mpeg technology primer cx380 mpeg explorer option rev. a02

MPEG Technology PrimerCX380 • MPEG Explorer Option

Rev. A02

Introduction to MPEG Video Compression techniques Compression standards Frame Types and Structure Program Specific Information

Digital Video Broadcast (DVB) MPEG & DVB relationship DVB Service Information (DVB-SI) MPEG transport stream (TS) Packetized Elementary Streams (PES) MPEG clock mechanisms (PCR, PTS, DTS) ETSI TR 101 290 test recommendation

CX380 CATV analyzer Network Overview MPEG Explorer option and video/audio metrics

Confidential & Proprietary Information of VeEX Inc. 2

Agenda

MPEG Technology Primer/CX380

Introduction to MPEG



Video Medium Evolution


The “N word” Analog signals are prone to corruption by Noise

Economics Optical media is cheaper to produce than magnetic media

Video digitization New digital video cameras capture directly to digital format Old film can be scanned with special machines to produce a digital stream

Video Encoding/Compression Once video is in a digital format, it makes a lot of sense to compress it Similar to image compression, we need to store video data as efficiently as possible maximize quality and minimize storage space and processing resources we can exploit correlation in both space and time domains


The Analog to Digital Transition


The need for video compression is obvious based on the raw bandwidth needed for HDTV and SDTV video types

While MPEG2 compression is widely adopted for SDTV broadcast applications, the newer H.264 compression standard is preferred for higher bandwidth HDTV signals


Digital Video Technologies Today


ITU (International Telecommunication Union) VCEG (Video Coding Experts Group)

ISO (International Standardization Organization) JPEG (Joint Photographic Experts Group) MPEG (Motion Picture Experts Group)


Standardization Organizations

TCPTCP UDPUDP

RTP/RTCPRTP/RTCP

IPIP

EthernetEthernetPPPPPP

H.261H.263H.264

H.261H.263H.264

RTSPRTSP

IGMPIGMP

MPEG-1 (11172)MPEG-2 (13818)MPEG-4 (14496)

MPEG-1 (11172)MPEG-2 (13818)MPEG-4 (14496)

Transport stream(13818-1)

Transport stream(13818-1)

ITU-T ISO/IEC

HTTPHTTP


Committee of experts that develop video encoding standards

Until recently, was the only authority and “show in town”

Suitable for wide range of videos

Low resolution to high resolution

Slow movement to fast action

Can be implemented either in software or hardware


Moving Pictures Expert Group (MPEG)



The MPEG Concept

MPEG-1 video compression is based upon the same technique used in JPEG, but includes techniques for efficient coding of a video sequence.

Consider the video sequence displayed below: The picture to the left is the first picture in the sequence followed by the picture in the middle and

then the picture to the right. The video sequence shows a man running from right to left with a house that is stationary.

Using MPEG video, only the new parts of the video sequence is included together with information of the moving parts

This applies only during the transmission of the video sequence to limit the bandwidth When displayed it appears as the original video sequence again.


Video contains a lot of spatial and temporal redundancy: Spatial redundancy and compression

Neighboring pixels are similar

Compresses each frame in isolation, treating it as a bitmapped image

Temporal redundancy and compression Adjacent frames are similar

Compress sequences of frames by only storing differences between them

MPEG Technology Primer/CX380 Confidential & Proprietary Information of VeEX Inc. 10

Compression with Motion Compensation

Performance can be improved by searching for just the right parts of the image to subtract from the previous frame

Motion Compensation (MC) based compression principle developed for H.261, is retained in all later video compression standards.

Spatial The compression of each frame is done with JPEG Each frame is a picture that can be independently compressed The Spatial compression engine looks inside each macroblock and determines what

information is absolutely necessary to maintain a visual reference Subtle color shades will be removed to reduce the required storage space

Temporal Certain frames are designated as Key frames Looks at the same blocks between pictures and uses prediction and motion estimation

algorithms to reduce the storage needed These predictions happen on Macroblock level Each frame between key frames is replaced by a “difference” frame Difference frames only store the differences between the frame and the preceding frame

or most recent key frame


Spatial and Temporal Compression


MPEG-1 Initial audio/video compression standard Used by VCD’s MP3 = MPEG-1 audio layer 3 Target of 1.5 Mb/s bit-rate at 352x240 resolution Only supports progressive pictures

MPEG-2 Current de facto standard, widely used in DVD and Digital TV Ubiquity in hardware implies that it will be here for a long time Transition to HDTV has taken over 13 years and is ongoing Different profiles and levels allow for quality control

MPEG-4 Includes support for AV “objects”, 3D content, low bit-rate encoding, & DRM In practice, provides equal quality to MPEG-2 at a lower bit-rate MPEG-4 Part 10 is H.264, which is used in HD-DVD and Blu-Ray


MPEG Video Compression Standards


MPEG-1 3 layers of increasing quality, MP3 (layer 3) being most common

16 bits Sampling rate (32, 44.1, or 48kHz) Bitrate (32 to 320kbps) De facto - 44.1 kHz sample rate, 192 kbps bitrate

MPEG-2 Supports >2 channels, lower sampling frequencies, low bitrate improvement

AAC (Advanced Audio Coding) More sample frequencies (8 kHz to 96kHz) Higher coding efficiency and simpler filter bank 96 kbps AAC sounds better than 128 kbps MP3

Usually CBR, but can do VBR


MPEG Audio Compression Standards


Relies on the eye's inability to resolve high frequency color changes Uses redundancy within each frame and between frames Discrete Cosine Transform, quantization & Huffmann coding predict a pixel value

from all adjacent pixel values, minimizing the overall bit rate Intra-frames (I-frames) are generated from the process


MPEG Video Compression Principle


MPEG codes video in a hierarchy of layers


MPEG Structure

Picture Layer(Frame)

Group of Pictures (GoP)

Video Sequence

Slice Layer

Macroblock Layer

Block Layer(8x8 pixels)

GoP Layer

I

BB

BB

I

BBBB P P

P

P

(Sequence layer not shown)



MPEG Frame Types



Motion Compensation & Frame Types


A set of consecutive frames that can be decoded without any other reference frames

Starts with an I-frame and ends with the frame right before next I-frame Consists of 12 or 15 frames typically Transmitted sequence is not the same as the displayed sequence The sequence of I, P and B frames is not standardized but can be chosen

according to the requirements of the application.


GOP (Group of Pictures)

Arrows show prediction dependencies between frames


Standard Application Bit Rate

JPEG Continuous-tone still-image compression Variable

H.261 Video telephony and teleconferencing over ISDN P x 64kb/s

MPEG-1 Video on digital storage media (CD-ROM) 1.5Mb/s

MPEG-2 Digital Television 2-20Mb/s

H.263 Video telephony over PSTN 33.6kb/s

MPEG-4 Object-based coding, synthetic content, interactivity Variable

JPEG-2000 Improved still image compression Variable

H.264 /MPEG-4 AVC

Improved video compression 10’s to 100’s kb/s


Compression Standard/Rate Summary


The ISO/IEC specifications describe profiles that define the structure of the encoded stream.

Profiles characterize the complexity of the encoding, indicating how difficult this signal will be to decode.


MPEG-2 Profiles

MPEG-2 Profiles

Abbr. Name Frames YCbCr Streams Comment

SP Simple Profile P, I 4:2:0 1 no interlacing

MP Main Profile P, I, B 4:2:0 1

422P 4:2:2 Profile P, I, B 4:2:2 1

SNRSNR Scalable Profile

P, I, B 4:2:0 1-2 SNR: Signal to Noise Ratio

SPSpatial Scalable Profile

P, I, B 4:2:0 1-3 low, normal and high quality decoding

HP High Profile P, I, B 4:2:2 1-3


Digital Video Broadcast (DVB)


Digital Video Broadcast http://www.dvb.org/ European standard for digital video broadcasting, now used globally DVB Project was launched in 1993 by an Industry-led consortium of over 250 companies

including broadcasters, manufacturers, network operators, software developers, regulatory bodies and others

Project became operational in 1995 Based on MPEG-2 transport streams Very flexible and can carry Internet traffic The standard also specifies mechanisms for interactive service with return channels

provided by PSTN, ISDN, GSM, DECT, LMDS, cable and satellite


Ever heard of DVB?


There are three major sub-standards of the DVB standard namely: DVB-S (Satellite) – using QPSK – 40 Mb/s DVB-T (Terrestrial) – using QAM – 50 Mb/s DVB-C (Cable) – using QAM/OFDM – 24 Mb/s

The sub-standards differ only as it applies to physical representation, modulation, transmission and reception of the signal.

DVB uses a MPEG-2 Transport Stream to carry it’s data and has added some features in the MPEG-2 standard

Can deliver to the home almost anything that can be digitized: High Definition Television (HDTV) Standard Definition Television (PAL / NTSC, SECAM) New broadband multimedia data and interactive services

Several tables have been added to the MPEG-2 Transport Stream specifications (CAT, EIT, etc.)


Digital Video Broadcast (DVB)


MPEG is primarily a compression standard.

The output from an MPEG encoder can be carried as an MPEG stream in a noise free environment, but it is not suitable for a noisy channel.

DVB provides error correction, program information and conditional access signaling, and modulation.

DVB guarantees the delivery of an MPEG stream over Cable (DVB-C), Satellite (DVB-S), Terrestrial Radio Channel (DVB-T), or Local Microwave Distribution Service (DVB-MC).


Why does MPEG need DVB?



Building the MPEG-2 Streams

Two kinds of multiplexed stream are specified: Transport Stream (TS)

The transmission channel where errors occur Designed for “lossy” links, such as networks or broadcast antennas Consists of relatively short fixed-length TS packets

Program Stream (PS) Uses error-free transmission channels (storage e.g. disks)


Stream Type Application Features

Transport Stream (TS) Used for transmission where cell loss and bit errors occur.

Error correction is not included in the MPEG standard.

Example: Broadcast applications

Fixed-length packets (188 bytes)

A PES packet is divided up and placed in the payload section of TS packets.

Multiple reference clocks possible


MPEG2 Transport Stream

The DVB stream consists of a series of fixed length packets which make up a Transport Stream (TS).

Streams carry higher layer packets derived from an MPEG stream.

It carries multiple streams, some synchronized to each other (for lip sync), others running independently.


Transport Stream Packet

Fixed length of 188 bytes

First 4 Bytes are the packet header while 184 Bytes are used for payload

13 bit for the PID enable identification of 8192 (213) different kinds of logical channels

Packet contains data (video, audio, data, program guide)

Carries timing information (PCR)

Every 4 Byte Header contains:

188 Byte Packet

4 Byte PacketHeader

Adaptation Field (if present)

Payload(if present)

Sync byte 0x47 Transport error indicator Payload unit start indicator Transport priority


PID Scrambling Control Adaptation field control Continuity Counter


What do MPEG-2 TS Packets Carry?

Two main types of data packets (streams and sections): Packetized Elementary Stream (PES)

Series of packets carrying video, audio and data streams Data Section

Block of data with one or more TS payloads carrying program information and other data

PES Packet Data Section

PID 2PID 1

Transport Stream

Audio/Video MPEG-2 coding Data coding



MPEG-2 Transport Stream

Specified in MPEG-2 Part 1, Systems (ISO/IEC standard 13818-1)

Allows multiplexing of digital video & audio and synchronizing the output

Features error correction for transportation over unreliable media, and is used in broadcast applications such as DVB and ATSC

Header 188 Bytes MPEG Packet 188 Bytes MPEG Packet ….….

188 bytes

Payload

SyncByte

Transport error indicator

Continuity counter

Adaptation field control

Transport priority

PIDTransport

scrambling controlPayload unit start indicator

Adaptationfield

Bits 8 1 1 1 13 2 2 4

AdaptationField length

Discontinuityindicator

Random accessindicator

Elementary streamPriority indicator

Optionalfields

Stuffing byte5 flags

Bits 8 1 1 1 5

PCR OPCRSplicing

countdownTransport private

Data Adaptation field Extension flag

Bits 33 + 6 + 9 33 + 6 + 9 8 8 + n 8 + 3 + 5 + n

Itw_valid flag Itw_offset Reserved Piecewise_rate Splice_type DTS_next_AU

Bits 1 15 2 22 4 3+1+15+1+15+1


A Transport Stream includes tables describing the relationship between the programs and the elementary streams making up each program

A program can be identified by using a 16-bit program number


Program Specific Information (PSI)

Table Name Standard PIDs Description

Program Association Table

MPEG 0x000 Associates program numbers with PIDs of TS packets sending A Program Map Table

Program Map Table MPEG Spec’d in PAT Specifies PID values of stream configuring a program

Network Information Table DVB Spec’d in PAT Physical network parameters e.g. FDM frequency, transponder number

Conditional Access Table MPEG 0x0001 Associates PID values and EMM stream sending subscription details for charged broadcasting

TS Description Table MPEG 0x02 Associates descriptors and the entire TS (application system)


Tables

Program Specific Information (PSI)

DVB-SI provides information to enable automatic configuration of the receiver to demultiplex and decode the various streams of programs Program Specific Information (PSI) Program Association Table (PAT) Conditional Access Table (CAT) Program Map Table (PMT) Network Information Table (NIT)

Additional Service Information Bouquet Association Table (BAT) Service Description Table (SDT) Event Information Table (EIT) Running Status Table (RST) Other tables: TDT, TOT, ST, SIT, DIT


DVB Service Information (DVB-SI)


PAT always has PID = 0 (zero)

CAT always has PID = 1

EIT always has PID = 18

PMTs have the PIDs specified in the PAT

The audio, video, PCR, subtitle, etc. PIDs for all programs are specified in their respective PMT


MPEG-2/DVB PID Allocation



MPEG-2 PSI & DVB-SI Relationship

PAT

PMT

CAT

NIT

BAT

SDT

EIT

ST

TDT

RST

TOT

Network Information Table

Bouquet Association Table

Service Description Table

Event Information Table

Stuffing Table

Time and Date Table

Running Status Table

Time Offset Table

PID 0x10

PID 0x11

PID 0x11

PID 0x12

PID 0x00

Program Association Table

Program Map Table

Conditional Access Table

PID 0x01

PID 0x13

PID 0x14

DVB SI (Service Information)

MPEG-2 PSI (Service Program Information) MPEG-2 PSI locates the program

DVB SI selects the program

PID 0xYY


Packet sync is performed by a unique value (Hex47) in the first byte of every packet. Once packet sync is acquired: The Sync byte ( 47HEX ) is extracted as timing reference and is used for generating the clock. Decoder achieves sync after receiving 3-consecutive sync bytes Only then can meaningful measurements on the PCRs be performed.

MPEG systems defines a Master clock and two decode time stamps: Program Clock Reference (PCR):

Used to maintain the decoder’s clock in sync with the encoder’s clock PTS/DTS:

Presentation Time Stamp – specifies when to present the access unit Decode Time Stamp – specifies when to decode the access unit Decoding and presentation take place when the decoder STC advances to the time

specified by the DTS and the PTS respectively Both timestamps are found in the PES packet header

System Time Clock (STC) 27 MHz clock ± 810 Hz


MPEG Clocks & Sync Mechanisms


The Decoder must first identify the beginning of packets before it can interpret the stream - it uses the Sync Byte field to do this!

The Sync Byte is always 0x47 (Hexadecimal) or 01000111 binary

The decoder looks for strings of zeros and ones which match the pattern of the sync byte (see red below)

Once the decoder finds a 0x47 in the stream, it looks 187 bytes down the stream, and looks for another 0x47

If decoder finds three Sync Bytes in a row, then Sync is achieved and decoder assumes packet boundaries from then on

Each packet is tested for 0x47 as soon as it arrives. If a packet arrives with an incorrect sync byte, the decoder starts over. This is called SYNC LOSS


Sync Byte

MPEG Header

01010001111010010101101010001100011110010111000

The continuity counter is a 4 bit field in the header which increments by 1 each time a packet comes out on a specific PID:

When a PID ‘skips’ one value of the continuity Counter, it is called a ‘Continuity Error.’ This means one or more packets were lost.


Continuity Counter

MPEG Header

0 1 2 3 4 5 6 7 8 14

15

0 1…

All Packets PID 0x52

0 1 2 3 7 8 9 10

11

…

All Packets PID 0x54

Continuity Error Here

Encoding process is driven by a 27MHz System Time Clock (STC)

Each program inserted into a TS contains a 27MHz timestamp (PCR)

Inserted by encoder/multiplexer in adaptation field every 40-100ms

PCR is a 42 bit field in the adaptation field of the Transport Stream (TS)

PCR field consists of a 9 bit part that increments at a 27MHz rate and a 33 bit part that increments at a 90kHz rate (when 27MHz part rolls over)


PCR Encoding Process


Decoding process is driven by a clock locked to the encoder's STC

Decoder uses the PCR to regenerate a local 27MHz clock

Decoder uses a Voltage Controlled Oscillator (VCXO) to generate a 27MHz clock

When received, the PCR is compared to a local counter which is driven by the VCXO. Any difference is used to correct the frequency of the VCXO ensuring the 27MHz clock is locked to the PCR.

Decoders use PCRs to generate video timing, color burst, etc.


PCR Decoding Process


TR 101 290 recommends a set of syntax and information consistency tests that can be applied to an MPEG-2 Transport Stream (TS)

The following assumptions and guiding principles were included when developing these tests: Mainly intended for continuous or periodic monitoring of an MPEG-2 TS in an operational

environment; Primarily designed to check the integrity of a TS at source; the general aim of the tests is to provide a "health check" of the most important elements

of the TS.

The tests are grouped into three tables according to importance; The first table lists a basic set of parameters which are considered necessary to ensure

that the TS can be decoded. The second table lists additional parameters which are recommended for continuous

monitoring. The third table lists optional additional parameters which could be of interest for

certain applications.


ETSI TR 101 290 Recommendation


Baseband measurements are split into 3 groups: 1st priority (necessary for decodability) 2nd priority (recommended for continuous or periodic monitoring) 3rd priority (application-dependent monitoring)


ETSI TR 101 290 Priority Groups



DVB-C Transmitter & Receiver Components

Mux adaptation,

Energy dispersal

Reed Solomon FEC

Coder

Convolution Interleaver

Byte to multiple

conversion

Differential encoding

Baseband shaping FIR filter

QPSK/QAM modulation

RF conversion

Multiplexed MPEG Transport stream

TX

RF conversion

QPSK/QAM demodulation

Matched FIR filter and equalizer

Differential decoding

Symbol to byte mapping

Convolution deinterleaver

Reed Solomon FEC

decoder

Sync inversion &

energy dispersal

Multiplexed MPEG Transport stream

RX


Testing MPEG-2 Systems with the CX380 MPEG Explorer option

43Confidential & Proprietary Information of VeEX Inc.

CX380 CATV Analyzer


MPEG Network Overview

Per the DVB-C standard, MPEG-2 video is usually transported from Master Headend over fiber using SONET/IP technologies that contain FEC or other error checking mechanisms.

At regional Headends/Hub sites, the MPEG-2 is extracted, QAM modulated, IF unconverted and inserted into 6/8MHz channels for transmission over the HFC network to customer STBs.

The key impairments that can occur are caused by micro-reflections, non-linearity problems in the network, and interference from adjacent analog channels (due to higher power levels).

MPEG-2 QoS testing will occur at the Master satellite Headend, or at any other point where the Service Information is changed, and before insertion into the coaxial plant.

HomeHFCMPEGMaster Headend

Headends & HubsIP Transport

Outside PlantInside Plant

CMTS

Coax Distribution Network

Combiners

Video QAM

Servicerouter


IP NetworkLayer 2/3

To start, there is no single, simple test solution

Terminology is new and confusing for those unfamiliar with digital video Elementary Stream (ES), Packetized Elementary Stream (PES), Transport Stream (TS),

Program-Specific Information (PSI), etc.

The best known Test guideline is known as ETSI TR 101 290 Measurement guidelines for DVB systems

The ATSC has also recently introduced ATSC Recommended Practice: Transport Stream Verification A78

Things to remember: Fix Continuity Problems first. Continuity errors create bogus alarms in other areas. Until

you resolve the continuity problems, it will be very hard to determine if you have other problems in your stream

The PAT is on PID 0x00. This is the first PID a decoder looks at – the MPEG ‘Base PID’


Test Challenges & Advice


Always check signal level & quality of QAM carrier/s

Without a good strong signal, analysis of the MPEG stream may not yield any useful information

Check FEC counters and use Constellation diagram to identify problems

Disable/enable Equalizer to check QAM decoder performance, group delay and frequency response


SLM Measurements – RF Domain

Displays number of programs detected on the MPEG-2 TS

Video, Audio, and Table statistics are provided for each program detected

Packet count associated with each is reported

Transport errors based on the transport error indicator in MPEG transport header set


MPEG TS Summary

Reconstructing a program from all its video, audio, & table components requires that the PID assignment is done correctly

Check consistency between PSI table contents and the associated video and audio streams. This is one the main testing issue in MPEG.

PAT (Program Association Table) always appears in PID 0x0000

PMT (Program Map Table) - Identifies elementary streams in program, and gives their PIDs.


Stream Summary

Statistics for each program are provided including video compression (SD or HD)

Verify PAT always appears in PID 0x00 Identifies MPEG-2 programs and gives PIDs for the PMT, Video and Audio.

CAT (Conditional Access Table) & NIT (Network Information Table)


Stream Details

Absolute MOS-V Considers image resolution, frame rate, codec and compression level, transmission impairments, frame loss

concealment Relative MOS-V

A MOS score relative to the ideal for the particular codec and image resolution in use. MOS-AV

1 to 5 score that considers picture & audio quality and the audio-video synchronization on the overall user experience. VSTQ

Video Service Transmission Quality, a 0-50 codec-independent score (50 being best) measuring the ability of the IP network to carry video reliably.

EPSNR the estimated Peak Signal to Noise Ratio expressed in dB. This is an estimate of the distortion that has occurred

between the source video stream and the output video stream.MPEG Technology Primer/CX380 Confidential & Proprietary Information of VeEX Inc. 50

Perceptual

Video Metrics

Note:To simplify comparing video quality for different service types, MPEG Explorer includes both Absolute and Relative MOS scores in its set of Video metrics

Identifies I, P, and B frames in unscrambled and encrypted video streams

Bandwidth used by I, P, B, SI & SP video frames is analyzed to estimate the quantization level applied by the video encoder

Average Bandwidth – Mean video bandwidth excluding IP overhead, FEC, & retransmissions

Max. Bandwidth - Peak video bandwidth excluding IP overhead, FEC, & retransmissions

SI‑frames/slices: Facilitates switching between coded streams; contains SI macroblocks (a special type of intra coded macroblock).

SP‑frames/slices: Facilitates switching between coded streams; contains P and/or I macroblocks


Bandwidth Metrics

Video Stream

Note: Using H.264 video compression, the picture can be segmented into sequences of macroblocks called slices. The encoder can choose the prediction style distinctly on each individual slice (SI & SP frames)

Detailed statistics for I, P, B, SI, SP frame types: number of received frames and proportion of each frame type impaired by packet loss

and discard are reported helps determine which GoP type and length should be used to obtain the best

performance from the video service I/P/B/SI/SP Frames Impaired - proportion of applicable frames impaired by packet

loss/discard


Frame Statistics

Video Stream

To form an accurate assessment of quality of experience, it is necessary to know not only the overall rates of packet lost or discarded, but also which frame types were affected.

MPEG Explorer reports detailed statistics for each frame type, including the number of received, lost, and discarded I, B, and P frames and the proportion of each frame type impaired by packet loss and discard.

These metrics can be useful for troubleshooting and can help determine which GoP type and length should be used to obtain the best performance from the video service.

Packets Discarded - number of packets discarded by the jitter buffer due to late arrival.


Frame Packet Results

Video Stream

MOS-A Audio MOS, a 1-5 score that considers the effects of the audio codec, bit rate, sample

rate, and packet loss on listening quality.


Audio Stream Metrics

TS_sync_loss: Loss of synchronization at the MPEG transport layer Sync_byte_error: Invalid MPEG transport sync byte Continuity_count_error: Incorrect packet order, duplicate packet, or lost packet. Transport_error: Transport error indicator in MPEG transport header set. PCR_error: Discontinuity in program clock reference (PCR). PCR_repetition_error: Time interval between two successive PCR values more than 40ms PCR_discontinuity_indicator_error: Difference between two consecutive PCR values is over 100ms

without discontinuity bit set. PTS_error: Interval between presentation timestamps more than 700ms.


ETSI TR 101 290 Metrics

TR 101-290 Priorities First priority:

Sync, PAT & PMT, Continuity Decoder lock

Second priority: PCRs, CRCs, RF FEC Program Decode

Third priority: EPG PSIP

The MPEG Explorer provides a convenient and practical way to evaluate user quality of experience levels using objective test data

MOS scores provide a familiar, intuitive representation of picture, audio, and overall audiovisual quality

Metrics such as Relative MOS and VSTQ can be useful in accurately comparing video quality across different service types

MPEG Explorer metrics are grouped into three layers: Perceptual Quality Metrics

High-level Quality of Experience (QoE) metrics that measure user's experience of the service

Video Stream Metrics Relate to the encoded video stream, including image size, frame rate, GoP structure, etc.

Transmission Metrics Relate to the performance of the IP network, UDP/TCP and RTP/MPEG Transport protocols


MPEG Explorer Test Summary

Any questions?


Thank you.


mpeg technology primer cx380 mpeg explorer option rev. a02

Documents

mpeg concept mpeg

rtsp igmp mpeg

video data

sdtv video types

video encoding standards

a02 slide

video medium evolution

mpeg2 compression