AQ=1 and AQ=2

[gelo333]

I'm reading information online and in AI, and I'm getting conflicting information. Some sources say that AQ=2 includes the parameters of AQ=1. This means AQ=2 can't be worse than AQ=1. In other words, AQ=1 is a spatial filter, AQ=2 is a temporal filter + spatial filter.
Other sources say these are alternative methods that don't include each other. In other words, AQ=1 is a spatial filter, AQ=2 is only a temporal filter.

I need to capture a screen in OBS. The content is combined: Windows and application interfaces, preview icons, and third-party video. For example, YouTube. Codec x264 and CRF, 60 FPS.

[rgr]

Adaptive quantization

While qcomp determines bit allocation for frames across the video, adaptive quantization (AQ) is in charge of doing this on a block-basis, distributing bits not only within the current frame, but also adjacent frames. It does so by distributing bits e.g. from complex to flat blocks.

There are three modes available in vanilla x264:

Allow AQ to redistribute bits across the whole video and within frames.
Auto-variance; this attempts to adapt strength per-frame.
Auto-variance with a bias to dark scenes.
Generally speaking, you'll likely get the best results with AQ mode 3. With the other two modes, you have to carefully make sure that darks aren't being damaged too much. If you e.g. have a source without any dark scenes (or only very few), it can be worth manually allocating more bits to darks via zoning and using AQ modes 1 or 2.

This comes along with a strength parameter. For modes 1 and 2, you usually want a strength between 0.80 and 1.30. Mode 3 is a bit more aggressive and usually looks best with a strength between 0.60 and 0.85.

Raising the AQ strength will help flatter areas, e.g. by maintaining smaller grain and dither to alleviate banding. However, higher AQ strengths will tend to distort edges more.

Older, grainier live action content will usually benefit more from lower AQ strengths and may benefit less from the dark scene bias present in AQ mode 3, while newer live action tends to benefit more from higher values. For animation, this setting can be very tricky; as both banding and distorted edges are more noticeable. It's usually recommended to run a slightly lower AQ strength, e.g. around 0.60 to 0.70 with mode 3.

To use e.g. AQ mode 3 with strength 0.80:


--aq-mode 3 --aq-strength 0.80

[gelo333]

Thanks for your reply. I'll try to understand your solution to the best of my knowledge.

But what about AQ=1 and AQ=2, the description I asked about?