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data representation sound video
A LevelComputer Science~4 min read
Overview
This lesson explores how sound and video are represented digitally, focusing on the processes of sampling, quantisation, and encoding. We will examine the factors affecting the quality and file size of digital audio and video, and understand the role of codecs in compression.
Digital Sound Representation: Sampling and Quantisation
Digital sound is created by converting continuous **analogue sound waves** into discrete **digital data**. This process involves two main stages: **sampling** and **quantisation**. 1. **Sampling**: An Analogue-to-Digital Converter (ADC) takes measurements of the analogue sound wave's amplitude at ...
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Key Concepts
- Sampling: The process of converting an analog sound wave into a digital signal by taking discrete measurements at regular intervals.
- Sampling Rate: The number of samples taken per second, measured in Hertz (Hz) or kilohertz (kHz). Higher rates mean better quality but larger file sizes.
- Quantisation: The process of converting the amplitude of each sample into a discrete numerical value, typically represented by a fixed number of bits.
- Bit Depth (Quantisation Resolution): The number of bits used to represent the amplitude of each sample. Higher bit depth allows for more precise amplitude representation, leading to better sound quality.
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Exam Tips
- →Be able to clearly define and explain the terms: sampling rate, bit depth, frame rate, and resolution, and discuss their impact on file size and quality for both sound and video.
- →Understand the difference between analogue and digital signals, and the role of ADCs and DACs in the conversion process for sound.
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