For the background material (including pictures, videos, animations, etc.) used after matting, the layer is at the bottom level. The recommended height and width ratio is 16:9 (1920×1080 or 1280×720), and the recommended size is no more than 1M. The recommended format is JPG live broadcast tips, icons, foreground and other textures. Set it at the top level. The size and position can be adjusted. You can design and crop it yourself without limitation. The recommended size is around 100K-200K. The recommended format is PNG
