[HELP] 2-Pass /Motion Vector Precision

[Selur]

What are the differences in none, 2pass-quarter and 2pass-full

In 1-pass rate control modes, the encoder will estimate the required QP for the macroblock and immediately encode the macroblock.

In 2-pass rate control modes, NVENC estimates the complexity of the frame to be encoded and determines bit distribution across the frame in the first pass. In the second pass, NVENC encodes macroblocks in the frame using the distribution determined in the first pass. 2-pass rate control modes can distribute the bits more optimally within the frame and can reach closer to the target bitrate, especially for CBR encoding.

• none
      1pass mode. (fast)
  
• 2pass-quarter
      Runs first pass in quater resolution, which results in larger motion vectors being caught and fed as hints to second pass.
  
• 2pass-full
      Runs first pass in full resolution, slower but generating better statistics for the second pass.
  

see: https://github.com/rigaya/NVEnc/blob/mas...ions.en.md

Motion Vector Precision, quarter pixel, half pixel and full pixel with NVENC?

Smaller the precision potentially allows to find more precise motion vectors and thus potentially increases compression, but also require more processing power.

but i need to know what it exactly does

If you want to exactly understand what the settings to up on:
a. how H.265 works (before that you should understand how MPEG compression in general works)
b. what options the NVEnc offers (https://docs.nvidia.com/video-technologi...rog-guide/ + https://github.com/rigaya/NVEnc/blob/mas...ions.en.md)

Set Lookahead to 32?

Look-ahead improves the video encoder’s rate control accuracy by enabling the encoder to buffer the specified number of frames, estimate their complexity and allocate the bits appropriately among these frames proportional to their complexity. This also dynamically allocates B and P frames.

Use Weigthed P-Frames?

yes, it potentially can help a lot. Read up on what weighted prediction means.

With the Turing Card i have, i thought i can go near a x265 CPU Bitrate, just testing out.

You are comparing:
a. noise source to an denoised source
b. a source with 1/4 higher resolution (960x720 vs 1280x960 pixels)
and expect to go near the same bit rate to archive similar quality.
-> You thought wrong.

Cu Selur