---
title: droppedFrameReason
framework: coremedia
role: symbol
role_heading: Type Property
path: coremedia/cmsamplebufferattachmentkeydefinitions/droppedframereason
---

# droppedFrameReason

Indicates the reason the current video frame was dropped.

## Declaration

```swift
static let droppedFrameReason: CVAttachmentKeyDefinition<CMSampleBufferAttachmentKeyDefinitions.ShouldPropagate, CMDroppedFrameReason>
```

## Discussion

Discussion Sample buffers with this attachment contain no image or data buffer. They mark a dropped video frame. This attachment identifies the reason the frame was dropped.