The distinguished features of screencontents lead to the development of the screen content coding (SCC) extension of High Efficiency Video coding (HEVC). Intra coding of HEVC-SCC has to evaluate traditional HEVC intr...
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The distinguished features of screencontents lead to the development of the screen content coding (SCC) extension of High Efficiency Video coding (HEVC). Intra coding of HEVC-SCC has to evaluate traditional HEVC intra coding modes and additional modes for screencontents, which poses a challenge for coding such a content on mobile devices. Furthermore, the heterogeneous mobile devices have varying complexity requirements. In this paper, a flexible screencontent intra coding scheme is proposed, which can trade between encoding complexity and rate-distortion performance degradation via cost sensitive learning. Taking the cost of different decisions into account, binary classifiers are designed to determine whether a particular kind of coding modes will be evaluated. By adopting the cost-proportionate weighted sampling, the proposed scheme can learn a flexible coding policy offline via reinforcement learning. Experimental results show the effectiveness of the proposed scheme.
This paper presents fast and efficient intra prediction algorithms for screen content coding (SCC). The proposed algorithms focus on smooth regions frequently appeared in screencontent videos, which have the characte...
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ISBN:
(纸本)9781467369985
This paper presents fast and efficient intra prediction algorithms for screen content coding (SCC). The proposed algorithms focus on smooth regions frequently appeared in screencontent videos, which have the characteristics of noiselessness. All the samples in a noiseless smooth region exhibit exactly the same pixel value. We then propose two intra coding techniques for noiseless smooth regions in SCC based on the smoothness of the boundary samples which are used for intra prediction. Our proposed algorithm can reduce computational complexity by at most 26.7% while keeping nearly the same video quality. Moreover, by removing the redundant coding bits for intra prediction modes, computational complexity can be further reduced to at most 53.3% in terms of encoding time with bitrate reduction up to 1.2%.
String Prediction (SP) is a special intra prediction mode for screen content coding, which can provide better coding efficiency while keeping lower coding complexity. In this paper, we present a string prediction-base...
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ISBN:
(纸本)9781450389075
String Prediction (SP) is a special intra prediction mode for screen content coding, which can provide better coding efficiency while keeping lower coding complexity. In this paper, we present a string prediction-based improved algorithm to third-generation of the Audio Video coding Standard (AVS3) screen content coding (SCC). The main content is to use the string vector (SV) of history-based block vector prediction (HBVP) as string vector prediction (SVP), and obtain the best SV by comparing the rate-distortion (RD) cost, which comes from CU-level estimation search and pixel-level motion estimation search. SV is equal to the sum of SVP and string vector difference (SVD). While the encoder only needs to signal the SVD and the HBVP index to the decoder. The experiments show that with little coding complexity increases, the algorithm presented in this paper achieves an average Y BD-rate of -5.02% (TGM)/ -3.06% (MC), U BD-rate of -5.10% (TGM)/ -3.39% (MC), V BD-rate of -5.08% (TGM)/ -3.66% (MC) from AVS SCC common test condition (CTC) test suite in all intra configuration.
Palette mode, as a new coding tool, is adopted in the screen content coding Extensions of High Efficiency Video coding (HEVC SCC) that is being defined by the Joint Collaborative Team on Video coding (JCT-VC). In the ...
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ISBN:
(纸本)9781479983407
Palette mode, as a new coding tool, is adopted in the screen content coding Extensions of High Efficiency Video coding (HEVC SCC) that is being defined by the Joint Collaborative Team on Video coding (JCT-VC). In the palette mode, pixels in a coding unit (CU) are represented by selected representative colours according to the characteristics of screencontents in which pixel values usually concentrate on few colour values. This paper introduces the palette mode in HEVC SCC, and our contributions to the palette mode are also presented. Experimental results show that disabling the palette mode suffers 20.3%, 13.0%, and 7.5% BD-rate increases for "YUV, text & graphics with motion, 1080p & 720p sequences" under all intra (AI), random access (RA), and low-delay B (LB) common test conditions, respectively.
This paper proposes a noise reduction method for screen content coding using HEVC. The proposed method focuses on that the histograms of pixel values for screencontent have distinct and sparse peaks respectively. Thi...
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ISBN:
(纸本)9781467369985
This paper proposes a noise reduction method for screen content coding using HEVC. The proposed method focuses on that the histograms of pixel values for screencontent have distinct and sparse peaks respectively. This property is often degraded by the coding distortion, which arises some small peaks around the original peak. This paper presents a method for removing the small peaks derived from the noise, and its implementation to HEVC as an extension of SAO. Experimental evaluation shows that the proposed noise reduction method significantly improves the visual quality of decoded screencontent with bit-rate reduction.
This paper presents a low-complexity lossless screen content coding method on top of a well structured dictionary based solution DictSCC. Both methods are implemented on the emerging High-Efficiency Video coding (HEVC...
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ISBN:
(纸本)9781479957521
This paper presents a low-complexity lossless screen content coding method on top of a well structured dictionary based solution DictSCC. Both methods are implemented on the emerging High-Efficiency Video coding (HEVC) Range Extensions (RExt) to demonstrate the coding efficiency. Compared with the DictSCC our scheme further explores the 2D correlation between neighboring image blocks for performance improvement, and reduces the complexity significantly by constraining the dictionary buffer which will be more favored by the hardware implementation. Results demonstrate averaged 17%, 10% and 8% bit rate reduction over HEVC for screencontent compression with respect to All Intra, Random Access and Low-Delay encoder configurations.
screencontent largely consists of static parts, e.g. static background. However, none of the available screen content coding tools fully employs this characteristic. In this paper we present the copy mode, a new codi...
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ISBN:
(纸本)9781479983407
screencontent largely consists of static parts, e.g. static background. However, none of the available screen content coding tools fully employs this characteristic. In this paper we present the copy mode, a new coding mode specifically aiming at increased coding efficiency for static screencontent. The basic principle of the copy mode is the direct copy of the collocated block from the reference frame. Mean weighted BD-Rate gains of 2.4% are achieved for JCT-VC test sequences compared to SCM-2.0. For sequences containing lots of static background, coding gains as high as 7.6% are observed. The new coding mode is further enhanced by several encoder optimizations, among them an early skip mechanism. Thereby, the encoder runtime complexity is reduced by up to 39%.
作者：
Yang, HaoShen, LiquanAn, PingShanghai Univ
Sch Commun & Informat Engn Key Lab Specialty Fiber Opt & Opt Access Networks Shanghai Peoples R China Shanghai Univ
Shanghai Inst Adv Commun & Data Sci Shanghai Peoples R China
screencontent videos play an important role in recent popular mobile technologies and cloud applications. With the new coding tools (including intra block copy, palette mode etc.) adapted, high efficiency video codin...
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screencontent videos play an important role in recent popular mobile technologies and cloud applications. With the new coding tools (including intra block copy, palette mode etc.) adapted, high efficiency video coding (HEVC) based screen content coding (SCC) achieves high coding efficiency but requires a very high computational complexity. In this paper, we propose a fast intra coding algorithm for SCC based on statistical learning. First, we analyze the complexity distribution of SCC encoders. Then, a classifier is designed to determine whether current coding unit (CU) should be split into four sub-CUs without performing intra prediction procedure at current CU depth level or not. If current CU should not be split into sub-CUs, another classifier is used to decide either 35 traditional intra modes or SCC modes (i.e. intra block copy mode and palette mode) will be performed at current CU depth level. Three kinds of features are chosen to generate the classifiers: (1) coding information of current CU;(2) texture information within current CU;(3) information of nearby CUs. Experimental results show that the proposed algorithm achieves a computational complexity reduction with 45% on average, and only 1.6% BDBR increase compared to the original coding in SCC reference software. (C) 2017 Elsevier B.V. All rights reserved.
As online collaborations become more prevalent, screencontent has become increasingly important in real-time video communications. To reduce communication costs, the H.265/HEVC standard introduced the screencontent ...
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As online collaborations become more prevalent, screencontent has become increasingly important in real-time video communications. To reduce communication costs, the H.265/HEVC standard introduced the screen content coding (SCC) extension, which achieves significant bits savings but comes with a higher encoding complexity. There is a need for ultrafast SCC encoding to meet the demands of real-time applications. Our key idea is to predict the rate-distortion (RD) cost of each possible coding unit under each possible mode, rather than performing actual coding to obtain the RD cost. Specifically, we construct neural networks to predict RD costs for intra prediction, palette, and normal intra block copy (IBC) modes. For IBC merge mode, we conduct motion compensation trials and use a linear regression network for prediction. Using the predicted RD costs, we create a partition-mode map set that determines not only block partitioning but also optimal modes, significantly reducing encoding complexity. Our experimental results demonstrate that our method achieves a more than 90% reduction in encoding time with an average 9.4% BD-rate increase compared to the HEVC-SCC reference software in the all-intra configuration.
Many of the existing video coding standards in use today were developed primarily using camera-captured content as test material. Today, with the more widespread use of connected devices, there is an increased interes...
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ISBN:
(纸本)9781479961399
Many of the existing video coding standards in use today were developed primarily using camera-captured content as test material. Today, with the more widespread use of connected devices, there is an increased interest in developing video coding tools that target screencontent video. screencontent video is often characterized by having sharp edges, noiseless graphics-generated region, repeated patterns, limited sets of colors, etc. This paper presents an independent uniform prediction (IUP) mode for improving the coding efficiency of screencontent video. IUP chooses one color out of a small set of global colors to form a uniform prediction block. Unlike existing palette-based modes, IUP does not have to construct and signal a color index map for every block that is coded. Experimental results using IUP in the HEVC Range Extensions 6.0 framework are presented, along with results using techniques that reduce complexity so that the IUP-based encoder is faster than the reference encoder.
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