Null video source, never return images. It is mainly useful as a template and to be employed in analysis / debugging tools.

It accepts as optional parameter a string of the form width:height:timebase.

width and height specify the size of the configured source. The default values of width and height are respectively 352 and 288 (corresponding to the CIF size format).

timebase specifies an arithmetic expression representing a timebase. The expression can contain the constants "PI", "E", "PHI", "AVTB" (the default timebase), and defaults to the value "AVTB".