4.2

Image resolution refers to the frame size of the
video. Image resolution is expressed in terms
of the width and height (the frame size) of the
image 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, iPod, and so on) have screen
resolution. Screen resolution is expressed in
terms of the width and height of the screen in
pixels (for example, 640 x 360 pixels).
When you share a movie, Compressor
determines appropriate resolution sizes you
can use, based on the image sizes used in the
resolution