SNT file format description
Released with mcc Synthesizer Version 1.00

A .SNT file begins always with the string "mcc Synth x.xx" (with final NUL,
15 bytes total), with x.xx the version number of the mcc Synthesizer. When
reading, synth.exe does not control the version number. It pretends only
the "mcc Synth" signature. After that modules follow. Each module begins
with 4 bytes (a long integer), where the most significant byte identifies
the module type, the other three bytes contain the module length (the module
id (the described 4 bytes) is not counted). These type of modules are defined:

ID 0 Length 0:
        File terminator. Not necessary, but synth.exe puts it.
ID 1 Length variable:
        Text. You can put every text you want here (the module description,
        copyright messages, ...). synth.exe simply ignores it.
ID 2 Lenght 1248:
        Sound bank. In given order:
        12 * 31 bytes containing sound names (strings must terminate with NUL)
        12 * 63 spectrum
        12 * 8  ADSR pots (integers)
        12 * 2  volume pots (integers)
ID 3 Length 188899
        Drum bank. In given order:
        43 * 31   bytes containing drum names (strings must terminate with NUL)
        43 * 256  spectrum
        43 * 4096 sampled drums (spectrum converted to samples)
        43 * 8    ADSR pots (integers)
        43 * 2    volume pots (integers)
ID 4 Length 104
        Sound:
        31 name
        63 spectrum
        8  ADSR
        2  volume
ID 5 Length 297
        Drum:
        31  name
        256 spectrum
        8   ADSR
        2   volume
ID 6 Lenght 41
        Effect:
        31 name
        10 potentiometers
ID 7 Length 11940
        Rhythm bank:
        12 * 2   rhythm potentiometers
        12 * 31  names
        12 * 2   number of passes (integer)
        12 * 800 rhythm sequences
        12 * 128 arrangements
        12 * 32  LEDs
ID 8 Length 995
        Rhythm:
        2   potentiometer
        31  name
        2   number of passes (integer)
        800 rhythm sequence
        128 arrangemet
        32  LEDs
ID 9 Length variable:
        Song:
        2      rhythm number (0 to 11)
        2      rhythm potentiometer
        13 * 2 track offsets (integers, the last represents last track end + 1)
        12 * 2 buttons (0 disabled, 1 play, 5 rec)
        2 * offset[12] event times
        2 * offset[12] events
ID 10 Length 4393
        Drum (with included sample):
        31   name
        256  spectrum
        8    ADSR
        2    volume
        4096 sample

IDs 11 - 127 reserved
IDs 128 - 255 free

All the potentiometers are integers. Acceptable values are in the range
0 - 155.

ADSR pots are:
        attack time: pot ^ 2 * 1000 / 11232 ms
        release time: pot ^ 2 * 1000 / 11232 ms
        sustain level: pot ^ 2 / 241 %
        releases time: pot ^ 2 * 1000 / 11232 ms
Effect pots are:
        delay time: pot ^ 2 / 54 ms
        delay level: pot ^ 2 / 246 %
        delay return: pot ^ 2 / 246 %
        delay modulation: pot ^ 2 / 246 %
        modulation period: pot ^ 2 * 12 / 45 ms
Volume pot is:
        volume: pot / 1.56 %
Rhythm pot is:
        BPM: pot ^ 2 / 50 + 2

The sound spectrum is made of unsigned chars in the range 0 - 180. The scales
(intensity and frequency) are linear.
The drums spectrum is made of unsigned chars in the range 0 - 63. The
intensity scale is linear, the frequency scale is linear in portions of 48
frequencies. Every 48th frequency the scale doubles. To keep the ideas clear,
here's the code that does the tranformation:
        n = k = 1;
        for(j = 1; j < 256; j++)
        {
          if(!(j% 48)) 
          k *= 2;
          for(i = 0; i < k; i++)
            drum[n++] = spectrum[j] * (random(2000) - 1000);
        }
        4096 poits FFT follows.

What sampled is 8 bit signed char.

The drum bank has the sampled data, because 43 4096-points FFTs are too long
to calculate and the user doesn't want to wait one minute for every drum bank
load.

The rhythm sequence is a circular linked list of records containing four
integers (in the given order): link to next node, time to next event, sound,
note. Every pass is divided in 4 time units. Sounds go from 0 to 12, where 12
means drum. The bit 7 of note is set for release, cleared for press. Note
number 127 is ignored. If sound is 12 (drum), note contains the drum (0 - 42).
If sound is in the range 0 - 11, note contains the semitone number, where 67
is 440 Hz. Only 100 rhythm events are possible 800 / (2 * 4). Arrangement
contains 4 sequences of 32 bytes, where each bit in the byte entry is used to
determine, whether the note in the accord position corresponding to that bit
will be played (if bit set). Bits 0 - 3 are actual accord positions, bits
4 - 7 play a note one octave higher. There are 4 sequences, the first for one
key pressed, the second for two keys, and so on. For every pass there is a
LED combination: 0 means first LED (red), 1 means the second (green), 2 the
third (green), 3 the fourth (green) and 4 all the LEDs.

The time unit for the songs is four times more precise than that of the rhythm,
so there are 16 units for rhythm pass. The timing in the song is absolute (in
the rhythm the timing entries represent the time between events). The events
are integers with the most significant byte containing the sound and the least
significant byte containg note. The sounds and the notes are as in the rhythm
case.