Boosting

Decreasing CQ value of encoded scene depending on brightness value of scene. (AOM only)
Intended to improve encoding quality of dark scenes.

How it works

For each scene geometrical mean of brightness is calculated from average brightness of every frame.
If brightness of scene is lower than 128, CQ will be decreased, lower values of brightness will receive bigger CQ decrease. CQ change range relates to 0-128 brightness range, meaning that the lowest value CQ will be at 0 brightness, half of that value at 64, etc..
For example (encoding cq = 40) :

Usage

• Enable with --boost
• Option -br will set maximum CQ change from original. Default: 15
• Option -bl will set hard cap on how low CQ can be set by boosting. Default: 10

Example

If this option --boost -br 30 -bl 15 set with --cq-level=30 will mean that we set boost CQ range to 30, and hard limit for boost at 15 . In this example all scenes with brightness 64 and lower will have minimum value of cq (15)