The OnePlus 7T recently received a 'secret' 960fps slow-motion video recording option via OxygenOS Open Beta 3 update. The feature is based on a software-based frame interpolation technique, thus it might not be considered as a 'true' 960fps implementation by photography experts. Nevertheless, as the entire processing is done by the camera stack of OxygenOS, one can theoretically enable this feature to older OnePlus phones sporting similar camera sensors and internal hardware. XDA Senior Member elmarian756 has basically done the same, as he has successfully enabled 960fps slow-motion support on the OnePlus 7 Pro. The cherry on top is that it is also possible to unlock the long-anticipated macro mode on this device with a similar mod.

OnePlus 7 Pro XDA Forums

As it turns out, the OnePlus 7 Pro is actually capable of utilizing these features, but they're disabled behind some hidden parameters. Based on what XDA Senior Member docnok63 found, XDA Senior Member elmarian756 then enabled the 960fps slow-motion recording on the OnePlus 7 Pro by modifying the CameraInfo_0.xml and the CameraInfo_5.xml preferences files of the stock camera app and adding a new string called Video960FpsSizes with the value 1280x720. As soon as you save them and re-launch the camera, you can find a third 960fps option on slow-motion mode, just like on the OnePlus 7T.

Talking about the macro mode in the camera, OnePlus did introduce it briefly on the OnePlus 7 Pro during the Android Q beta testing phase. The feature, however, didn't make it to the stable version. Now you can unlock it by toggling the value of the IsUWMacroSupported variable inside the CameraInfo_3.xml file from false to true. This particular experiment was carried out by XDA Senior Member gohan040. Keep in mind that while the 7 Pro, like the 7T Pro, uses the ultra wide-angle camera to take macro photos, the 7 Pro lacks the added macro motor that the 7T Pro has. Your mileage may vary on how well this mod works.

You have to install the latest beta version of OnePlus Camera (v3.10.17 or higher) on your OnePlus 7 Pro to be able to unlock these features. While it is possible to manually sideload the beta version of the camera app on the stable channel build of OxygenOS, it is recommended to install the newest Open Beta to ensure full compatibility. Root access is a mandatory prerequisite, and users can use apps like Preferences Manager to perform the aforementioned changes.

OnePlus 7 Pro Camera Modification — XDA Discussion Thread