Algorithms & implementation of advanced video coding standards

Advanced video coding standards have become widely deployed coding techniques used in numerous products, such as broadcast, video conference, mobile television and blu-ray disc, etc. New compression techniques are gradually included in video coding standards so that a 50% compression rate reduction is achievable every five years. However, the trend also has brought many problems, such as, dramatically increased computational complexity, co-existing multiple standards and gradually increased development time. To solve the above problems, this thesis intends to investigate efficient algorithms for the latest video coding standard, H.264/AVC. Two aspects of H.264/AVC standard are inspected in this thesis: (1) Speeding up intra4x4 prediction with parallel architecture. (2) Applying an efficient rate control algorithm based on deviation measure to intra frame. Another aim of this thesis is to work on low-complexity algorithms for MPEG-2 to H.264/AVC transcoder. Three main mapping algorithms and a computational complexity reduction algorithm are focused by this thesis: motion vector mapping, block mapping, field-frame mapping and efficient modes ranking algorithms. Finally, a new video coding framework methodology to reduce development time is examined. This thesis explores the implementation of MPEG-4 simple profile with the RVC framework. A key technique of automatically generating variable length decoder table is solved in this thesis. Moreover, another important video coding standard, DV/DVCPRO, is further modeled by RVC framework. Consequently, besides the available MPEG-4 simple profile and China audio/video standard, a new member is therefore added into the RVC framework family. A part of the research work presented in this thesis is targeted algorithms and implementation of video coding standards. In the wide topic, three main problems are investigated. The results show that the methodologies presented in this thesis are efficient and encourage

Improved intra-prediction for video coding

This thesis focuses on improving the HEVC (High Efficiency Video Coding) standard. HEVC is the newest video coding standard developed by the ITU-T Video Coding Experts Group (VCEG) and the ISO / IEC Moving Picture Experts Group (MPEG), as a successor to the popular state-of-the-art H.264/MPEG-4 AVC (Advanced Video Coding) standard. HEVC makes use of prediction to exploit redundancies in the signal and therefore achieve high compression efficiency. In particular, the Intra-Picture prediction block consists of predicting a block in the current frame using the reference information from neighbouring blocks in the same frame. It supports three different modes, the angular mode with 33 different directions, the planar mode and DC mode. HEVC is reportedly able to achieve in average more than 50% higher efficiency than H.264/MPEG-4 AVC, but this comes at the cost of very high computational complexity. The contributions of this thesis mainly consist in improvements to the Intra-Picture prediction block, with the goal of drastically reducing computational complexity and, at the same time achieving comparable compression efficiency as conventional HEVC. In average, 16.5% encoding operations can be saved using the proposed approach at the cost of relatively small compression efficiency losses.Éste proyecto se va a centrar en mejorar el estándar HEVC (High Efficiency Video Coding). HEVC es el estándar de codificación de video más reciente desarrollado por el UIT-T Video Coding Experts Group (VCEG) e ISO/IEC Moving Picture Experts Group (MPEG), siendo sucesor del popular estado del arte H.264/MPEG-4 AVC (Advanced Video Coding) estándar . HEVC hace uso de la predicción para aprovechar las redundancias en las señales y por lo tanto conseguir una alta eficiencia de compresión. En particular, el bloque Intra-Picture prediction consiste en predecir un bloque en el cuadro actual, utilizando información de referencia de bloques vecinos en el mismo cuadro. Soporta tres modos distintos, el modo angular con 33 diferentes direcciones, el modo Planar y el modo DC. HEVC es suficientemente capaz de lograr de media una eficiencia mayor del 50% que H.264/MPEG-4 AVC, a costa de una alta complejidad computacional. Las aportaciones a esta tesis consisten principalmente en mejoras en el bloque Intra-Picture prediction, con el objetivo de reducir drásticamente la complejidad computacional y a la vez, lograr una eficiencia de compresión comparable al HEVC convencional. En promedio, un 16.5% de las operaciones de codificación pueden evitarse usando el enfoque propuesto a costa de pérdidas relativamente pequeñas de la eficiencia de compresión

Hardware Implementation of a High Speed Deblocking Filter for the H.264 Video Codec

H.264/MPEG-4 part 10 or Advanced Video Coding (AVC) is a standard for video compression. MPEG-4 is currently one of the most widely used formats for recording, compression and distribution of high definition video. One feature of the AVC codec is the inclusion of an in-loop deblocking filter. The goal of the deblocking filter is to remove blocking artifacts that exist at macroblock boundaries. However, due to the complexity of the deblocking algorithm, the filter can easily account for one-third of the computational complexity of a decoder. In this thesis, a modification to the deblocking algorithm given in the AVC standard is presented. This modification allows the algorithm to finish the filtering of a macroblock to finish twenty clock cycles faster than previous single filter designs. This thesis also presents a hardware architecture of the H.264 deblocking filter to be used in the H.264 decoder. The developed architecture allows the filtering of videos streams using 4:2:2 chroma subsampling and 10-bit pixel precision in real-time. The filter was described in VHDL and synthesized for a Spartan-6 FPGA device. Timing analysis showed that is was capable of filtering a macroblock using 4:2:0 chroma subsampling in 124 clock cycles and 4:2:2 chroma subsampling streams in 162 clock cycles. The filter can also provide real-time deblocking of HDTV video (1920x1080) of up to 988 frames per second

x264 Video Encoding Frontend

x264 is a free video codec for encoding video streams into the H.264/MPEG-4 AVC format. It has become the new standard for video encoding, providing higher quality with a higher compression than that of XviD. x264 provides a command line interface as well as an API and is used in popular applications such as HandBrake and FFmpeg. Advanced Audio Coding (AAC) is a very popular audio coding standard for lossy digital audio compression. AAC provides a higher sound quality than MP3 at similar bitrates. This senior project describes the design and implementation of a x264 video encoding frontend that uses these codecs to encode videos. The frontend provides a simple and easy-to-use graphical user interface. Subtitles are preserved across encodes and the resulting encoded file is stored in a Matroska container format

Digital recording of performing arts: formats and conversion

B

Perceived quality of full HD video - subjective quality assessment

In recent years, an interest in multimedia services has become a global trend and this trend is still rising. The video quality is a very significant part from the bundle of multimedia services, which leads to a requirement for quality assessment in the video domain. Video quality of a streamed video across IP networks is generally influenced by two factors “transmission link imperfection and efficiency of compression standards. This paper deals with subjective video quality assessment and the impact of the compression standards H.264, H.265 and VP9 on perceived video quality of these compression standards. The evaluation is done for four full HD sequences, the difference of scenes is in the content“ distinction is based on Spatial (SI) and Temporal (TI) Index of test sequences. Finally, experimental results follow up to 30% bitrate reducing of H.265 and VP9 compared with the reference H.264