What action is directly related to using the ultra key in video editing?

Using the ultra key in video editing is primarily associated with creating visual effects, specifically for keying out backgrounds in a video using chroma keying techniques. This tool allows editors to replace a specific color (commonly green or blue used in chroma key backgrounds) with different imagery or video, effectively isolating the subject and enabling a new background to be placed behind them.

This technique is widely used in film and television to create seamless visual effects where the subject appears in different environments without the constraints of their original setting. The ultra key provides precise controls for fine-tuning the keying process, ensuring that edges are clean and that the overall composition looks natural.

The other choices do not directly relate to the function of the ultra key. Adjusting audio levels pertains to sound engineering rather than visual composition, importing clips is about bringing media into the editing software, and editing text layers involves working with written content on screen rather than manipulating video imagery.