Voukoder 4 - bugged presets and/or reframes setting

I've used to encode videos using Voukoder 1.2, 2.1, 2.2 with the following settings:

h264 NVENC

Preset: High Quality

Profile: High

Strategy: VBR

Bitrate: 28000

Max Bitrate: 30000

b-frames: 2

Reference frames: 4

Level: 4.1

In Voukoder 4 I can't use this settings because encoder always fails (wrong combination of options).

After a bit of testing I've discovered the following:

I can encode with the settings above if I disable Level (leave it unchecked). But the output video will have 8 reframes (level 5.0).

Actually, the output video will always have at least 8 reframes, even on Fast preset. Slow preset gives me 10 reframes. That's why I can't use level 4.1.

So, I've tried disabling Preset (leaving it unchecked):

h264 NVENC

Profile: High

Strategy: VBR

Bitrate: 28000

Max Bitrate: 30000

b-frames: 2

Reference frames: 4

Level: 4.1

But the encoder failed again (wrong combination of options).

Next step looked like this:

h264 NVENC

Profile: High

Strategy: VBR

Bitrate: 28000

Max Bitrate: 30000

b-frames: 2

Level: 4.1

This time it worked. Output video had 3 reframes.

Result: no matter what I do, Voukoder doesn't allow me to encode video using the amount of reference frames I want. It's always either 3, 8 or 10.

Went back to 2.2 and everyting works fine again.

Input video: mov (prores), 1080p, 25 fps, ~170 Mbps

Videocard: RTX 2080 (drivers 442.50)

CPU: Core i9 9900KF

Premiere Pro 2020 (14.0.3)

Tried encoding another video with lower bitrate (1080p, AVC, 50 Mbps) with the same result. Is there anything you can do to fix this problem? Maybe using another version of ffmpeg will help? 2.2 works great, but I really like all the filters in 4.0 ).

[23:45:36] =============================================

[23:45:36] Voukoder 4 (4.0.67)

[23:45:36] by Daniel Stankewitz

[23:45:36] ---------------------------------------------

[23:45:36] Intel(R) Core(TM) i9-9900KF CPU @ 3.60GHz

[23:45:36] 16 logical cores

[23:45:36] 32699 MB system memory

[23:45:36] Display #0 on: NVIDIA GeForce RTX 2080

[23:45:36] Display #1 on: NVIDIA GeForce RTX 2080

[23:45:36] ---------------------------------------------

[23:45:36] ---------------------------------------------

[23:45:36] Export started

[23:45:36] ---------------------------------------------

[23:45:36] Filename: E:\!Output\temp.mp4

[23:45:36] Application: Voukoder (Adobe Premiere)

[23:45:36] Passes: 1

[23:45:36] - Video -------------------------------------

[23:45:36] Frame size: 1920x1080

[23:45:36] Pixel aspect: 1:1

[23:45:36] Timebase: 1/30 (30.00 fps)

[23:45:36] Interlaced: No

[23:45:36] Encoder: h264_nvenc

[23:45:36] Options: _computeCapability=7.5 _pixelFormat=yuv420p b=28000000 bf=2 gpu=0 level=4.1 maxrate=30000000 preset=hq profile=high rc=vbr refs=4

[23:45:36] Side data: <none>

[23:45:36] Filters: <none>

[23:45:36] Color range: unknown

[23:45:36] Color space: unknown

[23:45:36] Color primaries: unknown

[23:45:36] Color transfer: unknown

[23:45:36] - Audio -------------------------------------

[23:45:36] Timebase: 1/48000

[23:45:36] Channels: 2

[23:45:36] Encoder: libfdk_aac

[23:45:36] Options: _sampleFormat=s16 _strategy=cbr b=320000 profile=aac_low

[23:45:36] Side data: <none>

[23:45:36] Filters: <none>

[23:45:36] ---------------------------------------------

[23:45:36] Opening codec: h264_nvenc with options: b=28000000|bf=2|gpu=0|level=4.1|maxrate=30000000|preset=hq|profile=high|rc=vbr|refs=4

[23:45:36] FFmpeg: Loaded lib: nvcuda.dll

[23:45:36] FFmpeg: Loaded sym: cuInit

[23:45:36] FFmpeg: Loaded sym: cuDeviceGetCount

[23:45:36] FFmpeg: Loaded sym: cuDeviceGet

[23:45:36] FFmpeg: Loaded sym: cuDeviceGetAttribute

[23:45:36] FFmpeg: Loaded sym: cuDeviceGetName

[23:45:36] FFmpeg: Loaded sym: cuDeviceComputeCapability

[23:45:36] FFmpeg: Loaded sym: cuCtxCreate_v2

[23:45:36] FFmpeg: Loaded sym: cuCtxSetLimit

[23:45:36] FFmpeg: Loaded sym: cuCtxPushCurrent_v2

[23:45:36] FFmpeg: Loaded sym: cuCtxPopCurrent_v2

[23:45:36] FFmpeg: Loaded sym: cuCtxDestroy_v2

[23:45:36] FFmpeg: Loaded sym: cuMemAlloc_v2

[23:45:36] FFmpeg: Loaded sym: cuMemAllocPitch_v2

[23:45:36] FFmpeg: Loaded sym: cuMemsetD8Async

[23:45:36] FFmpeg: Loaded sym: cuMemFree_v2

[23:45:36] FFmpeg: Loaded sym: cuMemcpy2D_v2

[23:45:36] FFmpeg: Loaded sym: cuMemcpy2DAsync_v2

[23:45:36] FFmpeg: Loaded sym: cuGetErrorName

[23:45:36] FFmpeg: Loaded sym: cuGetErrorString

[23:45:36] FFmpeg: Loaded sym: cuCtxGetDevice

[23:45:36] FFmpeg: Loaded sym: cuDevicePrimaryCtxRetain

[23:45:36] FFmpeg: Loaded sym: cuDevicePrimaryCtxRelease

[23:45:36] FFmpeg: Loaded sym: cuDevicePrimaryCtxSetFlags

[23:45:36] FFmpeg: Loaded sym: cuDevicePrimaryCtxGetState

[23:45:36] FFmpeg: Loaded sym: cuDevicePrimaryCtxReset

[23:45:36] FFmpeg: Loaded sym: cuStreamCreate

[23:45:36] FFmpeg: Loaded sym: cuStreamQuery

[23:45:36] FFmpeg: Loaded sym: cuStreamSynchronize

[23:45:36] FFmpeg: Loaded sym: cuStreamDestroy_v2

[23:45:36] FFmpeg: Loaded sym: cuStreamAddCallback

[23:45:36] FFmpeg: Loaded sym: cuEventCreate

[23:45:36] FFmpeg: Loaded sym: cuEventDestroy_v2

[23:45:36] FFmpeg: Loaded sym: cuEventSynchronize

[23:45:36] FFmpeg: Loaded sym: cuEventQuery

[23:45:36] FFmpeg: Loaded sym: cuEventRecord

[23:45:36] FFmpeg: Loaded sym: cuLaunchKernel

[23:45:36] FFmpeg: Loaded sym: cuModuleLoadData

[23:45:36] FFmpeg: Loaded sym: cuModuleUnload

[23:45:36] FFmpeg: Loaded sym: cuModuleGetFunction

[23:45:36] FFmpeg: Loaded sym: cuTexObjectCreate

[23:45:36] FFmpeg: Loaded sym: cuTexObjectDestroy

[23:45:36] FFmpeg: Loaded sym: cuGLGetDevices_v2

[23:45:36] FFmpeg: Loaded sym: cuGraphicsGLRegisterImage

[23:45:36] FFmpeg: Loaded sym: cuGraphicsUnregisterResource

[23:45:36] FFmpeg: Loaded sym: cuGraphicsMapResources

[23:45:36] FFmpeg: Loaded sym: cuGraphicsUnmapResources

[23:45:36] FFmpeg: Loaded sym: cuGraphicsSubResourceGetMappedArray

[23:45:36] FFmpeg: Loaded sym: cuDeviceGetUuid

[23:45:36] FFmpeg: Loaded sym: cuImportExternalMemory

[23:45:36] FFmpeg: Loaded sym: cuDestroyExternalMemory

[23:45:36] FFmpeg: Loaded sym: cuExternalMemoryGetMappedBuffer

[23:45:36] FFmpeg: Loaded sym: cuExternalMemoryGetMappedMipmappedArray

[23:45:36] FFmpeg: Loaded sym: cuMipmappedArrayGetLevel

[23:45:36] FFmpeg: Loaded sym: cuMipmappedArrayDestroy

[23:45:36] FFmpeg: Loaded sym: cuImportExternalSemaphore

[23:45:36] FFmpeg: Loaded sym: cuDestroyExternalSemaphore

[23:45:36] FFmpeg: Loaded sym: cuSignalExternalSemaphoresAsync

[23:45:36] FFmpeg: Loaded sym: cuWaitExternalSemaphoresAsync

[23:45:36] FFmpeg: Loaded lib: nvEncodeAPI64.dll

[23:45:36] FFmpeg: Loaded sym: NvEncodeAPICreateInstance

[23:45:36] FFmpeg: Loaded sym: NvEncodeAPIGetMaxSupportedVersion

[23:45:36] FFmpeg: Loaded Nvenc version 9.1

[23:45:36] FFmpeg: Nvenc initialized successfully

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuInit(0)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuDeviceGetCount(&nb_devices)

[23:45:36] FFmpeg: 1 CUDA capable devices found

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuDeviceGet(&cu_device, idx)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuDeviceGetName(name, sizeof(name), cu_device)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuDeviceComputeCapability(&major, &minor, cu_device)

[23:45:36] FFmpeg: [ GPU #0 - < GeForce RTX 2080 > has Compute SM 7.5 ]

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxCreate(&ctx->cu_context_internal, 0, cu_device)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxPopCurrent(&dummy)

[23:45:36] FFmpeg: supports NVENC

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxPushCurrent(ctx->cu_context)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxPopCurrent(&dummy)

[23:45:36] FFmpeg: InitializeEncoder failed: invalid param (8): Invalid Level.

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxPushCurrent(ctx->cu_context)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxPopCurrent(&dummy)

[23:45:36] FFmpeg: Calling dl_fn->cuda_dl->cuCtxDestroy(ctx->cu_context_internal)

[23:45:36] FFmpeg: Nvenc unloaded

[23:45:36] Failed opening codec: h264_nvenc

[23:45:36] Unable to open video encoder: h264_nvenc

[23:45:36] Closing encoders ...

[23:45:36] Opening encoder failed! Aborting ...

[23:45:36] 000000001C4C5EA0