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Streaming, webcasting and downloading

With rich media (audio and video) the license fees you pay, and the cost of actually hosting the files, depends on how you let your visitors access the files:

Streaming means that your server delivers the file gradually, at a speed decided by the viewer. Using special server software (NOT http servers) and matching client software such as Realplayer, Quicktime or Windows Media Player, the visitor and your server 'negotiate' a speed suitable for the network, and the server drip-feeds the data at that speed. The client software never SAVES the file to disk, it shows only what is being sent at the time. You can start and stop the playback, but you can't record it.
Streaming requires software to be installed on the server. Some, like Real's Radius Server, is free. Others cost money, but actually making the files themselves usually needs software as well. The advantage of streaming is that the server controls how many people can listen at once, and visitors find it very hard to save a copy of the file (though it's possible using illegal software). Many commercial sites, such as the systems BF@D operate for our clients, have dedicated streaming servers tucked away on the Web, so that downloads don't overload the web server itself. Streaming video is particularly demanding on servers, and throughputs of many gigabytes per hour are common.

Webcasting is a special form of streaming where the server delivers a constant program of data, and clients can choose to 'listen in'. It's the way Internet radio stations work, and critical to this method is the idea that the viewers cannot control the server - only listen in. They cannot pause playback or start again at the beginning. Payments and licenses for webcasting are different than for streaming.
Webcasting needs the same specialist software on the server as you need for streaming, and can be viewed in the usual client software like Real, Quicktime and WMP. The advantage for server operators is that viewers find it very hard to save copies to disk, the server loads are predictable and only active when a broadcast is being made, and license fees are very easy to calculate. One special form of webcasting is called simulcasting - where a broadcast is delivered on TV or radio AND on the Web AT THE SAME TIME. If the webcast is done later, or is delivered as a stream instead of a webcast, then it's not simulcasting. This is important as simulcasting attracts special license rules.

Downloading is the basic format for sharing files, with music or video placed on a web server using HTTP, which visitors can save to disk. Most viewing software will start playback before the file has finished downloading so it can 'look like streaming', but it's really download. The visitor chooses when to get the file, and critically they can save the file to their computer and watch it again without returning to your website. It costs nothing to set up, but it's difficult to calculate license fees and a popular site can easily be overwhelmed by the network traffic used in downloading. Since most standard webservers will send a file as fast as the user can receive it, a few users with very fast connections can easily use up the entire network capacity of your server and make it unavailable to anyone else. Downloading works with any type of file (MPEG4, AVI, AAC, OGG - all the types that can't be plugged into a streaming server) but of course if you let your visitors save copies, you have fun controlling what they do with them afterwards!

Digital Rights Management

DRM is the future for online music and video, love it or hate it. At the very basic level, it's like sitting in a hotel room watching pay-per-view TV - you can buy the right to listen to or watch a file, for a certain number of times, but you never actually own the thing itself. DRM operates using a clever license system built into the files themselves - they 'know' that they can't play without permission. You buy these permissions (as licence keys) from the people supplying the service, and the keys define how you can use the files. A key could say "play three times, no copying" or "play once" or "allow copying to CD" or "play forever but only on this PC". Pretty much anything can be controlled with DRM, and of course to make it work you need certain types of file! Plain MPG or AVI files can't be protected by DRM, as you could just read the data anyway. DRM files built for QuickTime, Real or Windows Media are encrypted so that without the data in the license key, your computer cannot play them. By making sure that only the 'official player software' can read the files, the producers can be pretty certain that the files cannot be opened without a license.

One advantage of DRM is that music or video can be 'loaned'. Just like renting a video, you can have a DRM music or video file that plays once then 'dies', which you can sell or give away without too much fear. There is also what's known in the industry as the "not on my tab" effect - users that have paid for a file are less likely to try and give free copies away.. after all it's their money!

The problem with DRM is delivering it. You need specialist software, both to send out the files AND to handle delivering and selling the licenses. Even creating a DRM-protected music file is a professional-level job! Users can get annoyed that their music 'dies' or won't play on their MP3 player, but gradually the industry is learning how to deliver DRM in ways that the public accept. Price is important, but so is fairness!