diff --git a/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_metadata_addKey.m b/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_metadata_addKey.m
index f8c22ff4d502e1a86903ac5e4e6475177ce90e39..430e46c9146d2c7706ff57585cd7536aa7c0f9c2 100644
--- a/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_metadata_addKey.m
+++ b/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_metadata_addKey.m
@@ -1,4 +1,4 @@
-function [ metadata ] = daffv15_metadata_addKey(metadata, keyname, datatype, value)
+function [ metadata ] = daffv15_metadata_addKey( metadata_in, keyname, datatype, value)
 %DAFF_METADATA_ADDKEY Adds another key to a DAFF metadata struct
 %   TODO:
 %   ITAToolbox schauen
@@ -9,42 +9,54 @@ function [ metadata ] = daffv15_metadata_addKey(metadata, keyname, datatype, val
 % You can find the license for this m-file in the application folder.
 % </ITA-Toolbox>
 
-%     if (~isempty(metadata))
-%         if (~isstruct(metadata)), error(['[' mfilename '] Wrong datatype for metadata']); end;
-%     else
-        metadata = struct('name', {}, 'datatype', {}, 'value', {});
-%     end
-    
-    if (~ischar(keyname)), error(['[' mfilename '] Key name must be a string']); end;
+     if (~isempty(metadata_in))
+         if (~isstruct(metadata_in))
+             error( 'Input metadata is not empty and not a struct' )
+         end;
+        metadata = metadata_in;
+     else
+         metadata = struct();
+     end
+     
+     keyname(ismember(keyname,' ')) = '_';
+     keyname(ismember(keyname,',.:;!')) = [];
+     
+    if (~ischar(keyname))
+        error('Key %s name must be a string', keyname )
+    end;
     
     % Keynames are case-insensitive (convert to upper case)
     keyname = upper(keyname);
     
     % Test wheather a key of the given name already exists
-    if any(strcmp({metadata(:).name}, keyname))
-        error(['[' mfilename '] Key ''' keyname ''' already exists']);
+    if isfield( metadata, keyname )
+        error(['Key ''' keyname ''' already exists']);
     end
     
-   if (~ischar(datatype)), error(['[' mfilename '] Datatype must be a string']); end;
+   if (~ischar(datatype))
+       error(['Datatype must be a string'])
+   end
    
    switch (upper(datatype))
        case 'BOOL'
-           if (~islogical(value)), error(['[' mfilename '] Value must be logical for boolean keys']); end; 
-           metadata(end+1) = struct('name', keyname, 'datatype', 0, 'value', value);
+           if (~islogical(value))
+               error(['[' mfilename '] Value must be logical for boolean keys'])
+           end; 
+           metadata.(keyname) = boolean( value );
            
        case 'INT'
            if (~isfinite(value)), error(['[' mfilename '] Value must be finite']); end; 
            if (~isreal(value)), error(['[' mfilename '] Value must be real']); end; 
            if (value ~= ceil(value)), error(['[' mfilename '] Value must be an integer number for integer keys']); end; 
-           metadata(end+1) = struct('name', keyname, 'datatype', 1, 'value', int32(value));    
+           metadata.(keyname) = int32(value);
            
        case 'FLOAT'
            if (~isfinite(value)), error(['[' mfilename '] Value must be finite']); end; 
-           if (~isreal(value)), error(['[' mfilename '] Value must be real']); end; 
-           metadata(end+1) = struct('name', keyname, 'datatype', 2, 'value', double(value));                 
+           if (~isreal(value)), error(['[' mfilename '] Value must be real']); end;  
+           metadata.(keyname) = double(value);            
            
        case 'STRING'
-           if (~ischar(value)), error(['[' mfilename '] Value must be a string for string keys']); end; 
-           metadata(end+1) = struct('name', keyname, 'datatype', 3, 'value', value);                 
+           if (~ischar(value)), error(['[' mfilename '] Value must be a string for string keys']); end;
+           metadata.(keyname) = char(value);                
    end
 end
diff --git a/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_write_metadata.m b/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_write_metadata.m
index 8d035adfff635f37d967005eec18c3e18b10cfc9..0232a0808626902b90ac5f5cb5942bd13db86e36 100644
--- a/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_write_metadata.m
+++ b/applications/VirtualAcoustics/openDAFF/OpenDAFFv1.5/daffv15_write_metadata.m
@@ -35,33 +35,42 @@ function [ ] = daffv15_write_metadata( fid, metadata )
             % Logical scalar (DAFF_BOOL)
             if islogical(value) && isscalar(value)
                 type = 'BOOL';
+                datatype = 0;
             end
 
             % Integer scalar (DAFF_INT)
             if isinteger(value) && isfinite(value) && isreal(value) && isscalar(value)
                 type = 'INT';
+                datatype = 1;
             end
 
             % Floating point scalar (DAFF_FLOAT)
             if isfloat(value) && isfinite(value) && isreal(value) && isscalar(value)
                 type = 'FLOAT';
+                datatype = 2;
             end        
 
             % String (DAFF_STRING)
             if ischar( value )
                 type = 'STRING';
+                datatype = 3;
             end
             
             if isempty( type )
                 error( 'Unsupported datatype %s for key ''%s'' in metadata', class( value ), name );
             end
             
-            metadata_new_format = daffv15_metadata_addKey( metadata_new_format, name, type, value );
+            %metadata_new_format = daffv15_metadata_addKey( metadata_new_format, name, type, value );
+            metadata_new_format(i).name = name;
+            metadata_new_format(i).datatype = datatype;
+            metadata_new_format(i).value = value;
         end
         
         metadata = metadata_new_format;
     end        
         
+    nkeys = length( metadata );
+    
     % Number of keys
     fwrite( fid, nkeys, 'int32' );