AP Topics 2.1 & 2.2 Review: Binary Numbers and Data Compression

Vocabulary flashcards covering binary conversions, ASCII, RGB images, analog sampling, and compression types for AP CS Principles Topics 2.1 and 2.2.

Bit

One binary digit, taking a value of 0 or 1.

Byte

A group of 8 bits that holds 256 values, numbered 0 through 255.

1111 1111

The binary representation for 255, which is the largest value a single byte can hold.

ASCII

An encoding format that stores characters as numbers and then in binary, using 7 bits (128 codes) with the 8th bit originally used for an error check.

ASCII Value for 'A'

The number 65, with the rest of the uppercase alphabet running in order from there.

ASCII Value for '0'

The number 48, demonstrating that the character representation is distinct from the numerical value it represents.

Pixel (RGB)

An image element consisting of three bytes (one for red, green, and blue), totaling 24 bits and 16,777,216 colors.

Bit depth

The number of bits used per pixel; for instance, 1 bit per pixel produces black and white, while 24 bits produces full color.

Metadata

The header data describing width, height, and bits per pixel, without which the same raw bits could be rendered as any shape.

Sampling

The process of measuring continuous real-world signals at regular intervals, producing discrete approximations stored by computers.

Compression

The process of reducing file size by finding and removing redundancy.

Lossless Compression

A compression method that guarantees exact reconstruction of the original file (e.g., ZIP, PNG, GIF, FLAC).

Lossy Compression

A compression method that permanently discards data human senses are least likely to notice (e.g., JPEG, MP3, H.264), usually producing smaller files than lossless.

Mbps vs. MB

Mbps represents megabits while MB represents megabytes; divide Mbps by 8 to convert to megabytes.