---
title: trimDurationAtStart
framework: coremedia
role: symbol
role_heading: Type Property
path: coremedia/cmsamplebuffer/attachmentkey/trimdurationatstart
---

# trimDurationAtStart

## Declaration

```swift
static let trimDurationAtStart: CMSampleBuffer.AttachmentKey
```

## See Also

### Attachment Keys

- [cameraIntrinsicMatrix](coremedia/cmsamplebuffer/attachmentkey/cameraintrinsicmatrix.md)
- [displayEmptyMediaImmediately](coremedia/cmsamplebuffer/attachmentkey/displayemptymediaimmediately.md)
- [drainAfterDecoding](coremedia/cmsamplebuffer/attachmentkey/drainafterdecoding.md)
- [droppedFrameReason](coremedia/cmsamplebuffer/attachmentkey/droppedframereason.md)
- [droppedFrameReasonInfo](coremedia/cmsamplebuffer/attachmentkey/droppedframereasoninfo.md)
- [emptyMedia](coremedia/cmsamplebuffer/attachmentkey/emptymedia.md)
- [endsPreviousSampleDuration](coremedia/cmsamplebuffer/attachmentkey/endsprevioussampleduration.md)
- [fillDiscontinuitiesWithSilence](coremedia/cmsamplebuffer/attachmentkey/filldiscontinuitieswithsilence.md)
- [forceKeyFrame](coremedia/cmsamplebuffer/attachmentkey/forcekeyframe.md)
- [gradualDecoderRefresh](coremedia/cmsamplebuffer/attachmentkey/gradualdecoderrefresh.md)
- [permanentEmptyMedia](coremedia/cmsamplebuffer/attachmentkey/permanentemptymedia.md)
- [postNotificationWhenConsumed](coremedia/cmsamplebuffer/attachmentkey/postnotificationwhenconsumed.md)
- [resetDecoderBeforeDecoding](coremedia/cmsamplebuffer/attachmentkey/resetdecoderbeforedecoding.md)
- [resumeOutput](coremedia/cmsamplebuffer/attachmentkey/resumeoutput.md)
- [reverse](coremedia/cmsamplebuffer/attachmentkey/reverse.md)