gen-define-lossless-versus-lossy-compression-and-give-one-short-6796

Define lossless versus lossy compression and give one short worked example.

# Lossless vs Lossy Compression ## Definitions **Lossless Compression**: Reduces file size while preserving ALL original data. The file can be perfectly reconstructed to its original state. - Examples: ZIP, PNG, FLAC **Lossy Compression**: Reduces file size by permanently discarding some data (usually imperceptible information). The original cannot be perfectly recovered. - Examples: JPEG, MP3, MP4 ## Worked Example: Text Compression **Original text (24 characters):** ``` AAAAABBBBBCCCCCDDDDDDD ``` ### Lossless (Run-Length Encoding): ``` 5A5B5C7D ``` - Compressed to 8 characters - Can perfectly reconstruct: AAAAA + BBBBB + CCCCC + DDDDDDD ✓ ### Lossy (Approximation): ``` 5A5B5C5D ``` - Compressed to 8 characters - Reconstructs to: AAAAABBBBBCCCCCDDDD**D** (only 20 D's instead of 7) - Smaller file, but **information is lost** ✗ --- **Key takeaway**: Use lossless when accuracy matters (text, medical images, archives). Use lossy when file size matters more than perfect quality (photos, music, video).