Ultra video quality settings from nvEnc in UE4

[JohnScott]

We're rendering inside UE4 on a client machine, then using the nvEnc capabilities in UE4 to encode to video to feed to a web browser. This avoids having to write custom plugins for each browser, and it works pretty well.

As the video streaming is now local, we don't care about the bandwidth so we want the highest imaginable quality - a 'pass through' mode (or as close as possible)

However, no matter what settings I try in the encoder, it only seems to send about 12-15 mbit to the browser. As there are numerous settings (to say the least) and we have an unusual use case, what would you recommend?

I'm using NV_ENC_PRESET_LOSSLESS_HP_GUID but if I try to set the required (?) constqp rate control it rejects the settings.

This seems quite pertinent: https://slhck.info/video/2017/03/01/rate-control.html

Cheers
John

[sophisticles]

I'm using NV_ENC_PRESET_LOSSLESS_HP_GUID but if I try to set the required (?) constqp rate control it rejects the settings.

Your answer is in the above sentence, you are using a lossless preset, bit rate settings will be ignored. use preset slow if you want to manually set a bit rate or a constant qp rate.

[JohnScott]

Thanks!

However, NV_ENC_PRESET_LOSSLESS_HP_GUID is most definitely not lossless and gives bit rates of 12-15 mbit even tho I specify a minimum bitrate of 20 mbit.

Googling is proving unhelpful unfortunately, but any links would be appreciated.

I realize the encoder is trying to help me but not letting me do something ridiculous, but in this case that is exactly what I need!

Setting VBR with a min and max qp at 20 seems to get my bitrate and quality up - at least the best results so far.


Cheers
John