Multimedia applications: We knew that many multimedia applications are already invaded the internet. In this post we confine only few applications which are based on audio and video. The technologies pertaining to these are presented in this section. We consider three board classes of multimedia applications.
- Streaming stored audio/video
- Streaming live audio/video
- Real-time interactive audio/video
Streaming stored audio and video
In multimedia applications, clients request on-demand audio or video files that are stored on servers. Stored audio files might contain audio from a professor’s lecture, rock songs, and symphonies, achieve of famous radio broadcasts, or archived historical recordings. Stored video files might contain video of a professor’s lecture, full-length movies, prerecorded television shows, documentaries, and video archives of historical events, cartoons, or music video clips. This class application has three key distinguishing features.
- Stored media – The multimedia content has been prerecorded and is stored at the server. As a result, a user may pause, rewind, fast-forward, or index through the multimedia content. The time from when a client should be on the order of one to ten seconds for acceptable responsiveness.
- Streaming– in a streaming stored audio/video application, a client begins play out of the audio/video of few second after it begins receiving the file from the server. This means that the client will be playing out audio/video from one location in the file while it is receiving later parts of the file from the server. This technique, known as streaming, avoids having to download the entire file (and incurring a potentially long delay) before beginning play out. There are many streaming multimedia products, such as Real-player, Quick Time and Media player.
- Continuous play out– Once play out of the multimedia content begins, it should proceed according to the original timing of the recording. This places critical delay constraints on data delivery. Data must be received from there server in time for its play out at the client. Although stored media applications have continuous lay out requirements, their end –to –end delay constraints are nevertheless stringent than those for live, interactive application such as internet telephony and video conferencing.