Question / Help Ultrafast preset & Profile High

[FAQU]

As far as i know , the main & high profiles are using CABAC ; the cpu preset "Ultrafast" is disabling CABAC .

So , here are my real questions : If i use Ultrafast preset + high profile , is the high profile actually working and doing it's job? If no, forcing CABAC (cabac=1) via x264 Options is gonna work ? If the answer of the 2nd question is yes , then will this option use more resources when encoding at high bitrates (80k for example)

Sorry for my bad english :D

 

[R1CH]

High profile doesn't set anything, it only constrains. You'll have to set cabac=1 manually if you want to enable it, and yes it will use more resources hence why it is disabled for ultrafast.

 

[JohnnyOmaha]

What does CABAC actually do for encoding?

 

[R1CH]

You can read up on it at https://en.wikipedia.org/wiki/Context-adaptive_binary_arithmetic_coding

 

[JohnnyOmaha]

Thanks Rich. Excited to try this out and see what it does visually. Looks really interesting!

 

[FAQU]

@R1CH Thanks for the help ! Also , i've got a little new question : I read that CABAC improves the "objective image quality" by 15% at the exchange of 20% more resources than without CABAC . Is that true ? If it is , then using CABAC while recording with CRF is gonna make the final file smaller ?