My system:
OS: Windows 8.1 x64
Movie ID: WANZ-356 /
http://www.dmm.co.jp/digital/videoa/-/detail/=/cid=wanz00356/
Playback: Local with DMM player (latest version)
Tested WANZ-356 before with WMP and it played perfectly so definitely caused by DMM player and not something on my system, also tried some non-DMM files (WMV without DRM) and those play jerky as well.
Understand that WMP isn't possible anymore due to Microsoft dropping server 2003 support and licensing software being solely designed for that, Silverlight however is already being dropped in Chrome and permanently in October so no workaround for streaming at least.
Microsoft will be dropping Silverlight in the next few years as well (supporting ending 2020 but no updates since ~2013 and no plans to maintain it), Windows 10's default browser won't offer support for it as well (only legacy IE).
Are you guys planning to move towards HTML5 DRM (Encrypted Media Extensions) in the near future?
Because that would mean less restrictions on mobile devices and more codec options (less bandwidth = less cost).