IPTV Overblik

IPTV overblik

Søren Andreasen System Engineer CCIE #3252

IPTV = IP network delivered TeleVision Today it usually includes: Switched Digital Broadcast channels (SDB) Video-on-Demand services (VOD) Digital Video Recorder services (DVR/PVR) Interactive TV applications (ITV)

Broadband IP Access Network

Today: xDSL, Cable Modem, IP-STB Analog or Digital TV FTTx, Metro Ethernet, Subscriber (Set Top Box) (increasingly HDTV) Future?: 3G, WiMax, BPL, ... Session Number Presentation_ID © 2006 Cisco Systems, Inc. All rights reserved. Cisco Confidential 2 What is VOD?

VOD = Video-On-Demand

Service Provider

VOD is about putting the consumer in control in accessing high-quality video- based content

Leverages Digital Cable or IP Set Top Boxes (STBs)

• Movies-on-Demand (MOD) • Subscription Video-on-Demand (SVOD) • Free Video-On-Demand (FVOD) • HDTV-on-Demand (HDVOD) • Network-based Personal Video Recording (nPVR) • Public, Educational & Governmental On-Demand (PEG-OD) City council meetings, Information Local sports & Community events • Distance Learning (EduVOD) Education-on-Demand Do-it-yourself tutorials • Advanced Advertising • Interactive TV (iTV) Video-based shopping

Session Number Presentation_ID Virtual ©museums, 2006 Cisco Systems, Inc. All rights vacations, reserved. etc. Cisco Confidential 4 MPEG Compression Overview

• The Need for Video Compression • Video Compression Standards • Video Compression Techniques • MPEG Transport Streams

• Uncompressed Digital Video in the SDI (Synchronous Digital Interface) format requires a tremendous amount of bandwidth to transmit 270Mbs for Standard Definition Service 1.485Gbs for High Definition Service • Aggressive compression techniques are required in order to deliver video services over IP networks • Compression is also required to reduce storage requirements for Video on Demand (VOD) systems

• Moving Picture Experts Group (MPEG) A working group within the International Standards Organization (ISO) that was establish in 1988 to define the standards for digital compression of audio-visual signals.

• MPEG has standardized the following compression formats and ancillary standards: MPEG-1: Initial audio and video compression standard. Later used as the standard for Video CD, and includes the popular Layer 3 (MP3) audio compression format. MPEG-2: Transport audio and video standards for broadcast-quality television. Used for over-the-air digital television ATSC, DVB and ISDB, digital satellite TV services like DirecTV, digital cable television signals, and (with slight modifications) for DVD video discs. MPEG-4: Expands MPEG-1 to support audio/video "objects", 3D content, low bit rate encoding and support for Digital Rights Management. A new higher efficiency video codec is included (an alternative to MPEG-2 Video). MPEG-4 Part 2: Full Protocol that includes support for advanced editing functions and 3D modeling MPEG-4 Part 10: Also known as the Advanced Video Codec (AVC) and H.264. MPEG-4 Part 10 is effectively an extension of MPEG-2 that incorporates the advanced compression techniques used in MPEG-4 Part 2. MPEG-4 Part 10 = H.264 = AVC Session Number Presentation_ID © 2006 Cisco Systems, Inc. All rights reserved. Cisco Confidential 9 Typical Compression Ratios

• For Broadcast Video Applications, the following compression ratios are typical: • MPEG-2 SD: 270Mbs SDI Æ 3.5 – 5 Mbs MPEG-2 Stream HD: 1.485Gbs SDI-HD Æ 15 – 20 Mbs MPEG-2 Stream Compressed stream is 50 to 100 times smaller • MPEG-4 SD: 270Mbs SDI Æ 1.5 – 2.5 Mbs H.264 Stream HD: 1.485Gbs SDI-HD Æ 8 – 12 Mbs H.264 Stream Compressed stream is 100 to 180 times smaller

• Performance of H.264 vs. MPEG-2 38 37 36 35 34 33 Quality 32 Picture Rating 31 30 29 H.264 28 MPEG-4 part 2 27 MPEG-2 26 25 0 500 1000 1500 2000 2500 3000 3500 Bit-rate [kbit/s]

• Limitations of human perception are used to determine what information can be discarded from the signal without a significant reduction in perceived signal quality • Visual Limitations Limited resolution Higher luminance resolution than color resolution Higher sensitivity for coarse picture details than fine details • Psychoacoustic Limitations Limited frequency response (Fra 20hz til 20.000hz) Non-linear frequency response Limited volume range (fjern svag og meget høj lyd)

• Blanking removal • Chroma sub sampling (færre farve samplinger end grå samplinger, samt pixel optimering) • Motion Prediction (Temporal Compression) • Spatial Compression (Still Image Compression, ala jpeg) Discrete Cosine Transform Quantization • Entropy Coding (Huffman Coding)

• Blanking Removal (ingen tab af kvalitet) The horizontal and vertical blanking areas are not recorded. They are replaced by short sync data words specific to the application. Example: ITU-R BT.601, 10 bits per sample, 4:2:2 bit-serial data stream has a bit rate of 270Mb/s. Removing the blanking data results in a reduced bit rate of 207Mb/s without affecting the picture quality.

Vertical Blanking Interval Horizontal Blanking Interval

Electron Gun

Picture Area

Lossy images utilizing Sub-sampling

The pixels in every second row and every second column are ignored. To compensate for this, the size of the remaining pixels are scaled up. Human perception fills in the gaps.

• Hierarchy of Data Group of Pictures (GOP) Frame Slice Macroblock Block • Fixed størrelse i Mpeg2, variabel • I Mpeg4 kan slices og blocks kan være for forskellige størrelser

• Frames of video are coded as pictures in a specific sequence • Types of frames I-pictures: intraframe encoded, do not use prediction P-pictures: interframe encoded using forward prediction B-pictures: interpolated bi-directional motion prediction

• Temporal Redundancy Motion Prediction

I Frame B Frame P Frame Only Motion Encoded Complete Frame Encoded Ball Encoded with Motion Vector Ball Bi-directionally from I & P from I frame Revealed Knee from P frame

• Coding of Moving Images Most video frames are similar except for movement

• Only the difference between frames is encoded and transmitted.

• Frame Types I-Frames or Intracoded Frames

•Frame Types P-Frames or Predictive Frames •Indeholder ”forskellen” fra sidste I eller P frame, f.eks rød pil viser hvor objekt vil bevæge sig hen.

•Frame Types B-Frames or Bidirectional Predictive Frames •Indeholder ”forskellen” fra sidste I/P frame og næste P frame. F.eks rød pil viser hvor objekt var i foregående I/P frame og blå viser hvor objekt er i næste P frame.

•GOP

• A GOP is usually described by a two number sequence describing The I frame interval The anchor frame interval (I or P frames)’ • Afstanden mellem I frames afgør ”channel change time”!!! • 12/3 er mest ”normalt” i mpeg, men også 15/3 bruges • Video med 30 fps og GOP på 15/3 vil have en I frame hvert ½ sekund

1 1 1 0 1 2 3 2 3 2 3 2 30

B B B I B B P B P B P B PI

Example of 12/3

• Functions of an Encoder 1. Process Composite and SDI Input signals. 2. Use Sub-sampling Compression. (Blank removal og “farve fjernelse”) 3. Use Temporal Compression methods to further compress data. 4. Use Spatial Compression methods. (JPEG lignende compression) 5. Use Mathematical Compression to further compress data.(ZIP lignende) 6. Multiplex Video and Audio data to produce a Single Program Transport Stream. (Lyd kan være flere sprog eg. Tysk, Dansk etc)

COMP 1 In Y Process ENCODER Cr signals SDI In Cb

2 3 4 5 6 TS

Use Temporal Multiplex Use Compression Use Use Spatial signals to Subsampling methods to Mathematical Compression Transport Compression further Compression Stream compress

• Multiple Streams Combined Transport stream is a multiplex of programs consisting of Video Multi Audio Single Program Program Transport Data Transport Stream Stream (Mest brugt i Program 1 Kabel-TV)

eg video text Program 2 Program 3 Program 4 Program Specific Information (PSI) is a series of Program 5 tables that define the actual structure of a Transport Stream. F.eks hvilke audio og video text der passer til video, hvilke type encryption/scrambling

188 bytes 188 bytes 188 bytes 188 bytes 188 bytes 188 bytes 188 bytes

G-2G-2 MPEG-2MPEG-2 MPEG-2MPEG-2 MPEG-2MPEG-2 MPEG-2MPEG-2 MPEG-2MPEG-2 MPEG-2MPEG-2 MPEG-2MPEG-2 MPEMPE acketacket SPTSSPTS packetpacket SPTSSPTS packetpacket SPTSSPTS packetpacket SPTSSPTS packetpacket SPTSSPTS packetpacket SPTSSPTS packetpacket SPTSSPTS packetpacket SPTSSPTS pp

Typically 7 MPEG-2 SPTS packets Time per 1362 byte Ethernet PDU

CC PP MM II UU CC PP MM II U ltipleltiple completecomplete P MultipleMultiple completecomplete P MultipleMultiple RR . . . HH AA P DD RR . . . HH AAMPEG-2MPEGP -2D EG-2EG-2 packetspackets vv MPEG-2MPEG-2 packetspackets vv MPEG-2MPEG-2 CC YY CC 44 PP CC YY CC 44 P 1-7 * 188 bytes 4 8 14 20 81-7 * 188 bytes 4 8 14 20 8 7 * 188 byt Standard Ethernet 1518 bytes max

• One to seven MPEG-2 Single Program Transport Stream (SPTS) packets per Ethernet frame delivered directly over UDP/IP/Ethernet • For each 3.75 Mbps SD stream, one Ethernet packet every ~2.8 msec For each 15.0 Mbps HD stream, one Ethernet packet every ~0.7 msec • Up to 250 streams at 3.75 Mbps/stream per Gigabit Ethernet output • UDP/IP/GigE delivery overhead is approximately 1 - (7*188/1370) = 4%

188 bytes 188 bytes 188 bytes 188 bytes 188 bytes 188 bytes 188 bytes

Typically 7 MPEG-2 SPTS packets Time per 1374 byte Ethernet PDU

II II ipleiple complete complete CC PP MM UU RR MultipleMultiple completecomplete CC PP MM U RR MultipleMultiple . . . H A PP D . . . H A PP RR H A v D TT RR H A v D TT EG-2EG-2 packetspackets v MPEG-2MPEG-2 packetspackets v P MPEG-2MPEG-2 CC YY CC 44 PP PP CC YY CC 44 P P 1-7 * 188 bytes 4 8 14 20 812 1-7 * 188 bytes 4 8 14 20 8 12 7 * 188 Standard Ethernet 1518 bytes max

• Adds RTP-layer time stamp, sequence number, and other capabilities defined by IETF RFC 1889 (RTP) and RFC 2250 (MPEG over RTP) • Still integral number of MPEG-2 TS packets per RTP message • For each 2 Mbps SD stream, one Ethernet packet every 5.264 msec For each 8 Mbps HD stream, one Ethernet packet every 1.316 msec • RTP/UDP/IP/GigE overhead is approximately 1 - (7*188/1382) = 5%

Packet 8 bits 1 1 1 13 2 2 4 bits Sync Transport Payload Transport Transport Adaptation Continuity Header byte error unit start Scrambling Priority PID Field Control Counter 0x47 Indicator Indicator Control 4 bytes 188 bytes ...... eam packet MPEG-2 Transport Stream packet MPEG-2 Tra ......

8 bits 1 bit 1 bit 1 bit 5 Adaptation Random Elementary Optional Stuffing Packet Payload Discontinuity field access Stream Flags Adaptation bytes (PES or PSI data) Indicator length Indicator Priority Fields 0xFF Start code 0x000001yy

42 + 6 res 42 + 6 res 8 bits variable Adaptation Splice TS private Adaptation PCR OPCR Fields countdown data field ext.

• Each 188 byte Transport Stream packet contains data from one elementary stream or PSI/SI data as defined by the 13 bit PID Session Number Cisco Confidential 30 Presentation_ID value © 2006 Cisco Systems, Inc. All rights reserved. Outline

• Overall headend signal flow • Sattelite subsystem • Receiver subsystem • Encoder subsystem • Local reception • Ad insertion

Video Headend Packet Core Access Infrastructure Subscriber Premises xDSL Satellite InternetInternet Modem STB Content ServiceService ProviderProvider Central Office

Off-air BRAS TDM Content Local PSTN Content BBDLC Packet FTTN/C Encoders Backbone

Access Ring Middleware Residential Nx GigE Gateway ADSL2+ VoD VDSL2 Servers Optical Packet Transport Switching

Encryption

ONT

Central FTTH Office Ad Insertion and Regional Video Headend Emergency Access

Video processers, manipulere video Justere lumincance, chromanence, Brightness, audio level op/ned GPS video syncronizing, så der kan skiftes mellem primær og backup uden ”tab” (Ikke særligt normalt at have)

Typisk MPEG2, ca 10% stadigt analogt. Future er MPEG4, men kun en provider i dag Med MPEG2 kan man presse 8- 12 feeds ind i hvad et analog fylder, med MPEG4 = 15-20

Et video feed per Kan også være RF Demodulere og dekryptere MPEG2 (ASI) eller encoder + Men fiber valgt pga PIP (typisk beskyttelse mod uncompressed SDI signal Tager Multi Program 96*96 pixel) lynnedslag, samt Output er IP længere afstand fra Transport Streams Tallerken til reciever og laver om til SPTS Typisk max 100m med coax Layer 1 video router, for redundans / backup Session Number Presentation_ID © 2006 Cisco Systems, Inc. All rights reserved. Cisco Confidential 33 Video Hub Block Diagram

ATSC SD/HD/SDI/ASI SwitchMatrix Fiber Optic Program AV H.264 Receiver Receiver HD Processor Encoder Frame Sync

Fiber Optic A/D AV H.264 Ethernet Switch Receiver Processor Encoder Analog Frame Sync

For more information on 6238 8VSB Demodulator http://www.scientificatlanta.com/customers/Source/7002786.pdf AV 8 VSB Program H.264 HD Processor Receiver Receiver Encoder Frame Sync

A/D AV Analog H.264 Processor Encoder Receiver Frame Sync

For more information on 6275 analog receiver http://www.scientificatlanta.com/customers/Source/7002588.pdf

• There are three main signal formats at the output of the satellite receivers: Analog Video Referred to as composite or baseband video DVB – ASI Digital Video Broadcast - Asynchronous Serial Interface Referred to as ASI (multiple MPEG signals <= 213mbit) SDI Serial Digital Interface (single uncompressed format, SD =270mbit, HD=1.4 Gig) Baseband digital video

Satellite receivers is a combination of a receiver and decoder also known as Integrated Receiver Decoder (IRD). Feed Horn Demodulate: separates the video signal from the modulated carrier Assembly Decrypt: descrambles, if the signal is encrypted Encryption systems vary around the world. Example, PowerVu® , Nagravision®Parabolic , Viaccess®LNB , IrDeto® Reflector DC Power V

H Power Divider (H Feed)

Power Inserter

Power Power Inserter Divider 75 ohm (V Feed) LNB co-axial Power LNB’s Supply cable

Earth Station Power Satellite Dividers Receivers / (signal splitters) Decoders

• Essentially there are two types of satellite receiver/ decoders: Units that output analog audio and video Referred to as composite or baseband video Units which output a digital stream, either: DVB – ASI Digital Video Broadcast - Asynchronous Serial Interface multiple MPEG signals <= 213mbit SDI Serial Digital Interface – Baseband digital video single uncompressed format, SD =270mbit, HD=1.4 Gig (op til 4 audio og 1 video på SDI)

ASI the physical interface for a MPEG transport stream. One or more programs can be transported via coaxial cable up to a maximum of 213 Mbps.

• Provides switching for ASI/SDI/HD-SDI signals. • Up to 2048 inputs and 1024 outputs.

MPEG Encoder

Single Program Transport Stream (SPTS) to Digital Multiplexer(ASI) or IP(ethernet) • Encoders will apply one of 3 compression schemes MPEG-2 MPEG4-10 H.264 VC-1 - Microsoft Windows Media Player 9 • Digital signals received via satellite today are in a MPEG-2 format. • MPEG-4 and VC-1 give up to two times the bandwidth efficiency of

HB0 HBO2 Hmm… I only want to use the Program 2 Program 5 primary stream from the local broadcaster; I don’t need SKY RAI2 ITV HBO2, and SKY and RAI2 both Program 8 Program 2 Program 5 have the same program number. How can I get them Local Local Broadcaster Broadcaster into the same transport Program 12 Program 13 stream?

• When MPEG2 Transport Streams are received via satellite and terrestrial receivers they typically are not in a format desired by the cable operator. • These streams can be manipulated by a device called a Digital Multiplexer.

ASI Digital Satellite Receiver GbE ASI Multiplexer or ASI RF Digital Satellite Receiver AM To ASI Transport Laser Hub

Digital Satellite Receiver QAMs RF Combiner ASI Or 8VSB ATSC Receiver Primary Hub AM To TX SONET Laser Hub GbE Digital Video GbE or ASI GbE or ASI RF Combiner Digital Transport Digital Server Transport Digital GbE RF or ASI

• A Digital Multiplexer, or multiplexer, is a High Density MPEG processing device that allows you to customize MPEG streams.

HB0 HBO2 Program 2 Program 5 VBR 2.5~3.9 VBR 2.3~3.8

Local BBC RAI2 SKY HB0 HBO2 BBC RAI2 Broadcaster Program 8 Program 2 Program 5 Program Program Program Program Program VBR 2.5~3.9 VBR 2.9~3.9 VBR 2.6~4.1 2 5 8 9 10 CBR 3.6 CBR 3.5 CBR 3.6 VBR 2.6~4.1 VBR 4.2 ~ 4.9 Local Local DCM D9900 Broadcaster Broadcaster VBR 4.2 ~ 4.9 VBR 3.9 ~4.5 Digital Program 12 Program 13 Content • Multiplexer features include: Manager MPEG stream customization of programs (add/drop/edit). Merge or combine single program streams into multiple program streams. Reduce bit-rate (transrate) for outgoing equipment or signals, or to maximize use of bandwidth. Replace national ads with local ad Local program insertion Scrambles • Capable of transrating, statistically multiplexing or rate-limiting up to 350 SD or 85 HD streams for each co-processor (up to 4)

• Part of the contracts between service providers and content providers allows them to substitute local advertisements for the advertisements in the satellite programming. This has been a very high margin business for cable companies. • These ads can consist of: National / local advertising National / local promotion of brand product Network cross-channel promotion

• Traditionally the switching was done via audible tones in the analog programming. • Digital Program Insertion (DPI) is done via additional coding in the MPEG-2 stream. SCTE 35 is the most common standard for this. • The problem for wireline operators is that the DPI signaling is lost in the conversion from MPEG-2 to SDI. • No system is currently in place convert the DPI information in MPEG-2 directly to the H.264 signals.

• Two solutions to the problem have been proposed: Convert all the signals to analog baseband and insert the ads and then convert the combined stream back to digital Only linear ad insertion possibilities

Convert the ads to H.264 and splice them at IP Allows for targeted adds to be sent to individual settops Additional equipment is required to convert the adds to IP

IRD Splicer MPEG-2 QAM RF

with DPI DCM D9900

MPEG-2 Ad Server

• IPTV Problem Ads are not in MPEG-4 During conversion to SDI the DPI information is lost

IRD SDI Splicer

Encoder H.264 w/DPI DCM D9900 DTMF Cue Tone Decoder Contact Closures

MPEG-2 SDI Ad Server PowerVu D9850 Encoder Program Receiver (IRD)

Session Number Presentation_ID © 2006 Cisco Systems, Inc. All rights reserved. Cisco Confidential 50 Session Number Presentation_ID © 2006 Cisco Systems, Inc. All rights reserved. Cisco Confidential 51