/* mid2dsp - Convert MIDI files to raw wave output. */ /* Copyright (C) 1997-2000 by David A. Madore * Permission is granted to use, copy and modify under the terms of * the GNU General Public License (version 2 or later, at your * option). This program is provided WITHOUT ANY WARRANTY: see the * the GNU General Public License for details. */ /* Compile with gcc -o mid2dsp mid2dsp.c -O6 -Wall -ansi -pedantic -W \ -Wwrite-strings -Wcast-qual -Wpointer-arith -Wstrict-prototypes \ -Wno-unused -lm */ /* Use with mid2dsp [MIDI file], piping the standard output to a * program that understands raw wave data, typically sox -t raw -r * 11025 -s -w - -t ossdsp /dev/dsp (where 11025 is actually the * SAMPLERATE given below). */ /* Note: the essential difference with a program like ``timidity'' is * that this does not use a set of patches: the patches are computed * on the fly from a set of numerical constants by using a few * oscillators. As a result, (i) this is extremely CPU intensive, and * (ii) it soulds awful - really awful. *But*, at least, you don't * waste some precious disk space with patches (or Internet bandwidth * downloading them :-). Please note that output is monophonic, and * that aftertouch and pitchbend are not supported. */ #include #include #include #include #include #include #include /* The sampling rate of the output (in Hz) */ #define SAMPLERATE 11025. #define MIDIFILESIG 0x4d546864 /* "MThd" in big-endian format */ #define MIDITRKSIG 0x4d54726b /* "MTrk" in big-endian format */ /* The type and functions with which to do the computations */ typedef double real_t; #define SIN sin #define FABS fabs #define PI 3.14159265358979323846 /* The structure that describes an instrument */ struct instrument_s { /* The envelope parameters: the volume linearly increases from 0 to * max_vol in time att_del, then it linearly decreases to sus_vol * (the sustain volume) in time dec_del. If irel==0, it is kept at * sus_vol so long as the note is not released; if irel==1, the note * is considered to be released immediately. After that, the volume * drops back linearly to 0 in time rel_del. */ real_t max_vol, sus_vol; /* Maximal and sustained volumes */ real_t att_del, dec_del, rel_del; /* Attack, decay and release delays * (in seconds) */ char irel; /* Release instantly (i.e. no * sustain)? */ /* The wave shape: 0 is sine, 1 is square, 2 is absolute value of * sine, 3 is sawtooth, 4 is alternate sine bump and zero. */ char shape; /* Wave shape */ /* The oscillators. These are added to the main wave. amp_ and * frq_ give their relative amplitude and frequency, while del_ * gives the delay before oscillator comes in: its amplitude * increases linearly between 0 and 1 in that delay, and then stays * at 1. shape_ of course is the oscillator's wave shape. */ real_t amp2, frq2; /* Second oscillator amplitude * (ratio) and frequency (ratio) */ real_t del2; /* Time taken for second oscillator * to reach its maximal amplitude */ char shape2; /* Second oscillator wave shape */ real_t amp3, frq3; /* Third oscillator amplitude * (ratio) and frequency (ratio) */ real_t del3; /* Time taken for third oscillator * to reach its maximal amplitude */ char shape3; /* Third oscillator wave shape */ /* The wobulator. It acts like an oscillator, except that it * perturbs time (frequency) instead of amplitude. */ real_t ampw, frqw; /* Wobulator amplitude and * frequency (ratio) */ real_t delw; /* Time taken for wobulator to * reach its maximal amplitude */ char shapew; /* Wobulator wave shape */ }; /* We now define some instruments. I'm quite bad at that exercice so * these really sound awful. Far more awful than they might. But I * think even with considerable skill in defining the instruments, * this program will never give a decent sound. */ #define MAKEINSTR(name,max_vol,sus_vol,att_del,dec_del,rel_del,irel,\ shape,amp2,frq2,del2,shape2,amp3,frq3,del3,shape3,ampw,frqw,delw,shapew) \ struct instrument_s name##_I = { max_vol,sus_vol,att_del,dec_del,rel_del,irel,\ shape,amp2,frq2,del2,shape2,amp3,frq3,del3,shape3,ampw,frqw,delw,shapew } /* A generic instrument that sounds very much like nothing and a * little bit like anything. */ MAKEINSTR(gener, 1.0,0.2,0.01,0.03,0.09,0, 0, 0.3,2.0,0.0,0, 0.1,3.0,0.05,0, 0.0,1.0,0.0,0); /* Highly symbolic brass instrument - I mean it */ MAKEINSTR(brass, 1.2,0.8,0.09,0.07,0.06,0, 0, 0.4,2.0,0.0,0, 0.15,3.0,0.0,0, 0.03,0.5,0.08,1); /* This sounds exactly like a recorder... having spent a couple of * years in a very damp place. */ MAKEINSTR(recorder, 1.1,0.9,0.01,0.01,0.05,0, 0, 0.1,1.5,0.05,0, 0.15,2.0,0.0,0, 0.0,1.0,0.0,0); /* This makes an almost tolerable whistle - unfortunately, nobody uses * that particular instrument :-( */ MAKEINSTR(whistle, 1.0,0.9,0.11,0.06,0.03,0, 0, 0.0,1.0,0.0,0, 0.0,1.0,0.0,0, 0.01,0.01,0.0,0); /* This is a horrible pizzicato string - it sounds more like a * pizzicato string than like an elephant sneezing, but I would hardly * dare say more. Note, however, the ingenious (?) use of one * oscillator to compensate another. */ MAKEINSTR(pizzs, 1.0,0.05,0.01,0.45,0.06,1, 3, -0.7,1.0,0.1,3, 0.7,1.0,0.1,0, 0.08,0.01,0.18,0); /* Some extremely imaginative persons might recognize the following * instrument as a stylized clarinet. */ MAKEINSTR(clarinet, 1.0,0.9,0.015,0.015,0.015,0, 0, 0.35,3.0,0.0,0, 0.2,5.0,0.03,0, 0.0,1.0,0.0,0); /* This has some very vague similarity with what might be considered * as a piano. */ MAKEINSTR(piano, 1.0,0.2,0.01,0.03,0.09,0, 0, 0.3,2.0,0.0,0, 0.1,3.0,0.05,0, 0.0,1.0,0.0,0); /* This sounds (very) slightly like a violin. */ MAKEINSTR(violin, 1.0,0.8,0.09,0.09,0.09,0, 3, 0.0,1.0,0.0,0, 0.0,1.0,0.0,0, 0.08,0.01,0.18,0); /* A rather satisfactory fantasia instrument */ MAKEINSTR(fantas, 1.0,0.5,0.01,0.03,0.09,0, 1, -0.8,1.0,0.1,1, 0.8,1.0,0.1,0, 0.0,1.0,0.0,0); /* For lack of a better place to put this... */ MAKEINSTR(crystal, 1.0,0.2,0.01,0.45,0.06,0, 1, -0.7,1.0,0.1,1, 0.7,1.0,0.1,0, 0.0,1.0,0.0,0); /* The MIDI instrument mapping table. This maps MIDI program numbers * to instrument structures. I just put in gener_I whenever I didn't * have anything better to suggest. */ struct instrument_s *instrtab[128] = { &piano_I,&piano_I,&piano_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &pizzs_I,&pizzs_I,&pizzs_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &pizzs_I,&pizzs_I,&pizzs_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &violin_I,&violin_I,&violin_I,&violin_I,&violin_I,&pizzs_I,&pizzs_I,&gener_I, &violin_I,&violin_I,&violin_I,&violin_I,&gener_I,&gener_I,&gener_I,&gener_I, &brass_I,&brass_I,&brass_I,&brass_I,&brass_I,&brass_I,&brass_I,&brass_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&clarinet_I, &gener_I,&gener_I,&recorder_I,&gener_I,&gener_I,&gener_I,&whistle_I,&gener_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &fantas_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &gener_I,&crystal_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I, &gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I,&gener_I }; /* The type for delta times. You might want to use long long if you * want to bicker. */ typedef unsigned long int dtime_t; int midif; /* MIDI file descriptor */ off_t midi_off; /* Offset relative to file start */ /* The MIDI file header */ unsigned long int header_len, header_end; struct { unsigned short int format; unsigned short int nbtrk; unsigned short int subd; } header_data; /* The MIDI tracks */ #define MAXNBTRK 65 /* Maximal supported number of * tracks */ struct { char active; /* Is the track active * (i.e. playing)? */ unsigned long int trk_data_start, trk_data_len, trk_data_end, trk_cur; /* Offsets for: start of track * data, length of track data (not * an offset), end of track data, * current position within * track. */ dtime_t pending; /* Pending delay: the number of * MIDI subdivisions before the * track's next event is * performed. */ unsigned char rstatus; /* Running status */ } trktab[MAXNBTRK]; int nb_active; real_t dtime_unit; /* Delta time unit (in seconds) */ real_t midi_time; /* Midi time (in seconds) */ real_t dsp_time_unit; /* Inverse of sample rate */ real_t dsp_time; /* DSP time (time of last byte * output, in seconds) */ /* The MIDI channels */ struct { unsigned char patch; /* Current patch on channel */ unsigned char main_vol; /* Main volume (controller number * 7) */ real_t chan_volume; /* Channel volume (as a real) */ } channels[16]; /* The notes */ #define MAXNOTES 50 /* Maximal number of simultaneous * notes supported */ struct { char playing; /* Is note being heard? (Or is the * entry available for use?) */ char sustained; /* Is note being sustained? (Or is * it in the release phase?) */ unsigned char chan; /* Channel note is running on */ unsigned char pitch; /* Note MIDI pitch */ unsigned char speed; /* Note MIDI speed */ struct instrument_s *instr; /* Patch used */ real_t freq; /* Frequency (as a real, in Hz) */ real_t volume; /* Volume (as a real), relative to * channel volume. */ real_t zero_time, cut_time; /* When the note started playing * and when the note started * releasing (unfortunate * names). */ } notes[MAXNOTES]; /* The frequency in Hz of the twelve notes in the lowest octave. */ real_t freqtab[12] = { 16.352, 17.324, 18.354, 19.445, 20.602, 21.827, 23.125, 24.500, 25.957, 27.500, 29.135, 30.868 }; void midi_read (void *buf, size_t count) /* Read some data from the MIDI file. */ { char *ptr; ssize_t res; for ( ptr=buf ; count>0 ; ptr+=res, count-=res, midi_off+=res ) { res = read (midif, ptr, count); if ( res == -1 ) { perror ("read()"); exit (EXIT_FAILURE); } } } unsigned long int midi_read_32 (void) /* Architecture-independent read a 32-bit quantity in big-endian * format */ { unsigned char c[4]; midi_read (c, 4); return ((((long int)c[0])<<24) | (((long int)c[1])<<16) | (((long int)c[2])<<8) | ((long int)c[3])); } unsigned short int midi_read_16 (void) /* Architecture-independent read a 16-bit quantity in big-endian * format */ { unsigned char c[2]; midi_read (c, 2); return ((((long int)c[0])<<8) | ((long int)c[1])); } unsigned long int midi_read_24 (void) /* Architecture-independent read a 24-bit quantity in big-endian * format */ { unsigned char c[3]; midi_read (c, 3); return ((((long int)c[0])<<16) | (((long int)c[1])<<8) | ((long int)c[2])); } dtime_t read_dtime (void) /* Read a delta time from MIDI file. */ { unsigned char c; dtime_t d; d = 0; do { midi_read (&c, 1); d = (d<<7) | (c&0x7f); } while ( c&0x80 ); return d; } void midi_seek (off_t offset) /* Seek the MIDI file */ { if ( lseek (midif, offset, SEEK_SET ) == -1 ) { perror ("lseek()"); exit (EXIT_FAILURE); } midi_off = offset; } void midi_seekfwd (long int offset) /* Advance (or more back) in the MIDI file */ { if ( lseek (midif, offset, SEEK_CUR ) == -1 ) { perror ("lseek()"); exit (EXIT_FAILURE); } midi_off += offset; } real_t pitch_to_freq (unsigned char pitch) /* Return the frequency (in Hz) for a certain pitch */ { int i; real_t t; t = freqtab[pitch%12]; for ( i=0 ; i>4 ) { case 0x8: midi_read (&data2, 1); note_off (rs&0x0f, data, data2); break; case 0x9: midi_read (&data2, 1); note_on (rs&0x0f, data, data2); break; case 0xa: midi_read (&data2, 1); aftertouch (rs&0x0f, data, data2); break; case 0xb: midi_read (&data2, 1); controller (rs&0x0f, data, data2); break; case 0xc: program_change (rs&0x0f, data); break; case 0xd: channel_pressure (rs&0x0f, data); break; case 0xe: midi_read (&data2, 1); pitchbend (rs&0x0f, ((short int)data) | (((short int)data2)<<7)); /* For some obscure reason, pitch bend data is in little-endian * format (everything else in MIDI is big-endian). */ break; case 0xf: /* A Meta or Sysex event */ switch ( rs & 0x0f ) { case 0x0: case 0x7: /* Sysex event. First comes the length, in delta time * format. */ midi_seekfwd (-1); /* Unread data byte */ len = read_dtime (); /* This is stored like a dtime */ midi_seekfwd (len); break; case 0xf: /* Meta event. We only honor track end (compulsory) and * tempo change. */ len = read_dtime (); /* Event length in delta time * format */ end = midi_off + len; switch (data) { case 0x2f: /* Track end */ trktab[tk].active = 0; nb_active--; break; case 0x51: /* Tempo change */ set_tempo (midi_read_24 ()); break; } midi_seek (end); break; default: fprintf (stderr, "Unknown event encountered!\n"); exit (EXIT_FAILURE); } break; } return rs; } real_t envelope (int not) /* Calculate note envelope. */ { real_t t; struct instrument_s *ins; t = dsp_time - notes[not].zero_time; ins = notes[not].instr; if ( t < ins->att_del ) /* Note is in attack phase. */ return ins->max_vol * t / ins->att_del; t -= ins->att_del; if ( t < ins->dec_del ) /* Note is in decay phase. */ return ( ins->max_vol - (ins->max_vol-ins->sus_vol) * t / ins->dec_del ); if ( notes[not].sustained && ! ins->irel ) return ins->sus_vol; if ( ins->irel || ( notes[not].cut_time - notes[not].zero_time < ins->att_del + ins->dec_del ) ) /* Release cannot start before decay ends; in instant release * instruments, that's exactly when it starts. */ notes[not].cut_time = notes[not].zero_time + ins->att_del + ins->dec_del; t = dsp_time - notes[not].cut_time; if ( t < ins->rel_del ) /* Note is in release phase. */ return ins->sus_vol * (1.0-t/ins->rel_del); /* Note has finished playing. It is dead. It should not be heard * (of) any more. */ notes[not].playing = 0; return 0.0; } real_t simpenv (real_t del, real_t x) /* Simple envelope, for oscillators and wobulator */ { if ( x < del ) return x/del; return 1.0; } real_t wave (char shape, real_t x) /* Calculate wave value of a certain shape */ { if ( shape == 0 ) return SIN (x*2.*PI); if ( shape == 2 ) return FABS (SIN (x*PI)); if ( shape == 4 ) { real_t tmp; tmp = SIN (x*2.0*PI); if ( tmp > 0. ) return tmp; else return 0.; } x -= floor (x); if ( shape == 1 ) { if ( x < 0.02 ) return x*50.0; if ( x < 0.48 ) return 1.0; if ( x < 0.52 ) return (0.52-x)*50.0-1.0; if ( x < 0.98 ) return -1.0; return (x-1.0)*50.0; } if ( shape == 3 ) { if ( x < 0.48 ) return x/0.48; if ( x < 0.52 ) return (0.52-x)*50.0-1.0; return (x-1.0)/0.48; } return 0.0; /* Does not occur. */ } short int calculate_output (void) /* The actual output calculation function */ { int i; real_t t, x, a, u; struct instrument_s *ins; a = 0.0; for ( i=0 ; iampw != 0.0 ) /* Wobulate */ x += ( ins->ampw * wave (ins->shapew, x*ins->frqw) * simpenv (ins->delw, t) ); u = wave (ins->shape, x); if ( ins->amp2 != 0.0 ) /* Oscillator 2 */ u += ( ins->amp2 * wave (ins->shape2, x*ins->frq2) * simpenv (ins->del2, t) ); if ( ins->amp3 != 0.0 ) /* Oscillator 3 */ u += ( ins->amp3 * wave (ins->shape3, x*ins->frq3) * simpenv (ins->del3, t) ); a += ( channels[notes[i].chan].chan_volume * notes[i].volume * u * envelope (i) ); } /* Now correct for saturation (we prefer using a differentiable * function rather than one which saturates to rapidly: it * introduces more deformation, but at least it doesn't saturate to * violently. */ /* XXX - Is this a good choice? */ a = a / ( 1.0 + FABS (a) ); /* Return the result as a short int. */ return (short int)(a*32766.0); } void produce_output (void) /* Calculate the output, output it, and make the time advance. */ { short int w; w = calculate_output (); fwrite (&w, sizeof(w), 1, stdout); dsp_time += dsp_time_unit; } void delay_action (void) /* Make a MIDI division delay pass. */ { midi_time += dtime_unit; while ( dsp_time < midi_time ) produce_output (); } int main (int argc, char *argv[]) { int number; int i; if ( argc < 2 ) { fprintf (stderr, "Usage is:\n %s FILENAME...\n", argv[0]); exit (EXIT_FAILURE); } number = 1; another: /* Open the MIDI file. */ fprintf (stderr, "Playing %s\n", argv[number]); if ( ( midif = open (argv[number], O_RDONLY ) ) == -1 ) { perror ("open()"); exit (EXIT_FAILURE); } midi_off = 0; /* Read the MIDI file header. */ if ( midi_read_32 () != MIDIFILESIG ) { fprintf (stderr, "This is not a MIDI file!\n"); exit (EXIT_FAILURE); } header_len = midi_read_32 (); if ( header_len < 6 ) { fprintf (stderr, "Oops! Header is too small for me.\n"); exit (EXIT_FAILURE); } header_end = midi_off + header_len; header_data.format = midi_read_16 (); /* XXX - Check this */ header_data.nbtrk = midi_read_16 (); if ( header_data.nbtrk > MAXNBTRK ) { fprintf (stderr, "Too many tracks - truncating.\n"); header_data.nbtrk = MAXNBTRK; } header_data.subd = midi_read_16 (); midi_time = 0.0; dsp_time = 0.0; set_tempo (500000L); dsp_time_unit = 1.0/SAMPLERATE; midi_seek (header_end); /* Initialize tracks and determine their positions. */ for ( i=0 ; i