As well known. Wyner-Ziv codec has low encoding complexity, while AVS codec has low decoding complexity. In this paper, our goal is to get benefits from both AVS and Wyner-Ziv to fit well some applications, such as mo...
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ISBN:
(纸本)9783642156953
As well known. Wyner-Ziv codec has low encoding complexity, while AVS codec has low decoding complexity. In this paper, our goal is to get benefits from both AVS and Wyner-Ziv to fit well some applications, such as mobile video communication. We propose a fast video transcoder from Wyner-Ziv to AVS. The transcoder design aims at reducing encoding complexity of AVS. Taking into account that mode decision in AVS is very time-consuming, in the proposed scheme, we discard the mode decision and directly re-use the corresponding decision results of Wyner-Ziv decoder. At the same time, motion estimation in AVS encoder is speeded up by using the derived motion vectors in Wyner-Ziv decoder as searching origins. Then motion vector refinement is performed to further improve the accuracy of motion estimation in the transcoder. Experimental results demonstrate that the proposed transcoder can significantly reduce the encoding complexity of AVS, and meanwhile provide close compression performance compared with that can be achieved by performing mode decision and a full-scale motion search.
This paper discusses a transcoder, TC-GXML, designed and developed by us as a part of an ongoing research project related to design and development of a speech based web-browsing system for visually challenged. It is ...
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ISBN:
(纸本)9780769539584
This paper discusses a transcoder, TC-GXML, designed and developed by us as a part of an ongoing research project related to design and development of a speech based web-browsing system for visually challenged. It is always easier to develop a visual application than a non-visual application based on speech interface. There are issues like Non-Standard format of HTML, due to which it is difficult for a developer to design a common non-visual interface. In the design of TC-GXML, we have considered all these issue in transforming HTML to GXML and then to VoiceXML or any other XML type. TC-GXML is an improvement over existing Transcoding techniques in terms of its capability of parsing a wider range of websites of varied structure.
Wyner-Ziv (WZ) coding of video utilizes simple encoders and highly complex decoders. A transcoder from a WZ codec to a traditional codec can potentially increase the range of applications for WZ codecs. We present a t...
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ISBN:
(纸本)9781424456536
Wyner-Ziv (WZ) coding of video utilizes simple encoders and highly complex decoders. A transcoder from a WZ codec to a traditional codec can potentially increase the range of applications for WZ codecs. We present a transcoder scheme from the most popular WZ codec architecture to a DPCM/DCT codec. As a proof of concept, we implemented this transcoder using a simple pixel domain WZ codec and the standard H.263+. The transcoder design aims at reducing complexity, since the transcoder has to perform both WZ decoding and DPCM/DCT encoding, including motion estimation. New approaches are used to map motion vectors for such a transcoder. Results are presented to demonstrate the transcoder performance.
With the progress of network, multimedia applications are widely used in daily life. It is very convenient to use those multimedia applications. However there are still some problems we have to face. One of the proble...
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With the progress of network, multimedia applications are widely used in daily life. It is very convenient to use those multimedia applications. However there are still some problems we have to face. One of the problems is that distinct media services deliver media streaming based on different kinds of streaming protocols and codecs. And handheld devices may not support some protocols such as real time message protocol (RTMP) which is not supported by iPhone and iPad. In order to solve this problem, we design and implement a cloud-based real-time RTMP/RTSP streaming transcoder service platform. The system provides the service of changing real-time streaming protocols and codecs. And by utilizing virtual machines in cloud the scale of platform is not constrained by machine size. In addition, we also can control lots of virtual machines dynamically and efficiently. As the request of transcoding service grows up, it is almost impossible to control virtual machines manually. Hence, we design the auto-scaling algorithm to make machine manage machines come true. Besides, it also optimizes the cost of running the transcoder service platform. Thus with the proposed methods, in this thesis, we implement a transcoder service platform to play a role of bridge for heterogeneous media streaming.
To guarantee the real-time transmission of a video stream, based on the stochastic optimal control method, a frame layer adaptive rate control algorithm for the wireless transcoder is proposed, which is capable of dyn...
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To guarantee the real-time transmission of a video stream, based on the stochastic optimal control method, a frame layer adaptive rate control algorithm for the wireless transcoder is proposed, which is capable of dynamically determining the transcoder＇s objective bit rate, according to the bandwidth variation of the wireless channel and the buffer occupancy. Then the transient performance, steady performance, and computational complexity of the algorithm are analyzed. Finally, the experiment results demonstrate that the algorithm can improve the synthetic performance of rate control through the compromise between the end-to-end delay and the playout quality.
A new single chip HDTV H.264 codec system LSI was designed using flexible codec architecture. It supports HP@L4.1 with full 1920x1080 resolution. The LSI supports MPEG2 and JPEG as well. The chip integrates one encode...
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A new single chip HDTV H.264 codec system LSI was designed using flexible codec architecture. It supports HP@L4.1 with full 1920x1080 resolution. The LSI supports MPEG2 and JPEG as well. The chip integrates one encoder and two decoders, which work independently and can be used in flexible ways including transcoding. It also integrates almost all the necessary functions for digital consumer application including an audio codec, graphics and video circuitry, peripherals, and a generic microprocessor.
The anticipated growth of IPTV makes selection of suitable congestion controllers for video-stream traffic of vital concern. Measurements of packet dispersion at the receiver provide a graded way of estimating congest...
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The anticipated growth of IPTV makes selection of suitable congestion controllers for video-stream traffic of vital concern. Measurements of packet dispersion at the receiver provide a graded way of estimating congestion, which is particularly suited to video as it does not rely on packet loss. A closed-loop congestion controller, which dynamically adapts the bitstream output of a transcoder or video encoder to a rate less likely to lead to packet loss, is presented. The video congestion controller is based on fuzzy logic with packet dispersion and its rate of change forming the inputs. Compared with TCP emulators such as TCP-friendly rate control (TFRC) and rate adaptation protocol (RAP), which rely on packet loss for real-time congestion control, the fuzzy-logic trained system's sending rate is significantly smoother when multiple video-bearing sources share a tight link. Using a packet dispersion method similarly results in a fairer allocation of bandwidth than TFRC and RAP. These gains for video traffic are primarily because of better estimation of network congestion through packet dispersion but also result from accurate interpretation by the fuzzy-logic controller.
To guarantee the real-time transmission of a video stream,based on the stochastic optimal control method,a frame layer adaptive rate control algorithm for the wireless transcoder is proposed,which is capable of dynami...
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To guarantee the real-time transmission of a video stream,based on the stochastic optimal control method,a frame layer adaptive rate control algorithm for the wireless transcoder is proposed,which is capable of dynamically determining the transcoder's objective bit rate,according to the bandwidth variation of the wireless channel and the bufier occupancy. Then the transient performance,steady performance,and computational complexity of the algorithm are ***,the experiment results demonstrate that the algorithm can improve the synthetic performance of rate control through the compromise between the end-to-end delay and the playout quality.
Video transcoding technique is an efficient mechanism to deliver visual contents to a variety of users who have different network conditions or terminal devices with different display capabilities. In this paper, we p...
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Video transcoding technique is an efficient mechanism to deliver visual contents to a variety of users who have different network conditions or terminal devices with different display capabilities. In this paper, we propose two types of transcoding methods for adapting the bitrate of streaming video to the bandwidth of the transmission channel;spatial resolution reduction (SRR) transcoding and temporal resolution reduction (TRR) transcoding. The two transcoding methods are alternatively operated according to the requirements of users. Experimental results show that the proposed transcoding methods can preserve image quality while transcoding to the low bitrate.
We propose a fast arbitrary-ratio image resizing method for transcoding of the compressed images. The downsizing process in the discrete cosine transform (DCT) domain can be implemented by truncating high-frequency co...
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We propose a fast arbitrary-ratio image resizing method for transcoding of the compressed images. The downsizing process in the discrete cosine transform (DCT) domain can be implemented by truncating high-frequency coefficients, whereas the upsizing process is implemented in the DCT domain by padding zero coefficients to the high-frequency part. The proposed method combines a fast inverse and forward DCT of composite length for arbitrary-ratio upsizing or downsizing. According to the resizing ratio, truncating the high-frequency coefficients and padding zeros are appropriately considered by combining the inverse DCT and forward DCT. The proposed method shows a good peak signal-to-noise ratio and less computational complexity compared with the spatial-domain and previous DCT-domain image resizing methods.
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