2.5 MULTIMEDIA

 

2.5  MULTIMEDIA

Interest in multimedia is currently rather pervasive—entertainment and educational groups are exploring new applications, and the computers, telecommunications, and home electronics industries are actively developing underlying technology.

1. Introduction

When we just had text on screen, the basic user interface was a DOS prompt or maybe a simple list of choices. Now that we have graphics and text at the same time, we can have a much more intuitive mouse-driven graphics based user interface with pull down menus, as in the Macintosh, Microsoft Windows and Presentation Manager. When we can add photograph-quality images, animation, good-quality sound, and interactivity, then we ought to be able to make computers much more powerful and much easier to use.

That's the concept behind multimedia, the newest buzzword. Multimedia, which typically refers to a syntheses of graphics, animation, optical storage, image processing, and sound, is not a single technology, product, or market. Instead, it is a collection of technologies that proponents believe will one day be joined together.

Today, the various technologies referred to as multimedia define a number of individual niches. One of the most important of these is animation, the capability to have moving images on your screen.

Animation is tightly tied in with another concept called desktop video—actually creating and manipulating video images, to produce in-house presentations, rough drafts of commercial videos, or training products.

Sound will also play a key role in multimedia presentations.

Video images also take up a lot of disk space. To handle this, some groups are loading at optical disc for storage, particularly as erasable optical media become more mainstream.

Desktop video and animation are all well and good, but what many proponents see is a way of combining all these elements into an interactive system—interactive multimedia or hypermedia.

The concept is to let a user select the direction of a multimedia presentation, easily moving from one element to another. Imagine a movie in which you can control what happens next.

Traditional computer languages are far too difficult for this task: perhaps an object-oriented programming system that includes a hypertext system would work. Apple, of course, sees HyperCard as the core element in such a system. This makes a certain amount of sense. HyperCard fits many of the basic criteria: It was designed to be customizable, capable of linking information and incorporating all kinds of information, including text, graphics, and animation.

That is not to say there aren't already markets for this technology. Multimedia applications have specific uses all over the spectrum, from professional-quality video production to corporate presentations to engineering visualization to better and easier training and computer-aided instruction products. But you can expect these markets to be more targeted (Vertical) than mass marketed, somewhere between CAD and desktop publishing.

Let us look at it this way: using a computer is still more difficult than driving a car or reading a newspaper. In some ideal future, it should be still more powerful, but with multimedia techniques, much easier to use.

What is MPC? MPC stands for “multimedia personal computer”. What it means is that your computing universe has just changed, forever and for the better. You know you have good reason to own a business-strength PC at home. It helps you complete the work chores that otherwise would deep you burning the midnight oil back at the office.

But what call yon do with your home PC powerhouse when you're not working? That's where multimedia comes in. It is relatively cheap and easy to add stereo sound, a CD-ROM drive, and Windows to today's work-at-home PC. What you end up with, though, is something far more revolutionary than just a computer that talks, plays compact discs, and displays pretty pictures. Your multimedia PC—MPC, for short —is the key to discovering books and encyclopedias that bring ideas to life through images and speech, games that match the quality and fun of the best arcade entertainment, and software that unleashes you personal creativity in music, animation, and video.

The requirements for an MPC are described in detail in Microsoft's Multimedia PC Specification Version 1.0. Here are the key elements of the specification.

·    BASE SYSTEM:A Windows-capable system with a 10MHz 286 or faster CPU; at least 2MB of RAM, a 30MB or larger hard disk, a 3.5 inch 1.44MB floppy drive; a 101-key keyboard; a two-button mouse; and parallel, serial, and joystick ports.

·    VIDEO:Standard VGA is all that's required. VGA+(8bit color at standard VGA resolution) is strongly recommended.

·    CD-ROM:A CD-ROM drive that transfers at least 150KB of data per second without taking up more than 40 percent of the CPU's attention, plays CD audio, and has average access time of 1second or less.

·    AUDIO:A sound board with 8-bit, 11.025kHz sampling and 22.05kHz playback; a synthesizer capable of playing eight notes simultaneously using five different sounds; a mixer to combine CD audio, sampling, and synch; a microphone input; and MIDI in, out, and thru ports.

Every new technology has its own buzzwords, and sorting them out can be real detective work. The following is two jargons of MPC.

·   FULL-MOTION VIDEO:Full-motion video is digitally recorded video played back at the broadcast of 30 frames per second, or close enough to that speed so the video appears smooth rather than jerky.

·    MIDI:MIDI is shod for Musical Instrument Digital Interface; a standard specification developed from one keyboard has grown into a method for putting musical instruments, tape recorders, VCRs, mixers, and even stage-lidlting under the control of a single computer.

2. Audio

An audio (sound) wave is a one-dimensional acoustic (pressure) wave. When an acoustic wave enters the ear, the eardrum vibrates, causing the tiny bones of the inner ear to vibrate along with it, sending nerve pulses to the brain. The listener perceives these pulses as sound. In a similar way, when an acoustic wave strikes a microphone, the microphone generates an electrical signal, representing the sound amplitude as a function of time. The representation, processing, storage, and transmission of such audio signals are a major part of the study of multimedia systems.

The frequency range of the human ear runs from 20Hz to 20,000Hz, although some animals, notably dogs, can hear higher frequencies. The ear hears logarithmically, so the ratio of two sounds with amplitudes A and B is conventionally expressed in dB (decibels) according to the formula.

The ear is surprisingly sensitive to sound variations lasting only a few milliseconds. The eye, in contrast, does not notice changes in light level that last only a few milliseconds. The result of this observation is that jitter of only a few milliseconds during a multimedia transmission affects the perceived sound quality more than it affects the perceived image quality.

Audio waves can be converted to digital form by an ADC (Analog Digital Converter). An ADC takes an electrical voltage as input and generates a binary number as output.

Digitized audio can be easily processed by software in-Computers Dozens of programs exist for personal computers to allow users to record, display, edit, mix, and store sound waves from multiple sources. Virtually all professional sound recording and editing are digital nowadays.

3. Video

The human eye has the property that when an image is flashed on the retina, it is retained for some number of milliseconds before decaying. If a sequence of images is flashed at 50 or more images/sec, the eye does not notice that it is looking at discrete images. All video (i.e., television) systems exploit this principle to produce moving pictures.

There are two video systems, analog system and digital system. They must display at least 25 frames/sec, but at that frame rate many people, especially older ones, will perceive the image to flicker (because the old image has faded off the retina before the new one appears). To solve this problem it is adopted to use interlacing technique in analog system.

However, in digital video system, since good quality computer monitors often rescan the screen from images stored in memory at 75 times per second or more, interlacing is not needed and consequently is not normally used—Just repainting the same frame three times in a row is enough to eliminate flicker.

4. Data Compression

It should be obvious by now that transmitting multimedia material in uncompressed from is completely out of the question. The only hope is that massive compression is possible. For- tunately, a large body of research over the past few decades has led to many compression techniques and algorithms that make multimedia transmission feasible.

All compression systems require two algorithms: one for compressing the data at the source, and the other for decompressing it at the destination. In the literature, these algorithms are referred to as the encoding and decoding algorithms, respectively. These algorithms have certain asymmetries that are important to understand. When the decoded output is not exactly equal to the original input, the system is said to be lossy. If the input and output are identical, the system is lossless. Lossy systems are important because accepting a small amount of infomation loss can give a huge payoff in terms of the compression ratio possible.

①The JPEG Standard.

The JPEG (Joint Photographic Experts Group) standard for compressing continuous-tone still pictures (e.g., photographs) was developed by photographic experts working under the joint auspices of ITU, ISO and IEC, another standards body. It is important for multimedia because, to a first approximation, the multimedia standard for moving pictures, MPEG, is just the JPEG encoding of each frame separately, plus some extra features for inter-frame compression and motion detection. JPEG is denned in International Standard 10918.

②The MPEG Standard.

The MPEG (Motion Picture Experts Group) standards are the main algorithms used to compress videos and have been inten ational standards since 1993. Because movies contain both images and sound, MPEG can compress both audio and video, but since video takes up more bandwidth and also contains more redundancy than audio, we will primarily focus on MPEG video compression below.

The first standard to be finalized was MPEG-1 (International Standard 11172). Its goal was to produce video recorder-quality output (352×240 for NTSC—National Television Standards Committee) using a bit rate of 1.2Mbps. Since uncompressed video alone can run to 472 Mbps, getting it down to 1.2 Mbps is not entirely trivial, even at this lower resolution. MPEG-1 can be transmitted over twisted pair transmission lines for modest distances. MPEG-1 is also used for storing movies on CD-ROM in CD-I and CD-Video format.

The next standard in the MPEG family was MPEG-2 (International Standard 13818), which was originally designed for compressing broadcast quality video into 4 to 6 Mbps, so it could fit in a NTSC or PAL (Phase Alternating Line) broadcast channel. Later, MPEG-2 was expanded to support higher resolutions, including HDTV (High Definition Television).

MPEG-4 is for medium-resolution video-conferencing with low frame rates (10 frames/sec) and at low bandwidths (64Kbps). This will permit videoconferences to be held over a single N-ISDN B channel. Given this numbering, one might think that the next standard will be MPEG-8. Actually. ISO is numbering them linearly, not exponentially. Originally MPEG-3 existed. It was intended for HDTV, but that project was later canceled, and HDTV was added to MPEG-2.

The basic principles of MPEG-1 and MPEG-2 are similar, but the details are different. To a first approximation, MPEG-2 is a superset of MPEG-1 with additional features, frame formats and encoding options. It is likely that in the long run MPEG-1 will dominate for CD-ROM movies and MPEG-2 will dominate for long-haul video transmission.

5. Multimedia Application

Faster computers and the rapid proliferation of multimedia programs will probably forever change the way people get information. The computer's ability to instantly retrieve a tiny piece of information from the midst of a huge mass of data has always been one of its most important uses. Since video and audio clips can be stored alongside text on a single CD-ROM disc, a whole new way of exploring a subject is possible. By using hyperlinks, a programming method by which related terms, articles, pictures, and sounds are internally hooked all together, material can be presented to people so that they can peruse it in a typically human manner, by association. Interactive games using moving footage, educational programs, and even motion pictures make multimedia one of the computer worlds most exciting and creative field.

Electronic games —By far the most widely used form of interactive multimedia are the electronic games from Sega, Nintendo, and other manufacturers. Each game is a highly interactive multimedia application that presents layered 2D animation with synchronizes sound effects and music. The hardware found in game playing systems is becoming more powerful and models often contain CD drives (for storage), video decompression hardware (for video playback), and 3D graphics hardware.

Interactive video applications—A video holds about 50,000 video frames, which is 30 minutes of video at normal play back speed. By attaching a videodisk player to a computer, multimedia software can randomly access specific frames and play selected sequences at various speeds. Computer controllable videodisk players have been available since the mid-1970s and applications built around these devices are among the earliest examples of interactive multimedia applications.

Hypermedia browsers—Hypermedia is a way of organizing multimedia information by linking media elements. The elements being linked are called nodes and the entire assemblage is a hypermedia web. Links represent semantic relationships—when a link exists between two nodes they should be related in some fashion. For instance, a digital image can be linked to a textual description of the image that is in turn linked to related audio or video material. A hypermedia browser lets users view nodes and traverse links from one node to another.

Multimedia presentation systems—A multimedia presentation system is an “engine” that displays, synchronizes, provides interaction with, and generally manipulates multimedia material. This is a nebulous category that overlaps with previous categories, in particular hypermedia browsers and electronic games. Examples include “presentation software”, used to compile and display electronic “slides”, and browsers for multimedia documents (for example, a multimedia encyclopedia browser).

Desktop conferencing systems—A desktop computer equipped with microphone speakers, and a video camera, and placed on a multimedia network, can establish audio and video connection between other, similarly equipped machines. This is the basis of desktop conferencing, when the computer plays the role of a multimedia communication device. A “conference” may be a short two-party conversation or a lengthy meeting between several participants, some of whom come and go as the conference proceeds. Adding multi-user tools, such as group editors increase the power of desktop conferencing. These tools allow conference participants to share documents and other forms of data. Participants can simultaneously edit the shared objects and view each other's changes.

Multimedia authoring systems—Preparation of multimedia material, in particular when used for presentations, training, or entertainment, is called authoring. An authoring system is a collection of software tools that help in the many steps of multimedia production. These steps include media capture, media conversion, media editing, media composition, adding interactivity, and media mastering.

Multimedia services—Finally, many multimedia application fit under the broad heading of “multimedia services”. Examples include interactive shopping, banking, educational and medical services where multimedia is used to enrich the interface, and VOD (Video On Demand), where users play back remotely stored digital video in their homes.

KEYWORDS

NOTES

（1）multimedia（多媒体）。就是利用计算机技术将正文、声音、图形、动画和图像等多媒体综合一体化，使之建立起逻辑连接，并能对它们进行采集、压缩编码、编辑、加工处理、存储和展示。

（2）MPC（Multimedia Personal Computer，多媒体个人计算机）。即具有多媒体功能的个人计算机。

（3）JPEG（Joint Photographic Experts Group，联合图像专家组）。EEG是用于处理静态图像的压缩标准，大致可以达到20:1的压缩率，而图像不会出现可见的失真。

（4）MPEG（Motion Picture Experts Group，运动图像专家组）。MPEG是用于动态图像的压缩标准。在图像质量基本不变的情况下，MPEG可把图像压缩50倍。

（5）NTSC（National Television Standards Committee，全国电视标准委员会）。它是1953年制定的一种兼容的彩色电视制式。

（6）PAL（Phase Alternating Line，相位交互制式）。它是德国于1962年制定的一种兼容的彩色电视制式。

（7）HDTV（高清晰度电视）。它是High Definition Television的缩写。它提供1200线的分辨率，16:9的长宽比。

（8）multimedia authoring systems（多媒体创作系统）。有时也称为多媒体著作系统、多媒体写作系统或多媒体编辑软件。在开发一个多媒体项目时，需要把文字、声音、图形、动画、视频图像这样一些制作多媒体项目的“元素”或基本构件组织和编辑成为一个整体，从而为某个特定的目标服务。多媒体创作系统就是为了实现“组织和编辑”操作而设计的软件系统。

（9）VOD（视频点播，是Video On Demand的缩写）。其含义是根据用户的要求瞬时提供包含影视节目在内的多媒体信息的一种服务。

EXERCISES

1. Fill in the following blanks.

（1）There are two video systems:           and          .

（2）All compression systems require two algorithms: the             and              

algorithms.

（3）         standard is for compressing continuous-tone still pictures (e.g., photographs).

（4）For MPEG-1 and MPEG-2,          will dominate for long-haul video transmission.

2. Which of the following multimedia applications can help in the many steps of multimedia production?

A．Electronic games

B．Interactive video applications

C．Hypermedia browsers

D．Multimedia presentation systems

E．Desktop conferencing systems

F．Multimedia authoring systems

3. Write out the full text of the following abbreviations in English.

（1）MIDI

（2）MPC

（3）ADC

（4）JPEG

（5）MPEG

（6）HDTV

（7）VOD

（8）AAC

（9）PAL

4. Translate the following words into Chinese.

（1）multimedia

（2）video

（3）audio

（4）graphics

（5）animation

（6）dB

（7）frame

（8）interlacing

（9）encoding

（10）lossy

5. Answer the following questions.

（1）What are the requirements for an MPC that are described in detail in Microsoft's Multimedia PC Specification Version 1.0?

（2）What's the relation between the JPEG MPEG-1 and MPEG-2 standard?

（3）List six multimedia applications.

READING MATERIALS

Many musical instruments even have a digital interface now. When digital instruments first came out, each one had its own interface, but after a while, a standard, MIDI (Music Instrument Digital Interface), was developed and adopted by virtually the entire music industry. This standard specifies the connector, the cable, and the message format. Each MIDI message consists of a status byte followed by zero or more data bytes. A MIDI message conveys one musically significant event. Typical events are a key being pressed, a slider being moved, or a foot pedal being released. The status byte indicates the event, and the data bytes give parameters, such as which key was depressed and with what velocity it was moved.

Every instrument has a MIDI code assigned to it. For example, a grand piano is 0, a marimba is 12, and a violin is 40. This is needed to avoid having a flute concerto be played back as a tuba concerto. The number of “instruments” denned is127. However, some of these are not instruments, but special effects such as chirping birds, helicopters, and the canned applause that accompanies many television programs.

The heart of every MIDI system is a synthesizer (often a computer) that accepts messages and generates music from them. The synthesizer understands all 127 instruments, so it generates a different power spectrum for middle C on a trumpet than for a xylophone. The advantage of transmitting music using MIDI compared to sending a digitized waveform is the enormous reduction in bandwidth, often by a factor of 1000. The disadvantage of MIDI is that the receiver needs a MIDI synthesizer to reconstruct the music again, and different ones may give slightly different renditions.

Music, of course, is just a special case of general audio, but an important one. Another important special case is speech. Speech is made up of vowels and consonants. Some speech generation and transmission systems make use of models of the vocal system to reduce speech to a few parameters, rather than just sampling the speech waveform.

THE MP3 PLAYERS

Hard drive-based MP3 players, which allow you to store massive amounts of MP3s and other files on a portable device, have been around for a few years. But recently, three new players have taken the concept to a new high, with impressive advancements in design, functionality, and interface. Each has its unique strong points, but they're all groundbreaking in their own way. Check out our hands-on reviews.

1. Apple iPod

Apple has followed up the successful launch of its original iPod with a new model that offers 10GB of storage (as opposed to 5GB) and updated firmware you now get some additional features, the most notable of which are an equalizer and a contact-list manager. However, since owners of the original iPod can update the firmware on their devices, the real upgrade here is only the extra storage space, for which you'll pay an additional $100. In other words, Apple has made a good thing even better, though we still wish that the company would include a carrying case and a belt clip, particularly considering the iPod's rather hefty price tag.

（1）Near-perfect design.

Design wise, Apple ad everything right with the original iPod, and it didn't make my changes to the cosmetics with this version. When you open the box, the first thing that you notice (after the multilingual sticker urging you not to steal music) is the casing, which is made of shiny stainless steel on the back and a thick slab of Lucite on the front. A large screen enables you to easily view the device's straightforward menu structure and songs categorized by playlist, album, or artist are all easy to find. We particularly appreciate the scroll wheel on the front of the iPod that allows you to effortlessly navigate through the menus. When holding the 6.5-ounce device in one hand, you can click through every song, album, or playlist very rapidly.

Unlike other jog dials or button navigation systems, the scroll wheel accelerates as you turn it, allowing for the kind of maneuvering that's necessary to get through 10GB worth of MP3s (about 2000 songs encoded at a bit rate of 160Kbps) in mere seconds. The iPod's sonic are quite good, producing clean sound through decent ear buds and featuring no fewer than 31 EQ settings, thanks to the new firmware. As noted, the equalization feature was absent in the 5GB version.

One problem that we wish Apple would address in its next firmware upgrade is the lack of a Resume feature. When listening to audiobooks, we had to scroll all the way through the long recording to end where we'd left off. As of right now, the iPod resumes only between songs. But in all of our testing, the iPod never missed a beat because it plays tunes from a skip-free flash-memory buffer that relays music from the hard drive. Still, if you want something specifically for jogging, you might be better off with a lighter flash-based MP3 player, which doesn't have moving parts. No one knows the effects that jogging has on hard drive-based players as of yet.

（2）I sync, therefore iPod.

Before the iPod appeared, USB was the fastest way to transfer files to an MP3 player. Thanks to the iPod's Firewire (IEEE1394) connection, filling up all 10GB takes only 20 minutes.  Performing the same feat via USB would take at least 10 hours. And the iPod not only has the fastest file transfers but also the smartest. It's the first MP3 player to automatically sync to jukebox software (in this case, iTunes 2.x). Just plug the iPod into your Mac, sit back, and watch iTunes start up and transfer every new song, album, and playlist onto the unit. At the same time, your new contacts transfer from compatible applications—currently Palm Desktop 4.0 or later and Entourage for Mac OS X or Mac OS 9, although my application that supports standard vCards (Outlook, and so on) can export to the iPod if you manually place them in the Contacts folder. The Firewire connection also recharges the iPod's battery, which lasts 10 hours. If you're not near your computer, you can recharge the unit with an ultracompact folding adapter that plugs into any wall outlet and powers up the iPod through the same Firewire socket.

The iPod doubles as a portable storage device to transport all file types between two compatible computers. Out of deference to copyright holders, it can sync MP3s to iTunes only on a single Mac. However, by activating the View Hidden Folders preference cant around this protection and freely ferry MP3s between computers. Another Easter egg: You can get your iPod engraved for an additional $50 if you order from Apple's online store.

（3）Take that, Bill!.

One common complaint has been the iPod's lack of Windows support. At the product announcement, Apple CEO Stew Jobs mentioned that such compatibility would eventually arrive, but he didn't seem to be in a big rush to add it. Alternatively, Windows users can turn to an often-updated piece of freeware called EphPod, which in addition to the Firewire card requires MacDrive or MacOpener, both of which run you an extra $50. However, PC fans still won't be able to auto sync contact lists or files (although both can be transferred manually). If this seems less than ideal, go with the Sonicblue Rio Riot instead, which costs less and houses twice the amount of music.

（4）The perfect MP3 player-for some.

Besides its steep $499 asking price, the only problems with this new iPod are its lack of a belt clip, a carrying case, and a Resume function, as well as the native Windows incompatibility. Third-party manufacturers have solved most of those problems, and Apple will likely add a Resume function future firmware upgrades, but it would be nice if the company included everything up front. That said, this is still the best MP3 player we've tested to date.

2. Creative Labs’ Nomad Jukebox 3

At first glance, Creative Labs, Nomad Jukebox 3 doesn't look all that different from the original Jukebox. But this hard drive-based MP3 player is smaller and sports a vastly improved user interface and feature set as well as comprehensive connectivity options. True, it may not be as slick-looking or as compact as the iPod, but the 20GB Nomad Jukebox3 still stands out from the rest of the hard drive-based pack.

Like its predecessor, the 10.5-ounce Jukebox 3 resembles a shrunken portable CD player, barely passing the jacket-pocket test at 5.5×5.5×1.5 inches. Creative has added a jog ad as well as Back and Find buttons, making for a more user-friendly interface than the one found on the previous version. We had a few gripes—song titles don't scroll as tunes play and the Lock Buttons feature must be activated via the settings menu rather than by a dedicated button—but they're pretty minor.

（1）Great connectivity.

Up to this point, the problem with all Windows-based hard drive MP3 players has been that they connect via USB, which is too slow to handle massive file transfers. Thankfully, Creative includes both a Firewire/IEEE 1394 port (Creative calls it SB1394) and a USB port, which translates into a nice combination of compatibility and speed. Also, this is the first hard drive-based player that we've seen to offer an optical digital-in, which allows you to record content from a wide variety of sources.

First, let's talk autosync. The Nomad 3 can sync with multiple PCs if they have the Creative PlayCenter software installed, a feat that no other hard drive-based player can currently lay claim to. What's the big deal about this? Well, it means that you can trade entire MP3 collections in a relatively short period of time. In contrast, the iPod has built-in copy protection that allows you to sync with the iTunes folder on only a single Mac.

On top of its unique—and possibly unkosher—a autosyncing capabilities, the PlayCenter software also handles automatic song tiding and organization, music importing, CD burning, and standard file transfers of any type. Third-party Nomad Explorer software (Web site) also lets you access the songs on the device using Windows Explorer or a remote Web browser among other things.

If that’s not enough, another area in which the Nomad Jukebox 3 breaks new ground is recording options. Using the analog-in or digital-in connections, you can record straight to the unit's hard drive from a variety of sources, including a powered mike. You can choose to record files as uncompressed WAVs or as MP3s compressed at bit rates of 128Kbps to 320Kbps. In other words, with the right accoutrement, you can easily turn old records, lectures, and concert recordings into MP3s or WAVs, upload them to your PC, and e-mail them or burn them onto a CD. We do wish that there were a way to monitor recording levels, but still, this is a great function.

（2）A sound foundation.

Soundwise, the Nomad 3's DSP settings take advantage of Creative Labs, substantial experience with sound processing. As a result, you have more options for tweaking the way your 4000 or so songs sound. Settings include a DSP that simulates auditorium or bathroom environ-

ments (among others); eight EQ presets, none of which are manual; a Time Scale feature, which changes music from half speed to time-and-a-half without altering pitch; a spatialization option (Wide, Narrow, or Full); and a Smart Volume feature, which tailors the sound for trains, cars, or quiet environments by Calibrating EQ to compensate for outside frequencies as well as normalizing volume across MP3s.

Tweaks aside, we're happy to note that the player features a crystal-clear 98dB signal-to-

noise ratio and full, rich sound. The Nomad 3 comes with decent-sounding wraparound head-

phones, but more discerning listeners will want to swap in a new pair. Creative claims seven minutes of antiskip protection; however, we don't recommend jogging with hard drive-based MP3 players.

（3）Optional accessories.

As far as battery life goes, you'll get up to 11 hours from the included lithium-ion rechargeable battery (an AC adapter is provided), which is about average for these types of devices. Though the Nomad 3 lacks an in-line remote, Creative says that it will offer one that includes an FM radio, a built-in mike, and a backlit LCD for $70 starting in May. The company will also sell additional accessories, including an extra battery for $50; a PC Dock with a wireless infrared remote for $60; a car-adapter kit for $40; a case with a belt clip for $20; and a variety of faceplates, also for $20.

At $400, the 20GB Nomad Jukebox 3 compares favorably to both the Rio Riot and the iPod. While it may not be as lightweight or as slickly styled as the latter, its impressive features and connectivity options make it the portable MP3 player for power users—at least until the 40GB version($500) arrives in May.

3. Rio Riot

With its 20GB hard drive and innovative playback options, the Rio Riot has been pegged by many MP3 aficionados as the iPod killer, especially since it's designed to work with Windows right out of the box. But the Riot is missing some key features, such as the ability to sync with your jukebox software and a fast connection to your system. While your music will sound great once it's on the Riot, getting tunes onto the player and organizing thousands and thousands of songs can turn into a headache-inducing chore.

（1）Auspicious beginnings.

The $400 Riot looks promising when you first take it out of the box. Weighing 10 ounces and measuring 5.38×3.63×1.38 inches, the player is smaller than a paperback book and somewhat resembles a handheld gaming device. The sturdy plastic case has convenient handgrips on either end and most of the controls—including a half-concealed scroll wheel; a lay-stop-forward-reverse mouse;and Menu, Select, and Back buttons are within easy reach. Smack dab in the middle of the device is an impressive 1.50×2.25-inch backlit display. The display is one of our favorite aspects of the Riot since it allows you to view the slick menu graphics and multitude of song titles while browsing. We just wish that the titles would scroll so that long song names would still be readable. Also, the display has a slight ghosting effect (you can see faint outlines of items that used to be on the screen), but we see this as a very minor problem—this is still the best MP3 player display that we've seen.

（2）Time to reinvent the wheel.

Unfortunately, the scroll wheel isn't as simple to use as it looks. Because only half of this dial appears outside of the Riot's case, we couldn't spin it nearly as quickly as the iPod's scroll wheel, which is fully exposed. Another design flaw: the small, hard-to-press volume-control buttons are hidden on the side of the Riot and are especially tough to access when the player is in its nice padded case. And while the Select, Back, and Menu buttons are well placed; they don't always work the way that you'd expect. For instance, from the Play Music menu, the Back button returns you to the previous menu. That's intuitive enough, but from the Radio menu, the Back key doesn't do anything. For some reason, in certain situations you must use the Menu key—rather then the Back button—to return from whence you came.

Transferring music to the Riot is relatively simple. Just fire up the included Real Jukebox software (iTunes for Mac users), add your music to the program's library, and drag the files to the Riot. Be prepared for a long wait, though. It took us 50 minutes to move about 1GB of MP3s over the Riot's USB connection; transferring the same amount of files over the iPod's Firewire port took 2 minutes. Do the math—it would take more than 16 hours to fill the 20GB Riot. While you probably won't be moving 20GB worth of files to the player everyday, we wish the Riot could transfer files over a faster, state-of-the-art Firewire or USB 2.0 connection.

（3）File syncing: Missing in action.

Once all of our tunes were on the Riot, we found ourselves missing the iPod's autosync function (not available to Windows iPod users). That's because the Riot doesn't sync you're your system's jukebox software. Sure, you can make your own playlists on the Riot itself, but our fingers started to go numb recreating all of the existing playlists on our system (And no, you can’t drag playlists from Real Jukebox or iTunes to the Riot). When you're dealing with 20GB of music, file-syncing capabilities or at least PC-based song organization is essential. That said, creating playlists on the Riot isn't too awful, thanks to the large display, the scrolling mechanism and a navigation system that works well for this task.

The Riot's heavy dependency on ID3 tags to organize music can work against it since so many MP3s are mislabeled. The Riot files songs by artist, album, or genre, which means that you'll have a tough time finding your MP3s if their ID3 tags aren't pretty complete—unless you enjoy plowing through thousands of songs by title. Thankfully, the included MoodLogic software can clean up most of those ID3 tags. We highly recommend that you use it before you transfer your songs to the player.

（4）Automatic playlists.

The Riot does break some new ground with its Rio DJ feature, which creates playlists based on your most—or least—played tracks, you most recently added music, songs from a specific decade, or random play. Just select how long you'd like your mix to be—anywhere from 15 minutes to every song on the player. And if you grow tired of listening to all 4000 or so of your own songs, the Riot comes with a built-in digital FM tuner that sports eight presets and pulls in channels clearly.

（5）Supreme sound.

Once you get all of your files in order, you're in for a treat because the Riot sounds great. Music is lush and vibrant with a generous low end, and you can tweak the treble and bass if you're so inclined. In comparison the iPod sounds a bit flat even with its new built-in equalizer. The Riot's volume could stand to be a little louder—we often found ourselves trying to turn it up in vain. But at least you'll be listening in comfort, for the player comes with a pair of comfy, decent-sounding headphones.

The Riot also ships with a sturdy carrying case and a belt clip, perfect for taking your music out on a stroll. However, think twice before taking the player on a marathon; the l0-ounce weight precludes jogging. The player never skipped during our tests, even when we shook it with reckless abandon, and its built-in, rechargeable batteries lasted for the 10 hours that Sonicblue promised.

（6）It's getting there.

If you're looking for a player to hold every last one of your MP3s, and you're willing to put up with slow file transfers and a hard-to-master user interface (UI) that makes organizing your music less than pleasant, the great-sounding Rio Riot is the hard drive-based MP3 player for you. To be fair, all of the other Windows-based MP3 players we've reviewed up to this point also use USB 1.0, so the slow transfers are still unfortunately par for the course (although the soon-to-be-reviewed Creative Labs Nomad III does support Creative's version of IEEE 1394/Firewire, called SB1394). But for our money, the smaller iPod, with its speedy Firewire connection file-syncing capabilities (Mac only) and simple UI, is still the player to beat if you own a Mac. If you have a PC and abhor the idea of buying and installing a Firewire card, the Riot could still be a contender since Sonicblue will probably fix many of the problems with future firmware upgrades.