Buying a Multimedia Computer

Make sure to select a balanced computer, in which all components work together to meet the demands of supporting multimedia applications. In multimedia systems, balance is more important than speed, because multimedia playback places heavy demands on the CD-ROM (for reading data), on the hard disk (for writing data), on the CPU (for decompressing data), and on the video and audio subsystems (for playback). A fast CPU alone does not guarantee a great playback system.

The PC 97 Hardware Design Guide introduced the Entertainment PC as a distinct category of Windows-based computer, differentiated from the Basic PC by its ease of use and the breadth and quality of its multimedia capabilities. For example, the graphics, video, and audio subsystems for Entertainment PCs are designed to optimize the capabilities of software that uses Microsoft DirectX interfaces.

An Entertainment PC 98 system is optimized for the following uses:

• Games, including the best titles, with the most complex, realistic graphics and audio.
• Education, using the most engaging titles, with full-screen video, interactive animation, and so on.
• Active Internet, providing enhanced Web communications capabilities, with personalized and animated Web sites, chat rooms, and so on.
• Personal communications through multimedia e-mail, Internet audio phone, video phone, and so on.
• Interactive, high-resolution television and movie viewing through higher video quality, real-time links to content producers, and so on.
• Connection with traditional consumer-electronics devices, providing home theater surround audio such as Dolby Digital (AC-3) for games and DVD movies, and fast and easy capture, editing, and playback of personal video.

The following sections provide guidelines for what to look for in a multimedia system, along with specifics for audio components, MIDI components, and video components.

What to Look for in Basic Computing Power

This section presents a summary of general system recommendations for a multimedia computer, including system board, memory, and BIOS. The minimum PC 98 performance recommendations consist of the following:

• 200-MHz Pentium processor with Intel MMX technology, or equivalent. The minimum microprocessor capability is specified to support the demands of rich media, Internet access, and conferencing.
• Minimum 256-KB Level 2 (L2) cache or equivalent.
• 32-MB minimum system memory. Recommended: 64 MB. Memory should be 66-MHz Dynamic Random Access Memory (DRAM) or better.
• Graphics adapter using PCI, AGP, or other high-speed bus.
• Adapter support for screen resolutions as defined by VESA up to the PC 98 required maximum, including 640 x 480 x [8, 15, 16, 24] bpp, 800 x 600 x [8, 15, 16, 24] bpp, and 1024 x 768 x [8, 15, 16] bpp.
• Two USB ports to support connection of auxiliary input devices, such as game pads, joysticks, and track balls.
• Two IEEE 1394 ports to support camcorders and other digital consumer electronics devices.
• Keyboards, pointing devices, and game pads and their connections compliant with the USB Device Class Definition for Human Interface Devices, Version 1.0 or higher, and with the USB HID Usages Table, whether implemented as wired or wireless devices.
• Data/fax/voice modem that supports V.pcm.

What to Look for in Audio Hardware

Audio for a multimedia computer should meet PC 98 audio requirements, which include requirements for audio hardware capabilities, performance metrics, and external connections. The following are some key features to look for when you want to purchase a multimedia computer with high-quality audio :

• A sound card with a 16-bit digital-to-analog converter (DAC) for playback and a 16-bit analog-to-digital converter (ADC) for recording (necessary for applications developers).
• Full-duplex support to record and play sounds at the same time. The device should be capable of capturing audio at one sample rate while playing audio at another sample rate.
• Full-duplex audio capability for audio hardware supporting H.323/H.324 video and audio conferencing.
• Audio hardware supporting CD-ROM and DVD media playback, made possible by built-in or external audio codec support for playback of 16-bit stereo PCM data at both a 44.1-kHz and 48-kHz sample rate.
• Audio hardware featuring the acceleration supporting 3-D games, made possible by built-in or external audio codec support for playback of 16-bit stereo PCM data at a 44.1-kHz sample rate.
• CD-ROM drive providing 12x or higher performance. The CD-ROM drive must support 1200 KB per second average throughput or higher performance when running in the fully on power state.
• Audio system providing support for basic data formats. The audio system must provide full-duplex support of the following audio formats:
  • Mono/stereo
  • 8-bit unsigned
  • 16-bit signed
• Audio system support for both recording and playing back of sample rates that include 8, 11.025, 16, 22.05, 44.1, and 48 kHz waveforms. Compact disc–quality sound uses 44 kHz. The 11 kHz and 22 kHz waveforms are fractions of 44 and are often used for compressed waveforms that are meant to save CPU processing. The 8 kHz waveform is used for compatibility with telephone audio, and 16 kHz waveform is used for speech recognition.
• Audio system with sufficient externally accessible inputs and outputs. At a minimum, the audio system must have the following features:
  • A monaural microphone, stereo line input, or both
  • Stereo line-level output
• Audio system support of full-duplex operation at independent sampling rates. Voice recognition and audio/video conferencing require the audio system to play back and record simultaneously. Incoming and outgoing audio should be capable of operating at independent sampling rates. This recommendation considers the entire system, including the possibility of USB speakers or microphones.
• Audio system providing hardware or software support for the Downloadable Samples (DLS) specification. Support for DLS as defined by the MIDI Manufacturers Association is recommended. For more information, see DLS Specification, version 1.0 or higher, at http://www.midi.org/.

For computers that support software or hardware decoding and playback of DVD-Video or MPEG-2 video, the audio decoder must be capable of supporting the following formats:

• One or both of the following formats, depending upon the local requirements for DVD audio:
  • AC-3 (Dolby Digital) less than or equal to 5.1 channels, at 48 kHz less than or equal to 384 Kbps.
  • MPEG-2 multichannel less than or equal to 5.1 channels, at 48 kHz less than or equal to 912 Kbps.
• MPEG-1 Layer 2 stereo, at 44.1 and 48 kHz less than or equal to 384 Kbps.
• Linear PCM (LPCM) less than or equal to 8 channels, 16-bit, 20-bit, and 24-bit at 48 or 96 kHz less than or equal to 6.144 Mb/s.

Note

Conversion to 48-kHz 16-bit stereo is acceptable when the content exceeds the available resolution, sampling rates, or number of output channels.

What to Look for in MIDI Support

Microsoft recommends that sound cards for both consumer and developer systems include the following:

• General MIDI support. General MIDI refers to a system of assigning numbers to each kind of instrument, so that, for example, instrument 12 on one computer is the same as instrument 12 on all others.
• Support for polyphony, the ability to play multiple sounds at the same time. Systems should include at least 32-voice polyphony. Support for more concurrent sounds means a fuller sounding playback.
• Wave table sound rather than FM synthesis.
• Standard MIDI port. This is normally implemented as an MPU-401 port. If you play a MIDI stream to the MPU-401 port, you will not hear anything unless you have a MIDI playback device attached to the port. You can use this port to plug in MIDI devices such as piano-style keyboards; it also supports joysticks.

  Note

  An external MIDI port is needed only if you have external MIDI equipment to connect to the computer.

• System audio hardware acceleration features, such as Downloadable Samples (DLS) wave-table MIDI synthesis and multistream Head Related Transfer Function (HRTF) 3-D.
• Hardware for higher quality or concurrency DLS wave-table MIDI synthesis, with associated mixing and SRC support. A wave table card should send the audio to the same speakers as their wave output.

What to Look for in Video and Broadcast Support

Video and broadcast television are becoming integral elements of computer usage, especially for an Entertainment PC. For Entertainment PC 98, important design issues include the following:

• Increased quality of video capture and playback. This includes increased image resolution and increased frame rates.
• Low-latency video delivery, displaying video from both internal and external video devices.
• Implementation of a graphics adapter video port for use by one or more video sources.

The Entertainment PC 98 hardware recommendations for video capture, television output, and DVD playback support include the following:

• DVD-Video support with MPEG-2 hardware.
• WDM support implemented for all video input and capture capabilities.
• Support for National Television System Committee (NTSC), Phase Alternation by Line (PAL), or both types of television output, except for systems bundled with a large-screen super VGA (SVGA) monitor.
• Super VGA resolution. At a minimum, the consumer system should have a Super VGA display, which provides at least 800 x 600-pixel resolution with approximately 64,000 colors (16 bpp) for users working with complicated graphics.
• Hardware-assisted DirectDraw acceleration, Direct3D acceleration, and video playback.