Microsoft Windows XP Professional Resource Kit 2003
ISBN: N/A
EAN: N/A
EAN: N/A
Year: 2005
Pages: 338
Pages: 338
Windows XP Professional offers many possibilities for playing, creating, and distributing digital media content and for using it more effectively.
For more information about configuring audio, video, and digital media devices, and workstation defaults (such as audio playback level), see Optimizing Workstations for Digital Media earlier in this chapter.
Windows XP Professional supports a wide range of playback devices and digital media sources, technologies, and file types. For example, you can play audio from a CD, a MIDI device, or a radio station that is broadcasting over the Web. You can play video or other digital media on DVD, or watch a streaming broadcast over the Web by using Windows Media Player.
For more information about specifying preferred devices for playing audio and video, see Configuring Sounds and Video earlier in this chapter.
You can play audio CDs on a CD drive or a DVD drive, but a standard CD drive cannot read DVD discs. When you insert an audio CD into a CD drive, Windows XP Professional starts Windows Media Player.
For more information about using Windows Media Player and playing audio CDs, see Windows Media Player for Windows XP earlier in this chapter, or see Windows Media Player Help.
To provide the best possible performance from CD drives, Windows XP Professional includes the 32-bit CD File System (CDFS), which quickly and efficiently reads files on CD. Windows XP Professional supports the UDF file system on DVD. It also reads and writes FAT32 files on DVD, but the UDF file system is more widely used. For more information about file systems on DVD, see DVD Formats and Devices earlier in this chapter.
When you are playing audio CDs in Microsoft Windows XP, it is important to be aware of the two options for CD playback digital and analog. With digital playback enabled, the CD drive transmits audio data digitally over the bus and requires a compatible drive. Analog playback uses a cable connected between the CD drive and a sound card in the computer. Digital playback often provides better sound quality than analog, but it results in additional performance overhead.
For more information about configuring analog or digital audio CD playback, see Configuring Sounds and Video earlier in this chapter.
Musical Instrument Digital Interface (MIDI) is a serial interface standard that allows for the interconnection of music synthesizers, musical instruments, and computers. Windows XP Professional follows the General MIDI Specification to determine which instruments and sounds to use. This specification is an industry standard that defines a common orchestra, or set of instruments that musicians and developers can use and expect consistent results.
Musicians use MIDI as a music development tool. Virtually all sophisticated electronic music equipment supports MIDI, and MIDI offers a convenient way to precisely control the sounds produced by the equipment. You can also use MIDI for listening to music files created using the MIDI standard. You can download standard MIDI files from the Web and play them using Windows Media Player.
Unlike CDs and digital audio files, MIDI files do not capture and store actual sounds. Instead, a MIDI file is a list of events that describe the specific steps that a sound card or other playback device must take to generate certain sounds. Events are described in terms of the value, volume, and duration of a note, the instrument used to play the note, and so on. This allows MIDI files to be much smaller than digital audio files. You can also edit the events, edit and rearrange the music, and compose interactively.
When you play a MIDI file, there are three different locations that create and produce the sound in different ways. When you select your preferred MIDI music playback device, you are also selecting the location of the sound production. Following is a short description of each option.
MIDI devices supported by Windows XP Professional include those discussed in the following sections.
Microsoft GS Wavetable SW Synth, a MIDI software synthesizer, is provided as a feature of Windows XP Professional but can be replaced by a third-party software synthesizer. The software synthesizer displays in the list of MIDI music playback devices as SW Synth or Software Synth. The software synthesizer reproduces instrument sounds by using your computer s memory, instead of the sound card s synthesizer. MIDI software synthesis might produce a higher quality sound with a wider range of instruments than a sound card can process. It also provides a larger variety of sets of sounds, such as downloadable sounds. The MIDI data is converted to audio, which is played on speakers or headphones plugged into the sound card. Because your computer s memory is doing all of the processing and sending music, rather than MIDI instructions, to the sound card, your computer s performance might be slower than when you are using a MIDI device.
If you select the computer s sound card as your default MIDI playback device, the sound card s hardware synthesizer creates and plays the music. The device listing is usually FM Synth, FM Synthesizer, or Wave Table Synth. The quality of the audio depends on the quality of the sound card and the library of sounds provided with it. The sound quality might not be as good as with a software synthesizer, but the computer s performance is not significantly impacted by using the hardware synthesizer because the sound card is recreating the instrument sounds. The music is then played on speakers or headphones plugged into the sound card.
If you want to play a MIDI file on an external MIDI device such as a keyboard, you must select the correct external device from the list of MIDI music playback devices. The device listing is either MPU-401, External MIDI, or MIDI OUT, which are types of MIDI ports on the computer to which the external MIDI device is attached. The MIDI data is sent to the external device, which processes it and plays the audio through speakers or headphones connected to that device. For more information about configuring a MIDI playback device, see Configuring Sounds and Video earlier in this chapter.
For more information about MIDI devices and the MIDI standard, see the MIDI Manufacturers Association link on the Web Resources page at http://www.microsoft.com/windows/reskits/webresources
For more information about playing digital media files using Windows Media Player, see Windows Media Player Help, or see the Windows Media Technologies link on the Web Resources page at http://www.microsoft.com/windows/reskits/webresources
You can use a wide range of input devices, such as digital video cameras, for creating audio, video, and digital media, and you can design content for a wide range of output formats (CD, DVD, and Web).
Different authoring and editing tools make it much easier to design and create digital media content. Some of the options for common authoring and editing tasks are discussed in the following sections.
By using Windows Sound Recorder in Windows XP Professional, you can record audio from a variety of input devices, and then save audio files in a variety of different formats. To use Sound Recorder you must have an audio input device, such as a microphone or a CD-ROM player, attached to the computer.
Once you have recorded an audio file, in Sound Recorder on the Effects menu you can add effects (such as echo), increase or decrease the speed and volume, and insert or mix other audio files. You can save audio files in standard CD quality, radio quality, or telephone quality formats. You can also choose a custom format to maximize file compression and use a specific audio format that uses available audio codecs to change the sound quality. For more information about using Sound Recorder to record, mix, and edit audio, see Windows Sound Recorder Help.
To select an audio format
On the Accessories menu, point to Entertainment, and then click Sound Recorder.
On the File menu, click Properties.
In the Choose from box, click Recording formats, and then click the Convert Now button.
In the Format box, select a format, and then in the Attributes box, select an attribute (such as the sampling frequency or number of channels) that is available for the selected format.
If you have a CD recording drive installed in your computer, you can record, or write, to a CD by using Windows Explorer in Windows XP Professional. You can write both data and audio files to a CD-R or CD-RW disc.
To create a data CD, use Windows Explorer to copy files and folders to the CD recording drive. Windows XP Professional writes the files to a temporary staging area, where they are held before they are copied to the CD. After you have copied all the files you want to put on the CD, you can record the files to the CD. In Windows Explorer, highlight the CD recording drive. On the File menu, click Write these files to CD. The CD Writing Wizard appears, and takes you through the steps to finalize writing your files to the CD.
| Note | When you write to a CD, you need 1.3 gigabytes (GB) of disk space for writing a full 650 MB of data, less if you are not recording a full CD. This amount of space is necessary for the temporary staging area. |
You can also write to an audio CD by using Windows Media Player. When you use Windows Media Player to write an audio CD, the file type is changed to .cda, and the audio CD can be played in any CD player. For more information about creating your own CDs in Windows Media Player, see Windows Media Player Help.
If you are using a CD-RW disc, you can delete files on the disc and append new files to a disc that already contains files.
You cannot duplicate a CD in Windows XP Professional without additional software.
| Note | Windows XP 64-Bit Edition does not support writing to CDs. |
For more information about writing to CDs, see Windows XP Professional Help and Support Center.
Windows Media Technologies in Windows XP Professional provides a straightforward way to combine audio, video, graphics, animation, and other elements into multimedia presentations that you can broadcast live or on demand over a network.
Using Windows Media Technologies you can create, deliver, and play streaming media files in the advanced streaming format, which includes files with .asf, .wma, and .wmv file extensions. This format solves the problem of long download times by starting playback while the data is still being sent. Windows Media files send the first part of the audio or video data first and collect it in a buffer. While that data is being played, the rest of the data continues to flow in time to be played. This ensures that playback is not interrupted by network congestion. The buffer can be manually increased for best performance by clicking the Tools menu in Windows Media Player, clicking Options, selecting the Performance tab, and changing the buffer size under Network buffering.
You can stream both live and on-demand (stored) content. You can stream on-demand content from a Windows 2000-based server with Windows Media Services installed, which provides both standard unicast streaming (delivering individual streams of live or on-demand content to multiple clients) and bandwidth-conserving multicast streaming (sending a single stream of real-time content to an unlimited number of users).
Intelligent Streaming is a set of features in Windows Media Technologies. It automatically detects network conditions and adjusts the properties of a video stream to maximize quality. This is important for low-bandwidth modem connections where the connection speed can vary widely depending on network congestion. Intelligent Streaming allows users to receive digital media content tailored to their connection speed to maintain a continuous presentation. To accomplish this, the Windows Media stream is encoded at multiple bit rates. In other words, up to 10 discrete video streams are encoded, from the same content, into a single Windows Media stream, each at a different transmission bit rate. The server and the client then automatically determine the current available bandwidth, and the server selects and serves the video stream at the appropriate bit rate.
Windows Media Encoder can encode stored content for on-demand playback. In addition, it lets you encode live audio and video feeds and then add them to dynamic mixtures of other media. Media Encoder synchronizes and compresses these media components into a single file, augments the file with error-correction information, and delivers it to the server running Windows Media Services, which then transmits it over the network.
Windows Media Technologies codecs play an important role in transferring data over limited-bandwidth connections. Because codecs compress large volumes of raw data, data is transmitted using less bandwidth and is then decompressed when it reaches its destination.
Content providers who want to send audio or video face a problem with file size. Uncompressed broadcast-quality video requires 160 Mbps of network bandwidth. Uncompressed CD-quality audio requires approximately 2.8 Mbps. Many Internet users connect at speeds of only 28.8 kilobits per second (Kbps), a speed that is at least 1,000 times slower than audio and video require.
A codec (compressor/decompressor) is a software module that compresses and decompresses audio and video files so that smaller files can be transmitted. Codecs are typically optimized for compressing either audio or video, and there are many different compression algorithms available for each type of media. When an audio or video file is compressed, it loses some of the original data that is not apparent to the viewer or listener, and the smaller file can be transmitted more quickly. Content providers struggle to balance the trade-off between delivering high-quality content without data compression, which results in slower data transmission; and achieving high data-compression rates, which lowers the content quality.
Unlike many other codecs, Windows Media Technologies codecs are optimized to deliver both high-quality content and high data-compression rates. This means that the user hears crisp, CD-quality sound and sees clear, smooth video even over slow Internet connections.
Content developers use codecs to compress or encode audio and video for real-time or local playback over the Internet and corporate intranets. Users do not need to know anything about codecs to play digital media content using Windows Media Player; they just click a link to the content, and it plays. Windows Media Player has an Automatic Updates feature that checks for updates to licensed codecs on a schedule determined by the user. The Automatic Updates feature can be customized in Windows Media Player on the Tools menu, clicking Options, selecting the Player tab, and changing the options under Automatic Updates.
You do not need special digital-media authoring software to create digital media presentations for broadcast over a network. You can use Dynamic HTML (DHTML) and HTML+TIME to add interactive digital media to your Web pages. For example, you can create slide-show-style or digital media presentations with synchronized text, images, audio, video, and streaming media. These presentations can be timed, interactive, or a both. HTML+TIME version 2.0 provides features such as animation and enhanced timing and synchronization functionality over the previous versions, and is available with Microsoft Internet Explorer version 5.5 and later.
You can incrementally enhance your Web pages by adding HTML+TIME elements or by adding HTML+TIME attributes to existing HTML elements. Using HTML+TIME elements, you can add media playback, animation, visual transitions and effects, and conditional rendering of content based on characteristics such as language, captioning, and connection speed to your Web page. Among other things, HTML+TIME attributes let you specify when an element appears on a page, how long it remains displayed, how many times it repeats, whether or not it is synchronized with other media or HTML elements on the page, and how the surrounding elements are affected.
The implementation of HTML+TIME builds on DirectX and Windows Media Technologies features. HTML+TIME changes properties of HTML elements or media over time. For every HTML element associated with a timeline, HTML+TIME provides scriptable properties and Document Object Model (DOM) methods.
For more information about using HTML+TIME to create dynamic Web pages that incorporate digital media, see the HTML+TIME link on the Web Resources page at http://www.microsoft.com/windows/reskits/webresources
| Note | Although some HTML+TIME features are available with Microsoft Internet Explorer version 5.0, due to the new and significantly enhanced features in HTML+TIME 2.0, use of Internet Explorer 5.5 or later is strongly encouraged. |
With Windows Media Tools, you can create digital media presentations and place them on your server running Windows Media Services for broadcast over a network. You can also broadcast live events or digital media in the same way. Windows Media Tools also allow you to configure and allocate resources on your server to optimize the use of bandwidth.
You can use Windows Media Encoder to encode digitized audio and video data in Windows Media Format. After the encoded data is created, you can either save it as a file or stream it. The Windows Media file is then either hosted on a server running Windows Media Services (for streaming over your network), or hosted on a Web server (for downloading). In either case, the user plays the broadcast on a computer running Windows Media Player.
To host a Windows Media stream file for streamed delivery, place the file on a server running Windows Media Services and create a link to the file.
Intelligent Streaming detects available bandwidth and makes full use of it to optimize multimedia playback, ensuring that users will receive the highest quality multimedia possible by adjusting for connection speed or network problems. Windows Media Services, running on the server, and Windows Media Player, running on the client, communicate with each other before and during file transmission to establish the optimum network throughput and automatically adjust the stream to changes in bandwidth while maximizing quality.
For more information about Intelligent Streaming, see Creating Streaming Content for the Internet earlier in this chapter.
Windows Media Player and Windows Media Services work together to maintain the quality of data transmissions through multi-datarate encoding, intelligent transmission processing, and a video playback enhancement filter.
Multi-datarate encoding ensures that, when a user clicks a link, Windows Media Player and Windows Media Services automatically determine the optimum data rate and quality based on the speed of the connection.
Windows Media Player and Windows Media Services respond to network congestion by intelligently degrading quality to preserve continuous playback. First, the server decreases the video frame rate to maintain audio quality and keep buffering to a minimum. If conditions worsen, the server stops sending video frames completely, but maintains audio quality.
Windows Media Player improves overall video quality, especially at low bandwidths, by using intelligent filtering to smooth pixelation and remove ghosting, the dim secondary images that appear due to signal problems in transmission.
Windows Media Services provides a set of services that work together to optimize digital media data transmission from the server to the client computer. The server is configured using Windows Media Administrator and network bandwidth can be controlled using Internet Information Services (IIS).
Windows Media Services components, which run on Windows 2000 based servers, are a set of services that can unicast and multicast audio, video, and other media to client computers. Windows Media Encoder compresses the audio and video feed in real time and passes it to the server running Windows Media Services for delivery to client computers, where it is played as live content. On-demand digital media files must be stored on a server and passed to the network by the server running Windows Media Services.
Server-side software includes the Windows Media Administrator, which is a set of administrative tools for managing, configuring, and monitoring Windows Media Services, and Windows Media Rights Manager, an optional component that is a digital-rights tool for reducing content piracy.
Windows Media Services can deliver live broadcasts or streaming stored multimedia content at rates as low as 3 Kbps (audio only) or as high as 6 Mbps (audio and video) and can scale to meet the heaviest demands. A single server can scale to support thousands of simultaneous user connections, letting you host large Internet broadcasts.
Windows Media Services, provides high bandwidth availability, which allows delivery of full-motion, full-screen MPEG video with guaranteed performance across high-bandwidth networks.
You can control the network bandwidth used by Internet Information Services (IIS) on a particular server either at the computer level or at the Web site level. With IIS, you can enable process throttling, which is a method for limiting the processing time used by out-of-process applications so that no one application can dominate processing time on a server. Process throttling is useful if you host multiple sites on one server and you are concerned that out-of-process applications on one site will use all of the CPU capacity, thereby preventing other sites from using the CPU. To enable process throttling, use IIS to set the percentage of CPU time that a site or application is limited to, and to enforce the action that is taken when a limit is exceeded. Actions include logging the error, idling the application, or halting the application. For more information about using IIS, see the Microsoft Internet Information Services 5.0 Resource Guide of the Microsoft Windows 2000 Server Resource Kit.
| Note | Before you decide to use process throttling, use System Monitor to examine the %-Processor Time counter in the Processor object and the specific instance counters for Maximum CGI Requests and Total CGI Requests in the Web Service object. It is also recommended that you enable process accounting and examine the DLLHOST object counters to determine the number of out-of-process Web Application Manager (WAM) and Internet Server Application Programming Interface (ISAPI) requests. |