duration

The <duration> element is the number of samples (images) that make up the child element. It is a is a 64-bit integer.

To create a gap, have a <span> that contains only a <duration>, without <path>.

Note: In most cases, the <duration> element is not required since the duration is derived from the media.
Attribute Description Data Type Allowed Values Attribute is...
type The data type of the element. character data time Required
version Version of the xml element. unsigned integer 4 Implied
Children
Mandatory
(rate?, nbTicks, dropMode)|#cdata
Note: #cdata must be an unsigned integer.
Parents
<clip>, <track>, <span>