TopToMidi Documentation

A general-purpose visual sonification TouchDesigner component by Function Store (Daniel Molnar) (@function.str; [email protected]).

IMPORTANT NOTICE: The component does not work out-of-the box on Mac machines due to the lack of td_pip support. You can still install the dependency manually to your machine probably.

The component is available on my Patreon, this page serves documentation purposes only. See this livestream for a quick overview.

Glossary

• Sonification: The process of converting data or information into sound or audible signals to facilitate analysis or understanding of complex patterns or phenomena.
• Sampling: The process of obtaining the color values of specific pixels in an image.
• VST: Short for Virtual Studio Technology, is a software interface standard used to integrate audio synthesizer and effect plugins with audio editors and recording systems.
  • You can run VSTs in TouchDesigner or any DAW (Reaper is a good free one)
• MIDI: Musical Instrument Digital Interface, is a technology that allows musical instruments and computers to exchange information such as pitch, tempo, and volume, enabling them to create and control music together.
  • MIDI notes have pitch and velocity.
  • Can control VSTs with it, or hardware synthesizers.
• Scale Mode: Variations of a musical scale that start on different notes but follow the same overall pattern, providing different emotional flavors or moods to the music.
• Root Note: The first and primary note of a musical scale or chord from which the rest of the notes are derived, often providing the foundational pitch that defines the key of a piece of music.

Getting Started

• This component allows you to sonify TOPs in TouchDesigner. It is a “general-purpose” component armed with everything you might need for that, but this comes at the cost of complexity, so see the next point.
• Please read this documentation carefully and see my demonstration video:
• TopToMidi_DEMO.toe will get you started with some examples.
• If the component shows an error on startup, just disable and re-enable cooking, or right click and Clear (Children) Script Errors
  • Otherwise contact [email protected]

Input slots

1. The only input slot of the component is the TOP to be sampled.

Parameters

The only input slot of the component is the TOP to be sampled.

Input tab

• Sampler: TOP or SOP operator to define the pixel positions for sampling. These can be animated too, of course!

• Offset 0.5: By default many SOPs are centered around the origin. This quick toggle shifts the Sampler’s center to (0.5, 0.5).

• Sample Preview: Opens a UI window to visualize and manually adjust the sampling points. Move them around with Left-Click+Dragging ; Scale with Scroll-Wheel (or +-), Reset with Middle-Click .

  • It also has some options on the bottom left to always show the points, toggle Offset 0.5 and Reset the adjustments

• RGB: Which attribute of the input image to perform further processing on.

  • Can be Luminance, Red, Green, etc., depends on the use-case. Can be left simply on Luminance or RGB Average.

• Threshold: Pre-processes the input image by thresholding between two values. This will also have an effect on when a note is triggered in **Index Mapping Mode.**

• Re-Range: Re-ranges the thresholded image to 0-1. This parameter is only interesting in Value Mapping Mode.

• Mapping Mode: This is the most important parameter to determine the mapping of pixel values to MIDI notes, before assigning to a Scale.

  • Index: The point/pixel indices of the Sampler determine the pitch of the notes, upon triggered by the sampled value reaching the Threshold. Notes are sustained while in the range. It is important to set a good Threshold with Index mode.
    • Important to note that the number of Steps is determined by the number of points. Be careful not to use big textures or SOPs with many points (anyway MIDI is limited to 128 notes).
  • Value: The sampled values determine the pitch of the notes, where the quantization is determined by the Steps parameter.
    • It means if you have identical sampled values they will trigged the same note twice.
    • Re-Range of the Threshold is suggested to be kept on usually.
    • In this mode you are more free to set more sampling points!

• Trigger Options: These parameters can give you more control how often/how long notes are being triggered. Can be very useful in busy scenes.

  • Re-Trigger Gate Length: This is an overall gate length in seconds. At 0 each trigger will be let through to the next stage, increasing it to e.g. 1 will only generate a new trigger every 1 seconds.
  • Trigger Gate Length: Determines how long a trigger needs to be active in order to generate a note.
  • Min Sustain Length: How long a note is kept on after triggered.
  • Re-Trigger Delay: How often the same generated note can be triggered.

Scale tab

• Scale: Determines the Scale Mode the triggered notes are mapped to. Scales determine a number of notes in a Scale, starting from a root note (Key). You can also define Custom Scales which will also show up in the dropdown!

  • **MIDI Scale** is a special one, see later.

• Key: Sets the musical root note of the Scale.

  • Can type any musical note notation, even wild things like A#bbb## (thanks to the mingus library). But usually the drop-down list should be more reasonable :)

• Octave: The octave of the root note.

• Steps: Number of MIDI notes to generate.

  • In Index mode it is fixed to the number of sampling points.
  • In **Value** mode it is the "quantization" of the pitch determined by the sampled pixel values.

• Extend Mode: When having more steps than the number of notes in the Scale, having this on will extend subsequent steps to the next octaves. Otherwise the same scale notes in the starting octave are repeated.

• Edit Custom Scales: Opens a Table DAT where in each column you can define a custom scale name where each note can be defined in the rows below using standard musical notation. For example: C#3.

• Keytrack Lookup: A multi-sample CHOP reference which can define the MIDI velocity based on the pitch.

• MIDI Scale: The parameters below are only relevant if Scale is set to **MIDI Scale**. They allow you to use this component as a live companion musical instrument.

  • MIDI In CHOP: Reference to a MIDI In CHOP which should be a MIDI keyboard to enable further functionality.
  • MIDI Scale Learn: Can define a Custom Scale by hitting notes one-by-one on your MIDI In instrument.
  • MIDI Live: Hitting chords on your MIDI keyboard determine the Custom Scale in real-time! This lets you duet with your visuals!
    • Live Octave Offset: Offsets the octave of incoming MIDI notes. This is good if you are playing an external synthesizer/VST in parallel to this component as a duet.
    • Sync Steps: Syncs the number of steps to the number of incoming notes. This is not available when Extend Mode is on.

• Randomize: Randomize the order of notes.

  • Seed: Seed of the randomization.

Output tab

• MIDI Active: Activates MIDI Out CHOP.
• MIDI Out CHOP: Reference to a MIDI Out CHOP, directly. No nulls or other operators after it, the MIDI Out CHOP itself!
• Channel: MIDI channel to output notes on.
• VST Active: Activates VST CHOP.
• VST CHOP: Reference to an Audio VST CHOP, directly. No nulls or other operators after it, the Audio VST CHOP itself!
• Channel: VST channel to output notes on.

About tab

• Author: That is me! Function Store/Daniel Molnar/Dan (@function.str; [email protected]).
• Install: In case mingus does not install automatically you can try pulsing this.

Output slots

Note: The MIDI/VST output happens directly by referencing a MIDI/VST output CHOP. See in Parameters.

1. Sampled values in TOP representation
2. Sampled values in CHOP representation
3. Note triggers
4. Sample Preview output

Additional Notes

• It is recommended that you run this in its own TD instance from your visuals, and run your VST in a DAW
• Be aware that your VST/MIDI will have a poly count and you can easily exceed that
• In MIDI Live mode be careful to release the notes at the same time. In general this can be improved.
• Check out the Data Sonification workshop by Elekktronaut at The NODE Institute! This tools is also featured in his course.

Contributors

• mingus: The python library providing the Scale Modes and musical notation interpretation.
• AlphaMoonbase.Berlin: Author of td_pip, creator of td-olib.
• Beta Testers: Elekktronaut, kim0slice
• Thank you to all my Patrons supporting my tool development!
• Thank you to Derivative for creating TouchDesigner!