Streaming media is multimedia that is constantly received by and presented to an end-user while being delivered by a provider. The verb to stream refers to the process of delivering or obtaining media in this manner.[clarification needed] Streaming refers to the delivery method of the medium, rather than the medium itself. Distinguishing delivery method from the media distributed applies specifically to telecommunications networks, as most of the delivery systems are either inherently streaming (e.g. radio, television, streaming apps) or inherently non-streaming (e.g. books, video cassettes, audio CDs). There are challenges with streaming content on the Internet. For example, users whose Internet connection lacks sufficient bandwidth may experience stops, lags, or slow buffering of the content. And users lacking compatible hardware or software systems may be unable to stream certain content. Live streaming is the delivery of Internet content in real-time much as live television broadcasts content over the airwaves via a television signal. Live internet streaming requires a form of source media (e.g. a video camera, an audio interface, screen capture software), an encoder to digitize the content, a media publisher, and a content delivery network to distribute and deliver the content. Live streaming does not need to be recorded at the origination point, although it frequently is. Streaming is an alternative to file downloading, a process in which the end-user obtains the entire file for the content before watching or listening to it. Through streaming, an end-user can use their media player to start playing digital video or digital audio content before the entire file has been transmitted. The term streaming media can apply to media other than video and audio, such as live closed captioning, ticker tape, and real-time text, which are all considered streaming text. Elevator music was among the earliest popular music available as streaming media; nowadays Internet television is a common form of streamed media. Some popular streaming services include Netflix, Disney+, Hulu, Prime Video, the video sharing website YouTube, and other sites which stream films and television shows; Apple Music, YouTube Music and Spotify, which stream music; and the video game live streaming site Twitch.