resolution

The frame size of the video expressed in terms of width and height (in pixels). Higher-resolution images contain more detail but also create larger files that take longer to download.

Your electronic devices (your computer, iPad, iPhone, and so on) have screen resolution, also expressed in terms of the width and height (for example, 640 x 360 pixels).

When you share a movie, Compressor determines the appropriate resolution sizes you can use, based on the image sizes used in the movie and on the preset that you’re using to output the file.