---
title: requestedTimeToleranceBefore
framework: avfoundation
role: symbol
role_heading: Instance Property
path: avfoundation/avassetimagegenerator/requestedtimetolerancebefore
---

# requestedTimeToleranceBefore

A maximum length of time before the requested time to allow image generation to occur.

## Declaration

```swift
var requestedTimeToleranceBefore: CMTime { get set }
```

## Mentioned in

Creating images from a video asset

## Discussion

Discussion The default value is positiveInfinity. Set the values of requestedTimeToleranceBefore and requestedTimeToleranceAfter to zero to request frame-accurate image generation; this may incur additional decoding delay.

## See Also

### Configuring image generation

- [maximumSize](avfoundation/avassetimagegenerator/maximumsize.md)
- [requestedTimeToleranceAfter](avfoundation/avassetimagegenerator/requestedtimetoleranceafter.md)
- [dynamicRangePolicy](avfoundation/avassetimagegenerator/dynamicrangepolicy-swift.property.md)
- [AVAssetImageGenerator.DynamicRangePolicy](avfoundation/avassetimagegenerator/dynamicrangepolicy-swift.struct.md)
- [appliesPreferredTrackTransform](avfoundation/avassetimagegenerator/appliespreferredtracktransform.md)
- [apertureMode](avfoundation/avassetimagegenerator/aperturemode-swift.property.md)
- [AVAssetImageGenerator.ApertureMode](avfoundation/avassetimagegenerator/aperturemode-swift.struct.md)