<!--
{
  "availability" : [
    "iOS: 6.0.0 -",
    "iPadOS: 6.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.9.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 6.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "CoreMedia",
  "identifier" : "/documentation/CoreMedia/kCMSampleBufferAttachmentKey_DroppedFrameReason",
  "metadataVersion" : "0.1.0",
  "role" : "Global Variable",
  "symbol" : {
    "kind" : "Global Variable",
    "modules" : [
      "Core Media"
    ],
    "preciseIdentifier" : "c:@kCMSampleBufferAttachmentKey_DroppedFrameReason"
  },
  "title" : "kCMSampleBufferAttachmentKey_DroppedFrameReason"
}
-->

# kCMSampleBufferAttachmentKey_DroppedFrameReason

Indicates the reason the current video frame was dropped (type `CFString`).

```
let kCMSampleBufferAttachmentKey_DroppedFrameReason: CFString
```

## 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. The value for this key is one of the string constants in `Sample Buffer Dropped Frame Reasons`.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)