[x264-devel] How can I disable Adaptive Quantization (AQ) completely?

[BugMaster]

On Tue, 18 Oct 2016 17:20:46 -0700, Raul Lopez wrote:
> Using x264 0.148.x built today, I was not able to completely
> disable AQ when I set "--aq-mode 0".

> I get a reduction in the range of QP in the Initial Intra Frame
> from 20-41 (without the --aq-mode 0 option) to 27-36, so the
> parameter is doing something, but, for testing purposes, I would
> want to have a single QP for the whole frame that adapts to the
> content and is regulated by Rate Control.

> Does --aq-mode 0 not work or do I need to set any other parameter at the same time?

> This is my command line:

> x264 --preset fast --bframes 0 --bitrate 3000 --vbv-bufsize 3000
> --vbv-maxrate 3000 --nal-hrd cbr --fps 30 --keyint 100 --min-keyint
> 100 --no-scenecut --aq-mode 0 --output
> sensor_3Mbps_CBR_VBV1Sec_IP_GOP100_noAdaptiveQP.h264 sensor_1920x1080p30.mov

> Any guidance would be appreciated.

> Raul 

Hi. "--aq-mode 0" disables AQ only but there other algorithms that
change QP at macroblock level like MBTree and VBV (row level). So if
you really want only single QP for full frame than you need to disable
them also i.e. --no-mbtree and don't use vbv options.