Multiple choiceQuestion 1 · Recall
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By the end you can choose lossy or lossless compression for a situation and justify the choice in a way that earns the marks.
Ask yourself: would losing any data cause a problem?
| Situation | Choose | Because… |
|---|---|---|
| Text documents, emails, source code | lossless | one changed character can change the meaning ("now" → "not") |
| A program file to download | lossless | one wrong bit could stop the program running or make it misbehave |
| Spreadsheets, databases, bank records | lossless | every value must be exactly right |
| Medical scans | lossless | removed detail could hide something a doctor needs to see |
| Music or video streamed to phones | lossy | much smaller files stream in real time with less bandwidth; listeners are unlikely to notice what's gone |
| Photos on a website | lossy | pages load faster; the tiny lost detail isn't noticed on screen |
| A photographer's master copies | lossless | they'll be edited and saved again, and each lossy save loses more |
| Logos, screenshots and diagrams with big blocks of colour | lossless | they compress well without loss, and lossy compression can smudge sharp edges and text |