Converting an object orientated file to a discrete (bitmap) file type
The equivalent of capturing data (as with digitised sound or bitmap image)
Difference is no input hardware is required
All the information about each object is lost.
Attributes can no longer be altered
Converting from OOD Digitised Sound file Often using ‘Save As’ or ‘Export’ function but can also be recorded internally Midi music Bitmap Image Scanning printed text or doing a ‘screen shot’ and pasting it into bitmap image software Text Bitmap Image Called ‘rendering’. Generates a flat (2D) image from a given point of view. 3D Image Bitmap Image Often in ‘Save As’ or ‘Export’ menu of drawing program 2D drawing Discrete data How it can be converted OOD
Object Orientated Data Topic 5: Multimedia Technology
A vector is a mathematical term for a line with a specific length and direction.
A raster monitor creates them image by drawing rows of dots
Vector displays use the electron beam to draw out the shapes (no colour)
Vector Vs Bitmap Scaling causes pixellation. Can be scaled to large sizes, keeping original quality. Only the image as a whole can be edited. Individual objects can be edited. Are very difficult to convert to vector formats Are easily converted to bitmap formats. File sizes can be large. File sizes are relatively small. Images can be very realistic (e.g. digital photograph). Difficult to create realistic images
Vector Vs Bitmap Size of image can be increased keeping quality and file size the same. Increasing the image size needs re-sampling and increases the file size. Only individual objects can be edited (it is sometimes impossible to edit only part of the object). Same appearance in all systems, regardless of hardware or software. Dependent on output hardware or software for appearance & quality. Pixel level editing is allowed - allowing effects such as spray paint, blur, effects and so on. Suitable for natural, hand-drawn looking, realistic images. Suitable for graphic, unrealistic images and designs.
MIDI is a standard that was created to allow musical instruments to be able to communicate with each other
A MIDI file consists of Channels (up to 16)
Each channel consists of a sequence of messages including:
Start of a note
Channel to use
Pitch of the note
Volume to play it at
End of note
Synthesised Sound Data (MIDI) Sets musical tone of note which is determined by the frequency Pitch Meaning Attribute Speed at which the piece of music is set Tempo Rate Determines length of note (number of beats) Duration Controls loudness/amplitude of note Volume Defines instrument being played Instrument