"Scrubbing and transport control" what it refers to?

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For “scrubbing” description in English

Glossary / Terminology

Alpha channel An alpha channel is a part of the image data that describes each pixel’s level of opacity or translucency. Contrast that with the other data, which describes light and color. Many people think of an alpha channel as a transparency mask. However, that can lead one to think of it as rather binary - opaque or transparent - whereas most often an alpha channel has at least 256 levels. Aspect ratio Aspect ratio is how the width of a rectangle compares with its height. In other words…

Transport controls are the controls for the player: play, pause, rewind, fast forward, previous, next.