how to auto-fit photo to 9:16 frame (cover crop) like the website does?

Hi,

I'm generating videos via your API (/v2/video/generate) using the talking_photo character type with Avatar IV (use_avatar_iv_model: true).

My issue is about how the photo fits in the 9:16 frame (720x1280).

When I create a video directly on your website, the photo automatically fills the entire portrait frame — it crops the sides if the photo is square or landscape. There are no white/black bars. This is exactly what I want.

But when I use the API, the photo is centered in the frame with white bars on the top and bottom.

I'm currently using scale: 1.0. I know I can increase the scale to zoom in and fill the frame, but I'm not sure if this is the right approach or if there is a dedicated parameter to achieve the same automatic "cover crop" behavior as the website.

My question: Is there a specific API parameter that tells HeyGen to automatically fit/crop the photo to fill the 9:16 frame — the same way your website does it — without manually guessing the scale value?

Thank you!