In the compositor I would like to add a driver to the Switch Node. I want to watch a frame value from a VSE strip. When the current frame count equals the Strip start frame I want to switch the node.

Here is an example of what I hope to achieve:

• when current frame is less than abs(var)+var_001 then pass no picture,

• if current frame is greater than abs(var)+var_001 then switch source through.

Of course what I have entered is unformatted nonsense. And the switch node expects to return a true or false not a value.

*nb. abs(var) changes negative number to integer.

Can I define the abs(var)+var_001 (it is the VSE strip trimmed start time) as a function of some sort to call elsewhere? It's a pain to define it all the time.

In the compositor I would like to add a driver to the Switch Node. I want to watch a frame value from a VSE strip. 
When the current frame count equals the Strip start frame I want to switch the node.

Here is an example of what I hope to achieve:

• When current frame is less than abs(var)+var_001 then pass no picture,

• if current frame is greater than abs(var)+var_001 then switch source through.

Of course what I have entered is unformatted nonsense. And the switch node expects to return a true or false, not a value.

*nb: abs(var) changes negative number to integer.

Can I define the abs(var)+var_001 (it is the VSE strip trimmed start time) as a function of some sort to call elsewhere? It's a pain to define it all the time.