static int mxf_write_header_metadata_sets(AVFormatContext *s)
{
    mxf_write_preface(s);
    mxf_write_identification(s);
    mxf_write_content_storage(s);
    mxf_build_structural_metadata(s, MaterialPackage);
    mxf_build_structural_metadata(s, SourcePackage);
    return 0;
}