Term | Definition |
Digital audio | built in microphone and audio software; record sound samples collected at periodic intervals and stored as numeric data in an audio file |
Analog to digital converter | sound waves samples many times per second by this |
Digital to analog converter | converter transforms bits to sound waves |
sampling rate | number of times per second that a sound is measured during the recording process where higher rates increase the quality of sound |
Audio format: AAC | very good sound quality based on MPEG-4; files can be copy-protected |
Audio format: MP3 | good sound quality that can be streamed over the Web; may need a standalone player or browser plugin, stored in compressed format |
Audio format: MAV | Good sound quality supported in browsers without a plugin; stored in raw uncompressed format |
Audio format: WMA | Very good sound quality in this compressed format which files can be copy protected |
Audio player | o Small standalone software application or mobile app that offers tools for listening to digital audio and managing playlists, typically included with your computer’s OS (operating system) |
Audio plugin | o Software that works in conjunction with your computer’s browser to manage and play audio from a Web page |
Live Stream | sends media from a server to your local device; webcasting- cannot be paused, stored or rewound |
On-demand stream | o Stream sends the media to your local device, where it is stored temporarily, or “buffered” until there is enough data to begin playback
o You can fast forward to any point in the stream without waiting for the file to download |
Digital audio extraction | "ripping"; importing tracks from CD or DVD to yours |
MIDI | specifies a standard way to store music data for synthesizers, electronic MIDI instruments, and computers
o instructions that specify the pitch of a note, the point at which the note begins, the volume of the note, etc. |
Speech synthesis | machines produce sound that resembles spoken word |
Speech recognition | ability of a machine to understand spoken words |
Text-to-speech software | analyzes the sounds of your voice and converts each word into groups of phonemes then compares the groups to the words in a digital dictionary to find a match, when found, the software can display the word on the screen or use it to carry out a command |
BMP | raster graphics, image file format used to store bitmap digital devices, independently of the display device |
JPEG | format for compressing image files |
GIF | lossless format for image files that supports both animated and static images |
PNG | file format for image compression that in time i expected to replace the GIF |
Image compression | any technique that recodes the data in an image file so that it contains fewer bits |
Vector | o The first graphics that appeared on computer screens were not photos, but simple shapes consisting of lines and curves |
Vector graphic | o consists of a set of instructions for creating a picture
o include standard shapes such as circles and rectangles |
Vector vs Bitmap | Resize better than bitmaps
o Require less storage space
o Not as realistic as bitmap images
o Editing an object is easier than in bitmap
o used for line art, logos, simple illustrations, infographic elements, and diagrams |
3D graphics | o based on vectors stored as a set of instructions describing the coordinates for lines and shapes in a three-dimensional space |
Wireframe | vectors from a wireframe that works like the framework for a tent |
Rendering | process of covering the wireframe surface with color and texture |
ray tracing | technique for adding light and shadows to a 3D image |
Frame | each bitmap image |
frame rate | number of frames that are displayed per second |
interlace scan | o contrasting scanning technique that produces an image by drawing every other line, then going back and filling in the in-between lines
o Digital video for computers typically uses progressive scanning; digital television uses interlaced scanning |
CODEC | o the software that compresses a video stream when a video is stored, and decompresses the file when the video is played |
Container formats | hold the compressed video stream and an audio stream |
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