---
title: AVAudioEngineManualRenderingBlock
framework: avfaudio
role: symbol
role_heading: Type Alias
path: avfaudio/avaudioenginemanualrenderingblock
---

# AVAudioEngineManualRenderingBlock

The type that represents a block that renders the engine when operating in manual rendering mode.

## Declaration

```swift
typealias AVAudioEngineManualRenderingBlock = (AVAudioFrameCount, UnsafeMutablePointer<AudioBufferList>, UnsafeMutablePointer<OSStatus>?) -> AVAudioEngineManualRenderingStatus
```

## Parameters

- `numberOfFrames`: The number of PCM sample frames to render.
- `outBuffer`: The PCM buffer the engine must render the audio for.
- `outError`: On exit, if an error occurs during rendering, a description of the error.

## Return Value

Return Value One of the status codes from AVAudioEngineManualRenderingStatus. Irrespective of the returned status code, on exit, the output buffer’s frameLength indicates the number of PCM samples the engine renders.

## See Also

### Getting Manual Rendering Properties

- [manualRenderingBlock](avfaudio/avaudioengine/manualrenderingblock.md)
- [manualRenderingFormat](avfaudio/avaudioengine/manualrenderingformat.md)
- [manualRenderingMaximumFrameCount](avfaudio/avaudioengine/manualrenderingmaximumframecount.md)
- [manualRenderingMode](avfaudio/avaudioengine/manualrenderingmode.md)
- [manualRenderingSampleTime](avfaudio/avaudioengine/manualrenderingsampletime.md)
- [isAutoShutdownEnabled](avfaudio/avaudioengine/isautoshutdownenabled.md)
- [isInManualRenderingMode](avfaudio/avaudioengine/isinmanualrenderingmode.md)