Lesson 20: Principles of data compression
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Lossless and lossy compression are the two main types of data compression. Lossless compression reduces file size by encoding information using fewer bits without any loss of quality, while lossy compression removes unnecessary information and redundant data, resulting in smaller file sizes but potential loss of quality when restoring files. Compression works by reducing the number of bits needed to store or transmit data, producing a smaller compressed file without modifying the original file.
Lesson 20: Principles of data compression
- 1. Computer Science CIE-Syllabus 2210 Lesson 20 Principles of data compression Tutor: Suraj Motee
- 2. Learning Outcomes • Differentiate between lossless and lossy compression.
- 3. What is compression? • Compression is the process of encoding information using fewer bits so that the compressed file size is smaller.
- 4. What is compression? Original A bits Compression Process Compressed B bits B < A
- 5. Types of compression Lossless Lossy
- 6. True or False • Compression produces a larger file size. • Compression works by reducing the number of bits. • Compression does not produce a second file but modify the original one. FALSE TRUE FALSE
- 7. LOSSLESS COMPRESSION Original 100 MB Compressed 50 MB Restored 100 MB LOSSLESS COMPRESSION can reduce file size without losing quality.
- 8. LOSSY COMPRESSION Original 100 MB Compressed 50 MB Restored 80 MB LOSSY COMPRESSION removes unnecessary information and redundant data so as to reduce the size of the file.
- 9. LOSSLESS OR LOSSY • Compressed file cannot be restored to the same original file. • Quality is affected. • Compression technique that produce a second file that can be restored back to original file size. LOSSY LOSSY LOSSLESS