RTP: Audio and Video for the Internet
In this chapter we move on from our discussion of networks and protocols, and talk instead about the design of systems that use RTP. An RTP implementation has multiple aspects, some of which are required for all applications; others are optional depending on the needs of the application. This chapter discusses the most fundamental features necessary for media capture, playout, and timing recovery; later chapters describe ways in which reception quality can be improved or overheads reduced. We start with a discussion of the behavior of a sender: media capture and compression, generation of RTP packets, and the under-lying media timing model. Then the discussion focuses on the receiver, and the problems of media playout and timing recovery in the face of uncertain delivery conditions. Key to receiver design is the operation of the playout buffer, and much of this chapter is spent on this subject.
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