There are two main ways to deliver audio & video content over the internet:
Stream Delivery – The process of sending compressed media from a server to a client. The client then plays back the media as it is received. The media can be pre-recorded or live. Media is not stored at all by the end client.
Progressive Download – The end user experience is similar to stream delivery, however the digital file is downloaded to a physical drive on the end user's device. The digital file is typically stored in the temp folder of the associated web browser if the digital media was embedded into a web page or is diverted to a storage directory that is set in the preferences of the media player used for playback.
Progressive download opens digital media to piracy in that it can be saved and shared by the end user. Due to this unrestricted access to the digital media file, entities concerned with piracy and security of their data opt for streaming-based solutions that create a small buffer in order to initiate playback. However, at no time during a streaming media session is the entire file downloaded locally as it is in the Progressive download scenario.