Dictionary:

compressor

  (kəm-prĕs'ər)

One that compresses, especially:

1. Mechanics. A pump or other machine that increases the pressure of a gas.
2. Medicine. An instrument or device that compresses, such as a forceps or clamp.
3. Anatomy. A muscle that causes compression of a body part.

A machine that increases the pressure of a gas or vapor (typically air), or mixture of gases and vapors. The pressure of the fluid is increased by reducing the fluid specific volume during passage of the fluid through the compressor. When compared with centrifugal or axial-flow fans on the basis of discharge pressure, compressors are generally classed as high-pressure and fans as low-pressure machines.

Compressors are used to increase the pressure of a wide variety of gases and vapors for a multitude of purposes. A common application is the air compressor used to supply high-pressure air for conveying, paint spraying, tire inflating, cleaning, pneumatic tools, and rock drills. The refrigeration compressor is used to compress the gas formed in the evaporator. Other applications of compressors include chemical processing, gas transmission, gas turbines, and construction. See also Gas turbine; Refrigeration.

Compressor displacement is the volume displaced by the compressing element per unit of time and is usually expressed in cubic feet per minute (cfm). Where the fluid being compressed flows in series through more than one separate compressing element (as a cylinder), the displacement of the compressor equals that of the first element. Compressor capacity is the actual quantity of fluid compressed and delivered, expressed in cubic feet per minute at the conditions of total temperature, total pressure, and composition prevailing at the compressor inlet. The capacity is always expressed in terms of air or gas at intake (ambient) conditions rather than in terms of arbitrarily selected standard conditions.

Air compressors often have their displacement and capacity expressed in terms of free air. Free air is air at atmospheric conditions at any specific location. Since the altitude, barometer, and temperature may vary from one location to another, this term does not mean air under uniform or standard conditions. Standard air is at 68°F (20°C), 14.7 lb/in.² (101.3 kilopascals absolute pressure), and a relative humidity of 36%. Gas industries usually consider 60°F (15.6°C) air as standard.

Compressors can be classified as reciprocating, rotary, jet, centrifugal, or axial-flow, depending on the mechanical means used to produce compression of the fluid, or as positive-displacement or dynamic-type, depending on how the mechanical elements act on the fluid to be compressed. Positive-displacement compressors confine successive volumes of fluid within a closed space in which the pressure of the fluid is increased as the volume of the closed space is decreased. Dynamic-type compressors use rotating vanes or impellers to impart velocity and pressure to the fluid.

(1) A device that diminishes the range between the strongest and weakest transmission signals. See compandor.

(2) A routine or program that compresses data. See data compression.

For more information on compressor, visit Britannica.com.

A machine for compressing air or other gases which is a basic component in some refrigeration systems; draws vaporized refrigerant from the evaporator at a relatively low pressure, compresses it, and then discharges it to a condenser.

Compressor
Developer:	Apple Computer
Latest release:	3.0
OS:	Mac OS X v10.4.9
Genre:	Data compression
License:	Proprietary
Website:	apple.com/finalcutstudio/compressor

Compressor is a video and audio media compression and encoding application for use with Final Cut Studio and Logic Studio on Mac OS X. It can be used with Qmaster for clustering.

History

The application used to be available as part of Final Cut Pro, Soundtrack Pro, Motion and DVD Studio Pro, but after those stand-alone products were discontinued, it is now only available as part of Final Cut Studio and Logic Studio.

See also a release history in context with the rest of Final Cut Studio.

Features

Compressor is used for encoding MPEG-1, MPEG-2 for DVD, QuickTime .mov, MPEG-4 (Simple Profile), MPEG-4 H.264 and optional (third Party and often commercial) QuickTime Exporter Components to export to Windows Media, for example. Among its other features are the ability to convert from NTSC to PAL and vice versa, and the ability to 'upconvert' from Standard Definition video to High Definition video with feature detail detection to prevent serious quality losses.

Compressor is mainly used to encode Final Cut Pro projects into the necessary DVD MPEG-2 format. Filters can be applied to video during the conversion process, and the video can be cropped.

External links and references

• Apple Compressor 2 User Manual (PDF)
• New Features in Compressor 2 (PDF)

Final Cut Studio
Major applications	Final Cut Pro 6 · DVD Studio Pro 4 · Motion 3 · Soundtrack Pro 2 · Color · Compressor 3
Minor applications	LiveType 2 · Cinema Tools 3 · Qmaster 2 · QuickTime Pro 7
Utilities	Apple Loops Utility · Batch Monitor 2 · Qadministrator · Final Cut Server

Apple Inc. software
OS	Mac OS X · "Cheetah" · "Puma" · "Jaguar" · "Panther" · "Tiger" · "Leopard"
Consumer	.Mac · iLife · iTunes · iWork
Prosumer	Final Cut Express · Logic Express
Pro	Aperture · Final Cut Studio · Logic Studio · Shake
Bundled	Front Row · iChat · Photo Booth · QuickTime · Safari
Server	Apple Remote Desktop · Mac OS X Server · WebObjects · Xsan
Discontinued	AppleWorks · HyperCard · MacDraw · Mac OS · MacPaint · MacProject · MacTerminal · MacWrite

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