[BUG] NVEnc / H265 / Tune "UHQ" = incompatible command

[tailland]

version 2026-11-11

problem:
   

"auto" works, "uhq" = crash

[Selur]

According to the documentation, that is kind of expected on 'older' cards, but your "NVIDIA GeForce RTX 4070 SUPER", should work fine. :/

--tune <string>
Extra tuning option to preset.

• hq (default)
  
• uhq
  For HEVC and AV1 only, and requires Turing Gen GPU or later.
  
• lowlatency
  
• ultralowlatency
  
• ossless
  Implicitly enables --lossless.
  

source: https://github.com/rigaya/NVEnc/blob/mas...une-string

I can reproduce the problem on my Geforce RTX 4080.
=> I'll look into it and probably report it to the author of NVEncC.

Cu Selur

[Selur]

Got it, UHQ with HEVC failed because Hybrid’s default of 3 B-frames is too few for it.
--tune uhq turns on NVENC’s temporal filter (tfLevel: 4) for HEVC and AV1, and that filter needs at least 4 B-frames.
Hybrid always writes --bframes, and its default is 3, so NVENC rejects the setup with error 8. Testing NVEncC directly:

Tested it on my system.

NVEncC --tune uhq:(RTX 4080, driver 621.14, NVEncC 9.40)

Codec	--bframes 0-3	--bframes 4	--bframes 3 --tf-level 0
HEVC	error 8	works	works
AV1	error 8	works	works
H.264	works	works	works

=> I'll adjust Hybrid to raise bFrames minimum to 4 under uhq (HEVC/AV1). Will report back once I did the fix and uploaded a new dev.

Cu Selur

[Selur]

Uploaded a new dev, which fixes the issue here.
Let me know whether that works for you too.

Cu Selur

[tailland]

that's an interesting find. cool