Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Optimized Bit Stream Switching for Mobile Video Streaming | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article 1D91797 Pages 1-19 DOI ASP 2006 91797 Optimized AVC-Based Bit Stream Switching for Mobile Video Streaming Thomas Stockhammer 1 Gunther Liebl 2 and Michael Walter2 1 Nomor Research GmbH Tannenweg 25 83346 Bergen Germany 2 Institute for Communications Engineering LNT Munich University of Technology TUM 80290 Munich Germany Received 12 August 2005 Revised 17 February 2006 Accepted 30 April 2006 In this work we show the suitability of MPEG-4 AVC extended profile for wireless video streaming applications. In particular we exploit the advanced bit stream switching capabilities using SP SI pictures defined in the MPEG-4 AVC standard. For both types of switching pictures optimized encoders are developed. We introduce a framework for dynamic switching and frame scheduling. For this purpose we define an appropriate abstract representation for media encoded for video streaming as well as for the characteristics of wireless variable bit rate channels. The achievable performance gains over MPEG-4 AVC with constant bit rate CBR encoding are shown for wireless video streaming over enhanced GPRS EGPRS . Copyright 2006 Hindawi Publishing Corporation. All rights reserved. 1. INTRODUCTION High-quality video streaming is becoming a killer application in wireless systems. For this type of systems compression efficiency as well as adaptivity are the most important features when selecting appropriate video codecs. The recently standardized MPEG-4 AVC codec denoted as AVC in the following provides both features but especially the latter has not been discussed in too much detail up to now. Adaptivity allows reacting to dynamics in the system resulting from bursty traffic patterns variable receiving conditions as well as handovers and random user activity. Due to the commonly used error control features on wireless links these variations mainly result .
