It is not necessary to have an Oculus. 

However using an Oculus enables some additional features, such as the ability to preview the immersive video while mixing and sending head-tracking information back to the Dolby Atmos VR Production Suite. This enables real-time auditioning during the mixing process. 

In addition, once your mix is finalized, you can also use the Oculus and the connected PC to play back the finalized audio/video mp4. 

Other HMDs will be evaluated as they become available.