AVTransport

MPEG-2 Transport

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 The MPEG-2 Standard

n ISO/IEC 13818 – 1994

n Source Coding
• Video (Partie 2)
• Audio (Partie 3)
• Advanced Audio Coding (AAC, Partie 7)
n Transport
• Error-free environments (PS)
• Error-prone environments (TS)
• Controle (DSM-CC)

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 MPEG-2 Broadcasting

n Packetized Elementary Streams (PES)

• Media: audio, video, subtitles
• Data: interactive services, program guide, IP traffic
n 2 multiplexing modes:
• Program Stream (MPEG-2 PS)
• Transport Stream (MPEG-2 TS)

Program stream
Video (ex: DVD)
PES Packetizer
Encoder MPEG-2 PS
Multiplexer
Audio
PES Packetizer
Encodeur

Transport Stream
Video
PES Packetizer (ex: DVB)
Encoder MPEG-2 TS
Audio Multiplexer
PES Packetizer
Encodeur

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 MPEG-2 Transport Stream

n MPEG-2 TS = multiplexing format

• For several TV channels
─ N * (Video + Audio(s) + Data) with different time bases
• Special Case: one program
─ Single Program Transport Stream (SPTS)
n 1 transport stream = sequence of transport packets
• Fixed size (188 bytes)
─ Helps integration with error correction tools
• Detection of data packet starts
• Synchronization after packet loss
n Two ways of transporting data
• Sections: meta data, EPG, etc…
─ Carousel
PTS DTS A/V Data
• PES Packets: audio, video PES
Start Stream
─ PTS+DTS, Clock Code ID
Packet Private Data
length
─ RAP, Size
Stuffing bytes

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 MPEG-2 PES

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 MPEG-2 Transport Stream

Program
AU PES
PES
Video Encoder Packetizer
Source Program

Multiplex TS
Audio Encoder PES-Pack.

Data Encoder PES-Pack.

Clock

Timing Private
SI / PSI CA
data Data

Control / other service info

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 MPEG-2 TS –Sections
n Data Transport
• Data Blocs or « tables », of any type
• No real-time constraint
• Supports data repetition or update (carousel)
─ Version number
n Table fragmentation: sections
• Maximum size: 1024 or 4096 bytes
• Current and total fragments: 8-bit
─ Max 256 sections / table
• 1 table < 256 KB or 1 MB
• Transport integrity: CRC32
n Table Multiplexing
• TableID
• Allows sending of different tables on a single PID

Extension ID: Multiplex ID pour PAT, Program ID

Données
pour PMT, …
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 MPEG-2 TS – Le paquet TS
n Fixed packet size
• 188 bytes
n Header 4 bytes:
• Synchronization word (1 byte): synchronization recovery when losses
• Error flag: if errors are still present in the TS packet
• Packet Identifier (PID): packet destination
─ (13 bits: max 8192 destinations)
• Start flag: PES or Section first byte in this packet
n Scrambling indicator
n Adaptation Field
• For header extensions
• Random Access Point (RAP) indication
• Clock (PCR)

TS Header

Error Start
Sync Word priority PID Scrambling AF CC
flag Flag

8 bits 1 bit 1 bit 1 bit 13 bits 2 bits 2 bits 4 bits

0x47
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 F.0.1 Transport Stream syntax

See Figure F.1.

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 MPEG-2 TS Timing

n Each program carries a clock

• Program Clock Reference (PCR)
• PES Timestamps relate to this clock
n Constraints:
• PCR shall be send often to compensate receiver clock
drifts
─ MPEG-2 <100 ms
─ DVB: < 40 ms (i.e. once per frame @ 25 Hz)
n Consequence
• At constant rate D, time between PCRi and PCRi+1 is:
PCRinterpolate = PCRi + BitsSincePCRi / D
• Interpolation allowed even if VBR

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 Program and Streams

n Program Association Table

• Identifies a multiplex (ID 16 bits)
• Lists all programs
─ Program Number (16 bit)
─ PID carrying PMT
• If PID= 0, NIT
n Program Map Table
• PID carrying the PCR
─ Not always a media stream !
• Program Descriptors
─ Protection systems, interactive apps …
• Lists all streams
─ PID: where stream data is carried in the multiplex
─ streamType: type of media compression
─ Stream descriptors
• Language, coding parameters, demux parameters, …

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 MPEG-2 TS: Core Concepts

n TS, PES Valeur du Description

n PID PID
• Indicates where the data goes 0x0000 Program Association Table (PAT)
─ Allows filtering of packet for non viewed
programs 0x0001 Conditional Access Table (CAT)
• Does not indicate PES/section or coding 0x0002 Transport Stream Description Table
type (TSDT)
• Reserved PID
─ Some PSI data 0x0003 IPMP Control Table
─ Program Assocation Table (PAT)
─ Conditional Acces Table (CAT) 0x0004 – Valeurs réservées
─ Transport Stream Description Table (TSDT) 0x000F
─ User-reserved: Other standard bodies 0x0010 – Valeurs utilisables pour:
(DVB, ATSC, …)
0x1FFE -Network information table (NIT)
n Stream Type
-Program Map Table (PMT)
• One per PID at any point in time
-PID des flux élémentaires
─ But may change if PMT changes !
• Indicates coding type 0x1FFF Paquet vide
• Implies transport type (PES or Sections)
n PSI “Program Service Information”
• Multiplex description
• Program description
• Stream Descirpion
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 MPEG-2 TS: streamType
Valeur Stream Type Valeur Stream Type
0x00 ITU-T | ISO/IEC Reserved 0x10 ISO/IEC 14496-2 Visual
0x01 ISO/IEC 11172-2 Video 0x11 ISO/IEC 14496-3 Audio with the LATM transport
Syntax as defined in ISO/IEC 14496-3/AMD-1
0x02 ITU-T Rec. H.262 | ISO/IEC 13818-2 Video
or ISO/IEC 11172-2 constrained parameter 0x12 ISO/IEC 14496-1 SL-packetized stream or FlexMux
video stream stream carried in PES packets
0x03 ISO/IEC 11172-3 Audio 0x13 ISO/IEC 14496-1 SL-packetized stream or FlexMux
stream carried in ISO/IEC14496_sections
0x04 ISO/IEC 13818-3 Audio
0x14 ISO/IEC 13818-6 Synchronized Download Protocol
0x05 ITU-T Rec. H.222.0 | ISO/IEC 13818-1
private_sections 0x15 Metadata carried in PES packets
0x06 ITU-T Rec. H.222.0 | ISO/IEC 13818-1 0x16 Metadata carried in metadata_sections
PES packets containing private data
0x17 Metadata carried in ISO/IEC 13818-6 Data Carousel
0x07 ISO/IEC 13522 MHEG
0x18 Metadata carried in ISO/IEC 13818-6 Object Carousel
0x08 ITU-T Rec. H.222.0 | ISO/IEC 13818-1
Annex A DSM-CC 0x19 Metadata carried in ISO/IEC 13818-6
Synchronized Download Protocol
0x09 ITU-T Rec. H.222.1
0x1A IPMP stream (defined in ISO/IEC 13818-11,
0x0A ISO/IEC 13818-6 type A MPEG-2 IPMP)
0x0B ISO/IEC 13818-6 type B 0x1B AVC video stream as defined in ITU-T Rec. H.264 |
ISO/IEC 14496-10 Video
0x0C ISO/IEC 13818-6 type C
0x1C- ITU-T Rec. H.222.0 | ISO/IEC 13818-1 Reserved
0x0D ISO/IEC 13818-6 type D 0x7E
0x0E ITU-T Rec. H.222.0 | ISO/IEC 13818-1 0x7F IPMP stream
auxiliary
0x80- User Private
0x0F ISO/IEC 13818-7 Audio with ADTS 0xFF
transport syntax

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 MPEG-2 TS: multiplex tune-in

TS PID 0 PID 17 PID…

21 PID 40 PID 50

Program Association Table

ProgID 12 PMT PID 21
Service Desc. Table - 11
ProgID 18 PMT PID 28
Prog_id 12
ProgID 24 PMT PID 38 Provider « TPS »
ProgID 30 PMT PID 60 Nom «M6 »

TS Program MAP Table - 12

pcr_pid 40
! DVB Table ! Video(pid=40, type=0x1B)
Audio(pid=50, type=0x0F)
Audio(pid=51, type=0x0F)
Data(pid=53, type=0x06)
…

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 MPEG-2 TS: Scrambling

n Scrambling may happen:

• At PES payload level
• At some sections payload level
• At TS packet level
─ Most common use case
─ PES headers are scrambled
n Exceptions
• PAT: required to get list of programs
• PMT: required to get protection system used
• NIT/TSDT: infrastructure management

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reserved, and user available descriptor tag values. An 'X' in the TS or PS columns indicates the applicability of the
descriptor to either the Transport Stream or Program Stream respectively. Note that the meaning of fields in a descriptor
may depend on which stream it is used in. Each case is specified in the descriptor semantics below.
descriptor_length – The descriptor_length is an 8-bit field specifying the number of bytes of the descriptor
immediately following descriptor_length field.

Descripteurs MPEG-2
Table 2-45 – Program and program element descriptors Table 2-45 – Program and program element descriptors

descriptor_tag TS PS Identification descriptor_tag TS PS Identification

0 n/a n/a reserved 34 X X FmxBufferSize_descriptor
1 n/a X forbidden 35 X multiplexbuffer_descriptor
2 X X video_stream_descriptor 36 X X content_labeling_descriptor
3 X X audio_stream_descriptor 37 X X metadata_pointer_descriptor
4 X X hierarchy_descriptor 38 X X metadata_descriptor
5 X X registration_descriptor 39 X X metadata_STD_descriptor
6 X X data_stream_alignment_descriptor 40 X X AVC video descriptor
7 X X target_background_grid_descriptor 41 X X IPMP_descriptor (defined in ISO/IEC 13818-11, MPEG-2 IPMP)
8 X X video_window_descriptor 42 X X AVC timing and HRD descriptor
9 X X CA_descriptor 43 X X MPEG-2_AAC_audio_descriptor
10 X X ISO_639_language_descriptor 44 X X FlexMuxTiming_descriptor
11 X X system_clock_descriptor 45 X X MPEG-4_text_descriptor
12 X X multiplex_buffer_utilization_descriptor 46 X X MPEG-4_audio_extension_descriptor
13 X X copyright_descriptor 47 X X auxiliary_video_stream_descriptor
14 X maximum_bitrate_descriptor 48 X X SVC extension descriptor
15 X X private_data_indicator_descriptor 49 X X MVC extension descriptor
16 X X smoothing_buffer_descriptor 50 X n/a J2K video descriptor
17 X STD_descriptor 51 X X MVC operation point descriptor
18 X X IBP_descriptor 52 X X MPEG2_stereoscopic_video_format_descriptor
19-26 X Defined in ISO/IEC 13818-6 53 X X Stereoscopic_program_info_descriptor
27 X X MPEG-4_video_descriptor 54 X X Stereoscopic_video_info_descriptor
28 X X MPEG-4_audio_descriptor 55-63 n/a n/a Rec. ITU-T H.222.0 | ISO/IEC 13818-1 Reserved
29 X X IOD_descriptor 64-255 n/a n/a User Private
30 X SL_descriptor
2.6.2 Video stream descriptor
31 X X FMC_descriptor
32 X X external_ES_ID_descriptor The video stream descriptor provides basic information which identifies the coding parameters of a video elementary
33 X X MuxCode_descriptor
stream as described in Rec. ITU-T H.262 | ISO/IEC 13818-2 or ISO/IEC 11172-2 (see Table 2-46).

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AVTransport 2-46 – Video
- MPEG-2 TSstream
- DVBdescriptor
- File Broadcasting
Syntax No. of bits Mnemonic
 Random Access in TS

n RAP Random Access Point

n MPEG-2 TS random access
• First locate PAT
• Then locate CAT if present
• Finally locate PMT(s)
• Required for demuxer+decoder(+descrambler) setup
n Media
• May be signaled in adaptation field
• Audio
─ Each AU is a RAP
• Exceptions about to de deployed with MPEG-H Audio
• Video
─ Intra frames (MPEG-2), IDR (AVC or HEVC) and CRA/BLA
(HEVC)

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 MPEG-2 Packetization Ex #1

Media Frame 1 Media Frame 2 Media Frame 3

PES HDR1 Media Frame 1 Media Frame 2 Media Frame 3

n PES HDR1
• PTS/DTS of Frame 1
• Size: sum of 3 frames
n Timing of frames 2, 3 ?
• Interpolation !
• Requires understanding the media (sample rate, samples/frame, …)
n Frames sizes for 1, 2, 3 ?
• Requires bitstream parsing !
• Start code and other framing mechanisms

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 MPEG-2 Packetization Ex #2

Media Frame 1 Media Frame 2 Media Frame 3

PES HDR1 MF 2 PES HDR2 Media Frame 2 MF 3

Media Frame 1
start continued start

n PES HDR2
• PTS/DTS of frame 3 (i.e of the first frame that starts in the packet)
n Timing of frame 2
• Interpolation !
• Requires understanding the media (sample rate, samples/frame, …)
n Size of frames 1, 2, 3 ?
• Requires bitstream parsing !
• Start code and other framing mechanisms
• Requires storing parsing context between 2 PES packets

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 MPEG-2 Packetization Ex #3

Media Frame 1 Media Frame 2 Media Frame 3

PES HDR1 MF 2 PES HDR2 Media Frame 2

Media Frame 1
start continued

n PES HDR2
• No PTS/DTS (the frame does not start in this PES packet)
n Timing of frame 2
• Interpolation !
• Requires understanding the media (sample rate, samples/frame, …)
n Size of frames 1, 2, 3 ?
• Requires bitstream parsing !
• Start code and other framing mechanisms
• Requires storing parsing context between 2 PES packets

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 MPEG-2 Packetization

n Alignment PES/frame
• May be indicated in adaptation field
• May match various media bitstream syntax elements:
─ Frame start
─ Frame start or slice start
─ Component Subset (SVC or MVC)
n In real-life
• DVB/ATSC/ISDB: Video aligned, 1 frame per PES
─ DVB allows N complete frames / PES
─ And allows other configurations “if supported” J
• Audio : usually not aligned
• Cf ETSI TS 101 154

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 AVC / HEVC Packetization

n NAL units produced by encoder

n Bitstream format before PES packetization
• Start-code 0x00000001 (or 0x000001)
• NAL data
• emulation prevention bytes for start codes
─ Avoids NALU data to be interpreted as a start code
─ 0x0000xx with x in {1,2,3} sequences in NALs
• Replaced 0x0000030x
n PES packet inspection
• By looking through start code (idem for MPEG-2 video)

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 Audio Packetization

n MP3
• Sync word in the header of MP3 AU
• Frame size in the header of MP3 AU
n AAC Format ADTS
• Sync word
• Frame size and other info (channels, sample rate)
• AU AAC payload
n Warning, no emulation prevention
• Fake start codes may happen
• Verify info coherence (channels, sample rate)
• Check stream coherence
─ position + Header(N).size = Valid Header(N+1)

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 PES to TS Packetization

PES HDR1 <= N x 184 bytes

AF : yes
Payload Start Indicator = 1 AF: no (most of AF: yes with padding
the time)

TS TS TS
A PES Data Data A PAD Data
HDR HDR HDR
F HDR … … F 0xFF End
#1 #k N

PCR Padding size

Random Acces Point
…

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 Section to TS Packetization

PSI
HDR <= N x 184 bytes

Payload Start Indicator = 1 AF: yes with padding

TS TS
Section

data Data A PAD Data

PRT

HDR

HDR HDR
prev … F 0xFF End
#1 N

n Pointer_field
• 1 byte if payload start Indicator = 1 Padding size
• Gives number of bytes before next
section (PSI) header

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 8-1:2006 (E)
1:2006
puted by
Timing model and decoder
(E)PCR_base(i) (see equation 2-2) and PCR_ext(i)
e PCR field indicates the time t(i), where i is the index
ted by PCR_base(i)
(see equation 2-3) respectively. The value
of the byte containing the last bit of the
_reference_base field. (see equation 2-2) and PCR_ext(i) (see equation 2-3) respectively. The value
PCR field indicates the time t(i), where i is the index of the byte containing the last bit of the
eference_base field.
n Transport Stream System
PCR(i) = PCR_base(i) $ 300 + PCR_ext(i) (2-1) Target Decoder (T-STD)
PCR(i) = PCR_base(i) $•300 +Hypothetical
PCR_ext(i) model (2-1)describing data transfer rates in the

PCR_base(i) = ((system_clock_ frequency demultiplexer and(2-2)decoder(s)

ISO/IEC 13818-1:2006 (E) 33
$ t(i)) DIV 300) % 2

PCR_base(i) = ((system_clock_ frequency $ t(i)) DIV 300) % 233 (2-2)

PCR_ext(i) = ((system_clock_ frequency $ t(i)) DIV 1) % 300 (2-3)

ytes the PCR_ext(i) = ((system_clock_

input arrival time, frequency
t(i) shown in equation $ t(i))
2-4 below, DIV 1) %
is computed 300
from (2-3)
PCR(i+) and the transport
ata arrive, where the transport rate is determined as the number of bytes in the Transport Stream between
aining the last bit of two successive program_clock_reference_base fields of the same program divided by
s the input arrival time, t(i) shown in equation 2-4 below, is computed from PCR(i+) and the transport
between the time values encoded in these same two PCR fields.
a arrive, where the transport rate is determined as the number of bytes in the Transport Stream between
ng the last bit of two successivePCR(i+
program_clock_reference_base
) i " i+ fields of the same program divided by
ween the time values
t(i) =encoded in these same two PCR + fields. (2-4)
system_clock_ frequency transport_rate (i)
PCR(i+ ) i " i+
t(i) = + (2-4)
system_clock_ frequency transport_rate (i)
is the index of any byte in the Transport Stream for i+ < i < i*.
is the index of the byte containing the last bit of the most recent program_clock_reference_base field
applicable to the program being decoded.
is the index of any byte in the Transport Stream for i+ < i < i*.
(i+) is the time encoded in the program clock reference base and extension fields in units of the system
is the index of the byte containing the last bit of the most recent program_clock_reference_base field
clock.
applicable to the program being decoded.
ate is given by
) is the time encoded in the program clock reference base and extension fields in units of the system
clock. ((i' – i+ ) $ system_clock_frequency)
transport_rate(i) = (2-5)
is given by PCR(i') – PCR(i'')

((i' – i+ ) $ system_clock_frequency)
transport_rate(i) = (2-5)
PCR(i') – PCR(i'')
is the index of the byte containing the last bit of the immediately following
program_clock_reference_base field applicable to the program being decoded.
< i ( i*
is the discontinuity,
a timebase index of indicated
the byte containing
by the the last bit
discontinuity_indicator in theoftransport
the packet
immediately following
adaptation field,
program_clock_reference_base
given in equation 2-4 and equation field applicable
2-5 for the timetoofthe program
arrival being
of bytes at decoded.
the input to the T-STD is not
ween
i ( i*the last PCR of the old timebase and the first PCR of the new timebase. In this case the time of
26 according
e bytes is determined Institut Mines-Télécom
to equation 2-4 with the modification
16/02/2017 that the transport rate used is that AVTransport - MPEG-2 TS - DVB - File Broadcasting
mebase
ween discontinuity,
the last and next to indicated
last PCR ofbythe
theolddiscontinuity_indicator
timebase. in the transport packet adaptation field,
en in equation 2-4 and equation 2-5 for the timeThe following
of arrival of bytes at notation is T-STD
the input to the used istonot describe the Transport Stream system target decoder and is partially illustrated
specified for the PCR values. The PCR tolerance
en the last PCR of the old timebase and the firstFigure is defined as the maximum inaccuracy allowed in of
PCR of the 2-1newabove.
timebase. In this case the time
 T-STD Constraints

n Max fetch rate from buffers

• Rxn <= RMAX, specified for each media type
• Video: depends on Profile/Level
• Audio, DATA: depends on number of channels
─ MPEG-1/2, Systems: 2 Mbps
─ AAC: up to 33 Mbps
n Buffer Sizes
• Transport Buffer size: 512 bytes
• ES Buffer Size given per media type
─ AAC: < 51 kBytes
─ MPEG-1/2: 3584 bytes
─ Systems: 1536 Bytes
─ Video: depends on Profile/Level
• AVC: 10 sec max delay between TBn et Ebn

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 AVTransport

DVB

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 DVB
n Created in 1992
• > 300 members, >35 countries - www.dvb.org
• Promotion of open standards for Digital TV broadcasting
n Principal Recommandations
• Physical Layer
─ Satellite: DVB-S, DVB-S2
─ Cable: DVB-C
─ Terrestrial: DVB-T, DVB-T2
─ Mobiles DVB-H, DVB-SH
• Signalisation
─ Information de services: DVB-SI
─ Services synchro: DVB-SAD
• Protection
─ DVB-CAS, DVB-CSA
─ Interface smartcard: DVB-CI, DVB-CI+

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 Transport Stream (TS): data structure defined in ISO/IEC 13818-1 [18]

NOTE: It is the basis of the DVB standards.

transport_stream_id: unique identifier of a TS within an original network

DVB Service Model

transposer: type of repeater which receives a DVB-T signal and re-transmits it on a different frequency

The relationships of some of these definitions are illustrated in the service delivery model in figure 1.

Networks Satellite Cable Terrestrial

Transponder Transponder Transponder Transponder C ha nnel C ha nnel C ha nne l Cha nnel C h a n ne l C hannel
Multiplexes

Bouquet
Services Service S ervi ce S ervice S er vice Service S ervice S ervice S ervice Service Service

Components V id eo A u di o 1 A ud io 2 D ata

Figure 1: Digital broadcasting, service delivery model

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ETSI
 Program Signaling Information / Service Information
n Network Information Table (NIT)
• Network topology (Frequencies, FEC, …)
• PID 16, TableID 64 | 65
n Service Description Table (SDT)
• Multiplex Description (channel names, …)
• PID 17, TableID 66 | 70
n Bouquet Association Table (BAT)
• Link to other services
• PID 17, TableID 74
n Event Information Table (EIT)
• Electronic Program Guide for present and following shows
• PID 18, TableID 78 | 79
n Time and Date Table (TDT)
• UTC clock
• PID 20, TableID 112
n Application Information Table (AIT)
• Interactive App signaling (MHP, HbbTV,…)
• PID dynamique, TableID 116
• Type d’application
n IP/MAC Notification Table (INT)
• IP Transport
• PID Dynamique, TableID 76

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 DVB SI Tables 16 n ETSI TS 300 468
ETSI EN 300 468 V1.11.1 (2010-04)

MPEG-2 defined
Defined in TS 300 468
Defined in the present document • Mais pas 100% complet J
n Short sections
• 1024 octet / section max
Actual Network Other Network • Exception: 18
EIT 4096ETSI max EN 300 468 V1.11.1 (2010-04
n Sub-table
For a more detailed description of the mechanism and functionality, specifically refer to clause 2.4.4 and annex C of
ISO/IEC 13818-1 [18]. • Independent set of sections of
a table Identified through
5.1.3 Coding of PID andtable_extension_id
table_id fields

n Repeat Rate >= 25 ms

Table 1 lists the PID values which shall be used for the TS packets which carry SI sections.

Table 1: PID allocation for SI

Table PID value

PAT 0x0000
CAT 0x0001
TSDT 0x0002
reserved 0x0003 to 0x000F
NIT, ST 0x0010
SDT, BAT, ST 0x0011
EIT, ST CIT (TS 102 323 [13]) 0x0012
RST, ST 0x0013
TDT, TOT, ST 0x0014
network synchronization 0x0015
RNT (TS 102 323 [13]) 0x0016
reserved for future use 0x0017 to 0x001B
inband signalling 0x001C
measurement 0x001D
DIT 0x001E
SIT 0x001F

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Table
Figure 2: General organization of the Service Information (SI)2 lists the values which shall be used for table_id for the service information, defined in the present document.
 DIT 0x001E
SIT 0x001F

Table 2 lists the values which shall be used for table_id for the service information, defined in the present document.
Defined DVB
Table SI ofTables
2: Allocation table_id values

Value Description
0x00 program_association_section
0x01 conditional_access_section
0x02 program_map_section
0x03 transport_stream_description_section
0x04 to 0x3F reserved
0x40 network_information_section - actual_network
0x41 network_information_section - other_network
0x42 service_description_section - actual_transport_stream
0x43 to 0x45 reserved for future use
0x46 service_description_section - other_transport_stream
0x47 to 0x49 reserved for future use
0x4A bouquet_association_section
0x4B to 0x4D reserved for future use
0x4E event_information_section - actual_transport_stream, present/following
0x4F event_information_section - other_transport_stream, present/following
0x50 to 0x5F event_information_section - actual_transport_stream, schedule
0x60 to 0x6F event_information_section - other_transport_stream, schedule
0x70 time_date_section
0x71 running_status_section
0x72 stuffing_section
0x73 time_offset_section
0x74 application information section (TS 102 812 [15])
0x75 container section (TS 102 323 [13])
0x76 related content section (TS 102 323 [13])
0x77 content identifier section (TS 102 323 [13])
0x78 MPE-FEC section (EN 301 192 [4])
0x79 resolution notification section (TS 102 323 [13])
0x7A MPE-IFEC section (TS 102 772 [50])

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 DVB Descriptors

n A Lot of them !
• > 80
n Physical Layer description
• frequencies, FEC, time-slicing, cellules, …
• 1 / standard: DVB-S / S2, DVB-C, DVB-T / T2, DVB-SH
n Non-MPEG Codecs Description
• VC1, AC3, DTS, DTS-HD, AAC
• Stream configuration (~= decoder specific information)
n Textual Descriptions
• Service names, Stream names (mono and multi-lingual)
─ Parental rating, icons
• Bouquet name (mono and multi-lingual)
n And various indications
• Service Redirection
• Data broadcast (carousel)
• Mosaic video
• Phone (back-channel setup), …

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 Data over DVB
n Data piping
• raw transport on a PID Application
n Data streaming
Object
• send in PES packets IP/UDP
data carrousel
carrousel
n DSM-CC Data carrousel DVB data
DVB-MPE
data
streaming carrousel
• Transport on sections Private
data
n Object Carrousel DSM-CC DSM-CC DSM-CC
piping
data data data
• Data Carousel + file system
n Multi Protocol Encapsulation (MPE) PES MPEG-2 TS Section

• IP datagram over TS
MPEG-2 Transport Stream

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 Object Caroussel

n Mix of MPEG-2 TS sections and CORBA

n Concept « modules »:
• Files
• File system (eg, HTML + JS + CSS)
• Events (notifications)
• Links to MPEG-2 TS PIDs
n Module updating
• Each module has its own version
• Update may happen on any number of modules

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 Object Caroussel

Carousel

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 IP on MPEG-2 TS: DVB MPE

n Pros
• Simple IPv4
encapsulation
• Fast
n Cons
• Only two
priority modes
(QoS …)
• Complex
• Overhead
(>=16 bytes)

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 DVB IP Platform

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 DVB MPE-FEC

n Increase resilience to transmissions errors

• Redundancy
• Reed Solomon 255/191, 25% redundant
n Without modifying existing implementations
• No modification on MPE sections

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 DVB MPE-FEC
192 Columns (Bytes) 64 Columns (Bytes)

DGRAM
IP DGRAM

RS Column N
RS Column 1
IP DGRAM Padding

RS Column 2
...
IP DGRAM
IP

n MPE
• Each MPE+IP on a section
• Aggregation of IP datagrams in memory
n FEC
• Each RS column is send in a section
• FEC aggregation is in another table
─ Can be ignored
─ Does not interfere with MPE

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 Example: DVB-H
n Mobile Broadcasting
• Compatible with DVB-T
• Time Slicing for power savings
• IP Transport everywhere, using DVB-MPE
─ RTP for AV streaming
─ FLUTE for file carousel (SDP for description, …)
• MPE-FEC for better error resilience
n Principles
• Data sent in burst (2Mbits/burst)
• Temporal buffer of services
n Pros
• Demod/demux off during ~ (N-1)/N (N= Nb
services)
• Inactive time slot can be used for roaming
handling
n Cons
• Service access time

Service 1
Service 5
Service 1

Service 4
Service 3
Service 2

Service 2
Service 3
Service 4
Service 5 t
DVB-T Multiplexe DVB-H Multiplexe
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 DVB-H Protocol Stack

Streaming
A/V
Signalisation Download Multicast Multicast
DVB-H (AVC, AAC) File/Data UDP IP

FLUTE
RTP ALC / LCT
UDP
IP
PSI / SI MPE / MPE-FEC
MPEG-2 TS
DVB-H

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 DVB Future

n Beyond MPEG-2 TS ?
• DVB-S/T/C: 188 byte / data packet
─ TS encapsulation « too heavy »
• 2% for Audio Video high bitrate
• 4 - 14% for IP over MTE
• DVB-S/T/C 2: LDPC with large bloc sizes (16k ou 64k
symbols)
─ Base-band frame large, variable size !!
n IP in video services
• Real-time communication:
─ RTP
─ Packet-base
• Over-The-Top services (HTTP Streaming)
─ File-based (DASH, HLD, Smooth, HDS)

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 DVB GSE: Generic Stream Encapsulation

n DVB-x2 Data Link

• ETSI TS 102 606
• GSE vs TS in T2/S2/C2 baseband frame
• GSE supports
─ Fixed or variable packet sizes
- Packets from Different protocols (IPv4, IPv6)
n Packetization
• Large PDUs cut in one or several GSE packets
• Several PDUs can be aggregated in one frame
─ NO REORDERING

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 }

Each GSE Packet is composed of a GSE Header followed by a GSE Payload, where the (fragment of the) encapsulated
GSE Header
PDU is located. The GSE Header is composed of the fields shown in figure 2. The unshaded fields are always present,
while the shaded fields may be omitted depending on the preceding control fields in the first 4 bits of the GSE Header.
The presence of possible Extension Headers is determined by the Protocol Type value. The minimum GSE Header
length is therefore 2 bytes.

¢ S(tart): packet start Figure 2: GSE Header format

¢ Total Length
¢ E: packet end • Source PDU size
The syntax
• ifand semantics
!S && of the
E, 4 bytes CRCGSE Packet
at end are defined in table 2.
of frame ¢ LT (Label Type): packet filtering
¢ GSE Length: size of frame • 00: 6 bytes, 01: 3 bytes
Table
• Includes PDU, header extensions & co 2: Syntax for GSE Packet
• 10:structure
no label (broadcast)
• Up to 4K payload ¢ Label
Syntax Number of bits Mnemonic
¢ Frag ID{ (if fragmentation)
GSE_Packet() • Network Point of Attachment
• Unique identifier for each GSE fragments of a
Start_Indicator 1 bslbf
same original PDU
End_Indicator 1 bslbf
• Up to 255 PDUs in parallel
Label_Type_Indicator 2 bslbf
if Protocol Type: type du PDU
¢ (Start_Indicator=="0") and (End_Indicator=="0") and
(Label_type_indicator=="00") {
• Type-1 [0,1535]: various header extensions
Padding_bits 4 bslbf
• [0,255]:
for(i=0;i<N1;i++) { mandatory extensions
• Type-2 [1536,0xFFFF]: EtherType
Padding_bytes 8 bslbf
}
46 } else {
16/02/2017 Institut Mines-Télécom AVTransport - MPEG-2 TS - DVB - File Broadcasting
GSE_Length 12 Uimsbf
 GSE does not include a mechanism for integrity check of single GSE Packets. A CRC-32 is only appended to the last
PDU fragment of a fragmented PDU to verify the correctness of the reassembly operation. GSE relies on the physical
layer being able to ensure the required error detection and/or correction probability (see [5] for best current practices in
GSE and Base Band Frame
IP networks). The present approach is independent of the specific physical layer provided that this meets the required
level for error detection capability.

Figure 1: GSE encapsulation within DVB protocol stack

In a system where ACM is utilized, transmission parameters typically change dynamically on a frame-by-frame basis. A
receiver will generally successfully decode only a subset of the transmitted frames, i.e. only the ones whose
transmission parameters are compatible with the receiver's current channel conditions. GSE does not require that Base
Band frames include a payload unit start indicator signalling the position of the first GSE packet in the frame. GSE
47requires that a Base BandInstitut
16/02/2017
always starts with the GSE HeaderAVTransport
frameMines-Télécom of the first- MPEG-2 TS - DVB
GSE Packet. - FilePacket
GSE Broadcasting
fragmentation
between Base Band Frames is therefore not allowed.