Vladimir Arnost, QA-Software
Updated: March 9, 1996
Version: 1.31
Internet: xarnos00@dcse.fee.vutbr.cz
FIDO: 2:423/36.2
A .MUS file is a simple clone of .MID file. It uses the same instruments, similar commands and the same principle: a list of sound events. It consists of two parts: header and body.
NOTE: All numerical values mentioned in this document are zero-based. If not specified otherwise, all numbers are given in decimal. Hexadecimal numbers are suffixed by 'h' (e.g. 5Ch). Bits are numbered in this fashion: LSB (right-most) = 0, MSB (left-most) = 7.
The MUS header has the following structure:
struct MUSheader { char ID[4]; // identifier "MUS" 0x1A WORD scoreLen; WORD scoreStart; WORD channels; // count of primary channels WORD sec_channels; // count of secondary channels WORD instrCnt; WORD dummy; // variable-length part starts here WORD instruments[]; };
NOTE: WORD is a 16-bit unsigned integer (little-endian)
The header has two parts: the fixed-length and the variable-length part. The former contains file identifier, score start and length, number of channels and number of used instruments. The latter part is actually a list of used instruments. The instruments are stored as numbers which are arranged in this fashion:
| Instrument Number | Meaning |
|---|---|
| 0 - 127 | standard MIDI instruments |
| 135 - 181 | standard MIDI percussions (notes 35 - 81) |
`scoreStart' is the absolute file position of the score and `scoreLen' is its length in bytes. Usage of a 16-bit number as length limits .MUS file size to 64KB.
`channels' tells you how many channels are utilized in the song. The channel number 15 (percussions) is not included in the sum.
Unlike MID files, MUS body contains only one track. File body is a sequence of sound events and time records. A sound event consists of one or more bytes encoded as follows:
1st byte – event descriptor:
+--7----6----5----4----3----2----1----0-+ |Last| Event type | Channel number | +---------------------------------------+
`Event type' is one of these:
0 - release note 1 - play note 2 - pitch wheel (bender) 3 - system event (valueless controller) 4 - change controller 5 - ??? 6 - score end 7 - ???
`Channel number' determines which channel this event refers to. Channels provide only logical score division. Every channel carries its own settings (instrument #, panning, volume) and the channel number specifies only which settings to use. In general, the channel number itself is almost irrelevant and may be chosen arbitrarily within the interval 0 to 14. The only exception is the channel number 15, which is dedicated ONLY to percussions.
`Last' - if set, the event is followed by time information. This means that this is the last event in a group of events which occur at the same time. The time information is a number of ticks to wait before processing next event. One tick is usually 1/140 sec (in Doom I, II and Heretic; Raptor uses 1/70 sec).
Time information can be read in this way:
1. time = 0 2. READ a byte 3. time = time * 128 + byte AND 127 4. IF (byte AND 128) GO TO 2 5. RETURN time
The time info is a series of 7-bit chunks. The bit #7 is set until the last byte whose bit 7 is zero. This scheme allows small numbers occupy less space than large ones.
Event Type
--------------------
0 Release note
+-7---6---5---4---3---2---1---0-+
| 0 | Note number 0 - 127 |
+-------------------------------+
1 Play note
+-7---6---5---4---3---2---1---0-+ +-7---6---5---4---3---2---1---0-+
|Vol| Note number 0 - 127 | | 0 | Note volume 0 - 127 |
+-------------------------------+ +-------------------------------+
`Note volume' is present only if `Vol' bit is set. Otherwise the
previous value is used and the second byte is not present.
NOTE: Each channel keeps track of its own last volume value.
More than one note can be played at once in one channel.
Channel 15 is dedicated to drums and percussions. `Note number'
acts as an instrument selector there. See Appendix C
2 Pitch wheel
+-7---6---5---4---3---2---1---0-+
| Pitch wheel value |
+-------------------------------+
Sets pitch wheel (bender) value of a channel. Some handy values are
shown in the table (all values in the range 0-255 can be used):
+-------------------------------+
| Value | Pitch change |
|-------+-----------------------|
| 0 | two half-tones down |
| 64 | one half-tone down |
| 128 | normal (default) |
| 192 | one half-tone up |
| 255 | two half-tones up |
+-------------------------------+
3 System event (Valueless controller)
+-7---6---5---4---3---2---1---0-+
| 0 | Number |
+-------------------------------+
Number MIDI ctrl Description
10 120 (78h) All sounds off
11 123 (7Bh) All notes off
12 126 (7Eh) Mono
13 127 (7Fh) Poly
14 121 (79h) Reset all controllers
NOTE: The second column (MIDI ctrl) lists the corresponding MIDI
controller number. It is not needed unless you want to
convert MUS file data to MIDI.
4 Change controller
+-7---6---5---4---3---2---1---0-+ +-7---6---5---4---3---2---1---0-+
| 0 | Controller number | | 0 | Controller value |
+-------------------------------+ +-------------------------------+
Number MIDI ctrl Description
0 N/A Instrument (patch, program) number
1 0 or 32 Bank select: 0 by default
2 1 (01h) Modulation pot (frequency vibrato depth)
3 7 (07h) Volume: 0-silent, ~100-normal, 127-loud
4 10 (0Ah) Pan (balance) pot: 0-left, 64-center (default),
127-right
5 11 (0Bh) Expression pot
6 91 (5Bh) Reverb depth
7 93 (5Dh) Chorus depth
8 64 (40h) Sustain pedal (hold)
9 67 (43h) Soft pedal
NOTE: MUS controller 0 has no equivalent MIDI controller, but
is encoded as MIDI event 0Cxh--patch change (`x' is the
channel number)
5 Unknown
Not known what data (if any) this command takes.
6 Score end
No data.
Marks the end of score. Must be present at the end, otherwise the
player may go off the rails. In DOOM this command restarts playing.
7 Unknown
Not known what data (if any) this command takes.
APPENDIX A - Note numbers
+=====================================================================+ | Octave | C | C# | D | D# | E | F | F# | G | G# | A | A# | B | ======================================================================| | 0 | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | | 1 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | | 2 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | | 3 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | | 4 | 48 | 49 | 50 | 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | | 5 | 60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 | 71 | | 6 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 | 81 | 82 | 83 | | 7 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | | 8 | 96 | 97 | 98 | 99 |100 |101 |102 |103 |104 |105 |106 |107 | | 9 | 108 |109 |110 |111 |112 |113 |114 |115 |116 |117 |118 |119 | | 10 | 120 |121 |122 |123 |124 |125 |126 |127 | | | | | +=====================================================================+
APPENDIX B - Instrument Patch Map
Block 0-7 PIANO Block 8-15 CHROM PERCUSSION 0 Acoustic Grand Piano 8 Celesta 1 Bright Acoustic Piano 9 Glockenspiel 2 Electric Grand Piano 10 Music Box 3 Honky-tonk Piano 11 Vibraphone 4 Rhodes Paino 12 Marimba 5 Chorused Piano 13 Xylophone 6 Harpsichord 14 Tubular-bell 7 Clavinet 15 Dulcimer
Block 16-23 ORGAN Block 24-31 GUITAR 16 Hammond Organ 24 Acoustic Guitar (nylon) 17 Percussive Organ 25 Acoustic Guitar (steel) 18 Rock Organ 26 Electric Guitar (jazz) 19 Church Organ 27 Electric Guitar (clean) 20 Reed Organ 28 Electric Guitar (muted) 21 Accordion 29 Overdriven Guitar 22 Harmonica 30 Distortion Guitar 23 Tango Accordion 31 Guitar Harmonics
Block 32-39 BASS Block 40-47 STRINGS 32 Acoustic Bass 40 Violin 33 Electric Bass (finger) 41 Viola 34 Electric Bass (pick) 42 Cello 35 Fretless Bass 43 Contrabass 36 Slap Bass 1 44 Tremolo Strings 37 Slap Bass 2 45 Pizzicato Strings 38 Synth Bass 1 46 Orchestral Harp 39 Synth Bass 2 47 Timpani
Block 48-55 ENSEMBLE Block 56-63 BRASS 48 String Ensemble 1 56 Trumpet 49 String Ensemble 2 57 Trombone 50 Synth Strings 1 58 Tuba 51 Synth Strings 2 59 Muted Trumpet 52 Choir Aahs 60 French Horn 53 Voice Oohs 61 Brass Section 54 Synth Voice 62 Synth Brass 1 55 Orchestra Hit 63 Synth Bass 2
Block 64-71 REED Block 72-79 PIPE 64 Soprano Sax 72 Piccolo 65 Alto Sax 73 Flute 66 Tenor Sax 74 Recorder 67 Baritone Sax 75 Pan Flute 68 Oboe 76 Bottle Blow 69 English Horn 77 Shakuhachi 70 Bassoon 78 Whistle 71 Clarinet 79 Ocarina
Block 80-87 SYNTH LEAD Block 88-95 SYNTH PAD 80 Lead 1 (square) 88 Pad 1 (new age) 81 Lead 2 (sawtooth) 89 Pad 2 (warm) 82 Lead 3 (calliope) 90 Pad 3 (polysynth) 83 Lead 4 (chiffer) 91 Pad 4 (choir) 84 Lead 5 (charang) 92 Pad 5 (bowed glass) 85 Lead 6 (voice) 93 Pad 6 (metal) 86 Lead 7 (5th sawtooth) 94 Pad 7 (halo) 87 Lead 8 (bass & lead) 95 Pad 8 (sweep)
Block 96-103 SYNTH EFFECTS Block 104-111 ETHNIC 96 FX 1 (rain) 104 Sitar 97 FX 2 (soundtrack) 105 Banjo 98 FX 3 (crystal) 106 Shamisen 99 FX 4 (atmosphere) 107 Koto 100 FX 5 (brightness) 108 Kalimba 101 FX 6 (goblin) 109 Bag Pipe 102 FX 7 (echo drops) 110 Fiddle 103 FX 8 (star-theme) 111 Shanai
Block 112-119 PERCUSSIVE Block 120-127 SOUND EFFECTS 112 Tinkle Bell 120 Guitar Fret Noise 113 Agogo 121 Breath Noise 114 Steel Drums 122 Seashore 115 Woodblock 123 Bird Tweet 116 Taiko Drum 124 Telephone Ring 117 Melodic Tom 125 Helicopter 118 Synth Drum 126 Applause 119 Reverse Cymbal 127 Gun Shot
APPENDIX C - Percussion Key Map
In channel #15, the note number does not affect the pitch but the instrument type. The default pitch for percussions is 60 (C-5).
Note Instrument Note Instrument
35 Acoustic Bass Drum 59 Ride Cymbal 2 36 Bass Drum 60 High Bongo 37 Slide Stick 61 Low Bango 38 Acoustic Snare 62 Mute High Conga 39 Hand Clap 63 Open High Conga 40 Electric Snare 64 Low Conga 41 Low Floor Tom 65 High Timbale 42 Closed High-Hat 66 Low Timbale 43 High Floor Tom 67 High Agogo 44 Pedal High Hat 68 Low Agogo 45 Low Tom 69 Cabasa 46 Open High Hat 70 Maracas 47 Low-Mid Tom 71 Short Whistle 48 High-Mid Tom 72 Long Whistle 49 Crash Cymbal 1 73 Short Guiro 50 High Tom 74 Long Guiro 51 Ride Cymbal 1 75 Claves 52 Chinses Cymbal 76 High Wood Block 53 Ride Bell 77 Low Wood Block 54 Tambourine 78 Mute Cuica 55 Splash Cymbal 79 Open Cuica 56 Cowbell 80 Mute Triangle 57 Crash Cymbal 2 81 Open Triangle 58 Vibraslap
TABLE 3 - General MIDI Minimum Sound Module Specifications
Voices: A minimum of either 24 fully dynamically allocated voices available simultaneously for both melodic and percussive sounds or 16 dynamically allocated voices for melody plus eight for percussion.
Channels: General MIDI mode supports all sixteen MIDI channels. Each channel can play a variable number of voices (polyphony). Each channel can play a different instrument (timbre). Keybased Percussion is always on Channel 10.
Instruments: A minimum of sixteen different timbres playing various instrument sounds. A minimum of 128 preset for Intruments (MIDI program numbers).
Note on/Note off: Octave Registration: Middle C(C3) = MIDI key 60. All Voices including percussion respond to velocity.
Controllers: Controller # Description 1 Modulation 7 Main Volume 10 Pan 11 Expression 64 Sustain 121 Reset All Controllers 123 All Notes Off
Registered Parameter # Description 0 Pitch Bend Sensitivity 1 Fine Tuning 2 Coarse Tuning
Additional Channel Messages: Channel Pressure (Aftertouch) Pitch Bend
Power-Up Defaults: Pitch Bend Amount = 0 Pitch Bend Sensitivity = +-2 semitones Volume = 90 All Other Controllers = reset