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A B C D E F G H I K L M N O P Q R S T U V W Z
In computer graphics, the measure of a pixel's opacity. A pixel with the maximum alpha value is opaque, one with a value of zero is transparent, and one with an intermediate value is translucent.
Method for combining two images that uses both pixel colors and alpha values to determine the color of the resulting pixel. This allows an image to be rendered on top of another image, with a blend of both images showing. When blending two pixels, the color components of both pixels are first scaled by their alpha values. Then, the bottom pixel is scaled by the inverse of the top pixel alpha value and added to the top pixel to form the final blended color.
The opacity of an image defined by an alpha value per pixel interleaved with the color components (for example, ARGB), an alpha value per pixel stored in a separate alpha surface, or a constant alpha value for the entire surface.
Portion of a 32-bit color that determines its opacity. In this case, the alpha value per pixel is interleaved with the color components (for example, ARGB). Less commonly, this term refers to an image with an alpha value per pixel stored in a separate alpha surface.
Level of opacity (alpha value) applied to an entire surface.
Particular use of alpha blending (and alpha channel information) to reduce aliasing by blending edges, based on pixel coverage information.
Description of a light source that illuminates everything in a scene, regardless of the orientation, position, and surface characteristics of the objects in the scene. Because it illuminates a scene with equal strength everywhere, the position and orientation of the frame that an ambient light source is attached to are inconsequential. Multiple ambient light sources are combined within a scene.
Mipmap filtering mode that compensates for anisotropic distortion.
Distortion visible in the image of a 3D object whose surface is oriented at an angle with respect to the viewing plane. The anisotropy is measured as the elongation (length divided by width) of a screen pixel that is inverse-mapped into texture space.
Alpha (opacity), red, green, and blue components of a pixel. Each color is represented in memory by data in BGRA order.
Group of objects organized into an array. Array objects make it simpler to apply operations to the entire group. The Component Object Model (COM) interfaces that enable you to work with array objects containing the GetElement and GetSize methods. These methods retrieve a pointer to an element in the array and the size of the array, respectively.
A series of adjustments applied by a synthesizer to the pitch, volume, and other parameters of an instrument sound to make it more realistic.
To connect multiple DirectDrawSurface objects into complex structures, such as those needed to support 3D page flipping with z-buffers. Attachment is not bidirectional, and a surface cannot be attached to itself. Emulated surfaces (in system memory) cannot be attached to non-emulated surfaces. Unless one surface is a texture map, the two attached surfaces must be the same size.
Physically connected to the system. A device may be installed but not currently attached.
Period at the beginning of a force-feedback effect when the magnitude is reaching its basic or sustain level.
Nonvisible surface to which bitmaps and other images can be drawn while the front buffer displays the currently visible image.
Far boundary of a viewing frustum beyond which objects are not rendered.
A MIDI controller that enables instruments to be chosen from different groups or banks, each identified by a 2-byte code.
A primitive that is oriented so that one face is toward the viewer. A texture, usually an animated sprite, is applied to the billboard to give the appearance of a 3D object in the scene.
2D technique of simulating the appearance of a 3D object in a scene. An application inserts a primitive, typically rectangular, into the scene, orients it so that one face is toward the viewer, and applies a texture or a set of textures. The texture or set of textures gives the appearance of an animated 3D object.
A graphics function that moves many continuous bits from one memory location to another in the most efficient manner supported by the hardware. Also known as bitblt or blit.
A graphics function that moves blocks of bits from one bitmap to another in the most efficient manner supported by the hardware.
See Other Term: bit block transfer
Description of how each color component is blended in texture blending.
Algorithm used to determine how a texture is blended with the colors of the surface to which the texture is applied.
One step in a texture cascade. A blending stage includes one texture and a set of texture-blending operations that are used when blending multiple textures.
See Other Term: bit block transfer
A technique for displaying interlaced video. In bob mode, each field is displayed individually. The gaps between scan lines are filled using interpolation.
Process of checking that an on-screen image is displayed within the bounds of the screen.
Technique for simulating the appearance of rough surfaces in 3D scenes. Variations in depth are stored in a texture and applied to a primitive, using standard texture-blending techniques.
Direct3DRMFrame object used by the viewport to define the viewing position and direction. The viewport renders only what is visible along the positive z-axis of the camera frame, with the up direction in the direction of the positive y-axis.
Frame of reference in which the viewer is at the origin, looking in the direction of the positive z-axis. Objects are transformed from world space to camera space by using the view transformation.
A scheme of chord progressions, arranged in a flowchart along a time line.
Series of rectangles that describes the visible areas of the surface.
DirectDrawClipper object.
An abbreviation for compressor/decompressor. Software or hardware used to compress and decompress digital media.
Process for determining if any pixels for two images share the same location on the screen.
A color used for transparent or translucent effects. An overlay surface is displayed in the region of the primary surface that contains the color key. In video production, color keys are used to combine two video signals. Also called a chroma key.
A model for representing color as three or more coordinates. Color-space models map color components onto a Cartesian coordinate system in three or more dimensions. A color space may use any of several types of color encoding and visualizing. The two most common types of color space models are RGB and YUV.
An array of n color values (normally RGB triples).
A technique for converting a color in one color space to another color space. Typically, this conversion is from YUV colors from a video source to RGB for display.
The collective term for several DirectDrawSurface objects, all of which are attached to a root surface. The complex-surface structure can be destroyed only by destroying the root.
A collection of tracks and (optionally) other compositions. At rendering time, the sources in a composition are composited into a single image.
Musical segment that controls certain aspects of playback. Normally it is the primary segment, but a secondary segment can be designated as the control segment.
Removing a face from the list of faces to render. Faces can be culled using a number of techniques including: back face, view frustum, and occlusion culling.
In DirectMusic, a continuous series of events with a start and end value, such as volume fade.
Light source that removes illumination from a scene. Dark light is created by specifying negative values for the colors of the light.
See Other Term: Display Control Interface (DCI)
Area within the physical range of an axis where the axis is considered to be at the center.
Zone around the offset of a force-feedback axis at which a condition is not active.
Texture that is rendered directly, as a visual. Decals are rendered into a viewport-aligned rectangle.
To combine the interlaced fields in a video frame so that, during playback, the lines of the video frame are painted sequentially.
A video frame that contains only the changes from the previous frame. In contrast, a key frame contains all the data necessary to construct that frame.
The color that is replaced on the destination surface.
Visible application window that Microsoft DirectDraw uses for display. Applications can have a device window for each display device attached to a given computer.
In DirectShow Editing Services, a series of device-independent bitmap (DIB) files rendered in a sequence as video frames.
A light source that is attached to a frame but appears to illuminate all objects with equal intensity, as if it were at an infinite distance from the objects. Directional light has orientation but no position, and it is commonly used to simulate distant light sources, such as the sun.
A COM object that processes multimedia data streams from buffers allocated by the client.
An interface that offers improved graphics performance as a result of direct video memory access.
A method of displaying a range of colors with a limited palette. Each pixel on the source image is represented by multiple pixels (usually a 2x2 square) on the destination image. From a distance, the eye blends the multiple pixels into one color that has more shades than the original palette. The technique results in a better visual appearance than the removal of low precision bits. See a standard graphics reference for details. Dithering is a supported option by DXSurface and Microsoft DirectX objects.
See Other Term: Downloadable Sounds (DLS)
See Other Term: DirectX Media Object (DMO)
A standard for synthesizing wave sounds from digital samples stored in software. The DLS level 1 and level 2 standards are published by the MIDI Manufacturers Association.
To reduce the sampling rate of a signal.
In a filter graph, the direction in which digital media samples travel.
The material property that determines whether a material emits light. The emissive property of a material is one of two properties that determines how the material reflects light.
See Other Term: emissive property
Frame to which a light applies.
In force feedback, a set of values that defines the shape of an effect by modifying the magnitude at the beginning (attack) and end (fade). In audio, a set of values that defines the shape of the amplitude or pitch of a sound. Downloadable sounds (DLS) level 1 defines a four-segment envelope: attack, decay, sustain, and release (ADSR). DLS level 2 defines six segments: delay, attack, hold, decay, sustain, and release (DAHDSR).
Second field, comprising a video frame in an odd/even field set. Also known as field 2.
A fully self-contained, independent packet of information that describes a 3D scene. An execute buffer contains a vertex list followed by an instruction stream. The instruction stream consists of operation codes, and the data that is operated on by those codes.
Single polygon in a mesh.
Period between the central, or sustain, portion of a force-feedback effect and its end.
Light attenuation between a spotlight's inner and outer cones.
A portion of an interlaced video frame. With interlaced video, the scan lines of even-numbered fields fall spatially halfway between the scan lines of odd-numbered fields.
Quality determining whether a field is an even field or an odd field. In odd fields, the trailing edge of the vertical refresh (VREF) does not occur during a scan line. In even fields, the trailing edge of the VREF occurs during a scan line.
Shimmering appearance on 3D primitives that results from a poor separation of z-values when doing decaling. Some pixels from the back texture are rendered onto the front texture and vice versa.
Swapping the addresses associated with the back and front buffer. This effectively swaps the image in the back buffer to the front buffer, thus displaying the image.
Series of surfaces attached to each other that can be flipped.
Any piece of memory that can be flipped.
An application window, visible or not visible, that Microsoft DirectDraw uses to hook window messages. The focus window's message handler receives input messages forwarded by DirectDraw. Applications can have only one focus window.
A single rendered image in a movie, an animation, or a 3D scene.
Memory that is displayed on the monitor or other output device.
Near boundary of a viewing frustum. Any object closer to the camera than the front clipping plane is not rendered. The height of the front clipping plane defines the field of view.
The non-linear function that maps changes in voltage to changes in brightness on a phosphor screen. The change in voltage needed to produce a specified change in brightness is not constant across voltage levels.
Process of synchronizing one video signal with another. Because they are synchronized, the genlocked signal can be mixed with the original signal, enabling dissolves, wipes, and other transition effects.
Subdivision of a beat. The number of grids per beat is part of the Microsoft DirectMusic time signature.
A value given to music during style playback. The groove level determines which patterns can be selected at any given time. The author assigns a range of groove levels to each pattern.
See Other Term: hardware abstraction layer
Hardware and device drivers that insulate applications from device-specific implementation details. If a capability requested by an application is not implemented by the current hardware, the capability is emulated by the software.
Consists of hardware and device driver mechanisms that insulate applications from device-specific implementation details. If a capability requested by an application is not implemented by the current hardware, the capability will be emulated by the software.
A hardware component, built into the display adapter, that performs efficient blit operations.
Software emulation for features that are not present in hardware.
A mathematical representation of the effect of the listener's physiology on the pitch and timing of sounds arriving from different directions.
See Other Term: hardware emulation layer
See Other Term: human interface device (HID)
A comparison of the mouse position with on-screen geometry. Commonly used to detect whether the mouse has been clicked over on-screen geometry.
In a video stream, the horizontal refresh (HREF) is active to signal that the display is to begin a new scan line.
On an Intel x86 computer, the byte order for the system, or host, is little-endian. Network byte order is always big-endian.
See Other Term: horizontal refresh (HREF)
See Other Term: head-related transfer function
A device that enables detailed button and control reporting resulting from human interaction (such as a keyboard, pen, game controller, and touch screen) using a bus-agnostic protocol originally developed by the Universal Serial Bus (USB) Device Working Group.
DirectDrawPalette object whose entries are indexes into another palette object.
An algorithm used by the filter graph manager to build graphs and connect filters. If an output pin is specified, the filter graph manager renders the data from that pin by using default renderers. If two filters are specified, the filter graph manager attempts to connect them. It will insert intermediate filters if necessary.
To display a video frame in two fields. One field contains the even lines of the frame, the other field contains the odd lines. During playback, the lines in one field are displayed first, then the lines in the second field are displayed.
The arrangement of video frames and audio samples in a file, such that video data alternates with audio data at regular intervals.
International Radio Engineers scale. A scale of values ranging from 0 to 100 that defines the brightness level of a broadcast video signal. The spectrum of low-to-high IRE values describes increasing brightness levels of a video signal. At 7.5 IRE brightness, the black cut-off threshold for a National Television System Committee (NTSC) signal, the electron guns of an NTSC display device are cut off and do not display images.
The operational state of a central processing unit (CPU) that enables full, unprotected access to a system. A driver or thread running in kernel mode has access to system memory and hardware.
A video frame containing all the data needed to construct an image without reference to previous frames.
See Other Term: light-emitting diode
A video display format in which black bars appear above and below the video image while it is played. The letterbox format maintains the original aspect ratio of an image when it is displayed in a window with a different aspect ratio.
Texture or group of textures that contain lighting information for a 3D scene.
A semiconductor device that converts electrical energy into light, used, for example, for the activity lights on computer disk drives. Light-emitting diodes work on the principle of electroluminescence and are highly efficient, producing little heat for the amount of light output. Acronym: LED.
Lobby management routines associated with the user's computer, including launching applications, updating the user interface, and communicating with the lobby server.
Lobby management routines associated with a remote server. The lobby server coordinates all the information about the users who are connected to a specific application.
Connection to a lobby server on which clients and the server have not been specifically written to interoperate.
An application that, at a minimum, supports being launched from a lobby.
A video format in which the number of audio samples in a specified number of frames is fixed. In unlocked audio, the number of samples in a set of frames may vary, although the average equals the stated sample rate.
To use data from later in the stream to process the current data. For example, the next key frame is used to calculate a delta frame.
Quantized bands of color that are perceived instead of colors smoothly blended across a 3D primitive.
A property that determines how a surface reflects light. A material has emissive, diffuse, ambient, and specular properties. The emissive property describes the color of light that a material emits. The diffuse, ambient, and specular properties describe the behavior of reflected light. The sharpness of specular highlights is determined by a power setting.
A structure that identifies a hardware data path between two devices on the host system. They can be devices on the same card, such as a crossbar and a tuner on a TV card; devices on separate cards; or external devices. Kernel-mode filters based on the Windows Driver Model can use mediums instead of media types to determine pin connections.
An object whose surface contains faces, each of which is described by a simple polygon.
Also known as MIP map (Latin: multum in parvo, translated as "much in little"). A sequence of textures, each of which is a progressively lower-resolution, prefiltered representation of the same image. A higher-resolution image is used when a visible object is close to the viewer. As the object moves farther away (and gets smaller), lower-resolution images are used.
In Microsoft DirectSound, a buffer that receives data from other DirectSound buffers rather than directly from the synthesizer.
In Microsoft DirectSound, the process of combining sound buffers that are playing, and writing the result to the primary sound buffer, which supplies audio data to the sound hardware. There is no limit to the number of buffers that can be mixed, except as restricted by the time available to complete processing.
A hybrid display mode derived from the standard VGA Mode 13. This mode allows the use of up to 256 KB of display memory (rather than the 64 KB allowed by Mode 13) by using the VGA display adapter's EGA multiple video plane system.
Coordinates that are relative to a local origin.
Frame of reference (used by model coordinates) that uses vertices relative to a single 3D model's local origin.
In Microsoft DirectMusic, a type of pattern played explicitly by an application to mark an event.
Repeated rendering of a 3D primitive while blending on a texture with each pass. This technique is widely used to achieve a variety of special effects.
A filter that combines multiple input streams into one output stream.
In Microsoft DirectMusic, a note in a pattern within a style whose pitch is defined only when it is transposed to the current chord according to the current play mode and subchord level.
See Other Term: multiplexer (MUX)
An algorithm that causes the Transmission Control Protocol/Internet Protocol (TCP/IP) service provider to buffer small data packets into larger ones before sending. Nagling prevents a TCP/IP server from transmitting many very small packets by requiring the server to wait either until it has accumulated enough small data packets to combine them into a single large packet or until it has received an acknowledgment of the prior packet. Nagling can reduce message overhead (and decrease required bandwidth), but also causes a delay before small data packets are sent (increasing latency).
The dominant television standard in the United States and Japan. NTSC delivers 30 interlaced frames per second at 525 lines of resolution.
An identifier for a device-specific parameter that can be accessed through a MIDI controller. Nonregistered parameters can be used for different functions by different manufacturers.
Imaginary ray extending perpendicularly from a surface that defines the face's orientation.
See Other Term: nonregistered parameter number (NRPN)
See Other Term: National Television Standards Committee (NTSC)
First field comprising a video frame in an odd/even field set.
Conceptually rectangular area in memory that is generally used to store bitmaps to be blitted to a back buffer before being displayed. Commonly used to store sprites.
Operation code that defines how to interpret the vertices in an execute buffer or how to change the state of the system.
Average number of times that a screen pixel is written to.
Conceptually rectangular area in memory whose stored image information covers the image information of the primary surface to which it is applied. Overlays are assumed to be on top of all other screen components.
Determines the order in which overlays clip each other, enabling a hardware sprite system to be implemented under Microsoft DirectDraw.
See Other Term: flip
See Other Term: phase alternate line (PAL)
Set of colors used by an object or application. In Microsoft DirectX, a DirectDrawPalette object.
Integer index into the palette table array that is used to select a particular color.
A surface where each pixel color is represented by a number that indexes into a color palette. Also called a color-indexed surface.
A digital video disc (DVD) display format in which a 16x9 video is cropped for display in a 4x3 window, by using parameters defined by the video author.
Relative volume, measured in hundredths of decibels, between the left and right audio channels.
Description of a light source that illuminates objects with parallel light, but the orientation of the light is taken from the position of the parallel point light source. For example, two meshes on either side of a parallel point light source are lit on the side that faces the position of the source.
In Microsoft DirectMusic, a musical figure, one or more measures long, consisting of a basic sequence of music values for each instrument part.
See Other Term: performance channel (PChannel)
Pulse-code modulation. A method of encoding information in a signal by varying the amplitude of pulses. Unlike pulse amplitude modulation, in which pulse amplitude can vary continuously, PCM limits pulse amplitudes to several predefined values.
In Microsoft DirectMusic, an object that manages the flow of data from the source to the synthesizer, and controls global values, such as timing, tempo, and master volume.
A MIDI channel in a particular channel group on a particular port. In Microsoft DirectMusic, a set of parameters used to play one or more parts in a segment. Each performance channel has its own instrument, pan, volume, and transposition settings, and belongs to a single audiopath.
A process of interpolating texture coordinates prior to sampling a texture so that a polygon that is angled away from the camera is stretched correctly for the apparent depth of the polygon.
The dominant television standard in Europe and China. PAL delivers 25 interlaced frames per second at 625 lines of resolution.
A universal serial bus (USB) class that enables humans to feel force feedback from a computer.
To search for visuals in a scene, given a 2D coordinate in a viewport.
See Other Term: physical interface device
Distance, in bytes, between an address that represents the beginning of a bitmap line and the beginning of the next line. Do not confuse memory pitch and memory width because not all display memory is laid out as one linear block. For example, with rectangular memory, the pitch of the display memory could include the width of the bitmap plus part of a cache.
See Other Term: Portable Network Graphics
Light source that radiates equally in all directions from its origin.
Simplest 3D primitive. A collection of unconnected points in 3D space.
A nonproprietary bitmap format using lossless compression.
In the specular property of a material, value that determines the sharpness of specular highlights. A value of 5 gives a metallic appearance, and higher values give a more plastic appearance.
To capture or play a number of video frames or a portion of audio data before encoding or rendering begins, in order to allow the source device to stabilize. Also used as a noun to describe the portion of the data to be prerolled.
A sound buffer in which all data is mixed before being passed to the sound rendering device.
Memory containing the image being displayed on the screen.
Frame of reference containing vertices after they are modified from their world space locations by the projection transformation. Projection space is a homogeneous cuboid space in which all vertices in a scene have x-coordinates and y-coordinates that range from -1.0 to 1.0, and a z-coordinate that ranges from 0.0 to 1.0. Projection space is sometimes referred to as post-perspective homogeneous space.
A matrix multiplication that converts a matrix from camera space to projection space.
A technique for digitizing audio into an uncompressed format by assigning a value to the amplitude of the signal at fixed intervals.
Mechanism for adjusting the rate of data flow in response to run-time conditions.
A four-dimensional vector [x,y,z,w] typically used to rotate an object about the (x,y,z) vector by an angle theta, where w = cos(theta/2). Quaternion operations are computationally more efficient than 4x4 matrix multiplications used for transformations and rotations. A quaternion also represents the most efficient rotation to interpolate between two orientations of an object.
A clock that provides a common reference time with which filters can be synchronized.
A control for a Component Object Model (COM) object. When an object is created, its reference count is set to 1. Every time an interface is bound to the object, its reference count is incremented; when the interface connection is destroyed, the reference count is decremented. The object is destroyed when the reference count reaches 0. All interfaces to that object are then invalid.
An absolute time established by a reference clock in the filter graph.
In downloadable sounds (DLS), range of notes for which a particular digital sample is used in synthesizing an instrument's timbre.
An identification number for a registered parameter that has been assigned a function by the MIDI Manufacturers Association and can be accessed through controllers.
Red, green, blue, and alpha (opacity) components of a pixel. Each color is represented in memory by data in ABGR order.
Reciprocal, homogenous vertices divided by w. The vertices are transformed in homogeneous space with (x,y,z) divided by w, which is the component of the quaternion that defines the rotation.
The attenuation of sound over distance.
Frame in Microsoft Direct3D that has no parent frame; it is at the top of a hierarchy of frames. The root frame contains the entire set of objects that make up a scene.
See Other Term: registered parameter number (RPN)
In input and force feedback, adjustment to an axis range so that minimum or maximum values are retrieved or set before the physical extremities are reached. If the maximum value in a range is 1,000 and the maximum saturation point is set to 900, the maximum value is reached after 90 percent of the travel in that direction.
Entire set of objects that make up a virtual environment, including visible objects, sounds, lights, and frames.
Frame of reference that relates 2D coordinates to locations in the frame buffer. Screen space coordinates typically display on a monitor. The origin, or (0,0) is defined at the upper left corner. Y increases in the downward direction; X increases to the right. You use a viewport transformation matrix to convert points from projection space to screen space.
In Microsoft DirectMusic, a file containing variables and routines that can be accessed from within an application.
Object that manages a single sound or audio stream and plays it to the primary sound buffer.
An object created each time a segment is played. It is used to get information about the state of playback and the audiopath for that instance of the segment being played.
A sound effect for a buffer that is applied by sending the sound data to a second buffer.
A dynamic-link library that supports communications over a telephone network through a set of exported service functions. The service provider responds to telephony requests, sent to it by the TAPI dynamic-link library, by carrying out the low-level tasks necessary to communicate over the telephone network. In this way, the service provider, in conjunction with TAPI, shields applications from the service- and technology-dependent details of the telephone network communication.
An object that manages the distribution of data from the synthesizer through buses to Microsoft DirectSound buffers.
A Microsoft DirectSound buffer that receives data directly from the synthesizer rather than from other DirectSound buffers.
In Microsoft DirectShow Editing Services, the decompression and recompression of source data only when the data must be altered in some way before being written to the destination file.
Object that manages Microsoft DirectSound audio data.
A color that, in the case of blitting, will not be copied or, in the case of overlays, will not be visible on the destination.
Material property that determines how a point of light on a shiny object corresponds to the reflected light source. The specular property of a material is one of two properties that determines how a material reflects light.
Light source that emits a cone of light. Only objects within the cone are illuminated. The cone produces light of two degrees of intensity, with a central brightly lit section that acts as a point source, and a surrounding dimly lit section that merges with the surrounding deep shadow.
A standard color space that enables various devices including cameras, scanners, displays, and printers to produce reasonably identical colors. Optimized for 8 bits per channel with a gamma of 2.2, white point of D65, and primaries identical to HDTV/ITU-R BT.709/5.
A secondary sound buffer that contains an entire sound. Typically it is filled with data only once.
In Microsoft DirectSound, ability to play sound buffers when the owning application does not have the input focus. For example, a DirectSound application could continue to play a sound buffer while the user is working in another application.
The current time minus the previous start time. Stream time is defined only in a running filter graph.
A secondary sound buffer that contains only part of a sound. Its data must be refreshed as it is playing.
Blitting an image into a destination with different dimensions. This operation is supported directly by some hardware.
Synonymous with pitch.
In Microsoft DirectMusic, a collection of musical patterns and other data that can be used to create a dynamic score. A style defines a basic melody and rhythm with variations, motifs, and embellishments, contains a time signature and a tempo, and can contain one or more bands.
A globally unique identifier (GUID) value that describes the specific format of data digital media stream.
Memory that represents pixel data. The surface is often display memory, but can also be system memory.
Period during which the basic magnitude of a force-feedback effect is attained, after the attack and before the fade.
A collection of one or more back buffers that can be serially presented to the front buffer.
A media sample that can be decoded without requiring the decompressor to examine any other samples. One example is a key frame.
Transmission Control Protocol/Internet Protocol. A protocol developed by the Department of Defense for communications between computers. It is built into the UNIX system and has become the standard for data transmission over networks, including the Internet.
A visual artifact that occurs when one displayed video frame contains parts of two different source video frames. It is usually caused by improper synchronization between video rendering and the graphics display.
In Microsoft DirectMusic, a segment that can be used in combination with a chordmap to compose a new segment at run time.
Subdividing geometry into tiles, usually involving subdividing mesh faces into triangles.
A single element in a texture. When a texture has been applied to an object, the texels rarely correspond to pixels on the screen. Applications can use texture filtering to control how a texture is sampled.
A rectangular array of pixels applied to a visual object.
Technique of combining the colors of a texture with the colors of the surface to which the texture is applied.
A set of coordinates that determines what texel is returned from a texture during sampling.
The process of combining one or more texel colors to generate a single texel color when a texture is sampled.
Application of a texture to an object. Because a texture is a flat image and the object is often not, the texture must be mapped to the surface of the object, using texture coordinates and wrapping flags.
Contains a texture and operations that can be performed on the texture. As used in Microsoft DirectX, a texture stage takes two arguments and performs a blending operation on them.
Removing a resource used in the current frame to reclaim memory for subsequent frames.
Restricting the number of messages to avoid sending them faster than the underlying transport can deliver them.
A digital signal applied to a stream. The signal assigns a number to every frame of video, representing hours, minutes, seconds, and frames.
The time on a media sample indicating when it was recorded or when it should be scheduled for playback.
In a Microsoft DirectShow Editing Services video-editing project, the root node that contains all the other objects.
In Microsoft DirectShow, a collection of nonoverlapping sources with a common media type (audio or video).
A filter that receives data from an upstream filter, processes it, and then delivers it to the next filter in the graph.
A filter that can modify data without copying it to a new buffer.
A mechanism for moving data from one point to another. In a filter, the transport moves media samples across pins. In an external device such as a digital video (DV) camcorder, the transport channels data from the device to a computer, or from the computer to the device.
Vector with a magnitude (length) of 1.0.
An 11-megabits per second bus for computer and device peripherals. Requires one host controller and supports multiple connections.
To increase the number of audio samples or pixels, through a process such as interpolation.
Universal serial bus
See Other Term: vertical blanking interval (VBI)
In music, the speed at which a MIDI key is pressed. This is roughly equivalent to the dynamic level at which the note is played in some instrumental timbres. In 3D sound, for purposes of calculating Doppler shift, velocity is the speed at which a sound source or listener is considered to be moving.
Point in 3D space.
In broadcast video, small period of time that elapses between video frames during which a display device refreshes its display for the next frame.
In a video stream, the VREF is active to signal that the display is to begin a new screen.
Single image in a video stream, comprised of one odd field and one even field.
See Other Term: camera space
Accumulation of all of a control's property values.
Matrix multiplication that converts vertices from world space to view space.
3D volume in a scene positioned relative to the viewport's camera. Objects within the frustum are visible. For perspective viewing, the viewing frustum is the volume of an imaginary pyramid that is between the front clipping plane and the back clipping plane. For orthographic viewing, the viewing frustum is cubic.
Rectangle that defines how a 3D scene is rendered into a 2D window. A viewport also defines an area on a device into which objects are rendered.
Software that manages a hardware or software system resource. These drivers are described using three letters, beginning with V and ending with D. The middle letter indicates the type of device, such as D for display, P for printer, T for timer, or x when the type of device is not under discussion.
In Microsoft DirectShow Editing Services, any object that can be contained in a composition.
See Other Term: vertical refresh (VREF)
See Other Term: virtual device driver (VxD)
A file format in which Microsoft Windows stores sounds as waveforms. Such files have the extension .wav.
A method to display interlaced video. In weave mode, alternating fields are combined into a single image.
Distance between two addresses in memory that represent the beginning of a line and the end of the line of a stored bitmap. This distance represents only the width of the bitmap in memory. It does not include any extra memory required to reach the beginning of the next line of the bitmap, such as a cache in rectangular memory.
Coordinates that are relative to the origin of a scene. See also "model coordinates" and "world space."
Coordinate space which declares vertices relative to a single origin within a 3D scene.
Matrix multiplication that converts vertices from model space to world space.
Procedure used to calculate texture coordinates for a face or mesh. The basic wrapping types are flat, cylindrical, spherical, and chrome.
Buffer that stores a depth value for each pixel in a scene. Pixels with a small z-value overwrite pixels with a large z-value.
See Other Term: flimmering