Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/253
Title: New architecture for dynamic frame-skipping transcoder
Authors: Fung, Kai-tat
Chan, Yui-lam
Siu, Wan-chi
Subjects: Compressed domain processing
DCT-based transcoder
Frame skipping
Rate control
Video transcoding
Issue Date: Aug-2002
Publisher: IEEE
Source: IEEE transactions on image processing, Aug. 2002, v. 11, no. 8, p. 886-900.
Abstract: Transcoding is a key technique for reducing the bitrate of a previously compressed video signal. A high transcoding ratio may result in an unacceptable picture quality when the full frame rate of the incoming video bitstream is used. Frame skipping is often used as an efficient scheme to allocate more bits to the representative frames, so that an acceptable quality for each frame can be maintained. However, the skipped frame must be decompressed completely, which might act as a reference frame to nonskipped frames for reconstruction. The newly quantized discrete cosine transform (DCT) coefficients of the prediction errors need to be re-computed for the nonskipped frame with reference to the previous nonskipped frame; this can create undesirable complexity as well as introduce re-encoding errors. In this paper, we propose new algorithms and a novel architecture for frame-rate reduction to improve picture quality and to reduce complexity. The proposed architecture is mainly performed on the DCT domain to achieve a transcoder with low complexity. With the direct addition of DCT coefficients and an error compensation feedback loop, re-encoding errors are reduced significantly. Furthermore, we propose a frame-rate control scheme which can dynamically adjust the number of skipped frames according to the incoming motion vectors and re-encoding errors due to transcoding such that the decoded sequence can have a smooth motion as well as better transcoded pictures. Experimental results show that, as compared to the conventional transcoder, the new architecture for frameskipping transcoder is more robust, produces fewer requantization errors, and has reduced computational complexity.
Rights: © 2002 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.
Type: Journal/Magazine Article
URI: http://hdl.handle.net/10397/253
DOI: 10.1109/TIP.2002.800890
ISSN: 1057-7149
Appears in Collections:EIE Journal/Magazine Articles

Files in This Item:
File Description SizeFormat 
dynamic-frame_02.pdf922.54 kBAdobe PDFView/Open


All items in the PolyU Institutional Repository are protected by copyright, with all rights reserved, unless otherwise indicated. No item in the PolyU IR may be reproduced for commercial or resale purposes.