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# VTMotionEstimationSessionRef

A reference to a Video Toolbox motion-estimation session.

```
typedef struct OpaqueVTMotionEstimationSession * VTMotionEstimationSessionRef;
```

## Discussion

A motion-estimation session supports two `CVPixelBuffer`s of the same size and type, and returns motion vectors in
the form of a `CVPixelBuffer`. The session is a reference-counted CF object. To create a motion-estimation session,
call [`VTMotionEstimationSessionCreate`](/documentation/VideoToolbox/VTMotionEstimationSessionCreate); then you can optionally configure the session using `VTSessionSetProperty`.
To create motion-estimations, call `VTMotionEstimationSessionCreateMotionEstimation`. When you are done with the
session, you should call [`VTMotionEstimationSessionInvalidate`](/documentation/VideoToolbox/VTMotionEstimationSessionInvalidate) to tear it down and `CFRelease` to release the
session object reference.

---

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