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# kAudioFileStreamProperty_FrameToPacket

Obtains the packet number corresponding to a frame number.

```
var kAudioFileStreamProperty_FrameToPacket: AudioFileStreamPropertyID { get }
```

## Discussion

Obtains the packet number corresponding to a frame number. Pass an `AudioFramePacketTranslation` structure with the `mFrame` field filled in, and values in the `mPacket` and `mFrameOffsetInPacket` fields are returned on output. For more information on the audio frame packet translation structure, see [Audio File Services](/documentation/AudioToolbox/audio-file-services).

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