This key facts covers Quick Reference - Images & Sound within Images & Sound for GCSE Computer Science. Revise Images & Sound in 3.3 Data Representation for GCSE Computer Science with 18 exam-style questions and 16 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 11 of 12 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Quick Reference - Images & Sound
Image Formula:
File Size (bytes) = Width × Height × Color Depth ÷ 8
Sound Formula:
File Size (bytes) = Sample Rate × Bit Depth × Duration × Channels ÷ 8
Common Values to Know:
- Image: 24-bit color depth = True Color (16.7M colors)
- Sound: CD quality = 44,100 Hz, 16-bit, stereo
- Sound: Stereo = 2 channels, Mono = 1 channel
- HD resolution: 1920×1080 pixels
Quality Trade-offs:
- Higher resolution: More pixels = better detail but larger file
- Higher color depth: More colors = better quality but larger file
- Higher sample rate: More samples = better sound but larger file
- Higher bit depth: More detail = better audio but larger file
Practice questions for Images & Sound
What does colour depth refer to in a digital image?
Explain the effect of increasing colour depth on a digital image. Refer to both file size and image quality in your answer.