Signalling Specifications for DTT deployment in Portugal

1.

Introduction........................................................................................................................................2 1.1. Scope .........................................................................................................................................2 1.2. Document conventions and organization...................................................................................2 1.3. Questions and Remarks ............................................................................................................2 2. References ........................................................................................................................................3 3. DTT Network Deployment Brief ........................................................................................................4 4. Service Broadcast .............................................................................................................................4 4.1 Video Characteristics .................................................................................................................4 4.2 Audio Characteristics.....................................................................................................................5 4.3 Teletext ..........................................................................................................................................6 4.4 Subtitling ........................................................................................................................................6 4.5 Electronic Programming Guide .....................................................................................................6 5. Additional Services............................................................................................................................7 5.1 Software update for DTT Receivers ..............................................................................................7 5.2 Data Services ................................................................................................................................7 5.3 Interactive Services .......................................................................................................................7 6. Service Support Signalling ................................................................................................................8 6.1 Introduction ................................................................................................................................8 6.2 Program Specific Information (PSI) ...........................................................................................8 6.2.1 Use of PSI tables and descriptors ......................................................................................8 6.2.2 CAT ..........................................................................................................................................8 6.2.3 PAT .........................................................................................................................................8 6.2.4 PMT.........................................................................................................................................9 6.3 System Information (SI) .......................................................................................................... 10 6.3.1 SI tables ............................................................................................................................... 10 6.3.2 NIT........................................................................................................................................ 11 6.3.3 SDT ...................................................................................................................................... 13 6.3.4 EIT........................................................................................................................................ 14 6.3.5 TOT/TDT .............................................................................................................................. 14 6.4. DVB SSU signalling .................................................................................................................... 15 6.5. Specific Descriptors for DTT....................................................................................................... 16 6.5.1 Logical Channel Number descriptor..................................................................................... 16 6.5.2 HD Simulcast Logical Channel Descriptor ............................................................................ 17 7. Content protection .......................................................................................................................... 18 8. Conclusions.................................................................................................................................... 18 9. Part A - Network Service ID and TSID ........................................................................................... 19 10. Part B - Genres List .................................................................................................................... 20 11. Part B - Service Types................................................................................................................ 25 12. Part B - Ratings .......................................................................................................................... 26

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1. Introduction 1.1.

Scope

This document describes the modes of operation of the Portugal Telecom SFN Digital Terrestrial Television network, and requirements and recommendations regarding Set Top Boxes (STB) and TV sets. This document addresses manufacturers of such products, who wish to position their products as devices for reception of Portugal Telecom services on the Portuguese retail market.

1.2.    

Document conventions and organization

Throughout this document the word “shall” is used to set as mandatory the requirement. The descriptors tables exhibited on this document use as requirements convention, the “Mandatory”, “Conditional” and “Optional” labels. See description on 6. This document is oriented at the transport stream level, namely television services, additional services and the information flow and semantics. This document refers to the original Portuguese version 1.0. There is no version control for the English version. In case differences are found between the English version and the Portuguese version, the Portuguese version prevails.

1.3.

Questions and Remarks

All the commentaries to this document must be addressed to Portugal Telecom web address at www.tdt.telecom.pt or at [email protected].

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2. References [1] ISO/IEC 13818-1 : « Information Technology – Generic coding of Moving pictures and associated Audio Information – Part I : Systems – International Standard (IS) » [2] ETSI EN 300 468 : « Digital Video Broadcasting (DVB) ; Specification for service Information (SI) in DVB systems » [3] ETSI TR 101 211 : « Digital Video Broadcasting (DVB) ; Guidelines on implementation and usage of service information » [4] ETSI EN 301 192 : « Digital Video Broadcasting (DVB) ; DVB Specification for data broadcasting » [5] ETSI TR 101 202 : « Digital Video Broadcasting (DVB) ; Implementation Guidelines for Databroadcasting » [6] ISO/IEC 13818-6 : « Information Technology – Generic coding of Moving pictures and associated Audio Information – Part 6 : Extension for Digital Storage Media Command and Control (DSM-CC) – International Standard (IS) » [7] ETSI TS 102 812 : « Digital Video Broadcasting (DVB); Multimedia Home Platform (MHP) Specification 1.1 » [8] IEC/CENELEC 62 216 - 1: « Baseline Digital Terrestrial TV Receiver Specification » [9] ETSI EN 300 743 : « Digital Video Broadcasting (DVB) ; Subtitling systems » [10] ETSI EN 300 472 : « Digital Video Broadcasting (DVB) ; Specification for conveying ITU-R System B Teletext in DVB bitstreams » [11] ETSI TS 101 154 : « Digital Video Broadcasting (DVB) ; Specification for the use of Video and Audio Codingin Broadcasting Applications based on the MPEG-2 Transport Stream» [12] ETSI TS 102 006 : « Digital Video Broadcasting (DVB); Specification for System Software Update in DVB Systems » [13] ISO/IEC 14496-10 : « Coding of audio-visual objects -- Part 10: Advanced Video Coding » [14] ATSC A/52: « Digital Audio Compression Standard (AC-3, E-AC-3) » [15] ISO/IEC 13818-7 « Generic coding of moving pictures and associated audio information -- Part 7: Advanced Audio Coding (AAC) » [16] ISO/IEC 14496-3:2001/Amd.1 « Coding of audio-visual objects -- Part 3: Audio » [17] ISO/IEC 14496-3:2005/Amd.2 « Coding of audio-visual objects -- Part 3: Audio » [18] RTP, SIC e TVI, Classificação de Programas de Televisão, 2006

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3. DTT Network Deployment Brief The network deployment in Portugal is done in 3 distinct networks: • Portugal Mainland • Autonomous Region of Azores • Autonomous Region of Madeira These 3 networks are deployed differently. The service offer at mainland is set as five Standard Definition channels and one High Definition channel. At Azores and Madeira, the offer is increased by one Standard Definition channel plus the remaining services offered on the mainland Mux. On network set up, Azores is a set of MFN networks where each one of the networks is available in different frequencies and with different parameters.

4. Service Broadcast The DTT service payload is composed for a set of data streams that at least must include the following components: • One or more streams of video, in standard definition (SD) and /or high definition (HD); • One or more streams of audio, set as audio mono, stereo or with multiple canals (5.1); • One or more streams of data; • Signalling adjusted for seamless access to all the programs; • One or more interactive streams. A user of the Portugal Telecom DTT network shall be able to access the programs, selecting the logical channel number (LCN), as indicated in the chapter 6 and additionally, the receiver shall feature the better quality stream that is broadcasted per program. This means that a receiver, in case of an HD simulcast program, shall select the HD stream if the receiver is able to reproduce the HD stream.

4.1

Video Characteristics

The video program elementary stream fulfil all the requirements of the H.264/MPEG4 part 10 standard [13] available in the following profiles: High definition:   

H.264 HP@L4 Variable Bit Rate with minimum of 1Mbps and maximum of 10Mbps Resolution 1920x1080i, 1440x1080i or 1280x720p

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Standard definition, format 16:9 or 4:3:   

H.264 MP@L3 Variable Bit Rate with minimum of 0,1Mbps and maximum of 10Mbps Resolution 750x576

The video stream can alternate format (16:9 or 4:3) at ant point of the transmission. The receiver device once triggered by this event shall make the right display change. The trigger to the receiver is according to standard AFD [11], indicated in chapter 5. In case of multiple video streams per service it must follow the same rules.

4.2 Audio Characteristics The program audio elementary stream is distributed in mono, stereo or multi-channel (5.1). In presence of audio 5.1 elementary stream the receiver shall make the downmix from 5.1 to stereo if no 5.1 output is active.

All the flows of audio must correspond to one of the following profiles: 

Mono or stereo, in MPEG 2 Layer [1]:  



Multichannel 5.1 in a52 (Digital Dolby AC-3) [14]: 



Minimum bandwidth of 64Kbps and a maximum of 128Kbps in mono; Minimum bandwidth of 128Kbps and a maximum of 265Kbps in stereo;

Fixed bandwidth of 384Kbps;

Mono, Stereo or multichanel in AAC-LC [15], AAC-HE V1 [16] or AAC-HE V2 [17]   

Minimum bandwidth of 16Kbps and maximum of 32Kbps in mono; Minimum bandwidth of 32Kbps and maximum of 128Kbps in Stereo; Minimum bandwidth of 128Kbps and maximum of 256Kbps in 5.1;

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4.3 Teletext Although the future of teletext remains uncertain due to tha fact that there is no standard on how to show telext on high definition interfaces, the teletext shall be supported for legacies devices and use cases, in such a way that current users are not impaired by the analog shutdown. The teletext services must follow the standard DVB Teletext [10].

4.4 Subtitling Subtitling functionalities may be present both embedded into the video, or on a separate stream. The manner of including the subtitles onto the stream instead of embedding it on the video offers significant advantages, from both the functionality and compression efficiency point of view. This document only covers the DTB subtitles. Subtitles based on teletext may be also present, and shall be supported as part of the teletext functionality. All subtitles based on DVB Subtitling [9] shall be supported. The signalling to use to identify the subtitles is described in Chapter 6.

4.5 Electronic Programming Guide The Electronic Programming Guide (EPG), is a cornerstone feature on the DTT, and thus shall be fully supported. For all events, programming information will be present for both the current event and the following event (EIT p/f actual) up to the 15 following days (EIT Current Schedule). Information regarding events in others multiplexers shall also be supported (EIT Schedule Others). This information is according to the rules described on DVB PSI/SI [2]. The following set of information shall, in order to maximize user experience:     

Event Title, with a recommended maximum size of 50 characters; Short Event Description, with a maximum size of 250 characters, with a brief of the event. This field shall never be shown concatenated with the Event Description, as the text may be dupplicated; Event Description, with a recommended maximum size of 4000 characters; Parental Rating; One or more genre. Up to 10 shall be supported. The use of the thematic subjects is defined in Chapter 5.

It can however be broadcasted additional information as optional presentation on receiver, example: year, actors, producers, country and others. This information must be present according to what is defined on chapter 6. The information of programs rating must be considered as essential. The available categories are described in the Annex B. All the receivers shall have basic mechanisms restrict access according to the rating defined per program.

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5. Additional Services To guarantee the best user experience over the DTT ecosystem, other services can be deployed as required by the content providers or the equipment manufacturers: software updates for DTT receivers, interactive services or data broadcast services.

5.1 Software update for DTT Receivers In order to ensure that most DTT receivers have the longest lifespan possible, all DTT receivers shall be able to receive software upgrades over the air. This will allow not only to bring required updates to DTT receivers but also to add new functionalities to be made available on already existing DTT receivers. The software delivery shall rely on DVB-SSU [12] enhanced profile. Since the amount and variety of receivers in the marketplace is something that is outside of the scope of the network provider, the availability of software updates for most DTT receivers cannot be guaranteed at all times, but can be scheduled, in such a way that both DTTuser or equipment can be notified of the next scheduled broadcast. This scheduling shall be agreed with the players on the marketplace that intends to enable this process. Future releases of this document shall bring the identifications (OUI) of the eligible manufacturers.

5.2 Data Services

To be specified on future releases.

5.3 Interactive Services To be specified on future releases.

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6. Service Support Signalling 6.1

Introduction

To the whole set of DVB PSI/SI tables that configure the DTT network we call them Signalling. These tables allow for automatic configuration of DTT receivers, without user intervention, and with high interoperability. For each of the tables and descriptors hereunder, the following information is always provided:  

Defining standard; Broadcast information o Mandatory - This information must be always present; o Conditional - This information must be always present if one given condition is applied. Changes to optional if such condition are not set; o Optional - This information can be present;

6.2

Program Specific Information (PSI) 6.2.1 Use of PSI tables and descriptors

The following tables defined as per ISO/IEC 13818-1 [11] (MPEG Systems) may be present on the DTT environment

Table

Broadcast

CAT

Conditional – Only present if encrypted content is being broadcasted

PAT

Mandatory

PMT

Mandatory

6.2.2 CAT At present time the use of this table is not foreseen. This may change on future revisions.

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6.2.4 PMT The PMT shall be present on either one of the following flavours: 

One PMT per program;



One PMT for all programs.

The DTT receivers shall accept both flavours and shall additionally interpret the following descriptors:

Name

Tag

Broadcast

subtitling_descriptor

0x59

Optional

Comments 

Only present if there are subtitles available;



If subtitles are not available, this descriptor is not present:



Availability of Subtitles for the hard of hearing or earring impaired shall be defined by this

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descriptor. teletext_descriptor

0x56

Optional



Only present if teletext is available;



If no teletext is available, this descriptor is not present:

AC-3_descriptor

0x6A

Optional



Only present if A/52 audio(Dolby AC-3) is available;



If no A/52 audio is available, this descriptor is not present:

data_broadcast_id_descriptor

0x66

Optional



This descriptor is present on the services carrying DVB SSU with data_broadcast_id = 0x000A

AAC descriptor

0x7C

Optional



Only present if AAC audio is available;



If no AAC audio is available, this descriptor is not present.

6.3

System Information (SI)

6.3.1 SI tables

The SI tables hereunder, defined by ETSI EN 300 468 [2] may be present on the DTT environment:

Table

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Broadcast

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BAT

Not used

NIT Actual

Mandatory

NIT Other

Optional – Only present in case of additional DTT Muxes

SDT Actual

Mandatory

SDT Other

Optional – Only present in case of additional DTT Muxes

EIT p/f Actual

Mandatory

EIT Schedule Actual

Mandatory

EIT p/f Other

Optional – Only present in case of additional DTT Muxes

EIT Schedule Other

Optional – Only present in case of additional DTT Muxes

TDT/TOT

Mandatory

6.3.2 NIT

The DTT network deployment consider 3 distinct networks : Continental, Autonomous Region of the Azores and Autonomous Region of Madeira. The following describers can be used in the NITs of the DTT:

Descriptor linkage_descriptor

Tag

Broadcast

0x4A

Mandatory

Comments/description The linkage_type usage is described on the table below.

network_name_descriptor

0x40

Mandatory



The network name shall not exceed 20 characters



The language shall be set as “PRT” Latin 9

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private_data_descriptor

0x5F

Optional

logical_channel_descriptor

0x83

Mandatory



The usage of this descriptor is defined in chapter 5.5.2

HD_simulcast_logical_channel_descriptor

0x88



Mandatory

The usage of this descriptor is defined in chapter 5.5.2

terrestrial_delivery_system_descriptor

0x5A

Mandatory

frequency_list_descriptor

0x62

Optional



This descriptor is mandatory for the Azores Mux.

service_list_descritor

0x41

Mandatory



The services list is described on annex C

Linkage Descriptors Description

Linkage_type

Comment

EPG

0x02

This linkage descriptor identifies which mux carries the EPG information, in case there are several muxes available.

Home

0x04

Transponder

This linkage Descriptor identifies which mux shall be initially used for channel search. The remaining muxes, if available shall only be accessed based on the SI information from the “Home Transponder”.

Receivers

0x09

update

This linkage Descriptor identifies which service carries DVB SSU updates.

Additionally, the following parameters shall be used: 

Original network id : 0x22C8



Network ID:   

Mainland : 0x3401 – channel 67 - 838-846 MHz Autonomous Region of Madeira : 0x3402 - channel 67 - 838-846 MHz Autonomous Region of Azores : 0x3403 o Island of S. Jorge - channel 47 - 678-686 MHz o Island of Pico - channel 56 - 750-758 Mhz o Islands of S. Miguel and Graciosa – channel 61 - 790-798 MHz o Island of the Faial - channel 64 - 814-822 MHz o Islands of Terceira, S. Maria, Flores and Corvo – channel 67 - 838-846 MHz

Any update on broadcasted service list shall be based on the version number, where the receiver shall refresh the list of services whenever this field is modified or, in alternative, shall inform the user of this event.

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On the Azores islands, a different use case exists. On the Azores islands the DTT network is composed of a series of different transmitters, but in some cases, the frequency assigned to a specific island may not be the best frequency available due to propagation effects. To cover this case, on the Azores island, the DTT receiver shall search initially for the proper frequency and after, search for each frequencies present on the frequency_list_descriptor. Only the frequency with the best signal reception shall be used for the service search.

6.3.3 SDT

On Service Description Table, only the service_descriptor is mandatory.

Descriptor service_descriptor

Tag 0x48

Broadcast Mandatory

Comments 

The service provider shall not exceed 20 characters;



The Service Name shall not exceed 20 characters;

linkage_descriptor

0x05

Optional



This linkage descriptor shall be present in case of a temporary HD and SD simulcast.



If the simulcast is permanent, then the specific descriptor shall be present instead.



This descriptor shall the DVB triplet

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(ONI,TSID,SID) identifying the HD program

The field “running_status” shall be used according to the table exhibited below: Value 0 1 2 3 4 5 6 to 7

Meaning Not defined Service not used Service start in a few seconds Service stop Service on air Service deactivated Reserve for future use

Comments Unused Unused Unused. Future usage includes enhancement of the operation of receivers capable of recording content. Unused Nominal value for a service Standard value for HD programs when not broadcasted Not used;

6.3.4 EIT

The set of tables EIT (Current EIT p/f, EIT p/f Others, EIT Current Schedule and EIT Schedule Others) must have the following descriptors:

Descriptor content_descriptor

Tag 0x54

DBroadcast Optional

Comments o

The genres list is described on Part B;

o

Per event may have up to 10 genres;

parental_rating_descriptor

0x55

Mandatory

o

The rating list is described on Part D.

short_event_descriptor

0x4D

Mandatory

The Event_id field shall unique for each event for the whole period for which EPG information is available. Therefore, DTT receivers may use this field to keep track of events, even in case the exhibition date and/or time is change or event if the Event Title is changed.

6.3.5 TOT/TDT These tables are responsible for the date and time information the DTT stream. Hereunder are the descriptors to be used

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Descriptor

Tag

Broadcast

Comments/description

local_time_offset_descriptor

0x58

Mandatory

• Country_code = PRT comply with ISO3166 • Country_region_id: 

"000001" – For Mainland and Autonomous Region of Madeira

 "000002" – For Autonomous Region of Azores • Local_time_offset_polarity: 

"0" – For Mainland and Autonomous Region of Madeira  “1” – For Autonomous Region of Azores • Local_time_offset : 1 hour • Time_of_change : Country local time change rules shall be applied • Next_time_offset: Country local time change rules shall be applied

6.4. DVB SSU signalling The management of the Update Notification Table, according to DVB SSU [12], where the following descriptors are used:

Descriptor

Tag

Broadcast

scheduling_descriptor

0x01

Mandatory

update_descriptor

0x03

Optional

message_descriptor

0x04

Optional

Comments/description

This Descriptor shall contain the message to be shown to the user, whenever the DTT receiver is being updated

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private_data_specifier_descriptor

0x5F

Optional

Use only if the manufacturer requires it, in order to ensure the correct function of the DTT receiver.

6.5. Specific Descriptors for DTT

6.5.1 Logical Channel Number descriptor PT as most DVB operators selected the logical_channel_descriptor to index the programs on DTT mux (see IEC/CENELEC 62 216 - 1[8]). The logical_channel_descriptor describer is defined as follows:

Sintaxe

payload

Tipo

Logical_channel_descriptor () { descriptor_tag

8

uimsbf

descriptor_length

8

uimsbf

for (i=0 ;i