Yamka is a cross-platform C++ SDK for creation/manipulation of Matroska container files. Yamka is focused on a concise and robust API. Yamka is designed around clear separation of responsibilities between an EBML Element and EBML Element Payload.
To get the yamka SDK check out the source code from svn (svn co https://svn.code.sf.net/p/yamka/code/trunk/yamka). There is no DLL, if you need one you can always make one yourself, or you can include any files you need into your project code base...