Needless to say the two pass get the file size better than the single pass
>>105643571
Well, my two pass give me about 8 frames the same as the OP parmas
Tried increasing the tiles, and nothing changed
Not the quality or the speed.
>>105643615
>-auto-alt-ref 1
Tried it didn't do much, maybe it got 0.5 frame faster?
Keep in mind this is i5-6500 so not the strongest thing.
However what I found that really helped was using -pix_fmt yuv420p instead, I get 16 frames.
Which was the only real thing that changed speed for me.