HPA Roundtable Presentation February 2, 2007 Laszlo Zoltan, VP Sales & Marketing © 2007 Computer Modules, Inc West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Why Packetization

188 Bytes West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Typical 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), 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) A Little Background

11409 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Simple A/D Converter

Frame Buffers West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Frame Buffers FR 1 Memory FR 2 Memory FR 3 Memory FR 4 Memory FR 5 Memory

11409 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) A Processor Examines the Redundancies in Each Sub Frame (Block)

11409 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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

11409 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Tables Consist of Two Types

PAT (PID 00 – Always) West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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) (Assigned PID #34 by Human) (Assigned PID #45 by Human)

A Typical PAT for A Three Program Transport Stream PID – 00 PAT PID – 23 – Program Map Table for Program 1 PID – 34 – Program Map Table for Program 2 PID – 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) A Typical PAT for A Three Program Transport Stream

PIDs can be found at three layers: PAT PMT PES West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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) West Bernardo Court San Diego, CA Tel: (858) Fax: (858) PSIP Basic Tables (U.S.) (Content Distribution)

PSIP West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) 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 West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Interesting Notes

Important Note The most important table for decoding is the VCT West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Important Note

Several Ways Transport Streams Can Be Carried 1) DVB-ASI – Asynchronous Serial 2) SMPTE 310M – Synchronous Serial 3) IP – Packets 4) FireWire® – Packets 5) USB West Bernardo Court San Diego, CA Tel: (858) Fax: (858) Several Ways Transport Streams Can Be Carried

–.8V P-P – Biphase Mark Encoded – 75 Ohm – Self Clocking West Bernardo Court San Diego, CA Tel: (858) Fax: (858) SMPTE 310M