Tips T0010

Streaming - All about Streaming Video

There is a lot of attention at the moment about adding streaming video to your web site. We look at exactly what this means and how it can be used to benefit your web site.

Streaming vs Download
The traditional method of adding video to a web site was to put an MPEG or QuickTime file on the web site and link to it like any other type of file. This was easy to do, but meant that the user had to download the entire movie file before they could view it. Some of the later movie players (e.g. Windows Media Player) attempt to play the movie as it is being downloaded, but they usually have to wait a while before they have enough data to play and then they only play a very short piece of the movie - this is especially true for large movie files viewed over slow modem connections.

What streaming video brings is the ability to send the movie from the web site at the same time as it is being viewed by the user. This means that the user doesn't have to download the entire movie before they can watch it.

There are three main streaming formats available today: RealMedia from Real Networks, QuickTime from Apple and Windows Media Format from Microsoft.

How Does It Work?
Streaming works by setting up an "intelligent" connection between the viewer's movie player and the host web site. The web site can find out how fast data is traveling to the movie player and send the appropriate amount of movie data. This means that if the movie player is connected to the web site over a slow internet connection, the web site can send highly compressed (and therefore low quality) video and audio. If the connection is via a fast cable connection, the web site can send higher quality video and audio by using less compression.

This trick is achieved at the web site by installing a streaming video server - a piece of software on the web site that makes the connection with the user's movie player. The server can continually monitor the speed of data going to the movie player and adjust the compression to compensate for any changes in data rate. The streaming video server software must be installed by the web hosting company.

Clever Streaming Tricks
When you produce a movie file for streaming from a web site, you can be asked to choose typical data rates that will be used by your viewing audience. The streaming movie file can therefore contain multiple movies, each compressed differently and suitable for a different connection data rate. The server will choose the appropriate movie for the current connection data rate.

If the connection data rate drops very low, the video picture can be stopped all together and only sound sent. In this way, the movie can still attempt to play even though the picture is lost. The picture can be restarted if the connection data rate improves later.

Additionally, the movie player can contain a buffer which contains a few seconds of movie ahead of what is actually being played. If there is a short break in the connection, the data from the buffer can be used until the connection is regained and there won't be any break in the movie playback.

Summary
Under the bonnet, streaming video technology can get very complex. As a user, we just need to know the pros and con's in order to make a decision as to whether we need to use it.

Benefits

• Instant playback. Streaming video starts playing almost immediately, allowing the viewer to start watching the movie without having to first wait for a large file download.
• Can't copy locally. It's possible with most streaming formats to stop the user from copying the movie to their local hard drive. This may be desirable for copyright reasons.
• Streaming live events. Streaming video can take its source from a live video camera, allowing it to show live events.
  

Disadvantages

• No server software. Not all web host providers have all the server software for all the streaming formats. Ensure that you web host has the correct software for your preferred streaming format.
• Low quality. For users with slow internet connections, the movie has to be heavily compressed in order to play in real time. This can lead to unacceptably poor video and / or audio quality.
• Can't copy locally. If you allow your viewers to replay the movie many times they may want to copy it to a local hard drive to avoid repeatedly connecting to the internet.