Images and sound Flashcards
(20 cards)
What is ASCII
7 bits
extended is 8 bit
What is Unicode
16 bits / 24 bits
can represent every language + emojis
(16 bit does not have some Chinese characters and dead languages)
What are the limitations of ASCII
only does the English language
What is Analogue sound
An electrical signal
natural sound wavers
continuous wave form
What is digital sound
An electrical signal
discreet digital format to represent natural sound waves
What is an ADC and DAC
convert continuous natural sound waves to digital - used together with analogue sensors (microphone) - measure and record amplitude at set intervals
Does the opposite of ADC
What is sample rate
How many samples are taken each second measured in Hz
What is sample resolution
How many bits store each sample
What is Nyquists theorum
That for a good sound samples should be taken just over double the highest frequency that a human can hear
What are MIDI files
Files that store instructions on how to play different recordings of instruments
How do you calculate file sizes for sounds
Size of a file = number of samples per second * number of bits pre sample * length of sample in seconds
What is a sound sample
A reading of the amplitude of the analogue sound
What is a Bitmap graphic
an image is broken down into pixels, each of which has a binary value assigned to it.
What is a vector graphic
represent images using geometric objects and shapes so no quality is lost when zoomed in
what is a pixel
Picture element, the smallest addressable part of a bitmap image
What is the resolution of an image
Number of pixels in the image (Num pixels width * height)
OR the number of dots (pixels) per square inch
what is the colour depth
How many bits represent the colour of one pixel
How do you calculate image size
File size = Size in pixels * colour depth
What is metadata and some examples
Additional data about the image that is stored but not necessarily displayed
Copyright information: Details about the copyright of the image
Size: The size of the image in bits and pixels
Color depth: The color depth of the image
Resolution: The resolution of the image
GPS coordinates: The GPS coordinates of the image’s location
Date / time the images was taken
