Encoding Images, Audio and Video Flashcards
What is a pixel?
A pixel is a single coloured ‘dot’ in a bitmap image. Pixels are usually arranged in a 2D grid to make up a picture.
Why are vector files often high quality, even after when you zoom in or out of the image?
Vector files remain high quality when you zoom in an out because the precise position of each part o the image can be recalculated using the coordinates and mathematic formulae.
What is resolution?
Resolution is a measure of how many pixels are used in a given area. They tell you how dense (and therefore how detailed) the image is.
What does ‘dpi’ mean?
DPI refers to the number of dots used per horizontal inch in the image. It is a measure of resolution of how detailed the image is.
Why do bitmap images often appear blocky if you enlarge them too much?
Bitmap images can appear blocky when you enlarge them too much because there is only a limited amount of detail in them. Individual pixels are enlarged to become larger rectangles.
What is the ‘colour depth’ of a raster image?
Colour depth is the number of alternative colours that a pixel can use.
What is metadata?
Metadata is data that describes other data, e.g. how an image is structured or organised, and the width and the height of the image.
What is the difference between stereo and mono audio?
Stereo audio usually requires twice as much data as mono audio.
Why does streamed video content sometimes pause during playback on a home computer?
Streamed video clips sometimes pause because of buffering.
What is the effect of increasing the frame rate of a video clip?
When the frame rate of a video clip is increased, motion become smoother and the file size increases.
What is a codec?
A codec is a program used to encode or decode data.
What is the bitrate of an audio file?
The bitrate of an audio fils tells you the amount of data used per second, usually measure in kbps.
What is bit depth?
Bit depth is noted number of bits it is possible to have in each sample or frame of a media file.
