In 2001, Apple introduced the iPod, an MP3 player with the unheard-of storage capacity of 5 gigabytes. Five iPod generations later, the device plays songs, movies and photo slideshows, and you can store up to 80 GB of any type of file you want. The evolution has been a lesson in consumer electronics marketing and development: Millions of people are so hooked on the iPod, they continue to buy it and its coordinating Apple products despite quick battery death and difficult repairs.

In this article, we'll find out why so many people buy iPod after iPod, dissect an iPod video to find out how it works and check out what type of software is available to enhance its functionality.

iPod Basics

The fifth-generation (5g) iPod video is much more than an MP3 player. It's a digital audio player, video player, photo viewer and portable hard drive, making it a full-fledged portable media center. It's available in 30-GB and 80-GB capacities and has a 2.5-inch, color LCD screen. In addition to the iPod 5G, the current generation of iPod players includes :

• iPod shuffle , with a 1-GB capacity, which only plays songs and has no display



• iPod nano , which plays digital audio, displays digital photos, comes in 2-, 4- and 8-GB capacities and has a smaller form factor than the iPod video

(from left) iPod shuffle, iPod nano, iPod video

Although the iPod is an Apple product, it works with both Mac and Windows machines. Since it's the top-selling media player in the United States, probably the big question is: What makes it different from any other digital media player? The answer will differ depending on who you ask. Some might say it's the form factor -- the 80-GB iPod video is just over half an inch (1.4 cm) deep and weighs about 5.5 ounces (156 grams). For comparison, the iRiver PMC-140 (a Windows-based portable media center) is 1.3 inches (3.3 cm) deep and weighs 9.6 ounces (272 grams), and it only holds 40 GB (but the screen is bigger at 3.5 inches).

iPod Features and Hardware :

In addition to the iTunes integration and autosync, the Click Wheel (more on this in the hardware section) and the slim form factor, some of iPod's more notable features include :

• Audio :
The 80-GB iPod stores up to 20,000 songs (7,500 for the 30-GB model). The search function lets you type in keywords (song name, artist, album) using the clickwheel to locate a song on the iPod hard drive. It supports MP3, WAV, AAC, AIFF, Apple Lossless and Audible 2,3 and 4 audio files. You can download songs from the iTunes Store, from a different MP3 download site or rip them from your CDs into the iTunes software. You need to go through the iTunes software to download files to the iPod (unless you download a hack that lets you bypass iTunes -- more on hacks in the Software section). You can listen to audio books at various speeds -- normal, faster or slower -- without seriously distorting the sound, and connect your iPod to your home stereo through a mini-to-RCA jack. The device comes with 22 equalizer presets for different music styles.



• Video :
The 80-GB version holds up to 100 hours of video. It supports H.264 and MPEG-4 files as well as MOV files converted to iPod-friendly video through the iTunes software. You can play video podcasts, music videos, feature films and TV shows on the iPod, plus your own DVDs and home videos that you encode using QuickTime Pro and download to your player through iTunes.



• Photos :
The 80-GB player holds up to 25,000 photos. It supports files converted from JPEG, BMP, GIF, TIFF, PNG and PSD. You can download your photos to the iPod from Mac iPhoto or Windows Adobe Photoshop Elements/Album. Using an RCA or S-video connection (S-video through the dock accessory), you can connect the iPod to your home-theater TV to watch photo slideshows (complete with soundtrack) or video on a larger screen.



• External hard drive :
The iPod can function as portable hard drive, carrying all file types between computers. Just choose "enable disk usage" in the iTunes software, and you can load whatever you want onto the player's hard disk.



• Calendar/contacts syncing :
iPod automatically downloads all new contact/calendar data added to Mac iCal or Microsoft Outlook/Outlook Express since the last time iPod was connected to your computer.



• Games :
iPod comes with four pre-loaded games. You can also download games from the iTunes store, from third-party companies or even create your own (see the "iPod Software" section).



• Car integration :
If you have an iPod and you're in the market for a new car or a new head unit receiver, you can get one that fully integrates your player into the sound system. There are manufacturer-built car stereos that support iPod integration to the level that you can control the device through the head-unit or steering-wheel controls.

iPod Hardware :

For most of the iPod video's functionality, we're dealing with seven primary components :

• Hard drive - 30-GB Toshiba 1.8-inch hard drive



• Battery - rechargeable lithium-ion (700 mAh, 3.7V)



• Click Wheel - navigation via touch-sensitive wheel and mechanical buttons



• Display - 2.5-inch TFT LCD



• Microprocessor - PortalPlayer PP5021C with dual ARM7TDMI cores



• Video chip - Broadcom BCM2722



• Audio chip - Wolfson Microelectronics WM8758 codec

When you remove the front casing, you're looking at the LCD, the motherboard and the Click Wheel :

The Click Wheel :

The Click Wheel is a touch-sensitive ring that you use to navigate through all of iPod's menus and control all of its features. It provides two ways to input commands: by sliding your finger around the wheel and by pressing buttons located under and in the middle of the wheel.

Under the plastic surface of the Click Wheel, there are four mechanical buttons (Menu, back, forward, play/pause), and there's one button in the center (select).

You've got five buttons and five corresponding contacts on the motherboard. When you press, say, the right side of the wheel while you're listening to a song, the wheel pushes down the forward button. The underside of each rubber button is metal, so pressing it completes the corresponding circuit on the motherboard. The motherboard tells the processor this circuit is complete, and the processor tells the operating system to fast-forward through the song.

The Click Wheel's touch-sensitive function lets you move through lists, adjust volume and fast forward through a song by moving your finger around the stationary wheel. It works a lot like a laptop touchpad. In fact, the company that supplied the Click Wheel for the 4G iPod was Synaptics, most widely known for making laptop touchpads. For the 5G, Apple created its own proprietary Click Wheel design based on the same capacitive sensing principle as the previous Synaptics-designed Click Wheel.