Algorithm to Convert ASCII Binary 0-255 to Specified Values for the 1s

UNIXcoffee928 · March 12, 2008

I'm considering a few methods of doing this, input from others is appreciated, before I get wrapped up in it.

Summary:

I want to create a MIDI drum pattern library that I can easily manipulate algorithmically.

All patterns of sequenced eighth notes can be easily represented via the ASCII representation of the binary equivalent of 0-255 (as note on or off patterns).

So, it would operate on a txt file like this:

I would like to be able to specify the values that the pattern will play, then generate a file of all possible combinations.

So, zero will be equivalent to no drum note playing, and one will be replaced by the MIDI note value of the drum to be played. For example, one could be assigned to a closed hi-hat, or a bass drum, or a snare drum, etc. I'll deal with other parameters, such as velocity, pan, & such, once it's working.

Bear in mind that MIDI files are not txt files, there will be a further conversion. This is just one step in the process of generating a drum pattern database.

Once the main algorithm is decided upon, it will allow the 0-255 to be concatenated with another list of 0-255 to provide 16th note resolution.

Ultimately, the program will allow for a specified # of different drum notes at run time, and will generate all possible drum patterns, with those instruments. An example of this would be 0-255 for Bass, Snare, Hi-hat closed & open, & so forth, generated automatically, then converted into a suitable MIDI file that Fruity Loops can display as separate 16th note patterns.

This will be the basis of building a drum pattern database for use in another sequencer.

So, before I get wrapped up in following a path that may be inefficient, perhaps some others here can help me get this to a point where it will be very efficient.

Any language, or method is acceptable here. Whatever means, as long as it generates a txt file of all of the correct values, for further manipulation.

Ideas on this?

Edited March 12, 2008 by UNIXcoffee928

Rybags · March 12, 2008

In BASIC, where BYTE is each decimal byte value:

HI=INT(BYTE/16)

LOW=BYTE-HIGH*16

HINYBBLE$=BINARY$(HI*4+1)

LOWNYBBLE$=BINARY$(LOW*4+1)

Have BINARY$ a string of length 64 containing the text "0000 0001 0010 0011" etc (without spaces).

In Assembler, it's a bit easier. Just a loop with LSR BYTE, then output a 0 or 1 to the text file depending on the Carry status.

kenfused · March 12, 2008

In straight Atari BASIC

10 DIM RESULT$(

11 PRINT "ENTER NUM TO CONVERT TO BIN";

12 INPUT NUM

15 D=128: FOR I=1 TO 8: DIGIT=INT(NUM/D) : NUM=NUM-DIGIT*D : RESULT$(I) = STR$(DIGIT) : D=D/2 : NEXT I

70 PRINT RESULT$

cas · March 12, 2008

In Forth, you can just change the base for numerical output to 2 (binary) and every output command will automatically print out binary values

( definition of .BINARY -- aka print binary )
: .BINARY ( n -- )
 BASE @	   \ store old base value on stack
 2 BASE !	  \ switch to binary utput
 SWAP		  \ swap value to print and old base
 U.			   \ print value without sign
 BASE !	  \ restore old base
;

to use this new definition:

15 .binary 1111  ok
20 .binary 10100  ok
8 .binary 1000  ok
hex  ok
ff .binary 11111111  ok

Edited March 12, 2008 by cas

UNIXcoffee928 · March 13, 2008

Thanks for the prompt response, but let me clarify the nature of the problem to be solved...

We aren't dealing with the binary values. The full list of binary #s 0-255 exists as a text file, as pasted above in the codebox.

What we are dealing with is the pattern of 1s & zeros. We want to keep it text, and assign a specific decimal value as a replacement for all 1s that occur.

So, if the replace variable is DEC 27, and the pattern is 10001000, we would end up with output like:

[27 0 0 0 27 0 0 0]

if it's 120 DEC we get:

[120 0 0 0 120 0 0 0]

& so forth. Think of it like this, if 120 DEC is a bass drum (BD) 10001000 will play like:

BD * * * BD * * *

where the * character represents blank metronome ticks.

which sounds like:

THUMP SILENCE SILENCE SILENCE THUMP SILENCE SILENCE SILENCE

Basically, a drumbeat.

So, this is more like a search & replace operation based on pattern matching, operating on a text file containing the binary patterns of 0-255.

This part of the program should basically be able to substitute the decimal values of 0-127 (the MIDI patch numbers) for the ones in each binary pattern, incrementing in a loop, doing the substitution for patch zero, writing the file, doing the substitution for patch 1, writing the file, the substitution for patch 3, writing the file, ans so on, until patch 127 is written.

It would write separate text files to a directory as a single database record, with a filename like 120-BD_10001000, incrementing the filename appropriately. This way it would be easy to see the pattern being worked on, just by viewing the filename.

Once all of the records have been written, substituting the binary pattern ones with the decimal range [0-127] there would be separate directories filled with all possible combinations of drum patterns for each drum instrument. (128 directories filled with all possible combinations of beat & silence.

Then a tool to recursively go through the directories & convert the patterns to short MIDI files would be applied.

The end result would import these midi files into a drum sequence database, allowing the user to insert any pattern into a sequencer.

The goal is to have the computer do the work, and create a full library of all possible patterns with all possible drum sounds, which can easily be inserted into a composition without didilying around with time wasting drum pattern creation for each measure.

Thanks again.

Edited March 13, 2008 by UNIXcoffee928

UNIXcoffee928 · March 15, 2008

Doing it in TCL/TK with regular expressions. Pic of an early beta attached, starting to look spiffy. I'll keep you posted on the progress. Feel free to talk about optimization techniques. Once it's fully functional for it's intended purpose, I'll add some Atari-specific uses for it, since, for the most part, it is a generalized byte twiddler. Should be a nice tool when it's done. Thanks for your suggestions.

L8R.

UNIXcoffee928 · March 16, 2008

Been hacking at this a bit today, developing some interesting GUI metaphors to streamline it's use. See pic.

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Algorithm to Convert ASCII Binary 0-255 to Specified Values for the 1s

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