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Streaming audio basics

Streaming audio basics

Nov 1, 2000 12:00 PM, Kevin McNamara

At one time, streaming audio or video required that you feed a signal through a codec that was attached to a dedicated digital telephone connection that would be terminated to your streaming host provider (SHP). The SHPs set themselves apart from Internet service providers (ISP) because they have access to the fastest machines and, more importantly, they have a big pipe connecting them to the Internet. Unlike the burstable data streams that are common to most Internet use, streaming media requires a continuous data flow.

Outsourcing Selecting and using an SHP is similar to selecting and using an ISP; however, there are a few factors to consider:

– Do they offer dedicated bandwidth to the Internet for your stream? If you share bandwidth with other users, expect to have degraded performance during peak hours. Be certain of any additional charges that may be incurred should bandwidth increase beyond the allowed amount. Most SHPs will add charges if the amount is exceeded. A rule of thumb is to assume that an audio stream will require about 1.5 Mb/minute.

– Are you limited to the number of streams that can be simultaneously accessed? SHPs can, and do, limit the amount of concurrent users based on your particular plan. An on-air promo directing listeners to your site may cause it to choke and prevent them from accessing it!

– Do you have a choice of encoding schemes? There are three basic types of media decoders in use: Microsoft Media Player, RealAudio and Apple QuickTime. Media Player is provided with every current Windows operating system, and a lite version of Real Player can be downloaded for free; these are the most widely used players for streaming media applications. Some SHPs allow you to deliver all three, if desired.

– Will they provide both live and on-demand streaming? Your PD may decide that including audio clips along with the live stream is a good idea. Most SHPs will provide this as an additional cost.

– Do you have the ability to manage the server from your office? Most ISPs and SHPs give you some limited ability to manage your server from any Web browser. Keep in mind that there are two primary types of hosting servers: shared and dedicated. Most general-purpose hosting takes place on PCs that run multiple sites. This approach is economical, but can bog-down significantly during peak times. Dedicated servers host only a single client and are typically used for sites requiring peak performance at all times. Since only your site occupies the dedicated server, the SHP may allow more direct control over its management.

– Can you extract information about who uses your site from the SHP? Perhaps one of the most valuable things about having a Web presence is its ability to deliver a wealth of information about who’s out there – in real time. Derive detailed media reports from the SHP or, even better, directly from the server management console.

– What are the setup fees? These costs vary greatly and should be understood upfront.

– What are the production costs? Most ISPs and SHPs will provide complete or partial turnkey production services. You may not require these if you have in-house talent or have contracted a design house to build your site, but it’s good to know what to expect in the event you need to use them.

In-house hosting The costs for streaming audio have plummeted, and it is possible for any station to locally host a streaming server. The local streaming server costs range from about $3,000 to more than $15,000. Here’s what you’ll need:

Dedicated connection to the Internet. This is accomplished through your ISP or, preferably, being connected directly to an Internet point-of-presence provider. In all cases make sure you have as much dedicated bandwidth as possible, ideally T1 or fractional T1. Stay away from services such as frame relay, since these transport methods are not designed for real-time delivery of packets. DSL will also work; however, I don’t advise using cable modem access because the actual bandwidth of the connection varies dramatically at peak hours.

Pentium II or higher processor. You could probably run it on less, but I wouldn’t advise it. If the budget permits, consider motherboards that support multiple CPUs, which can provide a significant increase in system performance.

Lots of RAM. At least 128MB; 256MB would be better.

High-quality, multimedia-rated hard drive. These drives typically operate at 7,200 rpm and are designed to have faster access under the heavy load of streaming data. The drive should have an SCSI interface; although many of the newer EIDE drives deliver excellent performance. Don’t skimp on the drive size – prices are very reasonable.

Good-quality audio card. Always consider using PCI-compliant audio cards, as these tend to place minimal load on system resources.

Software to support the encoding scheme desired. Windows Media Encoder 7 and Real Networks Real Producer 8 can be downloaded for free at their respective sites. Despite being free, they have enough features and power to run a decent streaming service, given the proper hardware and a reasonably fast connection to the Internet. For example, Media Encoder 7 will support up to 2,000 simultaneous streams, while Real Producer supports 25; however, Real Server Pro (not free) will support up to 3,000. Among others, the MP3 and WAV audio formats are supported by the encoders, while only the Real Networks products support those plus the Real Media format (RM).

Audio processing equipment. There are several manufacturers offering audio-processing systems tailored to this application.

One final thought, be careful with the selection of an operating system. These encoding packages generally only support certain systems. All of the above-mentioned encoders support the Windows platform, however, only Real Producer 8 supports Linux and most other platforms.