HandBrake

I plan to reencode movies from my camera and my phone (mov,mp4,ts)(in FHD and 4K) to universal format that will work on tv/phone/laptop.

I would like to tweak x264 settings to make quality and compression better (also with audio in stereo):
-v1 -f av_mp4 -m -e x264 --x264-preset veryslow --x264-tune film -q 13 --encoder-level=4.1 -E fdk_aac -B 320 -Q 100 --mixdown stereo -R 48

Can I tweak something more except "-q 13"?

Could you please post your HB logs, instructions can be found here:

https://handbrake.fr/docs/en/latest/hel ... y-log.html

"Universal format", but you fail to identify which of the target devices has the most limitations.

Those settings that I provided are working on all of them.
Even specification that I found for my TV is not more specific than:

*.mp4 MP4

H.264 BP / MP / HP
1920x1080 6 ~ 30 fps
25 Mbps
MP3 /ADPCM /AAC

MPEG4
SP / ASP
1920x1080 6 ~ 30 fps
8 Mbps
MP3 /ADPCM /AAC

XVID
1920x1080
6 ~ 30 fps
8 Mbit
MP3 /ADPCM /AAC

-q 13 is silly

For me constant quality is better, I have some movies that have a lot of movement and some that are slow moving.
For two pass encoding I would need to pick a good bitrate for those.

If those settings are meeting your goal, what is the issue?

Regardless of the source resolution, with the destination being limited to 1920x1080, "Blu-ray quality" would be obtainable with an RF value of 16 to 18. Using 13 may not be silly, but, given the targets, unnecessary.