MPEG-4 Software Video Encoding

A Thesis submitted in fulfillment of the requirements of the degree of doctor of Philosophy in the University of LondonThis thesis presents a software model that allows a parallel decomposition of the MPEG-4 video encoder onto shared memory architectures, in order to reduce its total video encoding time. Since a video sequence consists of video objects each of which is likely to have different encoding requirements, the model incorporates a scheduler which (a) always selects the most appropriate video object for encoding and, (b) employs a mechanism for dynamically allocating video objects allocation onto the system processors, based on video object size information. Further spatial video object parallelism is exploited by applying the single program multiple data (SPMD) paradigm within the different modules of the MPEG-4 video encoder. Due to the fact that not all macroblocks have the same processing requirements, the model also introduces a data partition scheme that generates tiles with identical processing requirements. Since, macroblock data dependencies preclude data parallelism at the shape encoder the model also introduces a new mechanism that allows parallelism using a circular pipeline macroblock technique The encoding time depends partly on an encoder’s computational complexity. This thesis also addresses the problem of the motion estimation, as its complexity has a significant impact on the encoder’s complexity. In particular, two fast motion estimation algorithms have been developed for the model which reduce the computational complexity significantly. The thesis includes experimental results on a four processor shared memory platform, Origin200

Generic techniques to improve SVC enhancement layer encoding: digest of technical papers

Scalable video coding is an important mechanism to provide different types of end-user devices with different versions of the same encoded bitstream. However, scalable video encoding remains a computationally expensive operation. To decrease the complexity we propose generic techniques. These techniques can also be combined with existing fast mode decision modes. We show that extending these existing techniques yield an average complexity reduction of 87%

Analog Video Encoding and Quality Evaluation

[Abstract] The most widespread analog video encoding systems in the literature are based on the use of the 2D and 3D DCT. These systems use both transformations indistinctly without assessing their suitability. In this paper, we present procedures to compress video using 2D and 3D-DCT and we evaluate the video quality for different compression levels.Xunta de Galicia; ED431C 2016-045Xunta de Galicia; ED431G/01Agencia Estatal de Investigación de España; TEC2016-75067-C4-1-

On the Interplay of Foveated Rendering and Video Encoding

Publisher Copyright: © 2020 Owner/Author.Humans have sharp central vision but low peripheral visual acuity. Prior work has taken advantage of this phenomenon in two ways: foveated rendering (FR) reduces the computational workload of rendering by producing lower visual quality for peripheral regions and foveated video encoding (FVE) reduces the bitrate of streamed video through heavier compression of peripheral regions. Remote rendering systems require both rendering and video encoding and the two techniques can be combined to reduce both computing and bandwidth consumption. We report early results from such a combination with remote VR rendering. The results highlight that FR causes large bitrate overhead when combined with normal video encoding but combining it with FVE can mitigate it.Peer reviewe

Efficient Parallel Video Encoding on Heterogeneous Systems

Proceedings of: First International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2014). Porto (Portugal), August 27-28, 2014.In this study we propose an efficient method for collaborative H.264/AVC inter-loop encoding in heterogeneous CPU+GPU systems. This method relies on specifically developed extensive library of highly optimized parallel algorithms for both CPU and GPU architectures, and all inter-loop modules. In order to minimize the overall encoding time, this method integrates adaptive load balancing for the most computationally intensive, inter-prediction modules, which is based on dynamically built functional performance models of heterogenous devices and inter-loop modules. The proposed method also introduces efficient communication-aware techniques, which maximize data reusing, and decrease the overhead of expensive data transfers in collaborative video encoding. The experimental results show that the proposed method is able of achieving real-time video encoding for very demanding video coding parameters, i.e., full HD video format, 64×64 pixels search area and the exhaustive motion estimation.This work was supported by national funds through FCT – Fundação para a Ciência e a Tecnologia, under projects PEst-OE/EEI/LA0021/2013, PTDC/EEI-ELC/3152/2012 and PTDC/EEA-ELC/117329/2010

Subjective Quality Assessment of the Impact of Buffer Size in Fine-Grain Parallel Video Encoding

Fine-Grain parallelism is essential for real-time video encoding performance. This usually implies setting a fixed buffer size for each encoded block. The choice of this parameter is critical for both performance and hardware cost. In this paper we analyze the impact of buffer size on image subjective quality, and its relation with other encoding parameters. We explore the consequences on visual quality, when minimizing buffer size to the point of causing the discard of quantized coefficients for highest frequencies. Finally, we propose some guidelines for the choice of buffer size, that has proven to be heavily dependent, in addition to other parameters, on the type of sequence being encoded. These guidelines are useful for the design of efficient realtime encoders, both hardware and software

Numerical analysis of a fin-tube plate heat exchanger with winglets

In this presented work, numerical analysis of heat transfer and flow characteristic using longitudinal vortex generators (LVGS) in fin and flat tube heat exchanger has been presented. Conjugate heat transfer 3D numerical model has been developed and successfully carried out. Rectangular winglets were set in pairs, with downstream orientation. The effects of impact angles of (20⁰ , 30⁰, and 40⁰ ) as well as tubes and winglets were placed in one row lined arrangement and air flow by forward arrangement and backward arrangement. Reynolds number is ranged from 500 to 5000. The numerical results showed that in the range of the present study, the variation of these parameters can result in the increase of heat transfer. The study focuses on the Influence of the different parameters of VGs on heat transfer and fluid flow characteristics of one row lined circular-tube banks. The characteristics of average Nu number and skin friction coefficient are studied numerically by the aid of the computational fluid dynamics (CFD) commercial code of FLUENT ANSYS 14. The results showed increasing in the heat transfer and skin friction coefficient with the increasing of Re number. It has been observed that the overall Nuav number of one circular tubes increases by 23-31% ,by 23-43% and by 23-47% with angles of (20⁰, 30°, and 40⁰) respectively, in forward arrangement and the overall Nuav number of one circular tubes increases by 23-42%, by 23-46% and 23-52%with angles of (20⁰, 30°, and 40⁰) respectively, in backward arrangement, with increasing in the overall average of skin friction coefficient. Also the results showed that the rectangular winglet pairs (RWPs) can significantly improve the heat transfer performance of the fin and-tube heat exchangers with a moderate pressure loss penalty