hi,
MP4 is support by Windows 10 but with other Video Type, e.g. H264 in MKV Container, it might happend that WMP say : no Codec
so you need a "Codec Pack". i recommend FFDshow (
https://sourceforge.net/projects/ffdshow-tryout/ )
FFDshow use Directshow and you can get Stream and "manipulate" it.
M$ don't want Directshow which do not support DRM so there own Codec have highest "Merit"
you need something like Win7DSFilterTweaker.exe *** (work also unter Windows 10) to change to FFDshow and "override" M$ "Merit"
***
http://www.codecguide.com/windows7_preferred_filter_tweaker.htmnow we get Video but no Audio ... hm
it is while "Mixer" get no Direct-Audio Stream. we have to use MatroskaSplitter.exe*** to split Stream.
***
https://haali.su/mkv/now you can play almost all Type of Video where Original WMP have fail before.
have Fun