This appendix, provided for the beginning streaming media creator, answers often-asked questions about producing clips for RealPlayer. It also provides URLs for Web sites where you can find tools and helpful information about developing streaming media presentations.
RealPlayer plays the media clips that you create. It can also display HTML pages that accompany your media presentation. You can download RealPlayer from http://www.real.com. See "Step 2: Learn the RealPlayer 10 Interface" for an introduction to the RealPlayer interface.
No. RealPlayer includes a subscription service that provides premium media content and music. But RealPlayer is designed to be a general-purpose media player for any type of free or paid media content.
No. RealPlayer can display HTML pages along with media, a combination that greatly enhances the viewing experience. You can also stream media alone, though, without displaying HTML pages along with your clips.
On Microsoft Windows, RealPlayer uses the existing version of Internet Explorer. Because Internet Explorer 4 is the earliest version that functions with RealPlayer, writing HTML content that can play in this browser guarantees access to the widest possible audience. This supported set of technologies includes Javascript 1.2 and Cascading Style Sheets 1 (CSS1).
Yes. You can still use RealPlayer to embed media clips directly into any Web page, as described in Chapter 20. However, the native RealPlayer interface provides an easier way to coordinate media and HTML pages, eliminating the cumbersome markup required to embed a presentation.
RealNetworks provides extensive digital rights management technology that allows you to protect copyrights for valuable media assets. You can learn more about this suite from the following Web page:
http://www.realnetworks.com/products/drm/index.html
RealProducer is the basic tool you use to create clips. Both the RealProducer 10 User's Guide and the product's online help guide you through the encoding process. This production guide provides background information and tips on creating high-quality streaming media.
You start with an audio or video source file in a digitized format on your computer. You then select the file and set encoding options. The encoding process creates a new streaming clip, leaving the source file unchanged.
Yes. RealProducer accepts live video input from a camera and live audio input from a microphone. The camera and microphone connect to an audio/video capture card on your computer. RealProducer then lets you select the live input as the source. In this case, you go directly from live input to encoded clip without creating a digitized source file.
Quality starts at the source. You need high-quality video and audio input for RealProducer to create high-quality streaming clips. Chapter 3 and Chapter 4 include tips on producing good audio and video, respectively. If you are new to media production, learn your editing hardware and software thoroughly, paying close attention to the manufacturers' recommendations for producing high-quality media files.
In addition to audio and video, RealPlayer can play the following types of clips:
To produce streaming media clips, you need audio and video production tools as well as RealProducer to handle the encoding.
You can use any hardware or software designed for capturing and editing audio or video. The digitized output must be in a format that RealProducer accepts, however. Some video editing programs save digitized video in a proprietary format that RealProducer cannot read. However, these programs typically let you export the video to a common format that RealProducer accepts, such as AVI, QuickTime, or MPEG.
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Tip: Check http://www.real.com/accessories/index.html for hardware and software tools that can help you with capturing and editing audio or video. |
RealProducer accepts many common audio and video formats. These may vary by operating system, though. RealProducer on Macintosh accepts the formats widely used on the Macintosh, such as QuickTime, whereas RealProducer on Windows or Unix supports the formats widely used on those operating systems. Check the RealProducer manual for your operating system for a list of accepted formats. Information is also available at the following Web page:
http://www.realnetworks.com/products/producer/features.html
RealNetworks makes versions of RealProducer for Windows and Linux. You can download RealProducer from RealNetworks' Web site:
http://www.realnetworks.com/products/producer/index.html
You can create RealPix presentations using the RealPix markup language, which is described in Chapter 7.
You create animation with Macromedia Flash. You can develop animations with Flash 2, 3, or 4. Chapter 5 provides tips for making Flash animation stream well to RealPlayer. It doesn't explain how to create Flash animations, however. You can learn more about Flash from Macromedia's Web site:
http://www.macromedia.com/software/flash/
SureStream provides advanced streaming technology for RealPlayer. For more information about SureStream, read "SureStream RealAudio and RealVideo".
SureStream is a technology that lets a single RealAudio or RealVideo clip stream at different bit rates. It does this by bundling into a single clip multiple streams, each of which runs at a different bit rate. You can make a SureStream clip that streams at either 28.8 Kbps or 56 Kbps, for example. When users request the clip, they automatically receive the stream that best matches their RealPlayer connection speed.
Using RealProducer, you can choose to use SureStream when you encode audio or video input. The number of SureStream streams you can encode in the clip depends on the type of RealProducer you use. RealProducer Basic encodes three speeds per clip, whereas RealProducer Plus encodes an unlimited number of speeds per clip.
No. A SureStream clip has several streams encoded in a single clip. Unlike Helix Server, a Web server cannot extract a specific stream to send to RealPlayer. If you plan to deliver clips from a Web server, you need to set RealProducer to use single-rate encoding.
Chapter 8 explains the basics of SMIL. Appendix B explains how to do some common tasks with SMIL. Appendix D provides a SMIL reference you can use once you are comfortable with SMIL.
Pronounced "smile," SMIL stands for "Synchronized Multimedia Integration Language." It is an industry-standard markup language used to lay out and time streaming media presentations. SMIL works for RealPlayer the way HTML works for a Web browser.
Not always. When you want to stream just one clip, such as a single RealVideo clip, you don't need to use SMIL. You just link your Web page to the clip through a Ram file. For more information, see "What is a Ram file?".
When you stream multiple clips, SMIL gives you the means to lay out the presentation and time its clips. It also provides other features, such as letting you create hyperlinks that display HTML pages, or that start new media presentations. For a rundown of basic SMIL features, see "Understanding SMIL".
SMIL is a simple markup language that you can write with a word processor or text editor. Some software tools create SMIL files automatically. Other SMIL editing tools are also available. Visit the following Web page for more information:
http://www.realnetworks.com/products/media_creation.html
As the numbers suggest SMIL 2.0 is an enhancement to SMIL 1.0, which was introduced in 1998. SMIL 2.0 greatly expands the capabilities of SMIL 1.0. Because it is newer than SMIL 1.0, though, not every media player that supports SMIL 1.0 can handle SMIL 2.0. RealOne Player or later can handle both SMIL 2.0 and SMIL 1.0. RealPlayer G2, RealPlayer 7, and RealPlayer 8 can read only SMIL 1.0 files, however.
Helix Server streams the clips created by RealProducer. You can stream clips yourself with Helix Server, through a service provider that has Helix Server available, or, in some cases, from a Web server.
Not necessarily. To run Helix Server, you need a computer connected to an intranet or one that has a direct presence on the Internet. You cannot run Helix Server if you use an Internet service provider (ISP) to connect to the Internet. If you use an ISP, check whether they have Helix Server and whether they can host your streaming presentations for you.
Helix Server runs on Windows NT/2000 and many Unix platforms, including Linux. For a list of available platforms, visit RealNetworks' technical support Web site at http://service.real.com.
Helix Server is available on the RealNetworks Web site at http://www.realnetworks.com/products/media_delivery.html. Helix Server Basic is free.
Sometimes. A Web server can deliver many types of clips, including RealAudio and RealVideo. There are limits to Web server delivery, however. If you plan to use a Web server for clip delivery, read "Limitations on Web Server Playback" first.
A Ram file, also called a metafile, is a simple text file with the extension .ram. It
typically consists of just one line: the URL to a streaming presentation. Your
Web page does not link directly to your presentation. Instead, it links to the
Ram file, which ensures that RealPlayer launches. RealPlayer then uses the
URL in the Ram file to request the presentation. "Launching RealPlayer with
a Ram File" explains how to write a Ram file.
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Tip: When you stream clips with Helix Server, you can eliminate the Ram file by using the Ramgen utility. For more information, see "Using Ramgen for Clips on Helix Server". |
Yes. The SMIL file lists the URLs for clips. The Ram file supplies RealPlayer with the URL to the SMIL file (or to your streaming clip, if you're not using SMIL). The Ram file is always necessary because its .ram extension launches RealPlayer.
Web servers use HTTP to deliver Web pages and graphics. HTTP is designed to download small files quickly and efficiently. It is not suited for streaming large media clips, though. RTSP, which stands for "RealTime Streaming Protocol," is an industry-standard protocol that overcomes the deficiencies of HTTP for streaming media. RTSP enables Helix Server and RealPlayer to stream long clips and compensate for changing network conditions.
When a clip resides on Helix Server, make sure that the URL used to request it
starts with rtsp:// rather than http://. An RTSP URL must be in a file read by
RealPlayer, such as a Ram file or a SMIL file. It cannot be in an HTML page
hyperlink, because a Web browser does not know how to make an RTSP
request. For more on this, see "The Difference Between RTSP and HTTP".
For full information about broadcasting media, see RealProducer 10 User's Guide and Helix Server Administration Guide.
Possibly. If you connect to the Internet through an ISP, you may be able to broadcast streaming media, provided that your ISP has Helix Server available and offers broadcasting services. To do this, you will need a fast Internet connection to your ISP. You cannot broadcast through an ISP by running Helix Server on your desktop computer.
Yes. Using SureStream is recommended because it ensures that users connecting at different speeds will each receive the best possible stream. You need to make sure, however, that the computer running RealProducer has enough power to encode all the SureStream streams at the same time. Check RealProducer's manual or online help for system requirements, and perform a trial run before streaming the actual broadcast.
No. You need Helix Server to broadcast streaming presentations. Web servers are designed to serve HTML pages and graphics to different users at different times. They are not designed to broadcast the same presentation to multiple users simultaneously.
No. "Broadcasting" means to send out a stream that more than one RealPlayer user can view at the same time. The broadcast can be live, meaning that the input originates from a microphone or video camera. Or it can be prerecorded, meaning that it originates from a digitized clip prepared in advance. If it's prerecorded, you don't need to use RealProducer during the broadcast. You just put the clip on Helix Server and then set up Helix Server to broadcast the clip as a simulated live event.
Yes. You can use SMIL to include ads with the broadcast, or deliver static clips alongside the broadcast. In the SMIL file, you simply treat the broadcast as a static clip. The only difference is that you use a special URL created by the Helix Server administrator that identifies the resource as a broadcast rather than a clip.
That depends entirely on your Helix Server and the network bandwidth it has available. For large broadcasts, you can use a network of Helix Servers to reach thousands of RealPlayers.
Yes. RealNetworks' Managed Applicaton Services (MAS) offers a wide range of services for hosting broadcasts. Learn more about MAS at:
http://www.realnetworks.com/products/mas/index.html
RealNetworks offers a range of technical support features and documentation.
RealNetworks Technical Support operates an extensive Web site at http://service.real.com. The site includes answers to frequently asked questions, a documentation library, and a searchable knowledge base.
RealNetworks Technical Support maintains a documentation library at http://service.real.com/help/library/index.html. Most documents are available as bundled HTML archives that you can download, uncompress, and read with a Web browser. Many documents are also available in PDF format, which is suitable for printing. To read PDF files, you need Adobe's Acrobat Reader, which is available from Adobe's Web site:
http://www.adobe.com/products/acrobat/readstep.html
The RealNetworks Resources area is the main information site for content authors and software developers working with RealNetworks products. You can find it at the following Web address:
http://www.realnetworks.com/resources/index.html
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