Under CopyrightKretschmer, M.M.Kretschmer2022-03-0631.07.20021998https://publica.fraunhofer.de/handle/publica/27334410.24406/publica-fhg-273344This thesis deals with the design and implementation of an enhanced RTP Translator that can be used for realtime data rate and/or encoding format transcoding of audio streams in IP-(Multicast) networks. It is embedded in the KISS 1 Concept as a Service Agent and thus uses the KISS-API's features to dynamically adapt its offered services to the users's needs. The so-called Audio Transcoder is typically deployed to lower the data rate of an existing audio stream if a listener is unable to receive the original stream because of its limited bandwidth. In a current MBone scenario such a listener would be kept out from participation. This approach offers the possibility to provide a session with a high quality and therefore high data rate stream that can be received by users on a high bandwidth network while users on a low bandwidth network are provided with a separate low(er) data rate stream, transparently. This publication is the English release of the author's "Diplomarbeit" handed in in February 1998 at the Fachhochschule Köln [16]. This work was embedded in the MOD 2 project of the Research Group on Interactive Broadcast Systems at the German National Research Center for Information Technology, Institute for Media Communication (GMD-IMK.IBS). For additional information about KISS you might give our web site 3 a try.1 Introduction S.3 2 Background S.5 - 2.1 Requirements of Real Time Streaming S.5 - 2.2 Structure of the Internet S.6 - 2.2.1 The TCP Protocol S.6 - 2.2.2 The UDP Protocol S.6 - 2.2.3 The IP Multicast Protocol S.7 - 2.2.4 Real Ttime Streaming on the Internet S.8 - 2.3 The Realtime Transport Protocol (RTP) S.9 - 2.3.1 The Translator S.10 - 2.3.2 The Mixer S.11 - 2.4 A Generic Streaming System S.12 - 2.5 Compressing Audio Information S.14 - 2.5.1 How Does an Audio Encoder Work? S.14 - 2.5.2 How Does an Audio Decoder Work? S.16 - 2.5.3 Comparison with Loss-free Procedures S.16 - 2.5.4 Multiple Codings S.17 - 2.6 Summary S.17 3 The KISS Concept S.19 - 3.1 A Model Scenario S.19 - 3.2 Architecture S.23 - 3.3 Description of a Streaming Service S.25 - 3.4 Communication Mechanisms S.27 - 3.4.1 Localizing a Network Access Point (NAP) S.27 - 3.4.2 Requesting the Service Catalog S.27 - 3.4.3 O ering Service Descriptions (SD) S.27 - 3.4.4 O ering and Requesting Multimedia Streams S.28 - 3.4.5 Connection Control/Clearing S.28 - 3.4.6 Authentication and Billing S.28 - 3.5 Summary S.29 4 The Audio Transcoder as a KISS Service Agent S.31 - 4.1 What Is an Audio Transcoder? S.31 - 4.2 KISS Application Scenarios S.32 - 4.2.1 Bit Rate Adaptation through a Transcoder S.32 - 4.2.2 Coding Format Conversion through a Transcoder S.32 - 4.2.3 The Transcoder as an Internet Tunnel S.33 - 4.3 RTP Conformity and KISS Extension S.34 5 Audio Transcoder Design S.35 - 5.1 The Controller S.36 - 5.1.1 The Service Access and Management Protocol (SAMP) S.37 - 5.1.2 Concatenated Transcoders S.40 - 5.1.3 Controlling the Transcoder Modules S.41 - 5.2 The Transcoder Module S.42 - 5.2.1 The Generic I/O Interface \IO wrapper" S.42 - 5.2.2 General Decoder/Encoder Structure S.43 - 5.2.3 The Decoder S.44 - 5.2.4 The Encoder S.46 - 5.3 Summary S.47 6 Implementation S.49 - 6.1 Used Software Components S.49 - 6.2 The Audio Transcoder Components S.51 - 6.2.1 The Control Process S.53 - 6.2.2 The Decoder Process S.56 - 6.2.3 The Encoder Process S.57 - 6.3 Program Execution of the Individual Objects S.58 - 6.3.1 Timer S.59 - 6.3.2 Multicast Group Server S.60 - 6.3.3 DNS Helper S.61 - 6.3.4 Dispatcher S.62 - 6.3.5 List Manager S.63 - 6.3.6 Query Manager S.64 - 6.3.7 Module Manager S.65 - 6.3.8 Module Controller S.66 - 6.3.9 Decoder Input Thread S.67 - 6.3.10 Decoder Output Thread S.68 - 6.3.11 Encoder Input Thread S.69 - 6.3.12 Encoder Output Thread S.70 - Summary and Outlook S.71 - 7.1 Summary S.71 - 7.2 Consideration of Scalability S.72 - 7.3 Integration of Scalable Video Codecs S.73en005006629diploma thesis