Data Compression - AP Computer Science Principles

Compression that allows original data to be perfectly reconstructed. No information is permanently lost during compression.

Lossy and lossless compression. These represent the fundamental approaches to data reduction.

It decreases the file size. Lower bit rates mean more compression and smaller files.

Number of bits processed per second in a compressed file. Determines data transmission speed and quality.

A lossless data compression algorithm using variable-length codes. Assigns shorter codes to more frequent characters.

A simple form of lossless data compression based on runs of data. Replaces repeated values with count and value pairs.

Larger file sizes compared to lossy compression. Perfect preservation requires more storage space.

Loss of data quality and fidelity. Irreversible information loss reduces file quality.

Higher entropy indicates less potential for compression. Random data has high entropy and resists compression.

Moving Picture Experts Group. Standards organization for audio and video compression.

Measure of randomness or disorder in data. Higher entropy means less predictable, harder to compress data.

Lossy compression. Removing data allows for greater size reduction.

4:1. Original size divided by compressed size: $200 ÷ 50 = 4$.

Data compression reduces file size by encoding information more efficiently. Essential technique for managing storage and bandwidth efficiently.

Ratio of the size of the compressed file to the original file. Lower ratios indicate better compression efficiency.

The JPEG algorithm. Widely used for image compression with quality loss.

When data integrity is critical, such as text files. Perfect reconstruction is essential for text documents.

The Lempel-Ziv-Welch (LZW) algorithm. Dictionary-based algorithm for efficient lossless compression.

Lossless compression. File archives require perfect data preservation.

Faster data transmission. Reduced file sizes improve network transfer speeds.

Medical imaging where data integrity is crucial. Critical applications require perfect data preservation.

Data with low entropy. Predictable data contains patterns for compression.

Compression generally increases data transmission speed. Smaller files transfer faster over networks.

Restoring compressed data to its original form. Process of expanding compressed data back to original.

Balancing compression efficiency with data quality. Optimizing both compression ratio and acceptable quality.

Data with high entropy. Random data lacks patterns for compression algorithms.

Higher redundancy increases potential for compression. Repeated patterns enable more effective compression.

A device or program for encoding or decoding data streams. Software that compresses or decompresses digital media.

The file is identical to the original. Lossless compression preserves every bit of data.