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In the quest of perceptually optimized video coding, coding textures is representing a challenging case. While a large body of research was put into the perception of static textures, dynamic textures are still not sufficiently explored. In this paper, we focus on short term consistent patches, known as dynamic textures, with a very limited spatial and temporal extent. We estimated the visual distortion...
A joint source-channel rate-distortion (RD) optimization is proposed for video communication systems. The source coding and channel coding options are optimized by seeking the best trade-off between the estimated end-to-end distortion of a video packet and the sum of the number of source bits and forward error correction bits used to encode that packet. The proposed RD algorithm controls the total...
Fisheye cameras have become extremely popular in applications where the goal is to capture large fields of view with only one camera. However, the wide-angle fisheye imagery has special characteristics that may not be very well suited for modern video codecs that employ block-based translational motion model. This model fails to describe complex deformable motion which is often present in fisheye...
Regular omnidirectional video encoding technics use map projection to flatten a scene from a spherical shape into one or several 2D shapes. Common projection methods including equirectangular and cubic projection have varying levels of interpolation that create a large number of non-information-carrying pixels that lead to wasted bitrate. In this paper, we propose a tile based omnidirectional video...
With the ability of representing 3D scene geometry, depth maps are used to synthesize virtual views in free view video (FVV) or 3DTV. However, compression artefact of the depth images always lead to seriously geometry distortions in synthesized view, which severely affects the visual perception of 3D display. To solve the problem caused by depth artifact, the bilateral filter based method is presented...
A cloud-based encoding pipeline which generates streams for video-on-demand distribution typically processes a wide diversity of content that exhibit varying signal characteristics. To produce the best quality video streams, the system needs to adapt the encoding to each piece of content, in an automated and scalable way. In this paper, we describe two algorithm optimizations for a distributed cloud-based...
In this paper, we pose a new problem of video enhancement transcoding, which converts the compressed dark video into compressed normal-lighting one. Distinct statistics of dark and normal videos result in quite different coding modes, which thus enforces latent constraints on mode conversion during transcoding. Following this idea, we propose a fast mode decision algorithm to speed up computation...
The upcoming JPEG XT standard for High Dynamic Range (HDR) images defines a common framework for the lossy and lossless representation of high-dynamic range images. It describes the decoding process as the combination of various processing tools that can be combined freely. In this paper we analyze the coding efficiency of different decoding tools through a large scale objective quality testing using...
This paper studies the influence of JPEG-XT on LDR generation using TMOs'. JPEG-XT encodes HDR images into a two layer scheme, encoding a LDR version of the image in a base layer, and the residual HDR information in an enhancement layer. The question addressed here is to understand if this model allows to extract a new LDR representation using a different TMO, independently of the TMO used to generate...
The latest video compression standard HEVC sets new benchmarks concerning the efficiency for both video coding and also still image coding, i.e., pure intra picture coding. Nevertheless, its high complexity created by the rate-distortion optimization procedure is a serious drawback. To reduce this computational burden, several algorithms for fast mode decision have been proposed. However, most of...
Network streaming video services have been growing explosively in the past decade, but how to measure and assure the video quality-of-experience (QoE) of end consumers is still an open problem. Poor presentation quality and playback stalling have been identified as the most dominant factors that degrade user QoE. Although both factors have been studied individually, little is known about the interactions...
In the absence of a commercial High Dynamic Range (HDR) distribution pipeline, two-layer backward-compatible HDR video coding is a viable solution for the imminent transition from Low Dynamic Range (LDR) to HDR content transmission. However, the performance of a two-layer coding solution is governed by the extension layer coding performance. In this paper, we propose an improved two-layer backward-compatible...
Real-time video applications, such as multi party video conferencing, involve the simultaneous transport of multiple and potentially multi-layered video sources to participating or interested parties. It is desirable to mix these multiple source videos into a single video stream at intermediary nodes in the network, e.g. at Multipoint Control Units (MCU). This has the advantage of reduced application...
While a number of existing high-bit depth video compression methods can potentially encode high dynamic range (HDR) video, few of them provide this capability. In this paper, we investigate techniques for adapting HDR video for this purpose. In a large-scale test on 33 HDR video sequences, we compare 2 video codecs, 4 luminance encoding techniques (transfer functions) and 3 color encoding methods,...
Inspired by recent advances in objective video quality assessment, this paper proposes a novel, local quantisation parameter (QP) determination approach for perceptual video compression, based on the experimental results of a QP selection test. This method has been fully integrated into the High Efficiency Video Coding (HEVC) reference codec for intra coding, which predicts coding tree unit (CTU)...
This paper investigates the effect that the QP offset value has on the coding performance of HEVC. We relate QP offset to the type of texture content present in the sequence. These then are used to develop a low-complexity adaptive QP offset selection method. This enables in-loop configuration of the QP offset parameter in a way that is content dependent and utilizes available encoding statistics...
Lossy compression techniques based on multi-component transformation (MCT) can effectively enhance the storage and transmission of whole-slide images (WSIs) without adversely affecting subsequent diagnosis processes. Component transforms that are designed for other types of images or that do not take into account all aspects of the compression algorithm applied on the transformed components yield...
Optimal rate allocation is among the most challenging tasks to perform in the context of multi-view video coding, because of the dependency between frames induced by motion compensation and depth image-based rendering. In this paper, using a recursive rate-distortion model that explicitly takes into account these dependencies, we approach the frame-level rate allocation as a convex optimization problem...
In this paper, we address the problem of the statistical multiplexing of video streams. Dynamic bitrate allocation is used to improve the overall video quality of a pool of channels. The balance is obtained by providing more bits to complex channels, while deprivations are applied to non-complex ones. In this study, the error minimization optimization of several compressed video is considered along...
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