Glossary·A

ADPCM (Adaptive Differential Pulse Code Modulation):An audio-compression technique.

animation:The display of a series of graphic images, simulating motion. Animation can be frame-based or cast-based. The Movie Player included with the Multimedia extensions uses cast-based animation.

applet:An application started from the Control Panel. Control Panel applets each configure a particular system feature; for example, printers, video drivers, or system sounds.

auxiliary audio device:Audio devices whose output is mixed with the MIDI and waveform output devices in a multimedia computer. An example of an auxiliary audio device is the compact disc audio output from a CD-ROM drive.·B

background:Images displayed behind other images in a movie. In the Movie Player, objects that appear behind other objects and objects located in lower-numbered channels in scores are all part of the background.

BitBlt (Bit Block Transfer):The BitBlt function, which is part of the Windows API, copies a bitmap from a source to a destination device context.

blitting:Process of transferring a bit map from a source device context to a window client area.

break key:In MCI, a keystroke that interrupts a wait operation. By default, MCI defines this key as CTRL+BREAK. An application can redefine this key by using the MCI_BREAK command message.·C

cast:A collection of bitmaps, graphical objects, and text displayed during playback of a multimedia movie.

cast-based animation:A form of animation, also known as object animation, where each object involved in the presentation is an individual element with its own movement pattern, color, size, shape, and speed. A script controls the placement and movement of objects at each frame.

cast member:A single visual object drawn on a multimedia movie frame for display. A cast member can be a bitmap, text string with supporting font characteristics, or a graphical object like a line or rectangle.

CD-DA (Compact Disc-Digital Audio):An optical data-storage format that provides for the storage of up to 73 minutes of high-quality digital-audio data on a compact disc. Also known as Red Book audio.

CD-ROM (Compact Disc-Read Only Memory): An optical data-storage technology that allows large quantities of data to be stored on a compact disc.

CD-XA (CD-ROM Extended Architecture):An extension of the CD-ROM standard that provides for storage of compressed audio data along with other data on a CD-ROM disc. This standard also defines the way data is read from a disc. Audio signals are combined with text and graphic data on a single track so they can be read at virtually the same time.

channel:MIDI provides a way to send messages to an individual device within a MIDI setup. There are 16 MIDI channel numbers. Devices in a MIDI setup can be directed to respond only to messages marked with a channel number specific to the device.:In the Movie Player, the score, which controls the cast members used in the animation, consists of a series of channels. Each channel can hold a cast member, a special effect such as a transition or change-tempo command, or a script command. The score is like a grid; columns represent frames, while rows represent channels. Each cell defines the behavior of one aspect of the animation for a single frame.

channel map:The MIDI Mapper provides a channel map that can redirect MIDI messages from one channel to another.

chunk:The basic building block of a RIFF file, consisting of an identifier (called a chunk ID), a chunk-size variable, and a chunk data area of variable size.

CLUT (Color Look-Up Table):A palette.

command message:In MCI, a command message is a symbolic constant that represents a unique command for an MCI device. Command messages have associated data structures that provide information a device requires to carry out a request.

command string:In MCI, a command string is a null-terminated character string that represents a command for an MCI device. The text string contains all the information that an MCI device needs to carry out a request. MCI parses the text string and translates it into an equivalent command message and data structure that it then sends to a MCI device driver.

compound device:An MCI device that requires a device element, usually a data file. An example of a compound device is the MCI waveform-audio driver.

compound file:A number of individual files bound together in one physical file. Each individual file in a compound file can be accessed as if it were a single physical file.

control change:See MIDI control-change message.·D

default palette:See system colors.

device element:Data required for operation of MCI compound devices. The device element is generally an input or output data file.

DIB (Device-Independent Bitmap):A Windows bitmap data structure consisting of header fields, an optional color table (palette), and bitmap data. Depending on the number of colors represented in a given bitmap, the bitmap bits can be represented in 1, 4, 8, or 24 bits, with or without a palette.·F

file element:An complete file contained in a RIFF compound file.

FM (Frequency Modulation) synthesizer: Asynthesizer that creates sounds by combining the output of digital oscillators using a frequency modulation technique.

foreground:Images displayed in front of other images in a movie. In the Movie Player, visual objects in higher-numbered score channels appear in front of objects in lower-numbered channels.

form type:A four-character code (FOURCC) identifying the type of data contained in a RIFF chunk. For example, a RIFF chunk with a form type of WAVE contains waveform audio data.

FOURCC (Four-Character Code):A code used to identify RIFF chunks. A FOURCC is a 32-bit quantity represented as a sequence of one to four ASCII alphanumeric characters, padded on the right with blank characters.:

frame:A segment of time in an animated movie. :In frame-based animation, the frame is an actual picture shown on a screen for a specified time period. Traditional motion pictures and animated cartoons, as well as old-fashioned animated flip books, use frame animation.:In cast-based animation, the frame is a time slice that defines the usage and position of cast members. There is no picture, only a collection of information defining the position and behavior of objects at a particular moment. The Movie Player uses cast-based animation.

frame-based animation:A series of screens displayed in quick succession. The changing appearance of the screens from frame to frame produces the animation.

frame hook:An application-supplied callback function that the Movie Player executes with each frame advance. The frame-hook function is passed frame and subframe numbers with one message and script-channel text with another message.

frame index:A Movie Player variable that tracks the current movie frame. The current movie frame is the one imaged in the off-screen buffer.·G

General MIDI:A synthesizer specification created by the MIDI Manufacturers Association (MMA) defining a common configuration and set of capabilities for consumer MIDI synthesizers.·H

HMS time format:A time format used by MCI to express time in hours, minutes, and seconds. The HMS time format is used primarily by videodisc devices.·I

identity palette:A 256-color palette in which the first and last 10 colors make up the system colors. The identity palette speeds up the loading of bitmaps.

IMA (International MIDI Association): The non-profit organization that circulates infor-mation about the MIDI specification.

IMA (Interactive Multimedia Association): A professional trade association of companies, institutions, and individuals involved in producing and using interactive multimedia technology.

ink effect:In Movie Player files, ink effects modify the way the Movie Player draws cast members to the stage. Ink effects also modify the appearance of cast members already on the stage. For example, the Transparent ink effect makes the background pixels of the cast member transparent (the background shows through the transparent pixels).·L

LIST chunk:A RIFF chunk with a chunk ID of LIST. LIST chunks contain a series of subchunks.

list type:A four-character code (FOURCC) identifying the type of data contained in a RIFF chunk with a chunk ID of LIST. For example, a LIST chunk with a list type of INFO contains a list of information about a file, such as the creation date and author.

logical palette:A Windows GDI data object that contains a list of colors needed by an application. An application can request that Windows use the colors in its logical palette (a process called realizing the palette).·M

Media Control Interface (MCI):High-level control software that provides a device-independent interface to multimedia devices and media files. MCI includes a command-message interface and a command-string interface.

MIDI (Musical Instrument Digital Interface):A standard protocol for communication between musical instruments and computers.

MIDI control-change message:A MIDI message sent to a synthesizer to change different synthesizer control settings. An example of a control-change message is the volume controller message, which changes the volume of a specific MIDI channel.

MIDI file:A file format for storing MIDI songs. In Windows with Multimedia, MIDI files have a .MID filename extension. RIFF MIDI files have a .RMI filename extension.

MIDI Mapper:Multimedia extensions software that modifies MIDI output messages and redirects them to a MIDI output device using values stored in a MIDI setup map. The MIDI Mapper can change the destination channel and output device for a message, as well as modify program-change messages, volume values, and key values.:The Control Panel includes a MIDI Mapper applet that allows a user to create and edit MIDI setup maps.

MIDI mapping:The process of translating and redirecting MIDI messages according to data defined in a MIDI map setup.

MIDI program-change message:A MIDI message sent to a synthesizer to change the patch on a specific MIDI channel.

MIDI sequence:Time-stamped MIDI data that can be played by a MIDI sequencer.:

MIDI sequencer:A program that creates or plays songs stored as MIDI files. When a sequencer plays MIDI files, it sends MIDI data from the file to a MIDI synthesizer, which produces the sounds. The Multimedia extensions provide a MIDI sequencer, accessible through MCI, that plays MIDI files.

MIDI setup map:A complete set of data for the MIDI Mapper to use when redirecting MIDI messages. Only one setup map can be in effect at a given time, but the user can have several setup maps available and can choose between them using the MIDI Mapper Control Panel applet.

MIDI time code (MTC):MIDI messages used for synchronizing MIDI sequences with external devices. The MCI MIDI sequencer does not support any type of synchronization.

MMA (MIDI Manufacturers Association):A collective organization composed of MIDI instrument manufacturers and MIDI software companies. The MMA works with the MIDI Standard Committee to maintain the MIDI specification.

MSF time format:A time format used by MCI to express time in minutes, seconds, and frames. The number of frames in a second depends on the device type being used. Compact disc audio devices use 75 frames per second. The MSF time format is used primarily by compact disc audio devices.

movie file:A Multimedia Movie Player data file with a .MMM filename extension. The movie file contains animation objects called cast members and control information called the score. The RIFF-based file format for movie files is called the RMMP format.:Movie files can be created using MacroMind Director. Director files written on the Macintosh can be converted to the Movie Player format using the Multimedia Movie Convertor utility. :

movie ID:A Movie Player instance identifier. When an application opens a Movie Player instance, it receives an identifier called a movie ID. Most Movie Player functions require the movie ID as a means of identifying the Movie Player instance.

Movie Player instance:An invocation, or copy, of the Movie Player. Each Movie Player instance can play one movie file at any given time.

MSCDEX (Microsoft Compact Disc Extensions): A terminate-and-stay-resident (TSR) program that makes CD-ROM drives appear to MS-DOS as network drives. MSCDEX uses hardware-dependent drivers to communicate with a CD-ROM drive.·O

object animation:See cast-based animation.

off-screen buffer:A memory area that the Movie Player uses to prepare movie frames off screen before displaying them in the stage window. Preparing movie frames off screen improves animation performance.·P

palette:In Windows, a palette is a data structure defining the colors used in a bitmap image. The palette consists of a palette header and a color table consisting of a series of RGB (red, green, blue) values. Bitmap data consists of indexes into the palette table, indicating which color to use for each pixel.

patch:A particular setup of a MIDI synthesizer that results in a particular sound, usually a sound simulating a specific musical instrument. Patches are also called programs. A MIDI program-change message changes the patch setting in a synthesizer. Patch also refers to the connection or connections between MIDI devices.

patch caching:Some internal MIDI synthesizer device drivers can preload, or cache, their patch data. Patch caching reduces the delay between the moment that the synthesizer receives a MIDI program-change message and when it plays a note using the new patch. Patch caching also ensures that required patches are available (the synthesizer might load only a subset of its patches).

pitch scale factor:An application can request that a waveform audio driver scale the pitch by a specified factor. A scale factor of two results in a one-octave increase in pitch. Pitch scaling requires specialized hardware. The playback rate and sample rate are not changed.

playback rate scale factor:In waveform audio, an application can request that the waveform audio driver scale the playback rate by a specified factor. Playback scaling is accomplished through software; the sample rate is not changed, but the driver interpolates by skipping or synthesizing samples. For example, if the playback rate is changed by a factor of two, the driver skips every other sample.

PPQN (Parts Per Quarter Note):A time format used for MIDI sequences. PPQN is the most common time format used with standard MIDI files.

preimaging:The process of building a movie frame in a memory buffer before it is displayed.·Q

QuickDraw objects:Macintosh graphical objects used as cast members in MacroMind Director movie files. The Movie Player supports the use of most QuickDraw objects.::·R

realizing the palette:The process of mapping colors in a logical palette into the system palette. An application requests that Windows provide it the colors in a logical palette. Windows provides exact matches for as many logical-palette colors as is possible given the capabilities of the display driver. Any logical-palette colors that Windows cannot provide are mapped to colors already available in the system palette.

Red Book audio:See CD-DA.

Resolution:For bitmaps, resolution depends on the size of the pixels that make up the image. Higher-resolution bitmaps are composed of smaller pixels than lower-resolution bitmaps. The video drivers included with the Multimedia extensions support two resolution levels: 640 by 480 pixels and 320 by 240 pixels.:For joysticks, resolution refers to the minimum and maximum intervals between joystick messages sent for a captured joystick.:For timers, resolution refers to the accuracy of the timer event. A resolution value of zero means that the event must occur at the exact time requested, while a resolution value of ten means that the event must occur within ten milliseconds of the requested time.

RIFF (Resource Interchange File Format): A tagged-file specification used to define standard formats for multimedia files. Tagged-file structure helps prevent compatibility problems that often occur when file-format definitions change over time. Because each piece of data in the file is identified by a standard header, an application that does not recognize a given data element can skip over the unknown information.

RIFF chunk:A chunk with chunk ID RIFF that includes an identifying code and zero or more sub-chunks, the contents of which depend on the form type.

RIFF file:A file whose format complies with one of the published RIFF forms.:Examples of RIFF files include WAVE files for waveform audio data, RMID files for MIDI sequences, RDIB files for bitmaps, and RMMP files for multimedia Movie Player movies.

RIFF form:A file-format specification based on the RIFF standard.·S

sample:A discrete piece of waveform data represented by a single numerical value. Sampling is the process of converting analog data to digital data by taking samples of the analog waveform at regular intervals.

sampling rate:The rate at which a waveform audio driver performs audio-to-digital or digital-to-audio conversion. For CD-DA, the sampling rate is 44.1 kHz.

score:A script that controls the activities of cast members in a movie. In MacroMind Director, the score appears as a grid into which an author can place animation commands. Grid rows are channels; columns of the grid are movie frames.

script channel:In Movie Player movies, one of the channels in the score can contain script commands. On the Macintosh, the script channel is used for Lingo script statements. Under Windows with Multimedia, the script channel can contain MCI commands, as well as user-defined commands to be interpreted by specific applications using the Movie Player.

seek:With file I/O, seek means to change the current position in the file. The current position is the location where the next read or write operation will take place. With a media device (such as a hard disk), seek means to position the media so a certain sector can be accessed. The seek involves a physical movement of the device, so the time it takes can often be perceived by the user.

sequence:See MIDI sequence.

sequencer:See MIDI sequencer.

simple device:An MCI device that does not require a device element (data file) for playback. The MCI compact-disc audio driver is an example of a simple device.

SMPTE (Society of Motion Picture and Television Engineers):An association of engineers involved in movie, television, and video production. SMPTE also refers to SMPTE time, the timing standard that this group adopted.

SMPTE division type:One of four SMPTE timing formats. SMPTE time is expressed in hours, minutes, seconds, and frames. The SMPTE division type specifies the frames-per-second value corresponding to a given SMPTE time. For example, a SMPTE time of one hour, 30 minutes, 24 seconds, and 15 frames is useful only if the frames-per-second value, or SMPTE division type, is known.

SMPTE offset:A MIDI event that designates the SMPTE time at which playback of a MIDI file is to start. SMPTE offsets are used only with MIDI files using SMPTE division type.

SMPTE time:A standard representation of time developed for the video and film industries. SMPTE time is used with MIDI audio because many people use MIDI to score films and video. SMPTE time is an absolute time format expressed in hours, minutes, seconds, and frames. Standard SMPTE division types are 24, 25, and 30 frames per second.

square-wave synthesizer:A synthesizer that produces sound by adding square waves of various frequencies. A square wave is a rectangular waveform.

stage window:The window in which the Movie Player plays a movie. Each MMP instance can have an associated stage window.

static colors:See system colors.

streaming:The process of transferring information from a storage device, such as a hard disk or CD-ROM, to a device driver. Rather than transferring all the information in a single data copy, the information is transferred in smaller parts over a period of time, typically while the application is performing other tasks.

system colors:A collection of 20 colors that Windows sets aside for use in coloring window components (such as borders, captions, and buttons). Also known as the static colors.

system-exclusive data:In MIDI, messages understood only by MIDI devices from a specific manufacturer. System-exclusive data provides a way for MIDI-device manufacturers to define custom messages that can be exchanged between their MIDI devices. The standard MIDI specification defines only a framework for system-exclusive messages.

system palette:The collection of colors available on a system. These colors are shared by all Windows applications. The size of the system palette depends on the capabilities of the display driver; a 256-color device can have a system palette with up to 256 colors.·T

tagged file format:A file format in which data is tagged using standard headers that identify information type and length.

tempo:In Movie Player animation, the amount of time a frame remains on screen before being replaced by the next frame. Each movie frame can have its own tempo setting, so the playback speed can change during the movie.:With the MIDI sequencer, tempo is the speed that a MIDI file is played. It is measured in beats per minute (BPM). A typical MIDI tempo is 120 BPM.

threshold:For the joystick interface, the movement threshold is the distance in device units that the coordinates must change before the application is notified of the movement. Setting a high thresh-old reduces the number of joystick messages sent to your application, however, it also reduces the sensitivity of the joystick.

time stamp:With recorded MIDI data (such as MIDI files), MIDI messages are tagged with a time stamp so that a MIDI sequencer can replay the data at the proper moment.

TMSF time format:A time format used by MCI to express time in tracks, minutes, seconds, and frames. The number of frames in a second depends on the device type being used. Compact disc audio devices use 75 frames per second. The TMSF time format is used primarily by compact disc audio devices.

track:A sequence of sound on a CD-DA disc. A CD-DA track usually corresponds to a song.:With a MIDI file, information can be separated into tracks, which are defined by the creator of the MIDI file. MIDI file tracks can correspond to MIDI channels, or they can correspond to parts of a song (such as melody or chorus).

transition :In Movie Player files, the method by which one frame changes to the next. MacroMind Director provides a variety of transition effects. The author can specify the time period over which the transition occurs, as well as the number of pixels changed in each transition movement.::::·V

volume scalar:A component of a MIDI Mapper patch map that adjusts the volume of a patch on a synthesizer. For example, if the bass patch on a synthesizer is too loud compared to its piano patch, the volume scalar can reduce the volume for the bass or increase the volume for the piano.:Applications playing waveform audio can also adjust the output volume.·W

WAVE file:A Microsoft standard file format for storing waveform audio data. WAVE files have a .WAV filename extension.

waveform audio:A technique of recreating an audio waveform from digital samples of the waveform.:

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