Adaptive quantization

[Michael Rampe]

[Stan Juznitok] “There are few of tehm that can be reached from x264 itself, as described in:
https://sites.google.com/site/linuxencoding/x264-ffmpeg-mapping“

This lists all of the options…..
Which ones specifically are you after?

Michael

[Stan Juznitok]

For example, there is:
–aq-strength (x264) — control the strength of adaptive quantization

Is there a way to control the adaptive quantization from the FFMEPG itself? I’m trying to get more details about the parameters that have a high influence on the resulting bitrates when x264 compression is done, and I guess the quantization has dominant role in it. Adaptive quantization seems to have the influence on the resulting bitrates, but what is the algorithm or logic that decides on this adaptivity?

Thank you!

[Michael Rampe]

[Stan Juznitok] “Is there a way to control the adaptive quantization from the FFMEPG itself?”

Yes. Quite recently, there is the added option to control x264 settings direct from FFmpeg.

Your example would require:
“-x264opts aq-strength=1”
….as an extra command line option.

Example:
$ ffmpeg -i tilt_shift_3.mov -vcodec libx264 -preset slow -x264opts aq-strength=1 -crf 6 tilt_shift_3h.mp4

If this does not work for you, upgrade your FFmpeg install.
Hope this helps.

Michael