A new scheme combining a scalable transcoder with space time block codes （STBC） for an orthogonal frequency division multiplexing （OFDM） system is proposed for robust video transmission in dispersive fading channe...A new scheme combining a scalable transcoder with space time block codes （STBC） for an orthogonal frequency division multiplexing （OFDM） system is proposed for robust video transmission in dispersive fading channels. The target application for such a scalable transcoder is to provide successful access to the pre-encoded high quality video MPEG-2 from mobile wireless terminals. In the scalable transcoder, besides outputting the MPEG-4 fine granular scalability （FGS） bitstream, both the size of video frames and the bit rate are reduced. And an array processing algorithm of layer interference suppression is used at the receiver which makes the system structure provide different levels of protection to different layers. Furthermore, by considering the important level of scalable bitstream, the different bitstreams can be given different level protection by the system structure and channel coding. With the proposed system, the concurrent large diversity gain characteristic of STBC and alleviation of the frequency-selective fading effect of OFDM can be achieved. The simulation results show that the proposed schemes integrating scalable transcoding can provide a basic quality of video transmission and outperform the conventional single layer transcoding transmitted under the random and bursty error channel conditions.展开更多
With the new promising technique of mobile edge computing (MEC) emerging, by utilizing the edge computing and cloud computing capabilities to realize the HTTP adaptive video streaming transmission in MEC-based 5G netw...With the new promising technique of mobile edge computing (MEC) emerging, by utilizing the edge computing and cloud computing capabilities to realize the HTTP adaptive video streaming transmission in MEC-based 5G networks has been widely studied. Although many works have been done, most of the existing works focus on the issues of network resource utilization or the quality of experience (QoE) promotion, while the energy efficiency is largely ignored. In this paper, different from previous works, in order to realize the energy efficiency for video transmission in MEC-enhanced 5G networks, we propose a joint caching and transcoding schedule strategy for HTTP adaptive video streaming transmission by taking the caching and transcoding into consideration. We formulate the problem of energy-efficient joint caching and transcoding as an integer programming problem to minimize the system energy consumption. Due to solving the optimization problem brings huge computation complexity, therefore, to make the optimization problem tractable, a heuristic algorithm based on simulated annealing algorithm is proposed to iteratively reach the global optimum solution with a lower complexity and higher accuracy. Finally, numerical simulation results are illustrated to demonstrated that our proposed scheme brings an excellent performance.展开更多
Video transcoding is to create multiple representations of a video for content adaptation.It is deemed as a core technique in Adaptive BitRate(ABR)streaming.How to manage video transcoding affects the performance of A...Video transcoding is to create multiple representations of a video for content adaptation.It is deemed as a core technique in Adaptive BitRate(ABR)streaming.How to manage video transcoding affects the performance of ABR streaming in various aspects,including operational cost,streaming delays,Quality of Experience(QoE),etc.Therefore,the problems of implementing video transcoding in ABR streaming must be systematically studied to improve the overall performance of the streaming services.These problems become more worthy of investigation with the emergence of the edge-cloud continuum,which makes the resource allocation for video transcoding more complicated.To this end,this paper provides an investigation of the main technical problems related to video transcoding in ABR streaming,including designing a rate profile for video transcoding,providing resources for video transcoding in clouds,and caching multi-bitrate video contents in networks,etc.We analyze these problems from the perspective of resource allocation in the edge-cloud continuum and cast them into resource and Quality of Service(QoS)optimization problems.The goal is to minimize resource consumption while guaranteeing the QoS for ABR streaming.We also discuss some promising research directions for the ABR streaming services.展开更多
Adaptive bitrate video streaming(ABR)has become a critical technique for mobile video streaming to cope with time-varying network conditions and different user preferences.However,there are still many problems in achi...Adaptive bitrate video streaming(ABR)has become a critical technique for mobile video streaming to cope with time-varying network conditions and different user preferences.However,there are still many problems in achieving high-quality ABR video streaming over cellular networks.Mobile Edge Computing(MEC)is a promising paradigm to overcome the above problems by providing video transcoding capability and caching the ABR video streaming within the radio access network(RAN).In this paper,we propose a flexible transcoding strategy to provide viewers with low-latency video streaming services in the MEC networks under the limited storage,computing,and spectrum resources.According to the information collected from users,the MEC server acts as a controlling component to adjust the transcoding strategy flexibly based on optimizing the video caching placement strategy.Specifically,we cache the proper bitrate version of the video segments at the edge servers and select the appropriate bitrate version of the video segments to perform transcoding under jointly considering access control,resource allocation,and user preferences.We formulate this problem as a nonconvex optimization and mixed combinatorial problem.Moreover,the simulation results indicate that our proposed algorithm can ensure a low-latency viewing experience for users.展开更多
H.264/MPEG-4 AVC standard appears highly competitive due to its high efficiency, flexibility and error resilience. In order to maintain universal multimedia access, statistical multiplexing, or adaptive video content ...H.264/MPEG-4 AVC standard appears highly competitive due to its high efficiency, flexibility and error resilience. In order to maintain universal multimedia access, statistical multiplexing, or adaptive video content delivery, etc., it induces an immense demand for converting a large volume of existing multimedia content from other formats into the H.264/AVC format and vice versa. In this work, we study the remultiplexing and resynchronization issue within system coding after transcoding, aiming to sustain the management and time information destroyed in transcoding and enable synchronized decoding of decoder buffers over a wide range of retrieval or receipt conditions. Given the common intention of multiplexing and synchronization mechanism in system coding of different standards, this paper takes the most widely used MPEG-2 transport stream (TS) as an example, and presents a software system and the key technologies to solve the time stamp mapping and relevant buffer management. The solution reuses previous information contained in the input streams to remultiplex and resynchronize the output information with the regulatory coding and composition structure. Experimental results showed that our solutions efficiently preserve the performance in multimedia presentation.展开更多
A fast mode decision algorithm is proposed in this paper to accelerate the process of transcoding videos into H.264with arbitrary rate spatial resolution down-scaling. The proposed algorithm consists of three steps. F...A fast mode decision algorithm is proposed in this paper to accelerate the process of transcoding videos into H.264with arbitrary rate spatial resolution down-scaling. The proposed algorithm consists of three steps. First, an early-stop technique is introduced to determine the 16× 16-mode blocks, which take up about 70% of all the macroblocks; then, a bottom-up merging process is performed to determine the mode of rest non-early-stopped blocks; and then, we adopt half-pixel motion estimation to further refine the acquired predictive motion vectors. In order to obtain the predictive motion vectors for early-stop and merging processes, we propose a motion vector composition scheme, which can reuse the information in the input pre-encoded videos to handle the spatial resolution down-scaling. Experimental results showed that our algorithm is about four times faster than the Cascaded-Decoder-Encoder method and has negligible PSNR drop and little bit rate increase.展开更多
A fast algorithm based on direction in intra frame downsizing in H.264 is proposed,which used modes information of macroblocks before transcoding and the direction relation of modes between decoding and re-encoding in...A fast algorithm based on direction in intra frame downsizing in H.264 is proposed,which used modes information of macroblocks before transcoding and the direction relation of modes between decoding and re-encoding in transcoding.This algorithm also made use of statistics between decoded modes and re-encoded modes,which came from a lot of sequences data experiments.Without full modes encoding,it can improve the speed of reducing intra-prediction frame resolution obviously.Comparing to traditional transcoding,it only needs to compute one of thirteen modes in re-encoding.The experiments show that this algorithm can significantly speed up 92 percent transcoding time in intra-prediction frame of H.264 with slight PSNR degradation.It also can support an improvement in real-time for transcoding and ability of bandwidths changing.展开更多
Efficient video delivery involves the transcoding of the original sequence into various resolutions,bitrates and standards,in order to match viewers’capabilities.Since video coding and transcoding are computationally...Efficient video delivery involves the transcoding of the original sequence into various resolutions,bitrates and standards,in order to match viewers’capabilities.Since video coding and transcoding are computationally demanding,performing a portion of these tasks at the network edges promises to decrease both the workload and network traffic towards the data centers of media providers.Motivated by the increasing popularity of live casting on social media platforms,in this paper we focus on the case of live video transcoding.Specifically,we investigate scheduling heuristics that decide on which jobs should be assigned to an edge minidatacenter and which to a backend datacenter.Through simulation experiments with different Qo S requirements we conclude on the best alternative.展开更多
Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and...Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and output video. In this paper, we first introduce a new spatial resolution reduction transcoding architecture of intra coded frames where the distortion can be calculated directly in compression domain. We then propose a fast mode decision algorithm in which only a small part of rate distortion optimization （RDO） calculation is needed for mode decision. For 4×4 luma block, the proposed scheme has average 21.3% computation saving, compared to the cascaded pixel-domain transcoding scheme with the fast intra mode decision algorithm proposed in JVT-G013. For 16×16 luma block, RDO calculation is completely avoided in our scheme while the scheme in JVT-G013 needs 2 RDO calculations. Experimental results show that our scheme outperforms that of JVT-G013 in terms of significantly computasavings with negligible loss of PSNR展开更多
ZTE Corporation announced on 1 March that its innovative IPTVlowbitrate highdefinition transcoding solution has been nominated for the World＇s Best Component or Enabler Award by the IPTV World Forum. The ZTE solution...ZTE Corporation announced on 1 March that its innovative IPTVlowbitrate highdefinition transcoding solution has been nominated for the World＇s Best Component or Enabler Award by the IPTV World Forum. The ZTE solution is on display at the Mobile World Congress 2012 （MWC 2012） in Barcelona.展开更多
文摘A new scheme combining a scalable transcoder with space time block codes （STBC） for an orthogonal frequency division multiplexing （OFDM） system is proposed for robust video transmission in dispersive fading channels. The target application for such a scalable transcoder is to provide successful access to the pre-encoded high quality video MPEG-2 from mobile wireless terminals. In the scalable transcoder, besides outputting the MPEG-4 fine granular scalability （FGS） bitstream, both the size of video frames and the bit rate are reduced. And an array processing algorithm of layer interference suppression is used at the receiver which makes the system structure provide different levels of protection to different layers. Furthermore, by considering the important level of scalable bitstream, the different bitstreams can be given different level protection by the system structure and channel coding. With the proposed system, the concurrent large diversity gain characteristic of STBC and alleviation of the frequency-selective fading effect of OFDM can be achieved. The simulation results show that the proposed schemes integrating scalable transcoding can provide a basic quality of video transmission and outperform the conventional single layer transcoding transmitted under the random and bursty error channel conditions.
基金support by the Major National Science and Technology Projects (No. 2018ZX03001014-003)
文摘With the new promising technique of mobile edge computing (MEC) emerging, by utilizing the edge computing and cloud computing capabilities to realize the HTTP adaptive video streaming transmission in MEC-based 5G networks has been widely studied. Although many works have been done, most of the existing works focus on the issues of network resource utilization or the quality of experience (QoE) promotion, while the energy efficiency is largely ignored. In this paper, different from previous works, in order to realize the energy efficiency for video transmission in MEC-enhanced 5G networks, we propose a joint caching and transcoding schedule strategy for HTTP adaptive video streaming transmission by taking the caching and transcoding into consideration. We formulate the problem of energy-efficient joint caching and transcoding as an integer programming problem to minimize the system energy consumption. Due to solving the optimization problem brings huge computation complexity, therefore, to make the optimization problem tractable, a heuristic algorithm based on simulated annealing algorithm is proposed to iteratively reach the global optimum solution with a lower complexity and higher accuracy. Finally, numerical simulation results are illustrated to demonstrated that our proposed scheme brings an excellent performance.
基金supported in part by the Natural Science Foundation of Jiangsu Province under Grant BK20200486.
文摘Video transcoding is to create multiple representations of a video for content adaptation.It is deemed as a core technique in Adaptive BitRate(ABR)streaming.How to manage video transcoding affects the performance of ABR streaming in various aspects,including operational cost,streaming delays,Quality of Experience(QoE),etc.Therefore,the problems of implementing video transcoding in ABR streaming must be systematically studied to improve the overall performance of the streaming services.These problems become more worthy of investigation with the emergence of the edge-cloud continuum,which makes the resource allocation for video transcoding more complicated.To this end,this paper provides an investigation of the main technical problems related to video transcoding in ABR streaming,including designing a rate profile for video transcoding,providing resources for video transcoding in clouds,and caching multi-bitrate video contents in networks,etc.We analyze these problems from the perspective of resource allocation in the edge-cloud continuum and cast them into resource and Quality of Service(QoS)optimization problems.The goal is to minimize resource consumption while guaranteeing the QoS for ABR streaming.We also discuss some promising research directions for the ABR streaming services.
基金This work was supported by National Natural Science Foundation of China(No.61771070)National Natural Science Foundation of China(No.61671088).
文摘Adaptive bitrate video streaming(ABR)has become a critical technique for mobile video streaming to cope with time-varying network conditions and different user preferences.However,there are still many problems in achieving high-quality ABR video streaming over cellular networks.Mobile Edge Computing(MEC)is a promising paradigm to overcome the above problems by providing video transcoding capability and caching the ABR video streaming within the radio access network(RAN).In this paper,we propose a flexible transcoding strategy to provide viewers with low-latency video streaming services in the MEC networks under the limited storage,computing,and spectrum resources.According to the information collected from users,the MEC server acts as a controlling component to adjust the transcoding strategy flexibly based on optimizing the video caching placement strategy.Specifically,we cache the proper bitrate version of the video segments at the edge servers and select the appropriate bitrate version of the video segments to perform transcoding under jointly considering access control,resource allocation,and user preferences.We formulate this problem as a nonconvex optimization and mixed combinatorial problem.Moreover,the simulation results indicate that our proposed algorithm can ensure a low-latency viewing experience for users.
基金Project supported by the National Natural Science Foundation of China(No.60502033),the Natural Science Foundation of Shanghai (No.04ZRl4084)and the Research Fund for the Doctoral Program of Higher Eduction(No.20040248047),China
文摘H.264/MPEG-4 AVC standard appears highly competitive due to its high efficiency, flexibility and error resilience. In order to maintain universal multimedia access, statistical multiplexing, or adaptive video content delivery, etc., it induces an immense demand for converting a large volume of existing multimedia content from other formats into the H.264/AVC format and vice versa. In this work, we study the remultiplexing and resynchronization issue within system coding after transcoding, aiming to sustain the management and time information destroyed in transcoding and enable synchronized decoding of decoder buffers over a wide range of retrieval or receipt conditions. Given the common intention of multiplexing and synchronization mechanism in system coding of different standards, this paper takes the most widely used MPEG-2 transport stream (TS) as an example, and presents a software system and the key technologies to solve the time stamp mapping and relevant buffer management. The solution reuses previous information contained in the input streams to remultiplex and resynchronize the output information with the regulatory coding and composition structure. Experimental results showed that our solutions efficiently preserve the performance in multimedia presentation.
基金Project supported by the National Natural Science Foundation of China (No. 60573176)the Key Technologies R & D Program of Zhejiang Province (Nos. 2005C23047 and 2004C11052), China
文摘A fast mode decision algorithm is proposed in this paper to accelerate the process of transcoding videos into H.264with arbitrary rate spatial resolution down-scaling. The proposed algorithm consists of three steps. First, an early-stop technique is introduced to determine the 16× 16-mode blocks, which take up about 70% of all the macroblocks; then, a bottom-up merging process is performed to determine the mode of rest non-early-stopped blocks; and then, we adopt half-pixel motion estimation to further refine the acquired predictive motion vectors. In order to obtain the predictive motion vectors for early-stop and merging processes, we propose a motion vector composition scheme, which can reuse the information in the input pre-encoded videos to handle the spatial resolution down-scaling. Experimental results showed that our algorithm is about four times faster than the Cascaded-Decoder-Encoder method and has negligible PSNR drop and little bit rate increase.
基金Sponsored by the National Natural Science Foundation of China(60772066)
文摘A fast algorithm based on direction in intra frame downsizing in H.264 is proposed,which used modes information of macroblocks before transcoding and the direction relation of modes between decoding and re-encoding in transcoding.This algorithm also made use of statistics between decoded modes and re-encoded modes,which came from a lot of sequences data experiments.Without full modes encoding,it can improve the speed of reducing intra-prediction frame resolution obviously.Comparing to traditional transcoding,it only needs to compute one of thirteen modes in re-encoding.The experiments show that this algorithm can significantly speed up 92 percent transcoding time in intra-prediction frame of H.264 with slight PSNR degradation.It also can support an improvement in real-time for transcoding and ability of bandwidths changing.
文摘Efficient video delivery involves the transcoding of the original sequence into various resolutions,bitrates and standards,in order to match viewers’capabilities.Since video coding and transcoding are computationally demanding,performing a portion of these tasks at the network edges promises to decrease both the workload and network traffic towards the data centers of media providers.Motivated by the increasing popularity of live casting on social media platforms,in this paper we focus on the case of live video transcoding.Specifically,we investigate scheduling heuristics that decide on which jobs should be assigned to an edge minidatacenter and which to a backend datacenter.Through simulation experiments with different Qo S requirements we conclude on the best alternative.
文摘Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and output video. In this paper, we first introduce a new spatial resolution reduction transcoding architecture of intra coded frames where the distortion can be calculated directly in compression domain. We then propose a fast mode decision algorithm in which only a small part of rate distortion optimization （RDO） calculation is needed for mode decision. For 4×4 luma block, the proposed scheme has average 21.3% computation saving, compared to the cascaded pixel-domain transcoding scheme with the fast intra mode decision algorithm proposed in JVT-G013. For 16×16 luma block, RDO calculation is completely avoided in our scheme while the scheme in JVT-G013 needs 2 RDO calculations. Experimental results show that our scheme outperforms that of JVT-G013 in terms of significantly computasavings with negligible loss of PSNR
文摘ZTE Corporation announced on 1 March that its innovative IPTVlowbitrate highdefinition transcoding solution has been nominated for the World＇s Best Component or Enabler Award by the IPTV World Forum. The ZTE solution is on display at the Mobile World Congress 2012 （MWC 2012） in Barcelona.
