Video Hosting - HTTP or Streaming Server

Video content can be hosted on either a HTTP server primarily designed to serve web pages or a specialized streaming server. How can you determine which is best for a particular streaming video?

The number of viewers is probably the most important consideration when choosing a server. Video can be hosted quite cheaply on a HTTP server as long as the number of viewers remains low. If there are hundreds of simultaneous requests to view the video, however, it should be hosted on a streaming server.

Streaming servers can deliver media content more efficiently than HTTP servers, but are usually more expensive. They must be hooked up to high-bandwidth data connections and require greater storage capacity in terms of hard drives because of the relatively large size of video files.

The choice between HTTP servers and video streaming servers is basically about bandwidth. So how much bandwidth you need for streaming video?

Bandwidth is determined by the amount of data that must be transferred from server (hosting computer) to client (end viewer). The amount of data is determined in turn by several factors – the dimensions of the video image, the number of frames per second (frame rate) and the amount of motion in the video image.

As one or more of these factors (dimensions, frame rate, motion) increase, they also cause the bandwidth requirements to increase. So a 640 x 400 video will require more bandwidth than a 320 x 200 video, and a frame rate of 30 frames per second (fps) will require more bandwidth than 15 fps, and if the video has a lot of action scenes, it will compress less, so will require more bandwidth.

In real-world terms for moderate motion videos, we're talking about a bandwidth requirement of about 250 kilobits per second (kbps) for a 320 x 200 video at 15 fps, or about 2000 kbps for a 640 x 400 video at 30 fps.

These figures must be multiplied by the number of simultaneous requests that come in. If 100 people want to watch your 30 fps 640 x 400 video your bandwidth requirements shoot up to 200,000 kbps.

Besides being able to handle the bandwidth requirements, streaming servers have several advantages over HTTP servers. They are better suited for delivering video streams because they can deliver the video content faster and more efficiently.

HTTP servers are relatively slow in terms of data delivery because they must verify that the data has arrived intact. If some data has been lost en route, it must be re-sent so that the requested webpage is displayed properly.

Streaming servers can also verify data delivery, but lost data packets are not so critical in the video stream. At worst, lost data may result in a temporary glitch in the video. For this reason, streaming servers can deliver video data at a faster rate than other types of data.

In addition, streaming servers are able to detect the connection speed between client and server and deliver the appropriate video. If the connection slows down because of network congestion the server will automatically deliver streaming video at a lower bit rate, resulting in skip-free video delivery to the viewer.