This glossary contains industry-standard terms and terms that apply to Autodesk Composite.
1D LUT A 1D Look-up Table (LUT) is generated from one measure of gamma (white, gray, and black) or a series of measures for each color channel. With a pair of 1D LUTs, the first converts logarithmic data to linear data, and the second converts the linear data back to logarithmic data to print to film.
1-point stabilizing A technique for removing the horizontal or vertical jitter motion from a camera.
1-point tracking Tracking or stabilizing a single feature in motion, then applying that motion to a second element, so that the two appear to be locked together.
2-point stabilizing A technique for removing the motion or changes in scale/rotation (zoom/roll).
2-point tracking A technique for tracking two features, using the relationship between the two to track scale/rotation.
3D LUT A type of LUT for converting from one color space to another. It applies a transformation to each value of a color cube in RGB space. 3D LUTs use a more sophisticated method of mapping color values from different color spaces. A 3D LUT provides a way to represent arbitrary color space transformations, as opposed to the 1D LUT where a component of the output color is determined only from the corresponding component of the input color. In essence, the 3D LUT allows cross-talk, i.e. a component of the output color is computed from all components of the input color providing the 3D LUT tool with more power and flexibility than the 1D LUT tool. See also 1D LUT.
4-point tracking Tracks four features, also referred to as corner pinning. With four-point tracking, four trackers are used to generate tracking data for anchoring the four corners of a bilinear surface to background footage.
alpha The name given to a fourth channel matte when bundled together with a three-channel color image. Also known as a matte channel. An alpha channel can be further described as either: 1. A TV signal that defines a portion of an image or clip to be keyed, or overlaid with a second image. A grayscale representation of an image used to create a mask for keying images.2. A matte or mask that defines a portion of an image or clip. The portion of a four-channel image that is used to store transparency information. 3. A raster channel defined by a paint or brush stroke.
animation The process of creating the illusion of moving images by displaying sequential images in rapid succession. In each successive image, two or more values are changed over time, and the items drawn or recorded in the images appear to move.
animation curve Also known as function curve or fcurve. It is a graphical representation of an animated parameter. The time and value of the animated parameter is displayed on two axes: the vertical axis representing the value, and the horizontal axis representing the time.
AutoKey A mode that, when activated, sets a keyframe whenever you change the selected object's properties.
background The composition background defines the rendering plane and sets its format after which other layers can be created.
bit depth 1. The number of bits used to represent the color of a pixel. Black and white images use a bit depth of 1; 16-color images use a bit depth of 4, 256-color images use 8, and so on. 2. The number of bits used to represent an audio sample. The more bits there are, the more accurately you can represent the amplitude at that point in time.
blue screen A special effects procedure in which the subject is photographed in front of a uniformly illuminated blue or green background. A new background image can be substituted for the blue or green during the shoot or in post production through the use of chroma key. See also keying.
Boolean A system of logic that lets you combine objects using logical operators, such as And, Or, Xor, Min, and Max. Boolean operators can be used for combining mattes in a single layer.
browsers A generic term which refers to the program or tool used for information searching in a window.
camera A device for viewing scenes from a different angle or “vantage point”.
capture 1. To digitally transfer audio or video material from an external device, such as a videotape recorder, to a shared storage location or the local disk storage on your workstation. 2. To convert analog video and audio signals to digital signals.
channel 1. A physical audio input or output. 2. One of several color components that combine to define a color image. An RGB image is made up of red, green and blue color channels. In color correction, you can redefine color channels by blending color components in different proportions.
chrominance An image processing property that defines the hue and saturation of a pixel.
color A means of identifying colors in a source according to its component parts of RGB, hue, saturation, chrominance, luminance, sharpness, softness, tolerance or threshold, and computer-generated imagery.
color correction The process of adjusting the color characteristics of video material to achieve an accurate representation of color and consistency of color from one clip in a sequence to another. The term generally refers to adjustment changes made as part of a single effect.
color curves Color curves lets you remove color spill by either suppressing a sampled color, by modifying the red, green, blue, or hue, by modifying the saturation, or by modifying the luminance of the selected color, or by shifting the hue of a color range to a sampled hue shift target. Each curve in color curves is a hue gradient. When you change the shape of a curve, the colors along the curve's gradient change to reflect the result. For example, if your hue shift target is magenta, as you raise the green portion of the default hue shift curve, it gradually becomes magenta, becoming fully magenta when you reach the full value (75%).
comparison operators Operators that use Boolean algebra to compare two values with each other, if the comparison is true the result is 1, if the comparison is false the result is 0.
composition Composition is media imported into the application that can be used to insert, merge, or link to or from another composition.
computer-generated imagery (CG) Images created or generated with a computer.
conform A compound object created by projecting the vertices of one object, called the Wrapper, onto the surface of another object, called the Wrap-To.
context point A specific tool node you mark as the target for a Player view. Context points are especially useful when you want to see how changes to a tool node that precedes the node with a context point affect the context point.
corner pinning A technique used to pin the four corners of one static image (usually) onto another static image.
cue marks High-level keyframe controls that let you associate a keyframe with a mark. Instead of viewing a clip over and over again in order to evaluate and record important timing points, you can view footage and add cue marks.
dependency graph A set of connected nodes consisting of one or more inputs, an output, and any number of effects or compositing operations.
depth of field The range of acceptable focus in front of and behind the primary focus setting. It is a function not only of the specific lens used but also on the distance from the lens to the primary focal plane, and of the chosen aperture. Larger apertures will narrow the depth of field, smaller apertures will increase it.
Domain of Definition (DOD) A usually rectangular region that defines the maximum boundaries of useful information in an image. Generally, everything outside of the DOD will have a value of 0 in all channels of the image. The DOD is usually determined automatically, as opposed to a Region of Interest. See also Region of Interest.
expressions Mathematical formulas that let you control any parameter that can be animated, such as translation, rotation, scaling, material, or texture.
Expresso calculator An extension of the standard calculator that allows you to create expressions that generate values used in numerical fields.
external matte A matte taken from another clip. See also matte, garbage matte, static matte and traveling matte.
garbage mask Garbage masks can key undesired elements in an image and to do rotoscope work. A garbage mask affects the image's alpha channel, which is where the transparency information is stored. You can use a mask to create the alpha channel, or you can use a mask to add to an alpha channel.
garbage matte A rough simple matte that you create in an image's alpha channel that isolates unwanted elements from the primary element in an image. Garbage mattes are also referred to as garbage masks. See also matte, external matte, static matte, and traveling matte.
hue A specific color from the color spectrum, disregarding its saturation or value.
intermediate results The results rendered at any node in the dependency graph, other than the output node.
interpolation A mode that automatically defines the shape of an animation curve between keyframes in the curve. Infers a point which does not actually exist by averaging real points near it, either in space or time. See also extrapolation.
keyframe The value of an animated parameter that you set at a given point in time. Parameter values between keyframes are obtained by interpolating between keyframe values.
keyframing The simplest form of animating an object. It is based on the notion that an object has a beginning state, or condition, and changes over time in position, form, color, luminosity, or any other property to some different, final state. Keyframing takes the stance that we only need to show the key frames or conditions that describe the transformation of the object, and that all other intermediate positions can be figured out from these.
keying The process of isolating a region of an image by selecting pixels of a particular color and making those pixels transparent, or creating an alpha channel where those pixels are located.
layer An object that you can composite over another layer using a matte. A layer composed of a source input that you assign to a geometrical support, or 3D geometry, and a material node that is automatically generated.
layers Layers are composed of three separate components: a surface (3D geometry) object and local axis, a multi-channel material object, and a layer element.
linear color space An abbreviation Linear color space. A color space in which the relationship between a pixel's digital value and its visual brightness remains constant (linear) across the full gamut of black to white.
lights An object (algorithm) used to illuminate your scene and apply lighting effects to surfaces. Different types of lights include: omni, directional, and spot.
log color space An abbreviation for Logarithmic color space. A nonlinear color space whose conversion function is similar to the curve produced by the logarithmic equation.
luminance An image processing property that defines the brightness of a pixel. Expressed in percentages, 0% luminance is black and 100% luminance is white. Values between 0 and 100% define a range of grays. Colored pixels have a luminance value equivalent to the mean of their RGB values.
LUT A Look-up Table (LUT) is an ASCII file that describes specific pixel values used for image data conversion both on import and export. For example, you can use a LUT to convert a 10-bit logarithmic film image to a 16-bit linear image on import. You can use two kinds of LUTs: 1D LUTs and 3D LUTs. See 1D LUT, and 3D LUT.
masking The process of hiding a region of an image. You can use masks to remove the area outside the mask shape and keep the area inside the mask shape, or you can use masks to remove the area inside the mask shape and keep the area outside the mask shape. Pixel Masking lets you temporarily isolate specific areas of the footage. You can apply effects to the selected area of an image without affecting the rest.
material A material defines how a layer interacts with lights to define how a scene is rendered. Each layer must have a material associated with it, but many layers can share a single material.
matte An image used to define or control the transparency of another image. When you pull a key, a matte that defines the transparency of the front source is generated. There are several types of mattes. See also keying, external matte, garbage matte, static matte and traveling matte.
metadata Information embedded in the image attained through tags that further describes the image.
motion blur A digital effect that simulates the blur of fast-moving objects.
multiple-point tracking Multi-point tracking tracks as many features as you want. You can apply the stored motion to various elements, such as the center point of an object. For example, you could track a halo over the head of a person in a clip. Assume that in the clip a woman tilts her head and advances toward the camera. You would want the halo to reflect the position, scaling, and rotational changes of the tracked features on the woman's head.
node An element for connecting a composition in a dependency graph. There are several types of nodes, including input, output, group, tool, and super tool.
NTSC National Television Standards Committee. The committee that established the color transmission system used in the United States, Canada, Mexico and Japan. Also the broadcast standard for North America. The NTSC standard uses 525 horizontal lines per frame with two fields per frame of 262.5 lines. Each field refreshes at 59.94 Hz. See also PAL, and SECAM.
object Any element in a 3D scene, such as lights, camera, and surfaces.
PAL Phase Alternate Line. The color broadcasting standard used in most of Europe, China, Australia, New Zealand, the Middle East, and parts of Africa. The PAL standard uses a total of 625 lines per frame scanned at a rate of 25 fps, with two fields per frame of 312.5 lines each. Each field refreshes at 50 Hz. See also NTSC, and SECAM.
Pick list A list of frequently used tools and other elements that you can pick and assemble.
pinning With corner pinning (also known as four-point tracking), you use four trackers to generate tracking data for anchoring the four corners of a bilinear surface to background footage. See also 4-point tracking.
premultiply An image whose red, green, and blue channels have been multiplied by a matte that is usually stored as the alpha channel of this image.
preset A saved configuration of views and settings appropriate for a particular task.
process To create the final image or sequence of images using effects, transitions, composite, or container clips in your sequence.
proxy A low resolution copy of a high resolution image, one for each frame. Proxies are used to provide real-time playback of processed results and to provide low resolution stand in clips in a compositing environment so composites can be quickly created. See also composition thumbnails.
Region of Definition (ROD) In Composite each image has a size and position within a 2D reference plane also called the Image Reference Frame (IRF). The Region of Definition (ROD) of an image is the rectangle enclosing that image in the IRF. This rectangular region is always aligned with the main X & Y axes of the IRF.
Region of Interest (ROI) A region (usually rectangular) that is determined by the user in order to limit certain calculations. See also Domain of Definition (DOD).
render The process of creating a final image or sequence of images from a scene.
resolution The amount and degree of detail contained in the video image, measured along both the horizontal and vertical axes by dots or lines.
RGB A color model that defines pixels according to red, green, and blue channel values.
ROI See Region of Interest. See also Domain of Definition.
safe action area, safe title area An area in the center of the video image considered safe to place a title or other graphic, or capturing movement, so that none of it is cut off at the edges of the TV screen. The safe action area is 10% percent smaller than the maximum image size, and the safe title area is 20% smaller.
saturation 1. Saturation is the brilliance or purity of a given color. For example, the difference between a pastel and a pure color is defined by the amount of saturation. 2. The intensity of colors. 3. The degree by which the eye perceives a color as departing from a gray or white scale of the same brightness.
Schematic A view in which the artist builds a dependency graph for a composition. See also dependency graph.
SECAM Séquentiel couleur à Mémoire. A color television standard developed in France and used throughout Eastern Europe. The SECAM standard uses 625 lines per frame. See also NTSC, and PAL.
shader A program that defines the look of objects in a scene. Shaders are part of the rendering pipeline.
sharpness Sharpness can be defined as the visual sense of the abruptness of an edge. It highlights the detail in an image or image sequence.
SMPTE Society of Motion Picture and Television Engineers. A frame numbering system used for electronic editing and timing of video productions. Each frame of video is assigned a number. Timecode denotes the hours: minutes: seconds: frames (00:00:00:00) elapsed on videotape. There are two types of timecode: drop frame and non-drop frame.
softness Colors that fall within the softness range are partially transparent. These areas appear gray (a dark gray to light gray range) in the matte. For example, softness makes the transition between the foreground and background of a composition more convincing by softening what would otherwise look like an abrupt cutout. Softness can also be used to retain transparent key-in materials or shadows that you want to appear in the result composition.
stabilizing To remove motion jitter and unwanted camera movement from a clip.
super tool A tool comprised of a set of tools that includes Reaction, Garbage Mask, 2D Compositor, Image Import, Keyer, Tracker, and Paint.
surface A geometric object onto which a source is mapped to create a layer for a composition. Geometric types include: bilinear, frustum, box, plane, and sphere.
tangent A line that extends from a control point that controls the direction of a Bézier curve. Tangent handles also control key points on function curves when the curve point's type is set to Bézier.
task group A set of one or more preset UI configurations grouped according to task.
tolerance Tolerance or Threshold is the colors that fall within the tolerance or threshold range is transparent. These areas appear black in the matte.
tracking Tracking allows the capture and storage of motion that's applied to a second element, so that the two appear to be locked together. Tracking of one, two, four or multiple features is possible using 1-point, 2-point, 4-point or multiple-point tracking.
traveling matte A matte that changes position or shape over time. See also matte, external matte, garbage matte and static matte.
X axis The horizontal axis in a three-dimensional system.
Y axis The vertical axis in a three-dimensional system.
Z axis The axis that is perpendicular to the X and Y axes in a three-dimensional system.
