RIFE model frame interpolation flicker phenomenon

[qii1102]

Describe the bug

Videos generated by frame interpolation using any RIFE model may flicker in certain frames, especially with 2x interpolation. Increasing the interpolation multiplier to 3x or 4x can alleviate the flickering, but only to some extent, not completely eliminating it.

To Reproduce

All videos generated by frame interpolation have a flickering phenomenon, and it has nothing to do with any settings. If it is not noticeable, you can verify it by playing the interpolated video at a slow speed, such as 0.25x speed.

Environment:

• OS: Windows 11 25H2
• CPU: 13th Gen Intel(R) Core(TM) i5-13500HX (2.50 GHz)
• GPU: NVIDIA GeForce RTX 4060 Laptop GPU (8 GB)
• Video2X Version: 6.4.0

[qii1102]

Based on my testing, there is currently only one way to completely eliminate frame interpolation flickering: using the bgra color sampling format.

You can configure the settings using the following options:
codec=av1_nvenc (Only hardware encoding supports the bgra format; choose your preferred hardware encoding based on your GPU.)
pix_fmt=bgra (This is the most important thing.)
cq=12 (Change the crf option to cq; I personally recommend setting the value to 12.)
preset=p7 (If you want to process it faster, you can use p4.)
rc=vbr (Add the rc option and set its value to vbr)

The above steps have only been tested on version 6.4.0; I cannot guarantee that they will work with other versions.