Mode decision for the H.264/AVC video coding standard

H.264/AVC video coding standard gives us a very promising future for the field of video broadcasting and communication because of its high coding efficiency compared with other older video coding standards. However, high coding efficiency also carries high computational complexity. Fast motion estimation and fast mode decision are two very useful techniques which can significantly reduce computational complexity. This thesis focuses on the field of fast mode decision. The goal of this thesis is that for very similar RD performance compared with H.264/AVC video coding standard, we aim to find new fast mode decision techniques which can afford significant time savings. [Continues.

Fast Motion Estimation Algorithms for Block-Based Video Coding Encoders

The objective of my research is reducing the complexity of video coding standards in real-time scalable and multi-view applications

End to end Multi-Objective Optimisation of H.264 and HEVC Codecs

All multimedia devices now incorporate video CODECs that comply with international video coding standards such as H.264 / MPEG4-AVC and the new High Efficiency Video Coding Standard (HEVC) otherwise known as H.265. Although the standard CODECs have been designed to include algorithms with optimal efficiency, large number of coding parameters can be used to fine tune their operation, within known constraints of for e.g., available computational power, bandwidth, consumer QoS requirements, etc. With large number of such parameters involved, determining which parameters will play a significant role in providing optimal quality of service within given constraints is a further challenge that needs to be met. Further how to select the values of the significant parameters so that the CODEC performs optimally under the given constraints is a further important question to be answered. This thesis proposes a framework that uses machine learning algorithms to model the performance of a video CODEC based on the significant coding parameters. Means of modelling both the Encoder and Decoder performance is proposed. We define objective functions that can be used to model the performance related properties of a CODEC, i.e., video quality, bit-rate and CPU time. We show that these objective functions can be practically utilised in video Encoder/Decoder designs, in particular in their performance optimisation within given operational and practical constraints. A Multi-objective Optimisation framework based on Genetic Algorithms is thus proposed to optimise the performance of a video codec. The framework is designed to jointly minimize the CPU Time, Bit-rate and to maximize the quality of the compressed video stream. The thesis presents the use of this framework in the performance modelling and multi-objective optimisation of the most widely used video coding standard in practice at present, H.264 and the latest video coding standard, H.265/HEVC. When a communication network is used to transmit video, performance related parameters of the communication channel will impact the end-to-end performance of the video CODEC. Network delays and packet loss will impact the quality of the video that is received at the decoder via the communication channel, i.e., even if a video CODEC is optimally configured network conditions will make the experience sub-optimal. Given the above the thesis proposes a design, integration and testing of a novel approach to simulating a wired network and the use of UDP protocol for the transmission of video data. This network is subsequently used to simulate the impact of packet loss and network delays on optimally coded video based on the framework previously proposed for the modelling and optimisation of video CODECs. The quality of received video under different levels of packet loss and network delay is simulated, concluding the impact on transmitted video based on their content and features

Fast Motion Estimation’s Configuration Using Diamond Pattern and ECU, CFM, and ESD Modes for Reducing HEVC Computational Complexity

The high performance of the high efficiency video coding (HEVC) video standard makes it more suitable for high-definition resolutions. Nevertheless, this encoding performance is coupled with a tremendous encoding complexity compared to the earlier H264 video codec. The HEVC complexity is mainly a return to the motion estimation (ME) module that represents the important part of encoding time which makes several researches turn around the optimization of this module. Some works are interested in hardware solutions exploiting the parallel processing of FPGA, GPU, or other multicore architectures, and other works are focused on software optimizations by inducing fast mode decision algorithms. In this context, this article proposes a fast HEVC encoder configuration to speed up the encoding process. The fast configuration uses different options such as the early skip detection (ESD), the early CU termination (ECU), and the coded block flag (CBF) fast method (CFM) modes. Regarding the algorithm of ME, the diamond search (DS) is used in the encoding process through several video resolutions. A time saving around 46.75% is obtained with an acceptable distortion in terms of video quality and bitrate compared to the reference test model HM.16.2. Our contribution is compared to other works for better evaluation

Pre-processing techniques to improve HEVC subjective quality

Nowadays, HEVC is the cutting edge encoding standard being the most efficient solution for transmission of video content. In this paper a subjective quality improvement based on pre-processing algorithms for homogeneous and chaotic regions detection is proposed and evaluated for low bit-rate applications at high resolutions. This goal is achieved by means of a texture classification applied to the input frames. Furthermore, these calculations help also reduce the complexity of the HEVC encoder. Therefore both the subjective quality and the HEVC performance are improved

Fast motion estimation algorithms for block-based video coding encoders

The objective of my research is reducing the complexity of video coding standards in real-time scalable and multi-view applications.EThOS - Electronic Theses Online ServiceGBUnited Kingdo