UNIVERSITY OF TEXAS AT ARLINGTON EE 5359 Spring 2011 Final Report AVS CHINA IMPLEMENTATION PERFORMANCE ANALYSIS OF ALL VIDEO PROFILES Instructor Dr K R Rao Submitted by Vamsi Krishna Vegunta Student ID 1000627648 Email vamsikrishna vegunta mavs uta edu AVS China Evolution High technology license fees have kept the Chinese consumer electronics industry in chains A new audio and video compression standard will set it free In March of 2002 video and audio coding experts from the Chinese Academy of Sciences and from a number of Chinese universities and manufacturers met with officials of the National Information Industry Ministry in Beijing to set up a Chinese national standard for audio and video coding The standard was to be used in digital disc players digital TV Internet Protocol television IPTV satellite TV mobile video phones and other applications Some of the experts suggested that China develop a standard independent of all foreign technologies but it became clear that this was not practical Researchers around the world have been working on audio and video coding for a long time and their legacy technologies are associated with intellectual property that China could not do without That left the group officially named the Audio and Video Coding Standard Working Group of China with a dilemma How could it develop a national standard that was technically competitive yet affordable that is with low license fees Five years later the group unveiled its answer AVS the Audio Video Coding Standard of China For the first time in creating an audio or video compression format a standards body did not consider just quality and bit rate but also considered the cost of the intellectual property The group set a price goal of 1 Yuan or 13 cents for the audio and video compression technology in each video player this far undercuts the typical 2 50 license fees for the MPEG 2 compression technology used in standard DVD players today 1 Color Space A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers typically as three or four values or color components 2 In AVS China color of a pixel is described by two values one luma essentially but not exactly describing its luminance brightness and one chrominance The first value in this scheme does not actually describe the luminance of the pixel s color As a result it is often called luma a term borrowed from the analog system used for television signals This term is a tip that the value does not quite describe luminance because of its nonlinear form And in fact the value pair giving the chrominance is also sometimes called chroma again primarily to tip us off to its nonlinear form But here we will use the term chrominance as it best matches normal editorial practice for the topic area we are considering Thus for each pixel there are three numerical values that collectively describe its color They are identified as Y and Y is the luma value and and collectively form the chrominance value 3 Chroma Sub sampling The human visual system is less sensitive to changes in color than in changes in luminance Hence Y can be stored with high resolution or transmitted at high bandwidth and two chroma components CB and CR that can be bandwidth reduced sub sampled compressed or otherwise treated separately for improved system efficiency This leads to a technique called chroma sub sampling The most popular patterns for sub sampling CR and CB values are 4 2 2 4 2 0 4 4 4 means that the 3 components Y Cr and CB have the same resolution hence a sample of each is present at every pixel location I e for every 4 luma samples there will be 4 CR and CB samples In 4 4 4 each pixel is represented by 24bits 4 4 4 sampling preserves the full fidelity of the chrominance components In 4 2 2 sampling there will be 2 CR and 2 CB components for every 4 luma samples In 4 2 2 each pixel is represented by 16bits 4 2 2 sampling is used for high quality color reproduction 4 2 0 means that CR and CB each have half the resolution of Y for every 4 luma samples there will be one CR and CB samples 4 2 0 sampling is popular in mass market digital video applications like TV broad cast and video conferencing 4 2 0 is sometimes described as 12 bits per pixel 4 Fig1 Chroma sub sampling 5 Data Formats 1 Progressive Scan AVS codes video data in progressive scan format This format is directly compatible with all content that originates in film and can accept inputs directly from progressive telecine machines It is also directly compatible with the emerging standard for digital production the so called 24p standard In the next few years most movie production and much TV production will be converted to this new standard It will also be the standard for digital cinema so there is convergence in the professional film and TV production industry toward a single production format offering the highest original quality AVS also codes progressive content at higher frame rates Such rates may be necessary for televised sports A significant benefit of progressive format is the efficiency with which motion estimation operates Progressive content can be encoded at significantly lower bitrates than interlaced content with the same perceptual quality Furthermore motion compensated coding of progressive format data is significantly less complex than coding of interlaced data This is a significant component of the reduced complexity of AVS coding 2 Interlaced Scan AVS also provides coding tools for interlaced scan format These tools offer coding of legacy interlaced format video 6 AVS China Parts Parts Part 1 Part 2 Part 3 Part 4 Part 5 Part 6 Part 7 Part 8 Part 9 Part 10 Content System for Broadcasting SD HD Video Audio Conformance Test Reference Software Digital Right Management Mobility Video System over IP File Format Mobile speech and audio coding Table1 Parts of AVS China 4 Different parts of AVS China are shown in Table 1 Part 2 and Part 7 target the video compression Part 2 is for high definition video broadcasting and part 7 is for low resolution and low complexity mobile applications AVS has been designed to give a near optimum performance with reduced complexity AVS video applications include HDTV HDDVD and broadband video networking 4 Profiles Levels and Applications Profile is a specified subset of the coding tools A subset of the coding tools will be implemented in each profile which target specific applications AVS Jiaqiang profile enhanced profile
View Full Document
Unlocking...