                                ┌┬──────────┬┐                                
                                ││  Filter  ││                                
                                └┴──────────┴┘                                
                                                                              
    Function key usage                                       Mouse            
                                                                              
   F1      - Display this help information.                  [Help]           
   F2      - Display file list.                              [Files]          
   F3      - Exit program.                                   [Exit]           
   F4      - Reset filter ranges.                            [Reset]          
   F5      - Initiate filtering.                             [Filter]         
   F9      - Decrement cell value.                           <left button>    
   F10     - Increment cell value.                           <right button>   
   Alt-F3  - Push to DOS.                                    [Push]           
   Alt-R   - Copy current cell to others in row.                              
                                                                              
 ┌─────────┐                                                                  
 │ Editing │                                                                  
 └─────────┘                                                                  
                                                                              
 Use the arrow keys to move the large block cursor around the screen to       
 select the available data fields or "cells".  On a color monitor, the data   
 in cells which can be changed will appear yellow.  Note the input area near  
 the bottom of the screen, indicated by ">" and the small blinking cursor.    
 To enter or change a selected cell, type into the input area and press       
 return.  The value entered will then appear in the cell (if the input was    
 valid).  A description of the valid input for the current cell will always   
 appear on the line above the input area.                                     
                                                                              
 Use the following keys for editing:                                          
                                                                              
  Return    - Retrieves the current contents of a cell and places it in the   
               input area for modification (if the input area is empty).      
  Insert    - Toggles between character insert and overwrite modes.           
  Delete    - Deletes the character at the cursor.                            
  BackSpace - Deletes the character before the cursor.                        
  End       - Moves to the end of the character string.                       
  Home      - Moves to the beginning of the character string.                 
  Escape    - Erases the input area.                                          
                                                                              
 ┌───────┐                                                                    
 │ Usage │                                                                    
 └───────┘                                                                    
                                                                              
 There are four basic data sections on the screen.  The first section         
 specifies input and output file names, and provides general information on   
 how the output relates to the input.  The second section allows the          
 filtering action of the sections below it to be restricted to the channels   
 and/or tracks specified.  The third section is mainly used to specify the    
 removal of certain types of MIDI messages.  The fourth section defines       
 various MIDI message conversions to perform.                                 
                                                                              
 To enter or change data, move the large block cursor to the desired field on 
 the screen using the arrow keys, or click directly with a mouse.  After you  
 have changed the filtering options as described in the following sections,   
 simply press F5 (Filter) to begin the process.                               
                                                                              
 ┌────────────────┐                                                           
 │ Input / Output │                                                           
 └────────────────┘                                                           
                                                                              
 When the program starts up, the block cursor will appear at the "Input file" 
 field.  Type the name of a MIDI file and press return.  Filter will load the 
 file in preparation for processing.  Once loading is complete (it may take a 
 few seconds), notice that the input file "Format" value will indicate the    
 file's format -0, 1, or 2.  Format 0 files contain a single track.  Format 1 
 files contain multiple tracks, with track 1 normally reserved for tempo      
 information.  Format 2 files are also multi-track, but the tracks are not    
 necessarily related to each other in time.  Formats 0 and 1 are most common, 
 with format 0 being the most portable; however, format 1 is more useful, and 
 therefore the one most often encountered.  Format 2 is rare, and not         
 supported by most MIDI applications.                                         
                                                                              
 If an input file name contains wildcard characters (* or ?), a list of all   
 matching files will be displayed for selection.  The F2 (Files) function may 
 also be used to select an input file.                                        
                                                                              
 To specify an output file different than the input file, move to the "Output 
 file" field and enter a name.  If no file extension (such as .MFF) is given, 
 the extension of the input file is assumed.                                  
                                                                              
 If a different output file is not entered, the input file will be replaced   
 and reloaded each time the Filter operation is performed.  Also, a backup of 
 the original file with an extension of .BAK is created each time.            
                                                                              
 The other entry fields in this section are described below.                  
                                                                              
 "Copy Tracks"                                                                
                                                                              
 This lists the tracks which are to be retained when creating the output      
 file.  By default, all input file tracks are selected.  Change the track     
 selection to extract only certain ones from the original file.  Note that    
 for format 1 files, track 1 should always be copied; otherwise tempo, time   
 signature, or other informational data may be lost.                          
                                                                              
 Anywhere a range of numbers (such as a track range) is required, simply list 
 the numbers, separated by spaces or commas.  A continuous range between two  
 numbers may be indicated with a dash (-).  You may also use the word "All"   
 to specify all possible numbers.                                             
                                                                              
 "Copy Channels"                                                              
                                                                              
 Only MIDI data for the channels specified here will be retained in the       
 output file (assuming the data appears in the copied tracks).  By default,   
 all channels (1-16) are selected.                                            
                                                                              
 (Output file) "Format"                                                       
                                                                              
 This number specifies the standard MIDI file format (0,1,2) to use when      
 creating the output file.  By default, it is the same as the input file's    
 format.                                                                      
                                                                              
 "Channelize"                                                                 
                                                                              
 This option only applies if the output file format is 1.                     
                                                                              
 If the input file is format 0 (single track), each input file channel will   
 be assigned to a separate track in the output file, rather than a to single  
 track.                                                                       
                                                                              
 If the input file is format 1 (multi-track), each input file track will be   
 assigned a different channel, regardless of the original channels used.  If  
 there are more than 16 active tracks, channels are assigned arbitrarily,     
 cycling from 1 thru 16.                                                      
                                                                              
 Channelization occurs after all other filtering has been done.               
                                                                              
 "Tempo Ratio"                                                                
                                                                              
 The output file tempo may be increased or decreased by changing this value.  
 The default is 100%, or no change.  Smaller values decrease tempo, and       
 larger values increase it.  Tempo changes only apply to files using a        
 metrical time base - not real-time files based on SMPTE or MIDI time code.   
                                                                              
 ┌─────────────────┐                                                          
 │ Filter Limiting │                                                          
 └─────────────────┘                                                          
                                                                              
 Event filtering may be limited to the tracks and channels appearing in the   
 second screen section.  Simply enter the desired range of tracks or channels 
 to be affected by filtering.  This limiting applies to the tracks and        
 channels which were included in the Copy Tracks / Channels fields in the     
 input/output section above.  If both track and channel limits are given,     
 only the channels represented in the specified tracks will be affected.  By  
 default, all track and channel data will be processed.                       
                                                                              
 ┌─────────────────┐                                                          
 │ Message Removal │                                                          
 └─────────────────┘                                                          
                                                                              
 The third screen section specifies messages (within the track/channel limit  
 ranges) to be removed from the file.                                         
                                                                              
 The following message types may be removed simply by indicating Yes:         
                                                                              
        "Aftertouch"        (mono and poly)                                   
        "Program Changes"                                                     
        "Pitch Wheel"                                                         
        "System Exclusive"                                                    
        "Control Changes"                                                     
                                                                              
 Control change removal may be further limited to specific controller numbers 
 by changing the default range of 0-127.                                      
                                                                              
 Velocity and Pitch ranges may also be given for note data.  Notes with       
 velocities below or above the specified limits will be discarded. Similarly, 
 notes with pitches below or above the given values will be removed.  Note C3 
 is middle C.  MIDI note numbers (0-127) may be entered instead of symbolic   
 values.  By default, the velocity and pitch ranges are set to retain all     
 note data.  The velocity limiting function behaves differently when the      
 Compressor option is activated (see next section).                           
                                                                              
 ┌──────────────────────┐                                                     
 │ Message Modification │                                                     
 └──────────────────────┘                                                     
                                                                              
 The fourth section of the screen specifies changes to be applied to MIDI     
 channel messages, rather than their removal.                                 
                                                                              
 "Map Channels"                                                               
                                                                              
 To change the channels associated with MIDI messages, enter the new channel  
 numbers beneath the original 16 listed across the screen.  By default, they  
 are the same as the original channel.  To change all channels to a single    
 channel, you can use the shortcut of typing in a single new value, and       
 pressing Alt-R to make all the other channel values the same.                
                                                                              
 "Map Programs"                                                               
                                                                              
 By default, program numbers are mapped from the range of 0-127 to the same   
 range of 0-127.  There is a one-to-one correspondence between programs in    
 the original range on the left, and the new range on the right.              
                                                                              
 Where there are fewer new programs specified on the right, the list will be  
 reused in a cyclical fashion to determine the mapping of the original        
 programs.  For example, the following mapping:                               
                                                                              
      Map Programs:  1,2,3,10-14,20      to: 4-6                              
                                                                              
   would result in:    Old  1  2  3 10 11 12 13 14 20                         
                       New  4  5  6  4  5  6  4  5  6                         
                                                                              
 All other programs would remain unchanged.                                   
                                                                              
 "Velocity Multiplier"                                                        
                                                                              
 Note velocities will be multiplied by this factor.  The default is 100%,     
 indicating no change.  Smaller values will reduce velocity, and larger       
 values will increase it.  Resulting notes with a velocity of zero will be    
 discarded.  Multiplication occurs after any limiting.                        
                                                                              
 "Compressor"                                                                 
                                                                              
 If Yes, the function of the velocity limits in the previous section is       
 altered.  Notes will no longer be discarded if they are outside the range.   
 Instead, the lower and upper limits are taken to mean compression limits,    
 and all note velocities will be scaled proportionally to fit within these    
 limits.  Arrow markers are displayed next to the velocity limits while       
 compression is in effect as a reminder of their altered function.            
                                                                              
 "Transpose"                                                                  
                                                                              
 This specifies the number of half steps (positive or negative) to transpose  
 notes.  Notes transposed outside the legal MIDI range of 0 to 127 (C-2 to    
 G8) are discarded.                                                           
                                                                              
                                                                              
 ┌─────────────┐                                                              
 │ Mouse usage │                                                              
 └─────────────┘                                                              
                                                                              
 When a Microsoft-compatible mouse is available and the mouse driver software 
 properly loaded, operations using the mouse will be enabled.  The mouse may  
 be used to select an input cell on the screen by positioning the small mouse 
 cursor on the cell and single clicking either button.  The cell will be      
 highlighted, just as if the cell had been selected using the arrow keys.     
                                                                              
 Any cell which can be changed using the F10/F9 keys to increment/decrement,  
 may be changed in a similar manner using the mouse.  Once a cell is selected 
 by clicking on it, subsequent clicking of the left button will decrement the 
 cell value, and clicking of the right button will increment it.              
                                                                              
 In mouse mode, the function key designations normally displayed at the       
 bottom of the screen are changed to selector blocks for each available       
 function.  Clicking on a block will perform the indicated function.  All     
 functions may still be invoked via the normal keyboard equivalents.          
                                                                              
 If mouse operations are not desired, add the -k option on the command line   
 when the program is run to force keyboard mode.                              
                                                                              
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