Повышение эффективности метода энтропийного кодирования в современных стандартах видеосжатия

Modern video coding standards have high coding efficiency, but the encoding performance has to be improved to meet the growing multimedia applications. The paper deals with the entropy encoding methods and algorithms in video coding standard H.264/AVC and H.265/HEVC. Context-based Adaptive Variable Length Coding (CAVLC) for the H.264/AVC standard was originally designed for lossy video coding, and as such does not yield adequate performance for lossless video coding. Context-Adaptive Binary Arithmetic Coding (CABAC) is a method of entropy coding first introduced in H.264/AVC and now used in the standard H.265/HEVC. While it provides high coding efficiency, the data dependencies in H.264/AVC CABAC make it challenging to parallelize and thus, limit its throughput. Accordingly, during the standardization of entropy coding for HEVC, both coding efficiency and throughput were considered. Based on an analysis of their advantages and disadvantages, a method called the entropy coding algorithm using the enumerative coding of the hierarchical approach is proposed. The proposed algorithm consists of the Context-Adaptive Binary Arithmetic Coding algorithm and the enumerative coding algorithm with a hierarchical approach. The proposed algorithm is tested in the Visual C ++ development environment on various test video sequences. The results of the experiments showed a greater efficiency of coding of multimedia data (the proposed one reduces on average up to 15% of the storage volume compared to the traditional CABAC method), while the method requires a longer coding time (approximately twice). The proposed method can be recommended for use in telecommunication systems for storage, transmission and processing of multimedia data, where a high degree of compression is required first.Современные стандарты кодирования видеоданных имеют высокую эффективность кодирования, но скорость кодирования может быть улучшена для удовлетворения растущих потребностей мультимедийных приложений. В статье рассматриваются методы и алгоритмы энтропийного кодирования в стандартах кодирования видеоданных H.264/AVC и H.265/HEVC. Контекстно-зависимое адаптивное кодирование с переменной длиной кодового слова CAVLC (Context-based Adaptive Variable Length) для стандарта H.264/AVC изначально предназначалось для ко-дирования с потерями и как таковое не давало адекватной производительности для кодирования без потерь. Контекстно-зависимое адаптивное бинарное арифметиче-ское кодирование CABAC (Context-Adaptive Binary Arithmetic Coding) — это метод энтропийного кодирования, впервые введенный в H.264/AVC и используемый в стандарте H.265/HEVC. Хотя он обеспечивает высокую эффективность кодирования, зависимости данных в H.264/AVC CABAC затрудняют распараллеливание и, таким образом, ограничивают его пропускную способность. Соответственно, во время стандартизации энтропийного кодирования для HEVC были рассмотрены как эффективность кодирования, так и пропускная способность. На основе анализа их достоинств и недостатков предложен метод энтропийного кодирования с последующим применением нумерационного иерархического кодирования. Он состоит из алгоритма САВАС и алгоритма нумерационного кодирования с применением иерархического подхода. Предложенный метод протестирован в среде разработки Visual C++ на различных тестовых видеопоследовательностях. Результаты экспериментов показали большую эффективность кодирования мультимедийных данных (уменьшает в среднем до 15% объема памяти хранения по сравнению с традиционным методом CABAC), но при этом метод требует большее время кодирования (примерно в два раза). Предложенный метод можно рекомендовать для применения в телекоммуни-кационных системах для решения задач хранения, передачи и обработки мультимедийных данных, где в первую очередь требуется большая степень сжатия

Video QoS/QoE over IEEE802.11n/ac: A Contemporary Survey

The demand for video applications over wireless networks has tremendously increased, and IEEE 802.11 standards have provided higher support for video transmission. However, providing Quality of Service (QoS) and Quality of Experience (QoE) for video over WLAN is still a challenge due to the error sensitivity of compressed video and dynamic channels. This thesis presents a contemporary survey study on video QoS/QoE over WLAN issues and solutions. The objective of the study is to provide an overview of the issues by conducting a background study on the video codecs and their features and characteristics, followed by studying QoS and QoE support in IEEE 802.11 standards. Since IEEE 802.11n is the current standard that is mostly deployed worldwide and IEEE 802.11ac is the upcoming standard, this survey study aims to investigate the most recent video QoS/QoE solutions based on these two standards. The solutions are divided into two broad categories, academic solutions, and vendor solutions. Academic solutions are mostly based on three main layers, namely Application, Media Access Control (MAC) and Physical (PHY) which are further divided into two major categories, single-layer solutions, and cross-layer solutions. Single-layer solutions are those which focus on a single layer to enhance the video transmission performance over WLAN. Cross-layer solutions involve two or more layers to provide a single QoS solution for video over WLAN. This thesis has also presented and technically analyzed QoS solutions by three popular vendors. This thesis concludes that single-layer solutions are not directly related to video QoS/QoE, and cross-layer solutions are performing better than single-layer solutions, but they are much more complicated and not easy to be implemented. Most vendors rely on their network infrastructure to provide QoS for multimedia applications. They have their techniques and mechanisms, but the concept of providing QoS/QoE for video is almost the same because they are using the same standards and rely on Wi-Fi Multimedia (WMM) to provide QoS

Image and Video Coding Techniques for Ultra-low Latency

The next generation of wireless networks fosters the adoption of latency-critical applications such as XR, connected industry, or autonomous driving. This survey gathers implementation aspects of different image and video coding schemes and discusses their tradeoffs. Standardized video coding technologies such as HEVC or VVC provide a high compression ratio, but their enormous complexity sets the scene for alternative approaches like still image, mezzanine, or texture compression in scenarios with tight resource or latency constraints. Regardless of the coding scheme, we found inter-device memory transfers and the lack of sub-frame coding as limitations of current full-system and software-programmable implementations.publishedVersionPeer reviewe

A Novel Multi-Symbol Curve Fit based CABAC Framework for Hybrid Video Codec's with Improved Coding Efficiency and Throughput

Video compression is an essential component of present-day applications and a decisive factor between the success or failure of a business model. There is an ever increasing demand to transmit larger number of superior-quality video channels into the available transmission bandwidth. Consumers are increasingly discerning about the quality and performance of video-based products and there is therefore a strong incentive for continuous improvement in video coding technology for companies to have market edge over its competitors. Even though processor speeds and network bandwidths continue to increase, a better video compression results in a more competitive product. This drive to improve video compression technology has led to a revolution in the last decade. In this thesis we addresses some of these data compression problems in a practical multimedia system that employ Hybrid video coding schemes. Typically Real life video signals show non-stationary statistical behavior. The statistics of these signals largely depend on the video content and the acquisition process. Hybrid video coding schemes like H264/AVC exploits some of the non-stationary characteristics but certainly not all of it. Moreover, higher order statistical dependencies on a syntax element level are mostly neglected in existing video coding schemes. Designing a video coding scheme for a video coder by taking into consideration these typically observed statistical properties, however, offers room for significant improvements in coding efficiency.In this thesis work a new frequency domain curve-fitting compression framework is proposed as an extension to H264 Context Adaptive Binary Arithmetic Coder (CABAC) that achieves better compression efficiency at reduced complexity. The proposed Curve-Fitting extension to H264 CABAC, henceforth called as CF-CABAC, is modularly designed to conveniently fit into existing block based H264 Hybrid video Entropy coding algorithms. Traditionally there have been many proposals in the literature to fuse surfaces/curve fitting with Block-based, Region based, Training-based (VQ, fractals) compression algorithms primarily to exploiting pixel- domain redundancies. Though the compression efficiency of these are expectantly better than DCT transform based compression, but their main drawback is the high computational demand which make the former techniques non-competitive for real-time applications over the latter. The curve fitting techniques proposed so far have been on the pixel domain. The video characteristic on the pixel domain are highly non-stationary making curve fitting techniques not very efficient in terms of video quality, compression ratio and complexity. In this thesis, we explore using curve fitting techniques to Quantized frequency domain coefficients. we fuse this powerful technique to H264 CABAC Entropy coding. Based on some predictable characteristics of Quantized DCT coefficients, a computationally in-expensive curve fitting technique is explored that fits into the existing H264 CABAC framework. Also Due to the lossy nature of video compression and the strong demand for bandwidth and computation resources in a multimedia system, one of the key design issues for video coding is to optimize trade-off among quality (distortion) vs compression (rate) vs complexity. This thesis also briefly studies the existing rate distortion (RD) optimization approaches proposed to video coding for exploring the best RD performance of a video codec. Further, we propose a graph based algorithm for Rate-distortion. optimization of quantized coefficient indices for the proposed CF-CABAC entropy coding

Feasibility Study of High-Level Synthesis : Implementation of a Real-Time HEVC Intra Encoder on FPGA

High-Level Synthesis (HLS) on automatisoitu suunnitteluprosessi, joka pyrkii parantamaan tuottavuutta perinteisiin suunnittelumenetelmiin verrattuna, nostamalla suunnittelun abstraktiota rekisterisiirtotasolta (RTL) käyttäytymistasolle. Erilaisia kaupallisia HLS-työkaluja on ollut markkinoilla aina 1990-luvulta lähtien, mutta vasta äskettäin ne ovat alkaneet saada hyväksyntää teollisuudessa sekä akateemisessa maailmassa. Hidas käyttöönottoaste on johtunut pääasiassa huonommasta tulosten laadusta (QoR) kuin mitä on ollut mahdollista tavanomaisilla laitteistokuvauskielillä (HDL). Uusimmat HLS-työkalusukupolvet ovat kuitenkin kaventaneet QoR-aukkoa huomattavasti. Tämä väitöskirja tutkii HLS:n soveltuvuutta videokoodekkien kehittämiseen. Se esittelee useita HLS-toteutuksia High Efficiency Video Coding (HEVC) -koodaukselle, joka on keskeinen mahdollistava tekniikka lukuisille nykyaikaisille mediasovelluksille. HEVC kaksinkertaistaa koodaustehokkuuden edeltäjäänsä Advanced Video Coding (AVC) -standardiin verrattuna, saavuttaen silti saman subjektiivisen visuaalisen laadun. Tämä tyypillisesti saavutetaan huomattavalla laskennallisella lisäkustannuksella. Siksi reaaliaikainen HEVC vaatii automatisoituja suunnittelumenetelmiä, joita voidaan käyttää rautatoteutus- (HW ) ja varmennustyön minimoimiseen. Tässä väitöskirjassa ehdotetaan HLS:n käyttöä koko enkooderin suunnitteluprosessissa. Dataintensiivisistä koodaustyökaluista, kuten intra-ennustus ja diskreetit muunnokset, myös enemmän kontrollia vaativiin kokonaisuuksiin, kuten entropiakoodaukseen. Avoimen lähdekoodin Kvazaar HEVC -enkooderin C-lähdekoodia hyödynnetään tässä työssä referenssinä HLS-suunnittelulle sekä toteutuksen varmentamisessa. Suorituskykytulokset saadaan ja raportoidaan ohjelmoitavalla porttimatriisilla (FPGA). Tämän väitöskirjan tärkein tuotos on HEVC intra enkooderin prototyyppi. Prototyyppi koostuu Nokia AirFrame Cloud Server palvelimesta, varustettuna kahdella 2.4 GHz:n 14-ytiminen Intel Xeon prosessorilla, sekä kahdesta Intel Arria 10 GX FPGA kiihdytinkortista, jotka voidaan kytkeä serveriin käyttäen joko peripheral component interconnect express (PCIe) liitäntää tai 40 gigabitin Ethernettiä. Prototyyppijärjestelmä saavuttaa reaaliaikaisen 4K enkoodausnopeuden, jopa 120 kuvaa sekunnissa. Lisäksi järjestelmän suorituskykyä on helppo skaalata paremmaksi lisäämällä järjestelmään käytännössä minkä tahansa määrän verkkoon kytkettäviä FPGA-kortteja. Monimutkaisen HEVC:n tehokas mallinnus ja sen monipuolisten ominaisuuksien mukauttaminen reaaliaikaiselle HW HEVC enkooderille ei ole triviaali tehtävä, koska HW-toteutukset ovat perinteisesti erittäin aikaa vieviä. Tämä väitöskirja osoittaa, että HLS:n avulla pystytään nopeuttamaan kehitysaikaa, tarjoamaan ennen näkemätöntä suunnittelun skaalautuvuutta, ja silti osoittamaan kilpailukykyisiä QoR-arvoja ja absoluuttista suorituskykyä verrattuna olemassa oleviin toteutuksiin.High-Level Synthesis (HLS) is an automated design process that seeks to improve productivity over traditional design methods by increasing design abstraction from register transfer level (RTL) to behavioural level. Various commercial HLS tools have been available on the market since the 1990s, but only recently they have started to gain adoption across industry and academia. The slow adoption rate has mainly stemmed from lower quality of results (QoR) than obtained with conventional hardware description languages (HDLs). However, the latest HLS tool generations have substantially narrowed the QoR gap. This thesis studies the feasibility of HLS in video codec development. It introduces several HLS implementations for High Efficiency Video Coding (HEVC) , that is the key enabling technology for numerous modern media applications. HEVC doubles the coding efficiency over its predecessor Advanced Video Coding (AVC) standard for the same subjective visual quality, but typically at the cost of considerably higher computational complexity. Therefore, real-time HEVC calls for automated design methodologies that can be used to minimize the HW implementation and verification effort. This thesis proposes to use HLS throughout the whole encoder design process. From data-intensive coding tools, like intra prediction and discrete transforms, to more control-oriented tools, such as entropy coding. The C source code of the open-source Kvazaar HEVC encoder serves as a design entry point for the HLS flow, and it is also utilized in design verification. The performance results are gathered with and reported for field programmable gate array (FPGA) . The main contribution of this thesis is an HEVC intra encoder prototype that is built on a Nokia AirFrame Cloud Server equipped with 2.4 GHz dual 14-core Intel Xeon processors and two Intel Arria 10 GX FPGA Development Kits, that can be connected to the server via peripheral component interconnect express (PCIe) generation 3 or 40 Gigabit Ethernet. The proof-of-concept system achieves real-time. 4K coding speed up to 120 fps, which can be further scaled up by adding practically any number of network-connected FPGA cards. Overcoming the complexity of HEVC and customizing its rich features for a real-time HEVC encoder implementation on hardware is not a trivial task, as hardware development has traditionally turned out to be very time-consuming. This thesis shows that HLS is able to boost the development time, provide previously unseen design scalability, and still result in competitive performance and QoR over state-of-the-art hardware implementations

Novi algoritam za kompresiju seizmičkih podataka velike amplitudske rezolucije

Renewable sources cannot meet energy demand of a growing global market. Therefore, it is expected that oil & gas will remain a substantial sources of energy in a coming years. To find a new oil & gas deposits that would satisfy growing global energy demands, significant efforts are constantly involved in finding ways to increase efficiency of a seismic surveys. It is commonly considered that, in an initial phase of exploration and production of a new fields, high-resolution and high-quality images of the subsurface are of the great importance. As one part in the seismic data processing chain, efficient managing and delivering of a large data sets, that are vastly produced by the industry during seismic surveys, becomes extremely important in order to facilitate further seismic data processing and interpretation. In this respect, efficiency to a large extent relies on the efficiency of the compression scheme, which is often required to enable faster transfer and access to data, as well as efficient data storage. Motivated by the superior performance of High Efficiency Video Coding (HEVC), and driven by the rapid growth in data volume produced by seismic surveys, this work explores a 32 bits per pixel (b/p) extension of the HEVC codec for compression of seismic data. It is proposed to reassemble seismic slices in a format that corresponds to video signal and benefit from the coding gain achieved by HEVC inter mode, besides the possible advantages of the (still image) HEVC intra mode. To this end, this work modifies almost all components of the original HEVC codec to cater for high bit-depth coding of seismic data: Lagrange multiplier used in optimization of the coding parameters has been adapted to the new data statistics, core transform and quantization have been reimplemented to handle the increased bit-depth range, and modified adaptive binary arithmetic coder has been employed for efficient entropy coding. In addition, optimized block selection, reduced intra prediction modes, and flexible motion estimation are tested to adapt to the structure of seismic data. Even though the new codec after implementation of the proposed modifications goes beyond the standardized HEVC, it still maintains a generic HEVC structure, and it is developed under the general HEVC framework. There is no similar work in the field of the seismic data compression that uses the HEVC as a base codec setting. Thus, a specific codec design has been tailored which, when compared to the JPEG-XR and commercial wavelet-based codec, significantly improves the peak-signal-tonoise- ratio (PSNR) vs. compression ratio performance for 32 b/p seismic data. Depending on a proposed configurations, PSNR gain goes from 3.39 dB up to 9.48 dB. Also, relying on the specific characteristics of seismic data, an optimized encoder is proposed in this work. It reduces encoding time by 67.17% for All-I configuration on trace image dataset, and 67.39% for All-I, 97.96% for P2-configuration and 98.64% for B-configuration on 3D wavefield dataset, with negligible coding performance losses. As a side contribution of this work, HEVC is analyzed within all of its functional units, so that the presented work itself can serve as a specific overview of methods incorporated into the standard

MASCOT : metadata for advanced scalable video coding tools : final report

The goal of the MASCOT project was to develop new video coding schemes and tools that provide both an increased coding efficiency as well as extended scalability features compared to technology that was available at the beginning of the project. Towards that goal the following tools would be used: - metadata-based coding tools; - new spatiotemporal decompositions; - new prediction schemes. Although the initial goal was to develop one single codec architecture that was able to combine all new coding tools that were foreseen when the project was formulated, it became clear that this would limit the selection of the new tools. Therefore the consortium decided to develop two codec frameworks within the project, a standard hybrid DCT-based codec and a 3D wavelet-based codec, which together are able to accommodate all tools developed during the course of the project

Prioritizing Content of Interest in Multimedia Data Compression

Image and video compression techniques make data transmission and storage in digital multimedia systems more efficient and feasible for the system's limited storage and bandwidth. Many generic image and video compression techniques such as JPEG and H.264/AVC have been standardized and are now widely adopted. Despite their great success, we observe that these standard compression techniques are not the best solution for data compression in special types of multimedia systems such as microscopy videos and low-power wireless broadcast systems. In these application-specific systems where the content of interest in the multimedia data is known and well-defined, we should re-think the design of a data compression pipeline. We hypothesize that by identifying and prioritizing multimedia data's content of interest, new compression methods can be invented that are far more effective than standard techniques. In this dissertation, a set of new data compression methods based on the idea of prioritizing the content of interest has been proposed for three different kinds of multimedia systems. I will show that the key to designing efficient compression techniques in these three cases is to prioritize the content of interest in the data. The definition of the content of interest of multimedia data depends on the application. First, I show that for microscopy videos, the content of interest is defined as the spatial regions in the video frame with pixels that don't only contain noise. Keeping data in those regions with high quality and throwing out other information yields to a novel microscopy video compression technique. Second, I show that for a Bluetooth low energy beacon based system, practical multimedia data storage and transmission is possible by prioritizing content of interest. I designed custom image compression techniques that preserve edges in a binary image, or foreground regions of a color image of indoor or outdoor objects. Last, I present a new indoor Bluetooth low energy beacon based augmented reality system that integrates a 3D moving object compression method that prioritizes the content of interest.Doctor of Philosoph