Learning objectives
Explain how a character set such as ASCII or Unicode gives every character a binary code, and compare the two on the number of bits used per character and the range of characters covered
Describe how a sound wave is sampled at regular intervals, and explain how the sample rate and the sample resolution each affect the accuracy of the recording and the size of the file
Describe how an image is stored as a grid of pixels that each hold a colour value, and explain how the resolution and the colour depth affect the quality of the image and the size of the file
Calculate the file size of a sound recording or of an image from given sampling or resolution values, and convert between bits, bytes, kibibytes, mebibytes, gibibytes and tebibytes
Explain why files are compressed before storage and before transmission, and describe how lossy compression and lossless compression each reduce the size of a file
Describe run-length encoding as a lossless method that records a repeated value once together with a count, and apply it to a short sequence of data
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