This chapter introduces you to streaming media and RealSystem G2. It shows you the different types of streaming media that you can create with RealProducer, what you need to get started, and discusses the importance of knowing your audience.
Although you do not need to know this information in order to use RealProducer for basic tasks, it is recommended that you have a working knowledge of these topics.
Streaming media created by RealProducer can be either RealAudio or RealVideo. Before the advent of streaming media, you had to wait for a media file to download from the Internet or a network server in order to experience it. When you create streaming media, users can view it almost instantly.
Streaming media allows you to send small packets of information over a network connection. The user receives the information packets and plays your media piece by piece. The process is almost invisible to the user, except for a small amount of buffering at the beginning.
RealProducer G2 is an integral part of the RealNetworks RealSystem G2. Below is a brief overview of the steps that you can take to create streaming media and put it on the Internet, or your company's Intranet.
RealProducer creates streaming media from two kinds of sources: audio and video. Whether the source is a digital file or a live feed directly to your computer, you can convert it into a RealMedia clip.
If you are creating a digital file for your source, you should save it under the following formats:
If you are sending audio and video directly to your computer, you will need:
For tips on creating your media source, see "Producing High-Quality Audio" or "Producing High-Quality Video".
RealProducer takes your input media source and records it into a RealMedia clip. Your clip can be saved as a file to be streamed at a later time, or it can be sent directly to a server as a live broadcast. The figure below shows how RealProducer converts your source into RealMedia.
RealMedia clips are also known separately as RealAudio and RealVideo. You will learn how to create these types in the next chapter, "Creating Streaming Media". Below is a brief description of each type.
A RealAudio clip is created by converting an audio file or by recording from a microphone (or other audio input) onto your computer. RealProducer uses various audio codecs (compression/decompression algorithms) to convert your standard audio into a format that can be streamed.
You also have various compression options based on the type of audio you are converting: voice, voice with background music, music only, or stereo music. As expected, the quality of the original audio will have the greatest effect on the ultimate quality of the compressed audio.
A RealVideo clip is created by converting a video file or by capturing from a video source, such as a video camera or video cassette player, to your computer via a video capture card. RealProducer converts different attributes of the video-such as frame rate, type of motion, and size of the image-into a RealVideo clip using a video codec.
If you are broadcasting your streaming media directly to a server, you can skip this step.
Once your streaming media clip is created, you will want to show it to your audience. With RealProducer, you can publish (upload) the clip to your server. This server can be either a RealServer™ G2 or a standard Web server. If you plan on using a Web server, you will not be able to take advantage of many G2 features.
See "Publishing to the Internet" for more information on publishing your clips.
You will use a RealServer G2 or a Web server to stream your clip to the Internet (or to an Intranet). The RealServer G2 is a separate software product, created by RealNetworks, that allows you to stream live or recorded RealAudio and RealVideo files to anyone using a RealPlayer. The server can work with Web servers to stream media over the Internet or to users on a corporate Intranet.
For more information on how you can obtain and use a RealServer G2, go to the RealNetworks Web site at http://www.real.com and look for the links to this product.
Once your audience has connected successfully to your streaming media clip, they will want to experience it. A RealPlayer™ G2 is all they need. Two versions of the RealPlayer are available from RealNetworks, a free version and a Plus version. The RealNetworks Web site (http://www.real.com) has more information about each version and how to install and use them.
Whenever you create a RealMedia clip, you should always keep in mind the connection speed of your audience. Are they using lower-speed modems, or are they playing your clip over a high-speed network?
This section introduces you to your target audience, and shows you a way to increase your audience: SureStream.
When you select a specific target audience, you are actually specifying a maximum bandwidth for your RealMedia stream at the selected target audience. Bandwidth, measured in kilobits per second (Kbps), is the amount of data that can be sent through an Internet or network connection during a set period of time. Standard modems are commonly referred to by the bandwidth they are able to receive--for example, 28.8 and 56 Kbps.
In addition to these standard audiences, you can record clips for connection speeds of 100 Kbps, 200 Kbps, or higher. These higher bandwidths, however, are generally more typical of corporate Local Area Networks (LANs) or entertainment-based Web sites.
Keep in mind that the maximum bandwidth a connection is capable of is greater than the average bandwidth carried across it. For that reason, 28 Kbps connections actually only use approximately 20 Kbps, while a 56 Kbps connection actually uses about 34 Kbps.
Normally, these constraints can affect your recording in many ways. Sometimes you have to compromise between reaching the largest audience (with the lowest-speed connections) and the quality of your work. Fortunately, RealProducer enables you to record for a number of target audiences simultaneously using SureStream.
With SureStream recording you can reach the widest possible audience, and provide all users with the best listening and viewing experience optimized for their bandwidth.
There are several advantages to using SureStream. You can create:
SureStream RealMedia files can combine several different streams that take advantage of any or all of these features.
For example, you can record a video clip for both 28 Kbps and 56 Kbps audiences, and RealPlayer G2 will automatically use the correct stream based on the user's connection speed.
Keep in mind that if you are broadcasting SureStream files, you must use a RealNetworks RealServer G2.
