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Adaptive rate control on wireless transcoder

Journal of Systems Engineering and Electronics 2007年第3期18卷 633-640页

作者： Chen Xudong Zhu Qingxin Liao Yong Fu Qingyun Xiong Guangze School of Computer Science and Engineering Univ. of Electronic Science and Technology Chengdu 610054 P. R. China

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.

关键词： streaming media rate control transcoder wireless local area network H.264/AVC.

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Deep learning ensemble with data augmentation using a transcoder in visual description

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MULTIMEDIA TOOLS AND APPLICATIONS 2019年第22期78卷 31231-31243页

作者： Lee, Jin Young Sejong Univ Sch Intelligent Mechatron Engn Seoul South Korea

Visual description is very challenging work in computer vision. Since it is usually performed with compressed videos, its performance strongly depends on coding distortion. Therefore, it is very important that visual description networks are trained using video datasets with both high and low qualities. In order to generate them from a given training dataset, this paper introduces a new data augmentation method employing a transcoder. It converts one video quality into another by controlling a quantization parameter (QP). Two different networks are trained on the high and low quality videos, respectively, and then the proposed deep learning ensemble model determines optimum sentence among candidates generated from these networks. Experimental results show that the proposed method is very robust to the coding distortion.

关键词： Deep learning Ensemble Data augmentation Visual description transcoder

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Spatio-temporal video transcoder for streaming over mobile communications networks

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IEICE TRANSACTIONS ON COMMUNICATIONS 2006年第10期E89B卷 2678-2686页

作者： Kim, Jae-Won Kwon, Goo-Rak Lee, June-Sok Kim, Nam-Hyeong Ko, Sung-Jea Samsung Elect Suwon South Korea Korea Univ Dept Elect Engn Sungbuk Ku Seoul 136701 South Korea

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.

关键词： transcoder transcoding refinement downsizing frame-skipping streaming

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Efficient Motion Vector Selection and Mode Decision Schemes for transcoder between DVC and VC-1

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2012年第3期58卷 905-911页

作者： Lee, Jae-Yung Han, Jong-Ki Sim, Dong-Gyu Sejong Univ Dept Informat & Commun Engn Seoul South Korea Kwangwoon Univ Dept Comp Engn Seoul South Korea

Transcoding between Distributed Video Coding (DVC) and VC-1 is an interesting research topic, has various applications, and VC-1 is one of most popular and efficient video codecs. Among the various techniques related to transcoders, we focus on motion estimation and mode decision. In this paper, we propose a Best Matched Vector Selection (BMVS) and fast mode decision to increase the accuracy and speed of the motion vector estimation and mode decision in the transcoder. BMVS is used to predict motion vectors for multiple reference frames that are far from the current frame. The proposed mode decision scheme selects a mode for the current coding block based on the information transferred from the DVC decoder, without calculating the Rate-Distortion (RD) costs for all possible candidate modes. Simulation results show that the proposed schemes simplify the transcoder significantly without degrading the transcoded video sequences(1).

关键词： DVC VC-1 transcoder

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Modified cubic convolution scaler for multiformat conversion in a transcoder

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OPTICAL ENGINEERING 2004年第7期43卷 1596-1608页

作者： Han, JK Kim, HM Sejong Univ Dept Informat & Commun Engn Seoul South Korea Korea Adv Inst Sci & Technol Dept Elect Engn Taejon 305701 South Korea

We derive a modified version of cubic convolution interpolation for the enlargement or reduction of digital images by arbitrary scaling factors. The proposed scaling scheme is used to resize various format pictures in the transcoding system, which transforms the bitstream compressed at a bit rate, such as the HD bitstream, into another bit rate stream, for example, the SD bitstream. The transcoding is performed in spatial domain. In many applications such as the transcoder, the resolution conversion is very important for changing the image size while the scaled image maintains high quality. The scaling process consists of two steps: fitting the original data with a continuous function, and resampling the function on a new sampling grid. We focus on the modification of the scaler kernel according to the relation between formats of the original and the resized image. In the modification, various formats defined in MPEG standards are considered. We show experimental results that demonstrate the effectiveness of the proposed interpolation method. The algorithm exhibits significant improvement in the minimization of information loss when compared with the conventional interpolation algorithms. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

关键词： scaler cubic convolution interpolation transcoder

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Low Complexity Intra Prediction Algorithm for MPEG-2 to H.264/AVC transcoder

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2010年第2期56卷 987-994页

作者： Liu, Xingang Yoo, Kook-Yeol Kim, Sung Won Yeungnam Univ Dept Informat & Commun Engn Taegu South Korea Yeungnam Univ Sch Elect Engn & Comp Sci Taegu South Korea

Transcoding MPEG-2 video into H.264/AVC format is highly necessary for the broad distribution of digital video contents to mobile terminals. Since H.264/AVC achieves great coding efficiency by employing computationally demanding algorithms, the computational complexity of the transcoder is one of technically challenging issues. The empirical results show that DCT energy trend in the decoded MB of MPEG-2 bitstream has strong correlation with the Intra prediction modes of H.264/AVC. Based on the relationship, the mode skipping rule of intra prediction mode decision in the H.264/AVC encoder part of the transcoder is proposed in this paper. The simulation results show that the proposed algorithm can achieve on average 72.36% reduction in computational complexity, compared with that of the conventional transcoder.

关键词： MPEG-2 H.264/AVC transcoder Intra Prediction MB Energy Trend Rate-to-Distortion Cost (RDCost)

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A single chip H.264/AVC HDTV encoder/decoder/transcoder system LSI

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2007年第2期53卷 630-635页

作者： Mizosoe, Hiroki Yoshida, Daisuke Nakamura, Taku Hitachi Ltd Ubiquitous Platform Syst R&D Lab Yokohama Kanagawa Japan

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.

关键词： H.264 HDTV encoder transcoder

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Arbitrary-ratio image resizing using fast DCT of composite length for DCT based transcoder

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2006年第2期15卷 494-500页

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

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.

关键词： arbitrary-ratio image resizing composite length DCT transcoder

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A Wyner-Ziv Video transcoder

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2010年第2期20卷 189-200页

作者： Peixoto, Eduardo de Queiroz, Ricardo L. Mukherjee, Debargha Univ Brasilia Dept Elect Engn BR-70910900 Brasilia DF Brazil Hewlett Packard Labs Palo Alto CA 94304 USA

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 differential pulse code modulation/discrete cosine transform codec. As a proof of concept, we implemented this transcoder using a simple pixeldomain WZ codec and the standard H.263+. The transcoder design aims at reducing complexity as a large amount of computation is saved by reusing the motion estimation, calculated at the side information generation process, and the I-frame streams. New approaches are used to generate side information and to map motion vectors for the transcoder. Results are presented to demonstrate the transcoder performance.

关键词： Distributed video coding H.263+ transcoder Wyner-Ziv coding

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Efficient implementation of a video transcoder

Efficient implementation of a video transcoder

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Conference on International Multimedia Management Systems

作者： Ratakonda, K IBM Corp Thomas J Watson Res Ctr Yorktown Heights NY 10598 USA

ISBN: (纸本)0819438758

Given a video stream encoded with a particular bit rate and compression scheme (C-1), transcoding the video stream refers to the process of re-encoding the input compressed stream at a different bit rate and possibly with different spatial resolution, temporal resolution and compression scheme (C-2). In this paper the special case of a transcoder which has a 4:2:2 format video stream as it's input and produces a 4:2:0 output stream at a lower bit rate is considered. Further more, it is assumed that both C-1 and C-2, like nearly all standard video compression algorithms, use 8 x 8 block DCT based compression. In this context, it will be shown how standard implementations of transcoders, as proposed by Ghanbari(1,2) and others mag. be simplified to obtain a reduction in the transcoder implementation complexity. In particular the problem of simplifying the process of down conversion from 4:2:2 to 1:2:0, so that this process can take place directly in the DCT domain, will be addressed. The MPEG-2 video standard treats interlaced and progressive video differently for compression purposes;the proposed scheme is shown to be applicable to both cases. Simulation results show that this simplification does not result in performance degradation when compared cases with standard, high complexity implementations.

关键词： transcoder video compression down conversion block DCT interlaced/progressive video

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