WEBVTT

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Representing images and sound.

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In this video, we will understand

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Computers do not see images or hear sounds the way humans do.

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Explain how images are stored using pixels.

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Describe how sounds are captured and represented using samples.

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Recognize that both images and sounds are stored as numbers inside a computer.

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Computers don't see images or hear sounds the way we do.

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Instead, they represent them using numbers.

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In this lesson, we'll learn how images are stored as pixels

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and how sound is captured using samples.

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An image is made up of tiny squares called pixels.

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The resolution tells us how many pixels are used.

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More pixels means a clearer picture.

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To show color, computers use the RGB model.

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Red, green, and blue light mix together to create millions of colors.

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The number of bits used for each pixel is called color depth.

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For example, 8 bit can show 256 colors,

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while 24 bit can show over 16 million.

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The file size of an image can be calculated using width multiplied by height multiplied by color depth.

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Sound is stored digitally through sampling and quantization.

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The red, continuous curve is the original analog sound wave.

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A sample is a snapshot of the sound wave taken at regular intervals.

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The yellow dots on the curve represent these individual samples.

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The green lines show the measured amplitude for each snapshot.

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The sampling rate is the number of samples taken per second.

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After sampling, the amplitude values are converted to a digital number,

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a process called quantization.

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Common image formats are JPEG, PNG, GIF, and BMP.

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For audio, we often use MP3, WAV, and FLAT.

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Compression helps reduce file sizes, but lossy compression,

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like JPEG makes files smaller, but reduces quality slightly.