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Create Streaming Media Just as there is a multitude of file formats that can be streamed, there is a multitude of different tools to use. These pages discuss some of the main tools for creating various types of Realmedia, as well as things to keep in mind during the production process. Creating RealAudio - Using RealProducer and your soundcard Creating RealVideo - Basics of video production; samples of good and bad uses of the technology; Using RealProducer Creating streaming presentations - Using RealSlideshow and RealPresenter Creating advanced multimedia shows - Beyond the simple slide presentation with audio narration, you can use SMIL technology, RealText and RealPix to add pep to your presentations. RealAudio is simple to produce. Anybody with a soundcard and a microphone connected to it can record a voicetrack directly to a RealAudio file with the free RealProducer, which also allows conversion of existing .wav, .mp3 or .au files to RealAudio. Required bandwidth for audio is low, so this works well over modem connections. The RealPlayer is ubiquitous, as part of our Network Services Kit it comes preconfigured as plugin for the major browsers. Recording Voice Tracks (Narrations)You need a microphone plugged into your soundcard's mike input (usually red, or labelled with a mike). Any standard computer mike will work, but you can get much better quality with professional mikes. It is extremely important to shut out as much background noise as possible, e.g. cover your PC with a blanket for the duration of the recording and turn off all fans. Recording Existing SoundtracksMake sure you have copyright clearance for materials that you wish to encode! There are three possible situations:
The conversion/recording steps:1. Just launch RealProducer, start a new session and choose to record from a file. Select the file and specify a location and name for the converted realmedia file. Hit OK. Now select the bandwidth template(s) you wish to use, click Start, and within seconds you are done. 2. You can choose between two methods here: 3. The steps here are the same as those for recording with a microphone. Just make sure to select Line In as your recording source in the soundcard's mixer applet instead of microphone. Then plug a cable with a mini-stereo plug into your soundcard's Line In connector (usually blue, or labelled with an arrow entering two parentheses) and plug the other end into your tape recorder, VCR, amplifier, walkman, or whatever. You cannot directly plug a record player into a soundcard! Any camcorder can be used to create the original footage, but there are many things to keep in mind when videotaping. We recommend an appointment at the ITL to discuss your plans and needs and to get valuable production tips before wasting time and nerves. A videocamera can also be borrowed from the ITL for a few days. RealVideo can then be created with the free RealProducer, either by recording directly from videotape or camcorder (needs Osprey capture card, as in ITL), or by converting a pre-existing digital video file in Quicktime (.mov) or Video for Windows (.avi) format. To get digital video, one needs to first capture the video (i.e. convert it to digital format) via a quality video capture card (as available at the ITL). This latter method is required if you need to edit the clip before the conversion to streaming format. Quality vs. BandwidthThe number one issue in streaming video is the quality tradeoff enforced by bandwidth limitations. The encoder needs to sacrifice part of the image data to transmit video files through a narrow pipe.
Creating Streaming Presentations Slide presentations can be converted to streaming format in avariety of ways:
RealPresenterThis tool allows one-step narration of MS Powerpoint presentations and inclusion of a live video capture of the speaker for higher bandwidth target audiences. The basic version allows publishing presentations on your own PC with the free included RealServer (which gets installed without asking and will start automatically unless you turn it off in Preferences). To actually get the files onto the ACCC RealServer, you need to use FTP and transfer the locally published presentation over to a new directory on the server. The Plus version ($199.95) allows remote publishing to a RealServer, and more importantly it allows creation of guided web-tours -- audio and speaker's video in RealPlayer synchronized with automatically changing pages in the web browser (but then you cannot also have slides, of course). RealPresenter will always create JPEG images of your slides at a fixed size. These are lower quality than PNG images for slides dominated by text, but useful for photos. Creating Advanced Multimedia Shows (SMIL) SMIL = Synchronized Multimedia Integration Language SMIL is a W3C standard similar to HTML. It is a tag-language, one of many in the XML family. Different from HTML, it is case-sensitive, and pretty much everything should be lower case! SMIL FeaturesSMIL is used to integrate different kinds of media into a coherent time-based presentation. All media have to be created separately — SMIL just controls their playback! Its tasks can be split into the following areas:
Creating SMILSMIL is a tag-based language similar to HTML, so you can write it with a plain text editor such as Windows Notepad . Better are HTML tag-editors that allow you to specify your own set of tags, such as Notetab Pro, Macromedia Homesite, or Arachnophilia. Having a set of tags predefined speeds up development of SMIL materials dramatically if you do this often. There are a few visual editors for SMIL, which allow dragging rectangles to specify the layout-regions visually. They also include a timeline tool where you can indicate what stream should play at which time in the overall presentation.
SMIL Syntax
RealPix, RealText, etc.RealNetworks has created some proprietary languages to create streaming image shows (RealPix), streaming text (RealText), and even streaming 3D-text with animation effects (RealText3D). Some simple RealPix effects are created by tools such as RealSlideshow and RealPresenter. To fully learn these languages, it is best to refer to RealNetworks' own documentation. See the SMIL samples page for ideas what to do with these. |