Jeff's SFZ tools Copyright 2006, Jeff Learman
No warranties. Programs are likely to be fragile, especially when taken outside the narrow range of test scenarios I've used!
Also, don't expect good coding. I wrote most of this long ago when I was new to Python, and I was more interested in the result than the code.
These tools include two programs that assist in taking a set of samples for an instrument and building an sfz format sample set.
The first tool, jCutSamps.py, takes one or more "layer" files, where each layer file is a recording of samples of different notes, all at the same velocity (dynamics, e.g., all mf or all pp), and chops them into files with one sample per file. It detects the pitchh of each note and puts the MIDI note number and note name in the name of each file.
(I'm considering an option to pre-specify the notes, which would be used when converting layer files recorded using MIDI, where you know the notes a-priori.)
The second tool, jMap.py, takes the output of the first program (all the single-note sample files) and a small text control file, and builds an SFZ sampleset, automatically mapping the samples to the notes and velocity ranges.
It works best using 16-bit source (layer) files. I have tested it using 44.1kHz and 48kHz. It also works best when you do any noise reduction on each layer file, though this is optional. This shouldn't be necessary when sampling a digital keyboard or plugin.
I have only used this under Windows. I don't remember if there are any Windows dependencies; it should work under Linux or Mac. If it does have a Windows dependency, it should be limited to file globbing in the main sections of the two main tools.
Only .wav format is supported. I start with that and convert later.
Things you'll need:
- A way to capture the wave data (mike, soundcard, etc.)
- A wave editor -- optional but useful for noise reduction or bit depth conversion.
- Python, download it from www.python.org and install it. (Python is a scripting language like Perl.) You may need to add it to your PATH.
- A little ability to use the DOS command shell.
- A fair measure of patience and motivation (not just to use these tools, but to create a good sample set!)
Installation: Extract all the .py files into a new directory of your choice. Put that directory on your executable path, or else you can specify the path to the programs explicitly.
A note on terminology: I'm using the term "layer" only for the purpose of what more sensible folks call "velocity splits", meaning a set of samples that were recorded with the same key velocity (or force or loudness). I'm NOT using it to refer to "layered instruments", where you have two sounds from two different instruments when you hit one key.
You may find the word "soundfont" where I haven't fixed it. The tools originally created a .sf2 result, but that is no longer supported.
To build your own sfz sampleset:
For each velocity layer, sample all keys you'll be sampling into a single wave file. The tools currently don't handle two .wav files for the same velocity layer -- if you do end up with more than one, use a wave editor to combine them into one. Ideally, sample in 24 bits.
Do not adjust the recording gain (record level) when recording a layer. Leaving it constant will preserve the instrument's natural dynamics in a given layer.
Note: Make sure there is some silence before the first note. If you're sampling a MIDI instrument, be sure not to start the MIDI with the first note playing immediately. Leave 100 msec or so at the start.
If you're recording an instrument that you're playing manually and you muff a note, just stop the note before a second has passed and that sample will be skipped. (If you're sampling sounds that are shorter than that, you'll need to make an adjustment; ask me about that.)
You should read about layer file names below before starting this step.
Optionally, de-noise the layer files in your favorite wave editor, such (free) Audacity. Then normalize, and convert to 16 bit format if they aren't already. Dithering optional but best. Make sure to normalize each layer file independently of the others.
If there are any snarks (sample attempts you don't want to keep) that are longer than the minimum sample duration (a configurable parameter in jCutSamps.py, defaulting to 1 sec.), delete them from the layer wave file. It's better to delete them rather than silence them, because the "silence" is sampled to help detect the end of a note, and a chunk of absolute silence can throw the algorithm off.
Snarks smaller than the minimum sample duration will be automatically ignored by the program.
Use the following format for the prepared layer file names:
<prefix>_<layername>.wav
where <prefix> is anything you want, usually an abbreviation for the soundfont or instrument. <layername> is also anything you want, but something that indicates to you what velocity the layer file samples were recorded at. When sampling a MIDI instrument, I use a 3-digit number for the velocity.
Examples for different layer file naming conventions:
- using MIDI velocities:
- sf1_v020.wav sf1_v040.wav sf1_v060.wav ... sf1_v120.wav
- using music notation:
- sf1_pp.wav sf1_p.wav sf1_mp.wave sf1_m.wave sf1_mf.wav ...
- using whatever:
- sf1_soft.wav, sf1_medium.wav, sf1_hard.wav, sf1_nuke.wav
Use anything that's meaningful to you, but the layer names will show up later. The prefix will simply be preserved by the program and doesn't mean anything specific.
Run jCutSamps.py to chop up the layer files into sample files. It produces a set of closely cropped sample files, suitable for building into a soundfont. Furthermore, it names them according to this schema:
<prefix>_<layer>_<notenum>_<notename>.wav
where
- <prefix> is as described above.
- <layer> is as described above.
- <notenum> is the MIDI note number in the sample, or 000 if it can't tell.
- <notename> is the note name in normal notation, using upper case for the note, lower case 'b' to indicate flat, and a one-digit octave number where C4 = middle C.
The program does not handle samples outside the range of an 88-key piano keyboard. As you can imagine, it's also not intended for percussion instruments and drums where the MIDI note isn't related to pitch. (It will cut these up, but the won't be named very effectively, and the subsequent steps won't work unless you manually rename the cut-up sample files according to the schema above.)
The pitch detection algorithm (auto-correlation) isn't the best algorithm, so it's touchy. Let me know if it tends to work or not for your instrument. It seems to work well for acoustic piano, Rhodes, and bass. If it maps a second sample to an already existing note, it adds a hyphen and number (e.g., -1). ROUND ROBIN IS NOT SUPPORTED in the next step (mapping.) Probably could be, though.
It's generally best to put all the chopped samples in a single folder. Keep different instruments in different folders. For this example, we'll keep the chopped samples in a "notes" directory, and the input wave files in the current directory (along with the soundfont and other control files).
Example: mkdir notes jCutSamps -f notes sf1_*.wav
Get a cup of coffee. This one takes a while, if you have lots of samples and/or a slow machine. My i7 takes about 5 seconds per sample on average.
When it's done, inspect the sample names. If you have samples with note number 000, figure out what note they really are and name them accordingly. It's not necessary to get the MIDI note number correct -- it's not used by the program.
You may find some samples with a "maybe" suffix. This is where the algorithm didn't quite hit its target but provided its best guess. You need to go through by hand and change these to the correct note names.
When going through the chopped samples to check for issues, I sort the directory in time order. Since I know what order I recorded the notes for each layer (I do them low to high), I can pretty easily spot a mistake, or figure out what a "maybe" should have been.
The algorithm has the hardest time with the very top piano notes and next hardest is the lowest notes especially if they're very bright.
Create a file that's your soundfont name but with a ".sfc" extension, for "soundfont control". See details in the example provided.
Example:
jMap.py sf1 samps/*.wav
This reads the control file (sf1.sfc) and, based on the names of the wave files found, creates a key map file (sf1.sfk). Take a look at the file it created to see if that's how you want your samples mapped. Adjust accordingly. This completes almost immediately. It does verify that the specified sample files exist, but doesn't inspect their contents. It trusts the file names to specify the note.
This step now also creates the 'sfz' format file (sf1.sfz), which (together with the cut-up sample files) can be used by any sfz- format-capable sample player or converter. Note that you can also edit the sfz file with any text editor. Find more details about this format at http://sfzformat.com .
Bingo, you're done. Test your soundfont in your favorite player. Make any necessary adjustments on the keymap config file and run the second program again -- just takes a moment.
jMap.py also creates a .sfk file, a text file that shows the keyboard map. This was originally to control creating the soundfont, but is now only a legacy. But you might find it interesting.
Most likely, you've learned what's not ideal about your sample set. Perhaps you needed more layers, or to sample more keys. Adjust the layer definitions (if necessary) and start over.
I use Extreme Sample Converter (from http://www.extranslate.com). It's archaic and fiddly but has the best loop editor I've seen.
Have fun! Jeff