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Compression

Compression makes files smaller for faster transmission and more efficient storage. It works by finding and reducing redundancy in data, either perfectly (lossless) or by discarding imperceptible information (lossy).

Need to know

What you need to know

  • **Advantage:** No loss of quality or data; the original can be perfectly restored.
  • **Disadvantage:** Achieves less reduction in file size (lower compression ratio) compared to lossy methods.
  • **Use Cases:** Archiving files (ZIP, RAR), source code, text files, and images where fidelity is key (PNG).

Explanation

Shrinking Digital Files

  1. Lossless compression — exact reconstruction (ZIP, PNG, FLAC).
  2. Lossy compression discards imperceptible detail (JPEG, MP3).
  3. Run-length encoding (RLE) for repeated data.
  4. Exam: calculate compressed vs uncompressed file sizes.
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