+ auto value = boost::lexical_cast<uint32_t>(what["VALUE"].str());
+ auto whence = what["WHENCE"].str();
+
+ if(boost::iequals(whence, L"REL"))
+ {
+ value = file_frame_number() + value;
+ }
+ else if(boost::iequals(whence, L"END"))
+ {
+ value = file_nb_frames() - value;
+ }
+
+ input_.seek(value);