NVenc Test Settings

[Chewtobacca]

Although NVenc is still no match for x264, it's improved to the point at which it's become useful to me under certain circumstances, especially making a quick "Just wanna watch it" encoding.  Here's a starting point that produces output that works with my BD player.  (Some of the settings spell out the defaults to demonstrate the encoder's options and are strictly speaking redundant.)

Code:

ffmpeg -i input.mkv -vcodec h264_nvenc -profile:v high -level 41 -rc vbr_hq -2pass 1 -qmin 0 -qmax 51 -maxrate:v 40000k -b:v 35000k -bufsize:v 30000k -bf 3 -refs:v 3 -spatial-aq 1 -temporal-aq 1 -aq-strength 8 -b_ref_mode 2 -rc-lookahead 32 -surfaces 48 -no-scenecut 0 -nonref_p 1 -strict_gop 1 -coder:v cabac -g 24 -bluray-compat 1 output.264

You can even make a relatively quick UHD-to-BD conversion, all in one step, without generating an intermediate file, which is handy if space is a consideration:

Code:

ffmpeg -i input.mkv -vf "zscale=t=linear:npl=100,format=gbrpf32le,zscale=p=bt709,tonemap=tonemap=hable,zscale=t=bt709:m=bt709:r=tv,format=yuv420p,scale=1920:1080" -sws_flags sinc -pix_fmt yuv420p -vcodec h264_nvenc -profile:v high -level 41 -rc vbr_hq -2pass 1 -qmin 0 -qmax 51 -maxrate:v 40000k -b:v 35000k -bufsize:v 30000k -bf 3 -refs:v 3 -spatial-aq 1 -temporal-aq 1 -aq-strength 8 -b_ref_mode 2 -rc-lookahead 32 -surfaces 48 -no-scenecut 0 -nonref_p 1 -strict_gop 1 -coder:v cabac -g 24 -bluray-compat 1 output.264

Note that not every NVIDIA card supports all the encoder's features, so tweak the settings accordingly, and make sure that your drivers are up to date.  Have fun testing!

[althor1138]

Thanks! I'll definitely give this a tryout. You've never led me down the wrong path .

Do you have any recommended settings for hevc using the newest nvenc that supports b-frames?

[Chewtobacca]

Ha! At present, this is all experimental, and I've purposely left some settings on the defaults, so if you spot any oversights or have any suggestions, please do let me know. I was hoping that you'd chime in, althor, because I remember that you were experimenting with NVIDIA hardware acceleration for various purposes a while back. If you're on Windows, you'll want to look at NVEncC: rigaya is busily working on it.

I'm afraid that I don't use HEVC/h.265 at all and haven't even tinkered with x265. The UHD content that I have is either left as it is or converted to standard HD, hence the UHD-to-BD settings above.