This appendix provides quick answers to common questions about producing streaming media clips. It also provides URLs for Web sites where you can find tools and helpful information about developing streaming presentations.
RealOne Player plays the media clips that you create. It can also display HTML pages that accompany your media presentation. You can download RealOne Player from http://www.real.com. See Chapter 1 for an introduction to the RealOne Player interface.
No. RealOne Player includes a subscription service that provides premium media content and music. But RealOne Player is designed to be a general- purpose media player for any type of free or paid media content.
No. RealOne Player 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, RealOne Player uses the existing version of Internet Explorer. Because Internet Explorer 4 is the earliest version that functions with RealOne Player, 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 RealOne Player to embed media clips directly into any Web page, as described in the Web page embedding chapter of RealNetworks Production Guide. However, the native RealOne Player interface provides an easier way to coordinate media and HTML pages, eliminating the cumbersome markup required to embed a presentation.
The extensive Media Commerce Suite 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/commerce/index.html
Helix Producer is the basic tool you use to create clips. Both the Helix Producer User's Guide and the product's online help guide you through the encoding process.
You start with an audio or video source file in a digitized format on your computer. You then use Helix Producer to select the file and set encoding options. The encoding process creates a new streaming clip, leaving the source file unchanged.
Yes. Helix Producer 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. Helix Producer 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 Helix Producer to create high-quality streaming clips. 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. See also the tips in Helix Producer User's Guide, as well as the audio chapter and video chapter of RealNetworks Production Guide.
In addition to audio and video, Helix Universal Server can stream the following types of clips:
When you create streaming media content, you can provide a RealOne Player download link so that users can get RealOne Player from RealNetworks' Web site and view your content. You can read RealNetworks' trademark policies and get RealOne Player logos at the following address:
http://www.realnetworks.com/company/logos/index.html
Every day, thousands of people visit RealGuide, RealNetworks' online guide for streaming media sites and live events (http://realguide.real.com). If you regularly host streaming media presentations of interest to the public, or if you have a live event you want to advertise, you can submit your listing to RealNetworks. Simply complete the following online form to list your site or live event:
http://realguide.real.com/info/?page=submit
To produce streaming media clips, you need audio and video production tools as well as Helix Producer 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 Helix Producer accepts, however. Some video editing programs save digitized video in a proprietary format that Helix Producer cannot read. However, these programs typically let you export the video to a common format that Helix Producer accepts, such as AVI, QuickTime, or MPEG.
 |
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. |
Helix Producer accepts many common audio and video formats. These may vary by operating system, though. Helix Producer on Macintosh accepts the formats widely used on the Macintosh, such as QuickTime, whereas Helix Producer on Windows or Unix supports the formats widely used on those operating systems. Check the Helix Producer 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 Helix Producer for Windows, Macintosh, and Linux. You can download the free version or purchase Helix Producer Plus at RealNetworks' Web site:
http://www.realnetworks.com/products/producer/index.html
Using RealSlideshow's graphical interface, you can create streaming RealPix presentations from still images. You can even add a soundtrack, or record a narration for each image. You can download RealSlideshow from this Web address:
http://www.realnetworks.com/products/slideshow/index.html
You can also create RealPix presentations by hand with the RealPix markup language, which is described in RealNetworks Production Guide, available at this Web page:
http://service.real.com/help/library/encoders.html
You create animation with Macromedia Flash. You can develop animations with Flash 2, 3, or 4. The Flash chapter in RealNetworks Production Guide provides tips for making Flash animation stream well with Helix Universal Server. 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 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 RealOne Player connection speed.
Using Helix Producer, 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 Helix Producer you use. Helix Producer Basic encodes three speeds per clip, whereas Helix Producer Plus encodes an unlimited number of speeds per clip.
No. A SureStream clip has several streams encoded in a single clip. Unlike Helix Universal Server, a Web server cannot extract a specific stream to send to RealOne Player. If you plan to deliver clips from a Web server, you need to set Helix Producer to use single-rate encoding.
Chapter 6 explains the basics of SMIL. Appendix B explains important concepts and rules to follow when writing 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 RealOne Player the way HTML works for a Web browser.
Not always. When you want to stream just one clip, such as a single video clip, you don't need to use SMIL. You just link your Web page to the clip through a Ram file, as described in Chapter 3.
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.
SMIL is a simple markup language that you can write with a word processor or text editor. Some software tools (RealSlideshow, for example) 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 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.
If you are intrigued by SMIL, download a copy of RealNetworks Production Guide from http://service.real.com/help/library/encoders.html. In that reference manual, you'll find more information about the SMIL features covered in this guide, as well as instructions for performing tasks such as the following:
Helix Universal Server streams the clips created by Helix Producer. You can stream clips yourself with Helix Universal Server, through a service provider that has Helix Universal Server available, or, in some cases, from a Web server.
Not necessarily. To run Helix Universal Server, you need a computer connected to an intranet or one that has a direct presence on the Internet. You cannot run Helix Universal Server if you use an Internet service provider (ISP) to connect to the Internet. If you use an ISP, check whether they have Helix Universal Server and whether they can host your streaming presentations for you.
Helix Universal Server runs on Windows NT/2000/XP and many Unix platforms, including Linux. For a list of available platforms, visit RealNetworks' technical support Web site at http://service.real.com.
Helix Universal Server is available on the RealNetworks Web site at http://www.realnetworks.com/products/media_delivery.html. Helix Universal 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, you cannot use SureStream RealAudio and
RealVideo clips. Additionally, you cannot use the SMIL clipBegin and clipEnd
attributes described in "Using Internal Clip Begin and End Times".
RealNetworks Production Guide has a section on Web server limitations in its presentation delivery
chapter.
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 RealOne Player launches. RealOne Player then
uses the URL in the Ram file to request the presentation. Chapter 3 explains
how to write a Ram file.
Yes. The SMIL file lists the URLs for clips. The Ram file supplies RealOne Player 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 RealOne Player.
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 Universal Server and RealOne Player to stream long clips and compensate for changing network conditions.
When a clip resides on Helix Universal 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 RealOne Player, 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 "Why Does Helix Universal Server Use
RTSP?".
For full information about broadcasting media, see Helix Producer User's Guide and Helix Universal 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 Universal 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 Universal 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 Helix Producer has enough power to encode all the SureStream streams at the same time. Check Helix Producer's manual or online help for system requirements, and perform a trial run before streaming the actual broadcast.
No. You need Helix Universal 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 RealOne Player 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 Helix Producer during the broadcast. You just put the clip on Helix Universal Server and then set up Helix Universal 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 Universal Server administrator that identifies the resource as a broadcast rather than a clip.
That depends entirely on your Helix Universal Server and the network bandwidth it has available. For large broadcasts, you can use a network of Helix Universal Servers to reach thousands of RealOne Players.
Yes. Real Broadcast Network (RBN) offers a wide range of services for hosting broadcasts. Learn more about RBN at:
http://www.realnetworks.com/products/rbn/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. To place a service call with Technical Support, fill out the e-mail form at the following Web page:
http://customerrelations.real.com/scripts/rnforms/contact_tech_servic e.asp
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
|
©2002 RealNetworks, Inc. All rights reserved.
For more information, visit RealNetworks Click here if the Table of Contents frame is not visible at the left side of your screen. |