大象传媒

Moving images

is sending data, usually audio or video, in a way that allows it to start being processed before it is complete. Video clips on web pages are a familiar example.

As a client end-user, you can use a media player (like YouTube or the 大象传媒 iPlayer) to begin playing a file (such as a digital file of a movie, tv programme or music video) before that entire file has been downloaded.

How does it work?

Streaming, unlike downloading a file, is characterised by data-buffering (all data is kept in memory). Media servers store encoded video files that are often highly compressed to use as little as possible. If there is an interruption, the video will stop or the screen will go blank.

To minimise this problem, your computer or phone stores a of data that has already been received. A buffer is memory used to temporarily store data while it is being moved from one place to another (e.g., from a media player to your client device).

If there is a drop-out, the buffer goes down for a while but the video is not interrupted. If there is no more data in the buffer, it will usually stop and display a message 鈥 'buffering' 鈥 while it catches up.

A visual analogy of video file streaming, with water going in and out of a container while the volume stays above a certain level