Brainlag PlusSampling sound, calculating sound file sizes, lossy and lossless compression, run length encoding and Huffman coding.
Sampling sound
Sound is an analogue wave.
To store it, the computer measures its height many times a second; each measurement is a sample.
- Sample rate: samples per second, in hertz (44 100 Hz for CD audio).
- Bit depth: bits per sample. More bits record each height more precisely.
- A higher sample rate or bit depth sounds closer to the original but makes a bigger file.
file size in bits = sample rate × bit depth × length in seconds
(Multiply by 2 for stereo.) The sample interval is the time between samples: 1 ÷ sample rate. At 50 000 Hz it is 1 ÷ 50 000 s = 20 microseconds.
The rest of this lesson and its 8 practice questions are in Plus.
Screen 1 of 3, free to read.
- 8 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards