I have asked question on stackoverflow http://stackoverflow.com/questions/33755148/how-i-can-specify-mime-types-for-media-in-imsmanifest-xml-file/33762441#33762441
and I have received following response:
MIME types are handled by the server serving the content, they are independent of SCORM and the imsmanifest.xml file. SCORM does not have any control over how the server handles MIME types. If you are running a local server (including servers that might be built-in to tools), you will need to configure it to handle the MIME types in question.
I would like to confirm that this is true. Any feedback is appreciated .. link to documentation, whatever, to confirm that statement.