1.3 · Lesson 3 of 3
Data compression
Syllabus 1.3.3Syllabus 1.3.4
What this lesson covers
- Explain the purpose of and need for data compression
- Explain lossy and lossless compression, including run length encoding
Key vocabulary
- Motion estimation
- Lossy video compression that stores only the movement between frames.
- Compression
- Reducing the amount of data used to represent a file.
- Lossy compression
- Compression that permanently removes data. The original can't be rebuilt exactly.
- Lossless compression
- Compression where no data is lost, so the original can be rebuilt exactly.
- Run length encoding (RLE)
- A lossless method that stores each run of repeated values as a count and the value.
- Bandwidth
- The amount of data that can be sent across a network in a given time.
- Perceptual music shaping
- Lossy sound compression that removes sounds people can't hear, or that louder sounds hide.
Check your learning
- Quick check: 4 questions
- Key vocabulary test: 7 terms
- Activity 1: Image compression · 8 questions
- Activity 2: Sound compression · 8 questions
- Activity 3: Text compression with RLE · 8 questions