---
title: "sourceTaggedDynamicBuffers(byTrackID:)"
framework: avfoundation
role: symbol
role_heading: Instance Method
path: "avfoundation/avasynchronousvideocompositionrequest/sourcetaggeddynamicbuffers(bytrackid:)"
---

# sourceTaggedDynamicBuffers(byTrackID:)

Returns the source tagged dynamic buffers for the given track ID. Returns nil if the video track does not contain tagged buffers, or if the track does not contain video. This function should only be called when supportsSourceTaggedBuffers is YES.

## Declaration

```swift
func sourceTaggedDynamicBuffers(byTrackID trackID: CMPersistentTrackID) -> [CMTaggedDynamicBuffer]?
```

## Return Value

Return Value The source CMTaggedBuffer array for the given track ID.

## See Also

### Accessing source data

- [attach(_:to:)](avfoundation/avasynchronousvideocompositionrequest/attach(_:to:).md)
- [sourceFrame(byTrackID:)](avfoundation/avasynchronousvideocompositionrequest/sourceframe(bytrackid:).md)
- [sourceReadOnlyPixelBuffer(byTrackID:)](avfoundation/avasynchronousvideocompositionrequest/sourcereadonlypixelbuffer(bytrackid:).md)
- [sourceReadySampleBuffer(byTrackID:)](avfoundation/avasynchronousvideocompositionrequest/sourcereadysamplebuffer(bytrackid:).md)
- [sourceSampleBuffer(byTrackID:)](avfoundation/avasynchronousvideocompositionrequest/sourcesamplebuffer(bytrackid:).md)
- [sourceSampleDataTrackIDs](avfoundation/avasynchronousvideocompositionrequest/sourcesampledatatrackids-3yiab.md)
- [sourceTimedMetadata(byTrackID:)](avfoundation/avasynchronousvideocompositionrequest/sourcetimedmetadata(bytrackid:).md)
- [sourceTrackIDs](avfoundation/avasynchronousvideocompositionrequest/sourcetrackids.md)