Broadcasting on the Wire


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Imagine a broadcast transmitter powerful and technically advanced enough to broadcast a radio station's signal all the way around the world. The broadcast signal would race at the speed of light, being heard in Hong Kong just milliseconds after transmission and received sounding as clear there as to those listeners located two miles from the transmitter. Although this awesome display of broadcast magnitude would be a rare event indeed for any local AM or FM radio station, this scenario happens every day by radio stations that broadcast “on the wire” or what is commonly referred to as webcasting.

The technology to broadcast on the Internet has been around for quite some time. Even so, large numbers of radio stations are still not webcasting. Many radio stations abandoned, and many more never started, webcasting when copyright threats and the potential financial liability outweighed the benefits. Then the U.S. Congress established a statutory license and the Library of Congress introduced the soundexchange.com for digital service providers, of which radio stations that webcast are included. As a result, radio stations are coming back to the Internet and many more are venturing onto the Internet for the first time.

Internet radio has an established presence. Click here to enlarge this graph.

Although there are many similarities between broadcasting over the airwaves and Internet streaming, the primary difference is in the listener's electronic reception device. An AM or FM receiver acquires the broadcast signal and converts the radio waves into audio output. When the listener uses the Internet to acquire radio programming, a computer is used to capture the digitally encoded stream and the computer decodes the series of ones and zeros into audio output.

Sounds simple right? Surprisingly, by today's standards of difficulty, streaming audio is fairly simple technology. Streaming a broadcast on the Internet is far less complicated than broadcast radio. The demand for higher bandwidth streams and better fidelity will impact online broadcasts to a much greater degree in the future, but today the state-of-the-art is still rudimentary in nature. Taking a rather robust broadcast-quality signal and compressing it down to a 16kb/s or 20kb/s stream might make an audio engineer cry. On the other hand, producing a great sounding Internet experience in spite of the signal compression is where a master of the airwaves can really shine.

In any event, the decision to webcast may have already been made or will be made in the near future. So how do you manage the implementation of this wired broadcast technology and integrate streaming into your already demanding responsibilities?

Getting started

First, you assemble the equipment and software required. You will need a personal computer, an audio capture card and an uninterruptible power supply (UPS). Download the free Microsoft Windows Media Encoder to the webcast personal computer.

You will also need unobstructed access to the Internet with an always-on Internet provider that offers a T-1, DSL, ISDN or cable modem connection.

You will need a static IP address or if you have a dynamic IP connection, you will require the services of a free IP address forwarding service. This is the short list of equipment and software required, but as easy as it sounds the devil is definitely in the detail.

While I focus on the Windows Media Systems technology, other operating systems can be used, such as Real Media, which are similar and may use various algorithms to code and decode the audio. Each codec system has its own strengths and weaknesses.

The subject of which technology is better has caused many an argument among knowledgeable streaming media gurus. We have chosen the Windows Media System because of the widespread distribution of the Windows Media Player and the non-scientific observation that webcasting in this technology appears to come with a lower overall cost of content delivery (COCD).

Webcasting a live radio program is all about processing speed. The faster the central processing unit (CPU), the better the overall digital output quality and the less likely other applications or running multiple streams will have a degenerating effect on the audio output. A CPU speed of 333MHz should be considered the bare minimum requirement for even a single 16kb/s bit-rate stream. I personally recommend a 2GHz or faster processor or even dual processors. I don't think there is such a thing as too fast.

Many stations provide multiple streams to allow dial-up and broadband listeners equal access to the most usable bandwidth. Using higher bandwidth streams and sending multiple streams to the media server may force you to increase the CPU processing speed. I don't recommend taxing the processor at more than a 50 percent usage on a continuous basis. Although other applications and processes will most likely be subordinate to the Windows Media Encoder output, continuously pushing a processor into 80 or 90 percent utilization is not worth risking the computer locking up and the webcast ending abruptly. Remember, faster is better. The Windows Media Encoder control panel indicates the continuous CPU utilization percentage in real time.

The sound card is the next most important item of equipment in the Internet streaming media configuration. Think of it this way: the transmitter simply pushes a carrier wave loaded with an amplitude-modulated or frequency-modulated signal. The quality of the broadcast audio signal started with the pre-transmission audio electronic equipment long before the signal was loaded onto the carrier wave. The hosted media server is equivalent to an Internet transmitter that distributes the Internet stream to listeners and in this way is similar to a broadcast transmitter. The media server simply takes the signal presented by the WMS encoder and faithfully redistributes the digitally produced output to hundreds or even thousands of online listeners.

If the audio source is clean and a high-quality audio capture card is used, theoretically, the low-bandwidth Internet stream will sound equally great no matter the listener's location on the planet.

I recommend a 24-bit sound card, but you may have to experiment with different brands to find the best integration with the PC's motherboard configuration. Broadcast automation systems frequently process more than one audio source simultaneously by incorporating multiple processor chips. Likewise, you can stream more than one audio source through the same computer. You may have two separate radio station broadcasts, one station broadcast and an Internet-only side-channel or other multiple-stream requirements.

Reliable service

While broadband use is increasing, dial-up is still common. Click here to enlarge this graph.

One single-processor sound card can encode different bandwidths of the same audio source if you run Windows XP. Using another Windows operating system, such as Windows 98 or Windows 2000, may require multiple sound cards even if the audio source is the same.

Computer sound cards come in many brands, but for low-bandwidth streaming, high-tech sound cards may mean a much more complex job of system integration and configuration. Some more costly sound cards will not stream at less than 32kb/s.

Microsoft maintains a list of WMS-supported sound cards on its website.

Remember that user statistics still show that just under half of all Internet listeners still use a dial-up Internet service provider. Most dial-up providers, although advertising a 56kb/s bandwidth downlink, rarely connect their customers at more than 19kb/s to 26kb/s. Consequently, a 32kb/s stream would be unusable by most dial-up listeners. The player would constantly drop out and be overpowered.

If you use a backup power supply to make sure the broadcast stays on the air, connect the Internet modem, router, firewall and Internet streaming computer to the same backup source. You may prefer to install a separate uninterruptible power supply (UPS) for just the webcasting equipment.

The free, downloadable Windows Media Encoder provides a stream setup wizard that is fairly intuitive and easy to use, but there are a few non-intuitive things to know to get the encoded source stream to a media server for distribution to the world. For example, the multiple bit-rate (MBR) setting will not work for live streaming one-pass radio broadcasts. You will select the continuous bit-rate (CBR) setting and only select one bit-rate stream from the bit-rate pick list.

If you do not use a router or firewall, the Windows Media Encoder will provide the IP address of the encoder installed on the PC. If a firewall or router is used, the encoder will only indicate the IP address of the network or protective device. Consequently, a couple of things must be done to have the Media Server hosting service pull the stream from the webcast PC. Although some hosting services allow the stream to be pushed to the Media Server, it is a more efficient use of bandwidth to have the hosting service pull the stream. If a router or firewall is used, open the HTTP port to allow the Media Server access to the webcast PC located on the station's network. Read the router or firewall device instructions as to how to open the port.

Use the broadcast security provided by the WME software. This will prevent denial of service attacks and keep unwanted intruders from redistributing the signal directly from the encoder.

Once the sound card is installed, the Windows Media Encoder is downloaded and it is possible for a Windows Media Sever to access the webcasting PC, you are port ready. Port refers to the HTTP port that is opened to allow the Media Server to pull the signal. The HTTP port default value is 8080, but you can designate your own port numbering strategy just as easily.

Quality counts

My number one rule of streaming on the Internet is if you don't care what the stream sounds like, don't bother. No one listens to a poor sounding Internet stream unless there is a disaster in his home community and that poor-sounding stream is the only way he can hear what's happening to loved ones or his own property. Strive for listener enjoyment and don't rush to the Internet just to be able to say that a webcast is on the Internet. Some listeners will stay with a station when they are driving on the fringe of a broadcast area, but there is no fringe area on the Internet. Low-fidelity laptop and desktop systems already have a strike against them. Don't let the streaming webcast quality drive listeners away from the station entirely.

Internet Service Providers come in various sizes and quality of service. There is a noticeable difference in the bandwidth and stability of connections so don't think one is just as good as the other. Going cheap is not prudent when it comes to the stream to the Windows Media Server. The station's connection to the server needs to be 5×5. You cannot control how the listener connects to the webcast, but you should make every effort to make the best decision when it comes to the station's only path to the Internet. If the stream to the media server goes down, everyone listening to the webcast goes down with it. Fast and stable are the two words I use to describe the most important aspects of an ISP. Of course, cost is another important element in the decision. It might be hard to justify a $300-per-month T-1 line vs. $26.95 per month for a DSL Internet connection.

If a telephone modem is unacceptable for streaming, then a decision to use DSL to stream the station's webcast should be weighed with great care. DSL providers often don't connect at the fully advertised upload throughput unless the customer complains that something doesn't work correctly. DSL connections are historically less stable than residential broadband hookups. ISDN and T-1 lines are more stable, but also more expensive. Choose wisely.

Finally, the desired type of IP address is static as opposed to dynamic. A static IP address never changes, but with a dynamic IP address, the Internet service provider recycles its connections when the PC or modem is rebooted, changing the IP address. When this happens the streaming media host will loose its connection with the webcast computer and require manual intervention to re-establish the stream.

The way to make a dynamic IP address a quasi-static IP address is with the use of a free IP forwarding service like No-IP.com. These free services provide a host name that the Media Server uses instead of an IP address. The IP forwarding service tracks any IP address changes and automatically switches the connection for you. Simply request a static IP address from your Internet service provider; however the ISP may have an extra monthly charge for the unchanging static IP address.

Here is a radical means of broadcasting on the wire: go through the air first. If you do not have the extra budget for a webcast PC but you still want to broadcast on the wire, there is a work-around. Use the PC and Internet connection of someone in the broadcast area who can receive a solid signal from the transmitter. A remote AM or FM receiver can feed the streaming encoder. This is not the ideal method, but it can work.

Wired broadcasting is in its early years and the more you learn about the technology of streaming media the better you will be able to take full advantage of its revenue-generating possibilities. Don't give away potential advertising revenue for the promise of low or no streaming costs. Take control of your Internet presence and run your own streaming media show. Broadcasting on the wire is easy, its local and the Internet webcast is your property. Take control and stream on.


Gathard is president of Barnabas Road Media Hosting, RC24x7.com, Indianapolis.




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