulting from Multiplex processing, PCR

Transport and PCR decoding in the SubtitlePlus DVB Server. It is in the range of 2 to 30 frames, depending mainly on the multiplexer and receiver

device used. The PTS Advance is actually how bigger from the received PCR should the PTSes be. Here we give an account for the delay from the

currently processed PCR (in the multiplexer) from the one that we receive. Usually it varies in-between 300 ÷ 500 ms.

Output PCR Advance is for development purposes, so please do not use it.

Use this arrow to show/hide the subtitle streams of a channel.

SUBTITLE STREAM DESCRIPTION FIELDS

Each subtitle row contains the following buttons and fields related to a single subtitle stream:

Push the PID button and enter the PID of the output stream where the relevant subtitles will be located.

In the drop-down list to the right, you must select the subtitles’ language.

The third field serves as a preview pane – the subtitles are displayed when the appropriate TC is received.

In the drop-down list to the right of the preview pane, you can select what type of subtitles you would like – text or graphics.

If you select graphics, set the number of colors you’ d like to use (4, 16 or 256) in the last drop-down list to the right.

If a file corresponding to the currently received Tape ID is found and loaded from the Watched Directory, its file path will be displayed under the PID

button. If there is no such file, [-none-] is displayed.

MENU SETUP

There are two rows in the File menu – Add Channel and Exit. At selecting the Add Channel item, a new channel will appear at the end of the

channels list. You can change its name by double-clicking in the cyan field [Channel #] by default.

The view menu provides options for opening additional information windows.

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Press the Subtitle Files menu item to view a list of all subtitle files available in the Watched directory. You can change the directory by pressing

the Watched Dir button and browsing for a new folder.

Click on the Received Timecode item if you want to view details of the received timecode (IP Address, Timecode and Tape ID of the currently

playing clip.

The following menu items are grouped in two categories – Receive and Transmit. According to your DVB system setup, you can view the relevant

receiving and transmitting parameters.

In Run menu, the Received Timecode is checked by default. Uncheck it if you do not want the subtitles to be displayed

(during some setup procedures for example).

In the list below, check one of the available receive sources (UDP, Deltacast, DVB Master). And one or more transmit destinations.

Running Nulls – the SubtitlePlus DVB Server will output continuously empty packets of each subtitle stream PID to the

multiplexer. Thus the multiplexers will “see” each stream, without generating subtitles at all. This is important to the Remapping process.

You will need this option only during the SubtitlePlus DVB Server installation and for testing.

Running PCR – this item is for test purposes only. It will output the current PCR in the form of packets.

Running PAT

The Multiplexer receives stream tables (subtitles and language). If the running PAT cannot put the Multiplexer on the right track, you have to describe

the input streams in the multiplexer Setup:

New Stream;

Type: Private 1;

PID (enter it manually). Note that you should remap the corresponding input PID to this value.

Descriptor: Subtitling descriptor, in which you should select the relevant language. The Composition and Ancillary pages should be set to [=0].

The SubtitlePlus DVB Server can compile its own PAT and PMT tables, containing the entire information from the channel setup. Click in the Running

PAT item to compile it.

Update PAT – generates a new version of the PAT and PMT tables (use this only if there is Running PAT).

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Use the Test menu to check if your subtitles are output correctly. Here is how to setup your system for a test:

You must specify the Host IP (the first button in the left). The host must be your playback PC. Then, you must add the channels with

your languages (there can be added 2 channels in the Demo version). Add a channel by right-clicking on the Channel button. In

View Subtitle files, browse for the folder where your subtitles are stored (you can download test subtitles from our FTP).

From View menu, choose the relevant Transmit item. If you have DeltaASI board, select Deltacast ASI Transmit.

If you do not have any hardware, select UDP Transmit then enter the IP address of a PC that will receive the

subtitle stream (there must be a player capable of receiving the subtitles installed on it) and check Activate.

Also, if you use VLC Player for input instead of your own playback application, you must check Run UDP

Receive. If you use your own playback application this is not needed.

UDP Receive and UDP Transmit must be set on different ports if the IP address is the same.

In Run, you must check Received Time Code, and the relevant Transmit (again, this depends on whether you have a DeltaASI or

not).

In Options select Running PCR and Running PAT if you use your own playback application. Then press Update PAT.

In the Test menu choose Output test video (if you are going to use VLC to watch the subtitles) and Generate PCR.

Start the VLC Player and go to File Open Network Stream, choose the UDP port selected in the SubtitelServer (1234 by default) and

press OK. Now, if everything is set correctly, you should see a 3 sec looped video and from Video Subtitles Track you will be able to

select which subtitle stream to watch.

One possible software player capable of receiving and playing such streams is VLC – www.videolan.net.

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How To

ADDING SUBTITLE STREAMS

Right-click on the Prog/PcrPID button and select Add Subtitle Stream…

DELETING CHANNELS

Right-click on the Prog/PcrPID button and select Delete Channel

ASSIGNING THE INPUT CHANNEL

Click on the far left button in the Channel row. A dialog will open for you to specify the machine address.

ASSIGNING THE SUBTITLE STREAM PID

Click on the PID button and enter the desired PID for your subtitle stream. Click OK

CHANGING THE CHANNEL NAME

If you want to change a channel’s name, double-click in the Channel field and type the new name in the dialog.

ASSIGNING A PROGRAM NUMBER OR PCR PID

It is crucial to specify the PCR source, as it is used in assigning the subtitles’ PTSes. To assign the PCR source, click on the Prog/PcrPID button and

enter the relevant information. If you want to view it in hexadecimal values, check the Hex box.

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SETTING THE PTS ADVANCE VALUE

Run the whole setup (the SubtitlePlus DVB server, the Multiplexer and the playout server).

Go to View menu and open the UDP Receive dialog

In the Address string, specify the IP address of the Multiplexer and the relevant port where the PCR is sent.

Go to Run menu and select UDP Receive. A tick will appear in the Active box.

Press the PTS button to view the incoming PCRs.

Select a subtitle row (use the PID as reference) and subtract the PCR value from the PTS value.

The difference (in milliseconds) is equal to the PTS Advance value that you must enter in the PTS Advance string (9).

Open the UDP receive dialog again and check the Offset.

IMPORTANT: According to the standard, the offset should not exceed 100 ms! If it is larger, increase further the value in the PTS Advance string.

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Glossary The terms below are quoted as defined in ETSI 300 743 V1.3.1 (2006-11)

Ancillary page: means of conveying subtitle elements that may be shared by multiple subtitle services within a subtitle stream

NOTE: For example, an ancillary page can be used to carry logos or character glyphs.

Colour Look-Up Table (CLUT): look-up table applied in each region for translating the objects' pseudo-colours into

the correct colours to be displayed

Composition page: means of conveying subtitle elements for one specific subtitle service

Display set: set of subtitle segments of a specific subtitle service to which the same PTS value is associated

Packet IDentifier (PID): Transport packet identifier

NOTE: See ISO/IEC 13818-1 [1].

PES packet: See ISO/IEC 13818-1 [1].

Pixel-data: string of data bytes that contains, in coded form, the representation of a graphical object

Presentation Time Stamp (PTS): See ISO/IEC 13818-1 [1].

Subtitle service: service that provides subtitling for a program for a certain purpose, such as subtitles in a specific

language or for the hard of hearing

NOTE 1: A subtitle service is displayed as a series of one or more pages.

NOTE 2: Typically, a subtitle service meets a single communication requirement (e.g. the graphics to provide subtitles in one language for one program).

ETSI EN 300 743 V1.3.1 (2006 11)

Note that in the document above Subtitle Services are referred to as Subtitle Streams

Subtitle stream: stream of subtitling segments carried in transport packets identified by the same PID

NOTE: A subtitle stream contains one or more subtitle services.

Transport packet: See ISO/IEC 13818-1 [1].

Transport stream: stream of transport packets carrying one or more MPEG programs

NOTE: See ISO/IEC 13818-1 [1].

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Digital Media Technologies Ltd.

7 Iskarsko shose Blvd.

Building 15, 5th Floor

1528 Sofia, Bulgaria

Tel.: +359 2 9703050

Fax: +359 2 9717700

playbox@playbox.tv

www.playbox.tv

All rights reserved copyright © 1999-2013