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A client-driven media synchronization mechanism for RTP packet-based video streaming
SPEINGER SCEINCE + BUSINESS MEDIA 2016 JOURNAL OF REAL TIME IMAGE PROCESSING Vol.12 No.2
<P>Media synchronization is used to correctly playback a video stream with its associated audio. To support synchronization between video and audio streams transported over IP networks, an RTP/RTCP protocol suite is usually employed. In conventional server-driven media synchronization, the server needs to periodically transmit an RTCP sender report (SR) packet to provide the client with a UTC time in NTP format corresponding to the RTP timestamp carried by each RTP packet. In this paper, we propose a precise client-driven media synchronization mechanism for an RTP packet-based multimedia streaming service. In the proposed method, the server does not need to send any RTCP SR packets for synchronization. Instead, the client device derives the precise normal play time (NPT) for each video and audio stream from the received RTP packets containing an RTP timestamp. Simulations show that the proposed client-driven synchronization method can provide accurate media synchronization without employing an RTCP SR packet and accordingly reduce the initial synchronization delay, the processing complexity at the client device, the number of required user datagram protocol ports, and the amount of control traffic injected into the network.</P>
Adaptive real-time reversible data hiding for JPEG images
SPEINGER SCEINCE + BUSINESS MEDIA 2018 Journal of real-time image processing Vol.14 No.1
<P>Data hiding used to embed data, such as copyright information, into various forms of media such as image, audio, or text with a minimum amount of perceivable degradation to the 'host' signal. Therefore, in many cases, the cover media contain distortions even after the hidden data have been extracted. Thus, to extend the application of data hiding to some sensitive domains such as military, medical, and fine arts, which require the embedded cover images to be properly covered, reversible data hiding has become another new branch of this field. Our proposed scheme is inspired by Chang et al.'s idea. In this paper, we propose adaptive real-time reversible data hiding for JPEG images using successive zero coefficients in zigzag sequences of discrete cosine transformation blocks. The contribution of our proposed scheme successfully enhances the hiding capacity while the image quality of stego image and reversibility are maintained. The result of experiments conducted indicates that the proposed scheme enhances data hiding capacity, image quality, and improves performance.</P>
Data hiding scheme improving embedding capacity using mixed PVD and LSB on bit plane
SPEINGER SCEINCE + BUSINESS MEDIA 2018 Journal of real-time image processing Vol.14 No.1
<P>In data hiding, pixel-value differencing and least significant bit are well-known techniques to embed secret data. In this paper, a novel data hiding scheme is proposed to provide high embedding capacity. In case of previous methods, pixel-value differencing and least significant bit techniques were used individually or in combination based on pixel, but the proposed method utilizes first by dividing the bit region and two schemes are used simultaneously in the same bit plane. The experimental results show that the proposed method has strength on embedding capacity maintaining visual image quality without distortion to the human eyes.</P>
Entropy difference-based early skip detection technique for high-efficiency video coding
SPEINGER SCEINCE + BUSINESS MEDIA 2016 JOURNAL OF REAL TIME IMAGE PROCESSING Vol.12 No.2
<P>Recently, high-efficiency video coding (HEVC) has been developed as a new video coding standard focusing on the coding of ultrahigh definition videos as high-resolution and high-quality videos are getting more popular. However, one of the most important challenges in this new standard is its encoding time complexity. Due to this it is quite difficult to implement the HEVC encoder as a real-time system. In this paper, we have addressed this problem in a new way. Generally, for a natural video sequence good amount of coding blocks are 'skip' in nature, which need not be transmitted and can be generated in the decoder side using the reference pictures. In this paper, we propose an early skip detection technique for the HEVC. Our proposed method is based on identifying the motionless and homogeneous regions in a video sequence. Moreover, a novel entropy difference-based calculation is proposed in this paper which can predict the skip coding blocks more accurately in a natural video sequence. The experimental result shows our proposed technique can achieve more than 30 % encoding time reduction than the conventional HEVC encoder with negligible degradation in video quality.</P>
Ko, Y.,Yi, Y.,Ha, S. SPEINGER SCEINCE + BUSINESS MEDIA 2014 JOURNAL OF REAL TIME IMAGE PROCESSING Vol.9 No.1
H.264/AVC video encoders have been widely used for its high coding efficiency. Since the computational demand proportional to the frame resolution is constantly increasing, it has been of great interest to accelerate H.264/AVC by parallel processing. Recently, graphics processing units (GPUs) have emerged as a viable target for accelerating general purpose applications by exploiting fine-grain data parallelisms. Despite extensive research efforts to use GPUs to accelerate the H.264/AVC algorithm, it has not been successful to achieve any speed-up over the x264 algorithm that is known as the fastest CPU implementation, mainly due to significant communication overhead between the host CPU and the GPU and intra-frame dependency in the algorithm. In this paper, we propose a novel motion-estimation (ME) algorithm tailored for NVIDIA GPU implementation. It is accompanied by a novel pipelining technique, called sub-frame ME processing, to effectively hide the communication overhead between the host CPU and the GPU. Further, we incorporate frame-level parallelization technique to improve the overall throughput. Experimental results show that our proposed H.264 encoder has higher performance than x264 encoder.