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# kVTCompressionPropertyKey_MaxFrameDelayCount

The maximum number of frames that a compressor is allowed to hold before it must output a compressed frame.

```
let kVTCompressionPropertyKey_MaxFrameDelayCount: CFString
```

## Discussion

This value limits the number of frames that may be held in the compression window. If the maximum frame delay count is M, then before the call to encode frame N returns, frame N-M must have been emitted. The default is [`kVTUnlimitedFrameDelayCount`](/documentation/VideoToolbox/kVTUnlimitedFrameDelayCount), which sets no limit on the compression window.

## Topics

### Delay Counts

[`kVTUnlimitedFrameDelayCount`](/documentation/VideoToolbox/kVTUnlimitedFrameDelayCount)

Indicates that no limit should be set on the compression window.


---

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