Animate in 24fps with 12fps appearance (with a twist)

Hello,

The goal is to have a 24fps animation appear as 12fps (double frames / animate on 2s). Example: a box moves from point A to B with simple Position keyframes, but the output is a box moving at 12fps.

I'm integrating this with a web script with limited AE features support so I can't:

• use a 12fps pre-comp nested in a 24fps with Preserve nested framerate advanced option
• use the Posterize Effect
• only use an expression with PosterizeTime
• scripts that don't return actual keyframes and native AE functionality

The closest flow I have is to use this expression, e.g. on the Position property:

animateon=2; framerate=(1/thisComp.frameDuration)/animateon; posterizeTime(framerate); value;

And then convert those with Convert Expression to Keyframes, but that returns a keyframe for every frame, whether it needs to or not.

I tried jdSmartBaker to reduce the keyframes, which mostly works very well but it chokes on certain properties like Rotation (for me anyway).

This process is cumbersome. Ideally, I would like everything (the entire comp) to be hard set double frames.

FYI, I am animating shape layers and won't be working with 'footage'.

Phew. Does anyone have any suggestions?

Thanks!

Nick