Standard version: 2.0

Major Change

Subcommittee

Entered by Pierre Jasmin

Overview

There is no way to set Parameter Interpolation Type in OFX

Example:  In Nuke (example of an host that does not support animated popup menus), we need to make an animated menu create an associated integer parameter that we set when user change the popup.  However the expected behavior would be Constant_Step, now the integer is interpolated, so somewhere between menu 3 and 1 we get menu is equal to 2

Other hosts have variations of the same.

The main issue needed to be addressed (in most hosts) is state parameters (either popup menus or integer meant to be animated steps for those not supporting animated popups). Variations of:   State 1 at time 0 KF,  State 3 at time 100 KF -  at time 2 we get State 2!  WRONG!

There is no effort to define a particular Smooth Interpolation type here. Whatever the host defaults too. However assuming that parameter KF write would get the memo.

Current workaround: We moved (not fixed everywhere) to look at only key-frame location (prev or equal) - even if it's not necessary what users see in their UI. Alternatively document to users to select all KFs and change interpolation type.

 

Solution

Add kOfxParamPropInterType 

- kOfxParamInterpTypeConstantStep
- kOfxParamInterpTypeLinear
- kOfxParamInterpTypeSmooth // whatever the type of curve the host defaults to

This is probably a param creation time only thing. 
Otherwise  to add support at KF level would require to add a new member to suite, thus versioning.