[Nico Claus]

Any MKV Converter software recommendation that can reduce file size without losing video quality? thanks before

[walgadon]

MKV is just a container and can include any file, generally though converting one lossy format into another will always decrease quality objectively.
As for converters, I personally recommend Handbrake and mess with the settings a bit to get something something where the quality is still fine but the file size is smaller.

[quicktip]

Xmedia recode is easier to use IMO

[saunteralong]

MKVToolNix is good for viewing and manipulating MKV contents, as a previous poster said, it's a container.

[randymiz]

Thanks good info

[zozobra]

i usually use ffmpeg

[watdus]

I +1 to the ffmpeg recommendation. You need to get used to its flags though, but the possibilities it offers are the biggest probably. In fact most of other commercial products use it as its backend.

Handbrake IIRC is a nice UI, but not sure how well it might handle your usecase