The Experts below are selected from a list of 1914 Experts worldwide ranked by ideXlab platform
Sina Vafi - One of the best experts on this subject based on the ideXlab platform.
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Motion-energy-based unequal error protection for H.264/AVC video bitstreams
Signal Image and Video Processing, 2015Co-Authors: Huu Dung Pham, Sina VafiAbstract:An unequal error protection (UEP) technique based on motion information of video bitstreams compressed by H.264/AVC standard is proposed. Motion activities of Macroblocks in a frame are analyzed, and those having high effects on the video performance are extracted. Suitable forward error-correcting codes with different rates are constructed according to the importance of Macroblocks and frames. Simulation results show that the proposed technique significantly improves the video quality, while maintaining a similar overall code rate in comparison with other UEP techniques.
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modified unequal error protection for the h 264 avc video frames with Macroblocks motion energy estimation
Asia-Pacific Conference on Communications, 2013Co-Authors: Huu Dung Pham, Sina VafiAbstract:This paper proposes an Unequal Error Protection (UEP) method for H.264/AVC video frames based on motion energy, which is defined as the necessary energy for a block movement between two different frames. The importance of a macroblock is determined on the basis of a threshold, which is estimated by its neighboring Macroblocks. The importance of a frame is determined depending on the majority of Macroblocks having high or low importance. This method provides better performance than other motion-based UEP methods, while significantly reducing the number of stuff bits used for channel coding.
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a multi level error protection technique based on Macroblocks importance of the h 264 avc video frames
Asia-Pacific Conference on Communications, 2013Co-Authors: Huu Dung Pham, Sina VafiAbstract:This paper presents a multi-level error protection for H.264/AVC video frames based on the importance of Macroblocks. It is basically accomplished by comparing motion activities of Macroblocks with their neighbouring areas. Those Macroblocks having higher motion activities than their neighbouring areas are highly protected. Two-level error protection formed by this comparison is extended to construct a multi-level error protection for the video frames. In this case, an algorithm is implemented, which considers motion activities of Macroblocks in two consecutive frames. Conducted analysis and simulation results express that the newly presented multi-level protection significantly improves the video performance compared to other motion-based error protection techniques, while similar code rates for channel codes are applied.
Wan-chi Siu - One of the best experts on this subject based on the ideXlab platform.
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Y.; Siu W.; “Priority Search Technique for MPEG-4 Motion Estimation of Arbitrarily Shaped Video Object
2016Co-Authors: Ko-cheung Hui, Yui-lam Chan, Wan-chi SiuAbstract:One of the main differences between the MPEG-4 video and the previously standardized video coding schemes is the support of arbitrarily shaped video objects, for which most of the existing fast motion estimation algorithms are not suitable. The conventional fast motion estimation algorithm works well for opaque Macroblocks, but not the case for a boundary macroblock which contains a large number of local minima on its error surface. In this paper, we propose a fast search algorithm which incorporates the binary alpha-plane to predict accurately the motion vectors of boundary Macroblocks. Besides, these accurate motion vectors can be used to develop a novel priority search algorithm which is an efficient search strategy for the remaining opaque Macroblocks. Experimental results show that, when compared to the conventional methods, our approach requires a low computational complexity and provides a significant improvement in terms of accuracy in motion-compensated video object planes. 1
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Macroblock-Based Algorithm for Dual-Bitstream MPEG Video Streaming with VCR Functionalities
2016Co-Authors: Yui-lam Chan, Wan-chi SiuAbstract:Abstract — Reverse playback is the most common video cassette recording (VCR) functions in many digital video players. How-ever, the predictive processing techniques employed in MPEG severely complicate the reverse-play operation. One approach to achieve the reverse playback is to store an additional backward-encoded bitstream into the server. Once the client requests a backward-play operation, the server will select an appropriate frame for the client from either the forward or backward-encoded bitstream by considering the cost of network bandwidth and the decoder complexity. Unfortunately, the forward and backward-encoded bistreams are encoded separately. The frame that has previously decoded by the client may not exactly identical to the reference of the current selected frame and the drift problem is occurred. In this paper, we propose a macroblock-based approach to alleviate the drift problem with the minimal requirements on the network bandwidth and the decoder complexity. The novel macroblock-based techniques are used to manipulate the necessary Macroblocks in the compressed-domain and the server then sends the processed Macroblocks to the client machine. Experimental results show that, as compared to the conventional dual-bitstream system, the new streaming system enhances the quality of the reconstructed frame significantly. I
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Improved Hybrid Coding Scheme for Intra 4x4 Residual Block Produced by H.264/AVC
2016Co-Authors: Li-li Wang, Wan-chi SiuAbstract:Abstract—In this paper, the intra residual macroblock produced by H.264 is investigated. Based on its characteristics, an efficient two-layer coding scheme for the intra residual macroblock is developed. The rate-distortion performance for the proposed coding scheme is evaluated. Experimental results show that our algorithm can achieve better coding performance. I
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Reverse-Play Algorithm for MPEG Video Streaming
2016Co-Authors: Yui-lam Chan, Wan-chi SiuAbstract:Reverse playback involves playing back video frames in reverse order. However, it is not a straightforward task in MPEG digital video due to the use of predictive processing techniques in MPEG. In this paper, we propose a compressed-domain approach for the efficient implementation of an MPEG video streaming system to provide the reverse-play operation over a network. In the proposed video streaming server, a novel macroblock-based algorithm is used to adaptively select the necessary Macroblocks, manipulate them in compressed-domain and send the processed Macroblocks to the client machine. Besides, we propose a technique of mismatch error compensation such that there is only a negligibly small PSNR degradation during reverse playback of the proposed algorithm. Experimental results show that, as compared to the conventional system, the new streaming system reduces the required network bandwidth and the decoder complexity significantly in reverse playback. Index Terms: Compressed-domain processing, digital vide
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Brief Papers Redundancy Reduction Technique for Dual-Bitstream MPEG Video Streaming With VCR Functionalities
2016Co-Authors: Yui-lam Chan, Wan-chi SiuAbstract:Abstract—With the proliferation of online video contents, it is highly desirable that video streaming systems are able to provide fast and effective video browsing. However, the predictive coding techniques adopted in current compression standards such as MPEG severely complicate these browsing operations. One ap-proach to achieve browsing functionalities is to store an additional reverse-encoded bitstream into the server. Unfortunately, this extra bitstream approximately doubles the storage requirement of the video server. In this paper, we make use of the redundancy inherent between the forward and reverse-encoded bitstreams in order to achieve a substantial reduction on the size of the reverse-encoded bitstream. A novel macroblock-selection strategy is then proposed in the server to access and manipulate various Macroblocks from the forward and reverse-encoded bistreams to facilitate various browsing operations. Experimental results show that, as compared to the conventional dual-bitstream scheme, the new scheme significantly alleviates the storage increase due to the additional reverse-encoded bitstream. Index Terms—Digital video browsing, digital video cassette recording (VCR), dual-bitstream scheme, MPEG video, streaming video. I
Bin Wei - One of the best experts on this subject based on the ideXlab platform.
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Memory Performance Optimizations For Real-Time Software HDTV Decoding
Journal of VLSI signal processing systems for signal image and video technology, 2005Co-Authors: Han Chen, Bin WeiAbstract:Pure software HDTV video decoding is still a challenging task on entry-level to mid-range desktop and notebook PCs, even with today’s microprocessors frequency measured in GHz. This paper shows that the performance bottleneck in a software MPEG-2 decoder has been shifted to memory operations, as microprocessor technologies including multimedia instruction extensions have been improving at a fast rate during the past years. Our study exploits concurrencies at macroblock level to alleviate the performance bottleneck in a software MPEG-2 decoder. First, the paper introduces an interleaved block-order data layout to improve CPU cache performance. Second, the paper describes an algorithm to explicitly prefetch Macroblocks for motion compensation. Finally, the paper presents an algorithm to schedule interleaved decoding and output at macroblock level. Our implementation and experiments show that these methods can effectively hide the latency of memory and frame buffer. The optimizations improve the performance of a multimedia-instruction-optimized software MPEG-2 decoder by a factor of about two. On a PC with a 933 MHz Pentium III CPU, the decoder can decode and display 1280 × 720-resolution HDTV streams at over 62 frames per second.
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memory performance optimizations for real time software hdtv decoding
International Conference on Multimedia and Expo, 2002Co-Authors: Han Chen, Bin WeiAbstract:This paper shows that the performance bottleneck in software MPEG-2 video decoders has shifted to memory operations, as microprocessor technologies have been improving at a fast rate during the past few years. We exploit concurrencies between the processor and the memory sub-system at macroblock level to alleviate the performance bottleneck. First, the paper introduces an interleaved-block order data layout to improve cache performance. Second, the paper describes an algorithm to explicitly prefetch Macroblocks for motion compensation. Finally, the paper presents an algorithm to schedule interleaved decoding and output at macroblock level. Our implementation and experiments show that these methods successfully hide the latency of memory and frame buffer. These techniques improve the performance of an already optimized software MPEG-2 decoder by about a factor of two. On a 933 MHz Pentium III PC, the decoder can play 720p HDTV streams at over 62 frames per second.
Huu Dung Pham - One of the best experts on this subject based on the ideXlab platform.
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Motion-energy-based unequal error protection for H.264/AVC video bitstreams
Signal Image and Video Processing, 2015Co-Authors: Huu Dung Pham, Sina VafiAbstract:An unequal error protection (UEP) technique based on motion information of video bitstreams compressed by H.264/AVC standard is proposed. Motion activities of Macroblocks in a frame are analyzed, and those having high effects on the video performance are extracted. Suitable forward error-correcting codes with different rates are constructed according to the importance of Macroblocks and frames. Simulation results show that the proposed technique significantly improves the video quality, while maintaining a similar overall code rate in comparison with other UEP techniques.
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modified unequal error protection for the h 264 avc video frames with Macroblocks motion energy estimation
Asia-Pacific Conference on Communications, 2013Co-Authors: Huu Dung Pham, Sina VafiAbstract:This paper proposes an Unequal Error Protection (UEP) method for H.264/AVC video frames based on motion energy, which is defined as the necessary energy for a block movement between two different frames. The importance of a macroblock is determined on the basis of a threshold, which is estimated by its neighboring Macroblocks. The importance of a frame is determined depending on the majority of Macroblocks having high or low importance. This method provides better performance than other motion-based UEP methods, while significantly reducing the number of stuff bits used for channel coding.
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a multi level error protection technique based on Macroblocks importance of the h 264 avc video frames
Asia-Pacific Conference on Communications, 2013Co-Authors: Huu Dung Pham, Sina VafiAbstract:This paper presents a multi-level error protection for H.264/AVC video frames based on the importance of Macroblocks. It is basically accomplished by comparing motion activities of Macroblocks with their neighbouring areas. Those Macroblocks having higher motion activities than their neighbouring areas are highly protected. Two-level error protection formed by this comparison is extended to construct a multi-level error protection for the video frames. In this case, an algorithm is implemented, which considers motion activities of Macroblocks in two consecutive frames. Conducted analysis and simulation results express that the newly presented multi-level protection significantly improves the video performance compared to other motion-based error protection techniques, while similar code rates for channel codes are applied.
Han Chen - One of the best experts on this subject based on the ideXlab platform.
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Memory Performance Optimizations For Real-Time Software HDTV Decoding
Journal of VLSI signal processing systems for signal image and video technology, 2005Co-Authors: Han Chen, Bin WeiAbstract:Pure software HDTV video decoding is still a challenging task on entry-level to mid-range desktop and notebook PCs, even with today’s microprocessors frequency measured in GHz. This paper shows that the performance bottleneck in a software MPEG-2 decoder has been shifted to memory operations, as microprocessor technologies including multimedia instruction extensions have been improving at a fast rate during the past years. Our study exploits concurrencies at macroblock level to alleviate the performance bottleneck in a software MPEG-2 decoder. First, the paper introduces an interleaved block-order data layout to improve CPU cache performance. Second, the paper describes an algorithm to explicitly prefetch Macroblocks for motion compensation. Finally, the paper presents an algorithm to schedule interleaved decoding and output at macroblock level. Our implementation and experiments show that these methods can effectively hide the latency of memory and frame buffer. The optimizations improve the performance of a multimedia-instruction-optimized software MPEG-2 decoder by a factor of about two. On a PC with a 933 MHz Pentium III CPU, the decoder can decode and display 1280 × 720-resolution HDTV streams at over 62 frames per second.
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memory performance optimizations for real time software hdtv decoding
International Conference on Multimedia and Expo, 2002Co-Authors: Han Chen, Bin WeiAbstract:This paper shows that the performance bottleneck in software MPEG-2 video decoders has shifted to memory operations, as microprocessor technologies have been improving at a fast rate during the past few years. We exploit concurrencies between the processor and the memory sub-system at macroblock level to alleviate the performance bottleneck. First, the paper introduces an interleaved-block order data layout to improve cache performance. Second, the paper describes an algorithm to explicitly prefetch Macroblocks for motion compensation. Finally, the paper presents an algorithm to schedule interleaved decoding and output at macroblock level. Our implementation and experiments show that these methods successfully hide the latency of memory and frame buffer. These techniques improve the performance of an already optimized software MPEG-2 decoder by about a factor of two. On a 933 MHz Pentium III PC, the decoder can play 720p HDTV streams at over 62 frames per second.
