Start from display dimensions
Rotation metadata and pixel aspect can change how a video should be displayed. Use display dimensions rather than blindly reading coded width/height.
Contain preserves the whole frame
Contain fits the complete video within the target box and may add letterboxing depending on output behavior.
Cover fills the box by cropping
Cover is useful for fixed social ratios but can remove content near the edges. Preview before export.
Do not upscale for quality
A larger frame can satisfy a technical dimension requirement, but it does not restore sharpness. Preserve the original when it contains the highest available detail.
Official marketplace references
Requirements can change. Review the source before publishing an important listing.
Mediabunny browser media toolkit documentation ↗