检索结果-内蒙古大学图书馆

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2001年第2期11卷 222-234页

作者： Wang, LM Luthra, A Eifrig, B Motorola Inc San Diego CA 92121 USA

In MPEG, the input pictures can be coded in three different types: I, P, and B. The three pictures require quite different numbers of bits because of different natures of their temporal processing. Hence, an intelligent bit-allocation strategy should assign a picture the number of bits according to the picture's type, as well as the picture organization, This implies a requirement of a prior knowledge of the picture types for a given bit budget. This requirement is not a problem for the encoder, as the encoder can decide the type for each input picture. In fact, the encoder can plan ahead the types of the pictures. A transcoder however has no such a priori knowledge about a picture's type before actually processing the picture. This creates a difficulty in bit allocation for the transcoder, This paper presents a novel rate control scheme for MPEG transcoder that requires no a priori knowledge of the picture types. Our study indicates that the picture target rates determined by the proposed rate control with and without a priori knowledge of the picture types are very close.

关键词： MPEG picture organization rate control transcoder

来源：评论

学校读者我要写书评

暂无评论

基于云端运算之即时影音串流转码服务平台之研制

基于云端运算之即时影音串流转码服务平台之研制

引用

作者：陈嘉祥国立清华大学

学位级别：硕士

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.

关键词： cloud computing transcoder rtmp rtsp

来源：评论

学校读者我要写书评

暂无评论

Smoothing transcoded MPEG-1 video streams for Internet transmission

引用

IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 2004年第4期151卷 298-305页

作者： Jammeh, E Fleury, M Ghanbari, M Univ Essex Audio & Video Networking Lab Dept Elect Syst Engn Colchester CO4 3SQ Essex England

An efficient smoothing scheme for the real-time transmission of MPEG-1 transcoded video over 'best-effort' IP networks is presented. The scheme uses intelligent partitioning and multiplexing of the packetised bit stream. Bit-rate smoothing is achieved by partitioning packets according to their picture type (I, P or B). Subsequently, the partitioned packets are multiplexed in such a way that each packet from an anchor (I and P) picture is followed by two packets from B-pictures. The proposed scheme smooths the bit rate of the encoded video, making it more suitable for adaptive video streaming applications. In such applications, the transmission bit rate is varied so as to adapt to the available network bandwidth. The scheme reorganises the transmission order of the packets, spreading the less important packets from the B-pictures into the more important packets from the anchor pictures. This indicates a reduction in the likelihood of losing more important anchor packets as the bandwidth bottleneck increases, implying an improvement in the quality of transmitted video. A variety of simulations results are presented to demonstrate these points.

关键词： .controller Smoothing periods transcoder bit rates network congestion GOP B-picture anchor pictures

来源：评论

学校读者我要写书评

暂无评论

A systematic literature review on video transcoding acceleration: challenges, solutions, and trends

引用

MULTIMEDIA TOOLS AND APPLICATIONS 2024年第24期83卷 64079-64108页

作者： Borges, Alex Zatt, Bruno Porto, Marcelo Correa, Guilherme Fed Univ Pelotas UFPel Grad Program Comp PPGC Video Technol Res Grp ViTech Pelotas Brazil

Audiovisual productions currently dominate internet content, accounting for approximately 82% of online traffic in 2022. With the popularization of adaptive video streaming over the internet, transcoding has become an essential task to allow for bitrate adaptation and compatibility between servers and client devices that support various standards and formats. However, such conversion presents a high computational cost due to its cascade features, which sequentially runs the video decoding and re-encoding processes. This high cost exists especially due to the various encoding mode possibilities allowed in video codecs, mainly in recent, highly efficient standards and formats. On the other hand, the cascade transcoder model allows the possibility of inheriting information from the original bitstream, which can be used to accelerate the re-encoding process. This survey presents a systematic literature review of the main works published in the literature that propose transcoding acceleration methods for the main video coding standards and formats developed in the last decades. The majority of the works focus on both homogeneous and heterogeneous transcoding for the MPEG-2, H.264/AVC, H.265/HEVC, H.266/VVC, VP8, VP9, and AV1 formats and standards, and are based on heuristics and prediction models trained with machine learning algorithms. Based on the systematic literature review, a classification of the works according to the transcoding type and the methodology employed for acceleration is presented. The results obtained in each solution are compared in terms of complexity reduction and compression efficiency, and future trends on the field are discussed.

关键词： Video transcoding transcoder Survey Systematic literature review

来源：评论

学校读者我要写书评

暂无评论

A fast DV to MPEG-2 IBP-picture conversion algorithm

引用

IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2003年第2期49卷 433-440页

作者： Kato, H Sano, T Yanagihara, H Nakajima, Y Hatori, Y KDDI R&D Labs Inc Kamifukuoka Saitama 3568502 Japan Tokyo Univ Sci Shinjuku Ku Tokyo 1628601 Japan

This paper describes a fast Digital Video (DV) to MPEG-2 conversion algorithm. At first, DCT domain 2x4x8 DCT to 8x8 DV conversion was employed for the DV to MPEG-2 I-picture conversion. DV to MPEG-2 W-picture conversion requires motion estimation, so fast hierarchical motion estimation was also employed. Since DCT information is available from DV data and 2x2 IDCT can be achieved by simple addition and subtraction operations, a low-resolution image is constructed and used for a coarse motion search. Then a fine search is performed using extended 2SS in the original image domain. The experimental results show that the proposed method is more than 40 times faster than a baseband domain conversion with the full search while about the same PSNR is obtained. Both the PSNR and the conversion speed are also greatly improved when compared with the conventional method.

关键词： DV motion estimation MPEG-2 transcoder

来源：评论

学校读者我要写书评

暂无评论

Design and analysis of an image resizing filter in the block-DCT domain

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2004年第2期14卷 274-279页

作者： Park, Y Park, H Korea Adv Inst Sci & Technol Dept Elect Engn Taejon 305701 South Korea

Image resizing of a compressed image can be performed in a spatial domain via decompression, resizing, and recompression, which is computationally inefficient. In order to reduce computation amount, efficient resizing approaches in the compressed domain have been developed. In this paper, we propose a novel approach to resize images that are compressed by 8 x 8 block-discrete cosine tranform (DCT)-based coding. The proposed image-resizing method is performed in the DCT domain and exploits the multiplication-convolution property of the DCT. Filter characteristics of the proposed image resizing method are analyzed by using a multirate filter bank representation. Since the characteristics of our resizing filters are better than those of others and the proposed image resizing method is computationally efficient, it can be widely used in a transcoder and shows visually fine results.

关键词： block discrete cosine transform (DCT) down-sampling image resizing symmetric convolution transcoder

来源：评论

学校读者我要写书评

暂无评论

Quantization/DCT conversion scheme for DCT-domain MPEG-2 to H.264/AVC transcoding

引用

IEICE TRANSACTIONS ON COMMUNICATIONS 2005年第7期E88B卷 2856-2863页

作者： Lee, JK Chung, KD Pusan Natl Univ Dept Comp Engn Pusan 609735 South Korea

The latest video coding standard, H.264/AVC [1], adopts 4x4 approximate transform instead of 8x8 discrete cosine transform (DCT) to avoid the inverse transform mismatch problem. However, that is only one of the factors that make it difficult to transcode pre-coded video contents with the previous standards to H.264/AVC in the common domain without causing cascaded pixel-domain transcoding. In this paper, to support the existent DCT-domain transcoding schemes and to reduce computational complexity, we propose an efficient algorithm that converts the quantized 8 x 8 DCT block into four newly quantized 4 x 4 transformed blocks. The experimental results show that the proposed scheme reduces computational complexity by 5-11 % and improves video quality by 0.1-0.5 dB compared with the cascaded pixel-domain transcoding scheme that exploits inverse quantization (IQ), inverse DCT (IDCT), DCT, and re-quantization (re-Q).

关键词： transcoder MPEG-2 H.264/AVC DCT quantization

来源：评论

学校读者我要写书评

暂无评论

Rate-adaptive video streaming through packet dispersion feedback

引用

IET COMMUNICATIONS 2009年第1期3卷 25-37页

作者： Jammeh, E. A. Fleury, M. Ghanbari, M. Univ Essex Dept Comp & Elect Syst Colchester CO4 3SQ Essex England

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.

关键词： packet dispersion feedback congestion controllers video encoder IPTV video-stream traffic telecommunication traffic transcoder TCP-friendly rate control real-time congestion control fuzzy control rate-adaptive video streaming telecommunication congestion control packet dispersion transport protocols video streaming video coding transcoding closed-loop congestion controller rate adaptation protocol fuzzy-logic controller

来源：评论

学校读者我要写书评

暂无评论

Motion Vector Refinement for High-Performance Transcoding

引用

IEEE TRANSACTIONS ON MULTIMEDIA 1999年第1期1卷 30-40页

作者： Youn, Jeongnam Sun, Ming-Ting Lin, Chia-Wen Univ Washington Dept Elect Engn Informat Proc Lab Seattle WA 98195 USA ITRI Comp & Commun Res Labs Hsinchu 31015 Taiwan

In transcoding, simply reusing the motion vectors extracted from an incoming video bit stream may not result in the best quality. In this paper, we show that the incoming motion vectors become nonoptimal due to the reconstruction errors. To achieve the best video quality possible, a new motion estimation should be performed in the transcoder. We propose a fast-search adaptive motion vector refinement scheme that is capable of providing video quality comparable to that can be achieved by performing a new full-scale motion estimation but with much less computation. We discuss the case when some incoming frames are dropped for frame-rate conversions, and propose motion vector composition method to compose a motion vector from the incoming motion vectors. The composed motion vector can also be refined using the proposed motion vector refinement scheme to achieve better results.

关键词： .video quality motion vectors transcoder Transcoding nement scheme incoming motion adaptive motion vector

来源：评论

学校读者我要写书评

暂无评论

Efficient MPEG-4 to H.264/AVC transcoding with spatial downscaling

引用

ETRI JOURNAL 2007年第6期29卷 826-828页

作者： Nguyen, Toan Dinh Lee, Guee-Sang Chang, June-Young Cho, Han-Jin Chonnam Natl Univ Dept Elect & Comp Engn Kwangju South Korea ETRI IT Convergence & Components Lab Taejon South Korea

Efficient downscaling in a transcoder is important when the output should be converted to a lower resolution video. In this letter we suggest an efficient algorithm for transcoding from MPEG-4 SP (with simple profile) to H.264/AVC with spatial downscaling First, target image blocks are classified into monotonous, complex, and very complex regions for fast mode decision. Second, adaptive search ranges are applied to these image classes for fast motion estimation in an H.264/AVC encoder with predicted motion vectors. Simulation results show that our transcoder considerably reduces transcoding time while video quality is kept almost optimal.

关键词： MPEG-4 part 2 H.264/AVC transcoder motion estimation mode decision spatial downscale

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：