Adaptive HTTP streaming requires a video to be encoded at multiple independently decodable bitrates. encoding of multiple bitrates is a complex and time consuming process, especially with the new video coding standard...
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ISBN:
(纸本)9781479983407
Adaptive HTTP streaming requires a video to be encoded at multiple independently decodable bitrates. encoding of multiple bitrates is a complex and time consuming process, especially with the new video coding standard HEVC. In this paper, we analyze the relation of HEVC block structures across encodings of a video at different bitrates. We propose a multi-rate encoding method for HEVC to decrease the overall encoding complexity while keeping the rate-distortion performance as high as possible. Experimental results show an average encoding time decrease of 27% compared to the reference HEVC encoder without degrading the rate-distortion performance.
3D-HEVC is the newest standard for compressing the Multi-View plus Depth (MVD) video. Inheriting from HEVC, 3D-HEVC presents a high encoding complexity by extra considering interview prediction. Under the encoding arc...
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ISBN:
(纸本)9781479983407
3D-HEVC is the newest standard for compressing the Multi-View plus Depth (MVD) video. Inheriting from HEVC, 3D-HEVC presents a high encoding complexity by extra considering interview prediction. Under the encoding architecture of 3D-HEVC, we develop fast algorithms for early decisions of CU splitting/non-splitting for both texture and depth frame coding. High correlation between the texture and depth domains is exploited such that when encoding one domain of information (texture or depth), the coding efficiency (RD characteristics or speedup) can be improved by adding suitably augmenting information from the other domain, thus achieving the so-called depth-assisted and texture-assisted coding. In texture coding part, optical flow features and depth edges are combined to form a feature vector for searching similar CUs in previously coded block buffers and inheriting the CU splitting decision accordingly. In depth coding part, optical flows and depth map features are used as inputs to a neural classifier for fast decision of CU splitting/non-splitting. Compared to the original 3D-HEVC implementation, our texture coding algorithm achieves a 46.6% of time saving at only 0.4% of bit rate increase and 0.04 dB of quality degradation. On the other side, our depth coding algorithm saves 35.8% of the encoding time at 2.65% of bit rate reduction and 0.16 dB of PSNR degradation. In comparison to prior works [4][5][10], our algorithm achieves more time saving at comparable bit rate increase and PSNR degradation.
Overcomplete transforms have received considerable attention over the past years. However, they often suffer from a complexity burden. In this paper, a low complexity approach is provided, where an orthonormal basis i...
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ISBN:
(纸本)9781479983407
Overcomplete transforms have received considerable attention over the past years. However, they often suffer from a complexity burden. In this paper, a low complexity approach is provided, where an orthonormal basis is complemented with a set of incomplete transforms: those incomplete transforms include a reduced number of basis vectors that allow a reduction on the coding complexity and ensure a certain level of sparsity. The solution has been implemented in the HEVC standard and compression gains of around 1% on average are reported while reducing the decoder complexity in about 5%.
This paper proposed a new fast intra prediction algorithm based on fast edge detection and CU partition for depth map to reduce the coding complexity of Multiview Video Plus Depth (MVD) coding in HEVC. The latest vide...
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ISBN:
(纸本)9781510821279
This paper proposed a new fast intra prediction algorithm based on fast edge detection and CU partition for depth map to reduce the coding complexity of Multiview Video Plus Depth (MVD) coding in HEVC. The latest video coding standard HEVC greatly improves the coding complexity of intra prediction because of complex coding unit (CU) partition and lots of prediction modes. Depth maps always have smooth regions separated by sharp edges. Smooth regions can help to speed up the CU partition and reduce the time of intra mode decision, and sharp edges must be protected to ensure the quality of synthetic viewpoints. In the new algorithm, an equation and a threshold T are used to detect whether there are edges in current CU. To different kinds of CU, different intra mode decision methods are taken. After simulation, the experimental results show that the proposed algorithm significantly reduces the coding times, while maintaining high bitrate and PSNR performance in comparison with original HEVC algorithm.
Transform skip modes (TSM) have previously been proposed for HEVC, where a transform on the prediction residual is skipped in one or both directions. TSM can improve coding efficiency when the prediction errors have m...
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ISBN:
(纸本)9781479986385
Transform skip modes (TSM) have previously been proposed for HEVC, where a transform on the prediction residual is skipped in one or both directions. TSM can improve coding efficiency when the prediction errors have minimal correlation in one or both directions. In this paper, improvements are proposed to the 1D transform skip mode design. Specifically, a unified dynamic range control method is proposed for the horizontal-only and vertical-only 1D TSM. It is also proposed to modify the scan order of the transform coefficients and to apply coefficient flipping to some 1D TSM cases. Finally, a number of efficient encoder complexity reduction methods are considered for the proposed 1D TSM. Experimental results show that the proposed method can achieve up to 4.7% gain in coding efficiency with limited encoder complexity increase. The proposed method also significantly improves visual quality, especially in areas rich in text and graphics.
As storage systems grow in size, device failures happen more frequently than ever before. Given the commodity nature of hard drives employed, a storage system needs to tolerate a certain number of disk failures while ...
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As storage systems grow in size, device failures happen more frequently than ever before. Given the commodity nature of hard drives employed, a storage system needs to tolerate a certain number of disk failures while maintaining data integrity, and to recover lost data with minimal interference to normal disk I/O operations. RAID-6, which can tolerate up to two disk failures with the minimum redundancy, is becoming widespread. However, traditional RAID-6 codes suffer from high disk I/O overhead during recovery. In this paper, we propose a new family of RAID-6 codes, the Minimum Disk I/O Repairable (MDR) codes, which achieve the optimal disk I/O overhead for single failure recoveries. Moreover, we show that MDR codes can be encoded with the minimum number of bit-wise XOR operations. Simulation results show that MDR codes help to save about half of disk read operations than traditional RAID-6 codes, and thus can reduce the recovery time by up to 40%.
Slide rectangular window structure for QC-LDPC codes (SRW-QC-LDPC) with flexible code lengths and code rates is proposed, which aim to eliminate the cycles of length 4 without computer search. The parity-check matrix ...
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ISBN:
(纸本)9788996865032
Slide rectangular window structure for QC-LDPC codes (SRW-QC-LDPC) with flexible code lengths and code rates is proposed, which aim to eliminate the cycles of length 4 without computer search. The parity-check matrix would have different extension factors and structures by using the slide rectangular window in the base matrix, the degree distribution is optimized by the optimal diagonal method. Because the dual-diagonal structure with many variable nodes of degree-2 may lead to high error floor, SRW-QC-LDPC codes with quasi tri-diagonal structure are also proposed by changing the location of the third diagonal to partly eliminate variable nodes of degree-2 for lower error floor. Simulation results show that SRW-QC-LDPC codes with quasi tri-diagonal structure can not only flexibly expand the code lengths and code rates but also reduce the encoding complexity and improve the BER performance compared to quasi dual-diagonal structure in IEEE802.16e QC-LDPC codes. The novel QC-LDPC codes are available and suitable for the adaptive transmission systems and hardware implementation.
In this paper, we propose a fast inter mode decision method for High Efficiency Video Coding (HEVC) in order to reduce its encoding complexity by simplifying the inter prediction unit (PU) mode decision process. Exper...
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ISBN:
(纸本)9781479912919
In this paper, we propose a fast inter mode decision method for High Efficiency Video Coding (HEVC) in order to reduce its encoding complexity by simplifying the inter prediction unit (PU) mode decision process. Experimental results show that encoding time is reduced by 46.5% at the consequence of only 1.1% coding efficiency loss when the proposed method is jointly used with the early CU termination (ECU) method.
In this paper the problem of reliable communication with a noisy encoder is examined. We explicitly provided the construction of the encoder and show that even when all logic gates that constitute the encoder are nois...
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ISBN:
(纸本)9781479980093
In this paper the problem of reliable communication with a noisy encoder is examined. We explicitly provided the construction of the encoder and show that even when all logic gates that constitute the encoder are noisy, reliable communication with a positive rate is still possible. The encoding complexity is shown to be O(log 1/p(tar) / log 1/epsilon) per bit to achieve a target bit error rate p(tar), where epsilon denotes the error probability of each noisy gate. This complexity upper bound is shown to coincide with a lower bound in order sense, and is hence tight. The key technique in the proposed construction is to embed noisy decoders inside the noisy encoder, which are utilized repeatedly to prevent the bit error rate from escalating. The proposed noisy encoder has a direct application in noisy computing of a linear transform.
This paper proposes a cloud-based distributed image coding scheme (Cloud-DIC) to exploit the strong correlations with external partial-duplicate images in the cloud. It features both high coding efficiency and low enc...
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ISBN:
(纸本)9781479957521
This paper proposes a cloud-based distributed image coding scheme (Cloud-DIC) to exploit the strong correlations with external partial-duplicate images in the cloud. It features both high coding efficiency and low encoder complexity, which makes it suitable for photo sharing on mobile devices. To get the side information in the cloud, a thumbnail of the current image is transmitted to retrieve highly correlated images and reconstruct through geometrical registration and adaptive patched-based stitching. The current image is then compressed by a transform-domain syndrome coding, bitplane by bitplane. Once a bitplane is received, the decoded high-quality image is further used to refine the side information in the cloud, which will benefit the coding of following bit-planes and the reconstruction. Experimental results on a landmark image database show that it can largely enhance the coding efficiency both subjectively and objectively with up to 5 dB gains and 58% bits saving over JPEG.
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