Streaming means delivering audiovisual content over the Internet or any lesser (especially private) computer network at actual playback speed, to let the recipient view or listen to it in real time. The method and the aggregate body of content often carries the name "the stream." Like a conventional water stream, the recipient does not normally capture or store the content permanently. Instead one prepares to view or listen to the content, as if one were playing back a track on an optical disk or even on a magnetic tape or vinyl disk. Designers of streaming server and client software deliberately, by mutual agreement, make capture of streamed content impractical and impracticable. This they do to provide security against copyright violation. Indeed, most dedicated streaming devices have no memory available for storing content.
History of streaming
Streaming began with certain popular Internet services for user-uploaded video content (YouTube, DailyMotion, the original Google Video, etc.). These services used Adobe Corporation's Flash Video protocol to store content. Any computer user having Internet access, and using a current browser, could navigate to the service, select a video, and play it in real time.
The Flash Video protocol is obsolete today. Yet the original streaming services continue. And commercial video content distributors (Netflix, etc.) began replacing their optical-disk rental and return services with streaming services. A user who "streams" a video offering does not have to return the disk. Instead, he rents the right to stream a title for an allowed time, and at a rental rate, comparable to those of the old video rental services.
In recent years, various "premium channel" providers have turned to streaming and away from their traditional method of on-demand content delivery over coaxial or fiber-optic cable ("cable television", the successor of the original "Community Antenna Television"). With the advent of mobile devices, all these services offered applications to let users access streaming services from "smartphones" and tablet devices. More recently still, at least three companies have developed dedicated streaming devices that can access thousands of streaming channels. Some of these devices are small enough to carry conveniently in a traveler's luggage for use on guest room television sets at hotels that offer Internet access included in the room price. (Which is to say, nearly every hotel chain, especially those catering to international and/or business travelers.)
Types of streaming devices
As has been the case since streaming began, anyone can "stream" content onto an Internet-connected computer, using a modern browser. Third-party developers have written software that a user can adapt to capturing content while streaming. Such software typically is not reliable. Nor would any streaming service support it. Use of such capture software, ipso facto, constitutes copyright violation.
Any smartphone or tablet device can run an "app" to sign onto a particular streaming channel or channels and access its content.
Recently, hardware developers have invented dedicated streaming devices for use at home or in hotels. The most sophisticated such devices can search for streaming channels or content by voice.
Most optical media players can now access a limited number of streaming channels, in addition to playing optical media of all types.
Finally, the most recent versions of the most popular operating systems on the market offer Digital Living Network Alliance service. Any computer running Microsoft Windows or the MacOS can act as a DLNA server, or run a program that can offer such service. A DLNA server offers private streaming to any computer, or any "smart" optical media player, having DLNA client software or firmware on board.
DLNA have no plans to offer streaming access by a user to content he stores on his own computers while he travels. But they have expressed an interest in developing a standard for cloud storage of user-captured audio-visual content, and the configuration of a dedicated audio-visual cloud storage service as a streaming channel.
Pricing of streaming content
A few streaming services, like the original YouTube, still carry no charge for subscription or content playback. But most streaming channels require a subscription. Even the original "free" channels have paid-subscription counterparts, like YouTube Red.
Many services offer some content for rental or purchase, at rates and prices comparable to those for conventional rental and purchase. Purchasing a streaming title allows the user to "stream" it as often as he wishes, for as long as he has an account with the streaming service. Services that rent or sell streaming licenses usually do not charge extra for access.
Other services charge nominal monthly or annual subscriptions to their channels. Subscribers enjoy full access to streaming content, free of charge for any specific title or track.
In the last year, at least one service (Sling Television) now offers a bundle of streaming channel subscriptions. One might consider the rate nominal in comparison to subscribing to member channels separately.
The obvious advantage of streaming to the user is: not having to store the content on one's own machine, or on more than one machine at home or in the office. The user has one other advantage: not having to use optical or other physical storage media, with all the wear-and-tear hazards they carry.
Users can also use streaming to access content while away from home or office. All one needs is a smartphone, a tablet device, or a television-connected streaming device small enough to pack in checked or carry-on luggage. One does not need to "lug" an optical disk player or a set of disks. A single semi-portable streaming device replaces an optical media player and a set of disks that together often have ten times the bulk and even more than ten times the weight.
Content providers have an advantage that induces them to offer their content for streaming. Copyright violation becomes almost as impractical as it was before the advent of audio-visual recording of any kind. A user cannot capture content while streaming, without great expenditure of effort and usually with some compromise in quality. Rents and purchase prices are also low enough to make such copyright violation literally not worth the effort or the legal risk.
Obviously the chief disadvantages of streaming are technical. Access to streaming content is only as secure as is access to the Internet (or to one's private network for DLNA-standard private streaming). And also as secure as the user's own memory for usernames or passwords.
An excessive number of simultaneous streaming users can overload a streaming service. Streaming service providers and developers today run a constant race to satisfy average and peak streaming demand.
Finally, today a user can access only commercially available content while traveling. Only with DLNA (or, to a lesser extent, with services like YouTube) can he privately stream content of his own creation to which no one other than himself has access.
But the technical disadvantages are no worse than the disadvantages of the content-storage and -delivery techniques streaming displaces. The "private content" disadvantage is only temporary, as DLNA's own officials are quick to point out to interested inquirers.