Bmxplay

Tiny player (up to 3 kb) for Jescola's Buzz by Joric^Proxium. First used in 64k-intro Yo-08 (2002). Completely written in plain C (mostly in october 2001), considering a future possibility of porting everything to assembly. Uses its own C++ classes implementation in plain C. Used to patch virtual methods table in order to comply with various versions of Buzz. If you want conventional or "modern" OOP, check out flashbmxplay or bmxplayjs.

Demo

Online demo: https://joric.github.io/bmxplayjs

Downloads

Download latest binary release from the releases section.
See https://bmxplay.sourceforge.net for older releases.

License

Player is public domain. MachineInterface.h (written by Oskari) and (therefore) all dlls are for non-commercial use. Note that player neither links them nor uses their API or header (they are only for composing music in Buzz), so you can use the player in a commercial app (or a keygen), without legal restrictions.

Generators

_303 (mono, 303-like synth, 6 global parameters, 3 track parameters). Totally based on the Paul Kellet's resonant filter. Accent and envmod are not implemented (yet). Just one base signal (sawtooth). Has a period slide feature, uses a slide note and a slide length (in ticks).
_xi (mono, sampler, 0 global parameters, 1 track parameter). XI samples loader and player. Only one track and one sample per machine. Supports envelopes, loops, can store wave data as 4-bit PCM to save some space.
_voice (mono, voice synth, based on 2-formant speech synth by Frank Baumgartner). Not finished, currently more like a PoC. Tries to be small (that's why only 2 formants).

Effects

_filter (mono, resonance and distortion, 3 global parameters, 0 track parameters). Also based on the resonant filter. Adds distortion feature (can boost output volume up to 64x).
_delay (stereo, cross-delay, 4 global parameters, 0 track parameters). A stereophonic delay (X-delay, ping-pong echo, etc.). Stereo filter that ties everything together.

Samples

Size-optimized ADSR with loops, can be stored as 4-bit (2 times smaller). Mostly ripped from Quad/Theta (Wired 1998).

bd.xi (5344 bytes) - Bass drum
cc.xi (6672 bytes) - Crash cymbal (this is the longest one and masterfully looped)
ch.xi (2323 bytes) - Closed Hihat
cp.xi (1924 bytes) - Clap
oh.xi (3950 bytes) - Open Hihat
sd.xi (3737 bytes) - Snare drum

References

Resonant filter

See http://www.musicdsp.org/showone.php?id=29 (posted by Paul Kellett)

This filter consists of two first order low-pass filters in series, with some of the difference between the two filter outputs fed back to give a resonant peak.

You can use more filter stages for a steeper cutoff but the stability criteria get more complicated if the extra stages are within the feedback loop.

//set feedback amount given f and q between 0 and 1
fb = q + q/(1.0 - f);

//for each sample...
buf0 = buf0 + f * (in - buf0 + fb * (buf0 - buf1));
buf1 = buf1 + f * (buf0 - buf1);
out = buf1;

Speech synthesizer

Based on the 2-formant speech synth from the Dialogos 2001 4K intro by Frank Baumgartner, published in Hugi magazine (example below). Older versions included 6-formant Klatt synth (klatt-3.04) used by Stephen Hawking since mid-80s, but it was considered too large.

// two-formant speech synthesizer
// (c) 2000-2001 by baumgartner frank
// example by joric for the bmxplay project

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define M_PI 3.141592654f
#define Ta ( 1.0f / 44100 )
#define exp2(x) ( pow( 2.0, x * 1.442695041 ) )

typedef struct {		// digital designed 12dB IIR resonator
	float  a, b, c;		// filter vars, coeff's
	float  y, z1, z2;	// (2 pole, 12 dB)
} T_BP;

T_BP bp[ 2 ];

void bp_init( T_BP &bp, float f, float bw ) {
	float r = exp2( -M_PI*bw*Ta );
	bp.c = - r*r;
	bp.b = r * 2.0f * cos( 2.0f*M_PI*f*Ta );
	bp.a = 1.0f - bp.b - bp.c;
}

void bp_iir( T_BP &bp, float in ) {	// 12 dB bi-quad
	bp.y = bp.a*in + bp.b*bp.z1 + bp.c*bp.z2;
	bp.z2 = bp.z1;
	bp.z1 = bp.y;
}

typedef struct {
	char ch;
	int f1, f2, b1, b2, a1, a2, asp, len;
} phoneme;

phoneme phonemes[] = {
	{' ', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'a', 700, 1100, 60, 90, 100, 100, 0, 7000},
	{'b', 190, 760, 60, 90, 100, 100, 255, 500},
	{'c', 190, 2680, 60, 150, 25, 25, 255, 500},
	{'d', 190, 2680, 60, 150, 25, 25, 255, 500},
	{'e', 600, 1800, 60, 90, 100, 100, 0, 4500},
	{'f', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'g', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'h', 190, 1480, 30, 45, 100, 100, 255, 1000},
	{'i', 300, 2200, 60, 90, 100, 100, 1, 5000},
	{'j', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'k', 190, 1480, 30, 45, 100, 100, 255, 1000},
	{'l', 460, 1480, 60, 90, 100, 100, 1, 4000},
	{'m', 480, 1000, 40, 175, 100, 100, 1, 5000},
	{'n', 480, 1780, 40, 300, 100, 0, 0, 3000},
	{'o', 610, 880, 60, 90, 100, 100, 0, 5500},
	{'p', 190, 760, 60, 90, 100, 100, 255, 500},
	{'q', 190, 1480, 30, 45, 100, 100, 255, 1000},
	{'r', 490, 1180, 60, 90, 100, 100, 1, 5000},
	{'s', 2620, 13000, 200, 220, 5, 15, 255, 4000},
	{'t', 190, 2680, 60, 150, 100, 100, 255, 500},
	{'u', 300, 950, 60, 90, 100, 100, 1, 5000},
	{'v', 280, 1420, 60, 90, 100, 100, 255, 1000},
	{'w', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'x', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'y', 550, 2000, 60, 90, 0, 0, 1, 1500},
	{'z', 1720, 14000, 60, 90, 10, 10, 255, 5000}
};

int main() {
	printf("Writing out.wav...\n");
	memset( &bp, 0, sizeof bp );
	float fm1 = .0f, fm2 = .0f, bw1 = .0f, bw2 = .0f, am1 = .0f, am2 = .0f, as = .0f, saw = .0f, mul;
	FILE *fp = fopen("out.wav", "wb");
	int wav[] = {1179011410, 73284, 1163280727, 544501094, 16, 65537, 44100, 44100, 524289, 1635017060};
	fwrite(wav, 1, sizeof(wav), fp);

	for (const char *p = "teklords"; *p; p++) {
		phoneme *f = &phonemes[ *p>='a' && *p<='z' ? *p+1-'a' : 0 ];
		bw1 = 50.0f; bw2 = 150.0f;

		// write wave data
		for ( int i=0; i<f->len; i++ ) {
			mul = f->asp ? 1.0f : 1.0f / 512.0f;
			fm1 += ( f->f1 - fm1 ) * mul;
			fm2 += ( f->f2 - fm2 ) * mul;
			bw1 += ( f->b1 - bw1 ) * mul;
			bw2 += ( f->b2 - bw2 ) * mul;
			am1 += ( f->a1 - am1 ) * mul;
			am2 += ( f->a2 - am2 ) * mul;
			as  += ( f->asp - as ) * mul;
			bp_init( bp[0], fm1, bw1 );
			bp_init( bp[1], fm2, bw2 );
			saw += 90.0f/44100.0f - (int)saw;
			double src = (saw-0.5f) * (1.0f-as/256.0f) + as/256.0f * ((rand()&255)/256.0f - 0.5f);
			bp_iir( bp[0], src * am1 );
			bp_iir( bp[1], src * am2 );
			float out = bp[0].y + bp[1].y;
			char s = out * 0.3f;
			fputc((s+255)/2, fp);
		}
	}
	fclose(fp);
}

joric / bmxplay