[INFO] Feature Request: Per scene encoding

[Werve]

But it seems it is not possible because --passes is already set to 1 in Constant Quality mode (and there isn't the two-passes one in hybrid)

There is no contant quality rate control mode.

            --end-usage=<arg>           Rate control mode
                                             vbr, cbr, cq, q

vbr = variable bit rate
cbr = constrant bit rate
cq = constrained quality
q = constant quantizer

Hybrid offers '--passes=2' with 'vbr' and 'cq' as 2pass doesn't make sense for constant quantizer or constant bit rate rate control.

Sorry I mean 'q' constant quantizer. Based on the previous linked articles the encoder need 2pass to enable scene-detection.

2-pass was extremely important in vpxenc-vp9, as not only was it the only way for the encoder to utilize scene-detection, but it also allowed for the placement of alternate reference frames. Not doing that seriously cripples the encoder in what it can do. It also disables other stuff, but this also applies to aomenc-av1, so letÂ’s move on to the AV1 encoder again.

In aomenc-av1, 2-pass allows for these things in particular:
- More advanced scene detection when the lookahead buffer is high enough.
- Partition recoding: the encoder itself can decide whether or not to redo partition selection based on the preset on other conditions, resulting in better partition selection.
- Better auto-alt-ref placement through the encoded stream.

It also does some more advanced things, so IÂ’d advise keeping it on if you can

So yeah, always use 2-pass if you can. Luckily, itÂ’s set by default in the standalone encoder, so you donÂ’t need to do anything if you utilize a utility like nmkoder or av1an