Blend Layer Fit Mode
blend-fit
Controls how the blend layer image fills the box set by blend-w and blend-h. The default is clip.
Valid values are clip, crop, scale, max, min, fill, fillmax, and clamp.
Aliases: blendfit, bf.
Use blend-fit[N] to target a specific blend layer, where N is 0–3. Layer 0 is either the bare blend-fit or blend-fit[0]; if both are supplied, the bare name wins.
Imgix Video runs no detectors on a blend layer, so blend-fit=area, facearea and facecopy all behave as clip.