hpa roundtable presentation february 2, 2007 laszlo zoltan, vp sales & marketing © 2007...

HPA Roundtable Presentation

February 2, 2007

Laszlo Zoltan, VP Sales & Marketing

© 2007 Computer Modules, Inc.

11409 West Bernardo Court San Diego, CA 92127

Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Understanding Transport Streams

A video stream created by an MPEG-2 encoder (compressor) that is specifically encoded to be transmitted by modern digital networks and has the following characteristics:

1) It is packetized to 188 byte frames (Historical)

2) It has some basic tables appended to it every 100 milliseconds that conform to: • PSI – MPEG standard tables• SI or PSIP – ATSC or DVB video standard – tables


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Understanding Transport Streams

1) Short and fixed size packets are amenable to error correction and switching

2) Packets have headers which identify packet types and route packets to proper place in a sequence


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Why Packetization

188 Bytes


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Typical PacketTypical Packet

4 Bytes 184 Payload (Video or Data)

But

MPEG Header (Not TS Header)

The Enabling Technologies for MPEG-2 Transport Streams

1) Video rate analog to digital converters (ADC’s), 10-25 Mhz sampling rate

2) Digital computers fast enough to compute discrete cosine transform (the core algorithm of MPEG compression)

3) Space based Satellites for Video Traffic that use MPEG-2

4) Cheap Memory ICs for frame memories to buffer video frames


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

A Little Background


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Simple A/D Converter

Frame Buffers


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Frame Buffers

FR 1 Memory

FR 2 Memory

FR 3 Memory

FR 4 Memory

FR 5 Memory


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

A Processor Examines the Redundancies in Each Sub

Frame (Block)


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Bit of History of MPEG Streams

JPEG • Created in 80’s• Intraframe• 25:1

MPEG-1 • Created in early 90’s• Intraframe for motion• 100:1

MPEG-2 • Intra + Interframe• Created in mid 90’s• 200:1

MPEG-4 • Advanced version of MPEG-2• 400:1


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Multiplexing and Table Structures

A collection of information inserted recurringly in a “table structure” in specific locations of an MPEG-2 transport stream to help “humans” and “IRD’s” understand what is being decoded.


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

PSI/SI/PSIP Tables

Decoder Oriented: – Encoder bit rate

– Time Info– Channel ID’s

Human Oriented:– Time Info– Channel ID’s– Cost of Content– Text Messages


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

TablesConsist of Two Types

PAT (PID 00 – Always)


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

PSI (MPEG) Table Hierarchy

NIT PMT 1 PMT 2 PMT 3

PES PIDS PES PIDS PES PIDS

(#36,#37,#38)

(Assigned PID #23 by Human)



A Typical PAT forA Three Program Transport Stream

PID – 00 PATPID – 23 – Program Map Table for Program 1PID – 34 – Program Map Table for Program 2PID – 45 – Program Map Table for Program 3

But, the PMT for Program 2 at PID 34 would show the following PIDs:

36 – Video and PCR 37 – Audio 38 – Data


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

A Typical PAT forA Three Program Transport

Stream

PIDs can be found at three layers:

• PAT

• PMT

• PES


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Remember!

STT – System Time

RTT – Rating Region (Voluntary)

MGT – Master Guide Table (Memory allocation, etc.)

VCT – Virtual Channel Table (All channels or will be channels)


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

PSIP Basic Tables (U.S.)(Content Distribution)

PSIP


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

PSIP/ATSC Table Hierarchy

STT RRT MGT VCT

EIT ETT

Base Tables

1) Each channel in VCT is further described in an EIT (Event Information Table) that is good for three hours

2) There must be four EITs in every stream


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Notes About VCT

Interesting Notes

1) Some PSIP info can and often is used in cable systems, but the VCT becomes CVCT with different channel properties

2) On cable systems, EIT and ETT are optional


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Interesting Notes

Important Note

The most important table for decoding is the

VCT


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Important Note

Several Ways Transport StreamsCan Be Carried

1) DVB-ASI – Asynchronous Serial

2) SMPTE 310M – Synchronous Serial

3) IP – Packets

4) FireWire® – Packets

5) USB-2


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

Several Ways Transport Streams

Can Be Carried

– .8V P-P

– Biphase Mark Encoded

– 75 Ohm

– Self Clocking


Tel: (858) 613-1818 Fax: (858) 613-1815

www.dveo.com

SMPTE 310MSMPTE 310M

hpa roundtable presentation february 2, 2007 laszlo zoltan, vp sales & marketing © 2007...

Documents

west bernardo court

memory slide

mpeg header

packetization slide

memory fr

ts header slide

advanced version of

little background slide