A widescreen transfer refers to a process in which an image or video is converted from one aspect ratio (the relationship between width and height) to another. This can involve stretching, letterboxing, or pillarboxing the original content to fit within the new aspect ratio. Widescreen transfers are commonly used when converting standard-definition media into high definition formats with a widescreen aspect ratio, such as 16:9. The term "widescreen" refers to the wider dimensions of the image compared to older, square aspect ratios like 4:3.