subcheck was also used to validate the binary subtitle file format EBU STL. To make this possible the binary STL file was translated first into an XML representation of the binary structure. After that, the resulting XML structure was validated using Schematron rules.

Apart from the subcheck service, the validation engine was also implemented in the workstation-based product IMF analyser. The tool is written in C# and C++.

Especially the integration of the W3C XML Schema validation was a challenge. It needs more work and design changes to become a generic solution.