UE4.25 & nvEnc for WebRTC

UE4 comes with a sample nvEnc implementation, but this seems to fail to initialize. How do I make it work?

The error is ‘Failed to register input back buffer (status: 9)’ from the ‘_NVENCSTATUS Result = NvEncodeAPI->nvEncRegisterResource(EncoderInterface, &RegisterResource);’ call.

There was a warning with the stock UE4.25 - ‘Warning - Call to NvEncodeAPICreateInstance with version 71020008, expected 71020010’ so I updated to the latest nvEnc which gave the warning - ‘Warning - Call to NvEncodeAPICreateInstance with version 7002000b, expected 71020010’. Does this matter at all?

It is very similar to this problem - but I’m not using the EOS SDK at all - https://epicsupport.force.com/devportal/s/question/0D52L00004eKmmESAS/the-ue4-avencoder-failed-in-the-initialization-with-eos-overlay-enabled-is-this-a-bug?language=en_US

This is cross posted in UE4 and nVidia forums

Cheers
John

GeForce 2070 RTX - 457.09
cuda_11.1.1_456.81_win10
Node.js 14.15.0 LTS

This was due to the RenderDoc plugin being enabled in UE4

Cheers
John