Multimedia Input Devices

Multimedia input devices vary in functionality based on the type of input being gathered. Two broad categories of multimedia input are audio and video. Digital motion and still cameras are incredibly popular as a replacement for similar video products that do not transfer information to a computer, making sharing and collaboration so much easier than before. The following sections present information on these multimedia input devices:

• Web cams
• MIDI-enabled devices
• Digital cameras and camcorders

Web Cams

Years ago, owing to the continued growth in the Internet’s popularity, video camera-only devices, known as web cams, started their climb in esteem. Today, anyone who does a fair amount of instant messaging, whether professional or personal, has likely used or at least been introduced to web cams, often used in conjunction with messaging user interfaces.

Web cams make great security devices as well. Users can keep an eye on loved ones or property from anywhere that Internet access is offered. Care must be taken, however, because the security that the web cam is intended to provide can backfire on the user if the web cam is not set up properly. Anyone who happens upon the web interface for the device can control its actions if there is no authentication enabled. Some web cams provide an activity light when someone is using the camera to watch whatever it’s pointed at. Nevertheless, it is possible to decouple the camera’s operation and that of its light.

A web cam connects directly to the computer through an I/O interface, such as USB or WiFi, and does not have any self-contained recording mechanism. Its sole purpose is to transfer its captured video directly to the host computer, usually for further transfer over the Internet, hence the term web. Web cams that have built-in wired and wireless NIC interfaces for direct network attachment are prevalent as well. A now maturing evolution of the web cam for laptops resulted in manufacturers building the device into the bezel of the display. Connectivity is generally through an internal USB or FireWire interface.

MIDI Devices

Microphones, audio playback, and audio synthesizing devices are common input components connected to a sound card or serial port so that audio from these devices can be collected and processed. As an example, consider Musical Instrument Digital Interface (MIDI) devices, called controllers, which create messages describing, and thus synthesizing, the user’s intended musical performance. These devices do not make sound that is recorded directly; they are merely designed to somewhat realistically fabricate the music the instruments they represent might produce. MIDI files, therefore, are much smaller than files that contain digitized audio waveforms.

Modern MIDI controllers use 5-pin DIN connectors that look like the original AT keyboard connector. Controllers can be interconnected in one of two ways. The original method is to provide devices with two ports, an input and an output port, and daisy-chain them in a ring. This arrangement introduces a delay caused by devices processing and retransmitting messages that were not destined for them but instead for devices downstream from them. One solution is to replace the output port with one that merely replicates the input signal. If the receiving device is the intended destination, then the unnecessarily repeated message is ignored by downstream recipients. Otherwise, the actual recipient receives its message with far less delay. The second method of connection is another solution that reduces delay. A device with one input and multiple outputs interconnects many devices directly.

Regardless of the controller interconnection method, computers can receive MIDI controllers directly, such as through a sound card with a built-in MIDI interface or through the use of an external MIDI interface that originally connected to the computer’s game port. Today, USB and FireWire ports are more commonly used. Ethernet-attached interfaces also exist and require very little processing power to convert the MIDI messages into Ethernet frames.

Digital Cameras and Camcorders

A digital camera is a device that takes still pictures and records them to digital media of some sort for later access. A camcorder is a video capture device that performs a similar function to that of the digital camera, but for moving video. Most of today’s multimedia recording devices perform the functions of both the digital camera and the digital camcorder. Depending on the device, both pictures and video can be stored on the same or different media within the same device. In fact, the most basic smartphone can perform both of these functions, often with exceptional quality.

Early versions of digital cameras relied on the storage media of the day, 3.5″ floppy diskettes, for instance. Eventually, models with internal flash memory were developed, which led to hybrid models that also featured a memory card slot, resulting in the flexibility to grow the camera’s storage capacity as the technology produced larger cards.

A similar evolution occurred in the world of camcorders. Originally, camcorders required one of a variety of analog tape formats to record on. This gave way to digital tape formats and then to burnable optical discs, hard disk drives, and today’s high-capacity flash storage. Once a removable memory card was added on, the possibilities for what can be recorded and how much became nearly endless. Figure 3-51 shows a digital camcorder on the left and a digital camera on the right.

Figure 3-51: A digital camera and camcorder

The mechanism by which the digital information is transferred to a computer varies somewhat among these devices. In some cases, a cable—USB, for instance—can be attached between the device and the computer. A drive icon might then appear in Windows Explorer, or you might have a specific application for access to the content. In other cases, removable media was recorded on and this media can be removed and transferred directly to a reader on the computer system, be it an optical drive or card reader. Certain manufacturers have developed docking stations for their product line. The dock can remain attached to the computer system, and the device can be interfaced to the dock, usually by simply sitting it down on the docking station. In some cases, these stations also charge the device while it is docked.