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# VTDecompressionMultiImageCapableOutputHandler

A type alias for callback that the system invokes when it finishes decompressing a frame.

```
typealias VTDecompressionMultiImageCapableOutputHandler = @Sendable (OSStatus, VTDecodeInfoFlags, CVImageBuffer?, __CMTaggedBufferGroup?, CMTime, CMTime) -> Void
```

## Parameters

`status`

A value of `noErr` if decompression succeeds; otherwise, an error code if decompression fails.

`infoFlags`

A [`VTEncodeInfoFlags`](/documentation/VideoToolbox/VTEncodeInfoFlags) pointer to receive information about the decode operation.

    The [`asynchronous`](/documentation/VideoToolbox/VTDecodeInfoFlags/asynchronous)     bit may be set if the decode is (or was) running asynchronously.

    The [`frameDropped`](/documentation/VideoToolbox/VTDecodeInfoFlags/frameDropped)     bit may be set if the frame was dropped (synchronously).

    Pass     `NULL`     if you don’t want to receive this information.

`imageBuffer`

The decompressed pixel buffer.

`taggedBufferGroup`

A <doc://com.apple.documentation/documentation/CoreMedia/CMTaggedBufferGroupRef> that contains the multiple images for the decompressed frame, if the decompression succeeds; otherwise, `NULL`.

`presentationTimeStamp`

The frame’s presentation timestamp; otherwise, <doc://com.apple.documentation/documentation/CoreMedia/CMTime/invalid> if the value isn’t available.

`presentationDuration`

The frame’s presentation duration; otherwise, <doc://com.apple.documentation/documentation/CoreMedia/CMTime/invalid> if the value isn’t available.

## Discussion

Pass a callback of this type to [`VTDecompressionSessionDecodeFrameWithMultiImageCapableOutputHandler`](/documentation/VideoToolbox/VTDecompressionSessionDecodeFrameWithMultiImageCapableOutputHandler) to handle the decompressed frame output. The system doesn’t necessarily invoke the callback in display order. If the multi-image decompression call returns an error, the system doesn’t call this block.

> Important:
> The video decompressor may still reference the pixel buffers that this callback provides if the ``doc://com.apple.videotoolbox/documentation/VideoToolbox/VTDecodeInfoFlags/imageBufferModifiable`` flag isn’t set. It’s not safe to modify the returned pixel buffers in this state.

---

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