---
title: kVTScalingMode_Letterbox
framework: videotoolbox
role: symbol
role_heading: Global Variable
path: videotoolbox/kvtscalingmode_letterbox
---

# kVTScalingMode_Letterbox

The source image buffer’s clean aperture is scaled to a rectangle fitted inside the  destination clean aperture that preserves the source picture aspect ratio.

## Declaration

```swift
let kVTScalingMode_Letterbox: CFString
```

## Discussion

Discussion The remainder of the destination image buffer is filled with black. If a destination pixel aspect ratio is not set, the source image’s pixel aspect ratio is used. The pixel aspect ratio used is set on the destination image buffer.

## See Also

### Scaling Modes

- [kVTScalingMode_Normal](videotoolbox/kvtscalingmode_normal.md)
- [kVTScalingMode_CropSourceToCleanAperture](videotoolbox/kvtscalingmode_cropsourcetocleanaperture.md)
- [kVTScalingMode_Trim](videotoolbox/kvtscalingmode_trim.md)