Pure Data

OpenScofo is available in Pure Data as the openscofo~ external. It can follow an OpenScofo score from a mono audio signal, report the current score event and tempo, execute score actions through Pure Data receivers, and output audio descriptors for real-time or offline analysis.

Syntax

[openscofo~]
[openscofo~ rms centroid mfcc]

Create openscofo~ with no arguments for score following only. Pass descriptor names as creation arguments when you also want descriptor output from the analyzed signal.

Inlets and Outlets

openscofo~ has one signal inlet.

• Signal inlet: mono audio stream analyzed by OpenScofo.
• Left outlet: current score event index as a float.
• Middle outlet: current tempo in BPM as a float.
• Right outlet: descriptor messages, created only when descriptor names are passed as object arguments.

Descriptor messages use the descriptor id as the selector:

mfcc <float...>
centroid <float>
onnx <label> <float>

Basic Use

If the filename has no extension, openscofo~ looks for a .scofo file. Relative paths are resolved from the current patch.

Messages

score

Loads a score file using score <score_path>.

After a successful load, openscofo~ resets the current event to 0, outputs the current BPM and event index, and reads the score configuration such as FFT size and hop size.

start

Starts following the loaded score from event 0.

start clears pending actions, resets the follower to the beginning of the score, outputs the current BPM and event index, and enables following.

follow

Enables or disables score following without reloading the score.

set verbosity

Sets the amount of OpenScofo logging printed in the Pure Data console. The levels are 0 warning, 1 info, 2 debug, and 3 trace.

set justdescription

Switches descriptor-only processing on or off. This is useful when you create the object with descriptor arguments and want analysis output without score following.

set onnxmodel

Loads an ONNX model and tells OpenScofo which descriptors were used to train it. The descriptor order must match the order used during model training.

get description

Processes audio from a Pure Data array and outputs the requested descriptors once. get descriptors <array-name> <sample-rate> <start-sample-index>. The <start-sample-index> is optional argument is the start index inside the array. openscofo~ reads one FFT window from that position, pads with zeroes if the array ends early, and sends descriptor messages through the descriptor outlet.

Score Actions

OpenScofo score actions are delivered to Pure Data receivers. For example, this score fragment:

NOTE C4 1
    sendto event-hit [1 C4]
    delay 1 tempo sendto event-hit [0 C4]

can be received in Pure Data with:

[r event-hit]

If a sendto action has no arguments, openscofo~ sends a bang. If it has arguments, it sends them as a Pure Data list. Action arguments can be numbers or symbols.

Lua actions in the score are executed by openscofo~ when the external is built with Lua support. The Pure Data Lua module is available as pd inside score LUA { ... } blocks:

LUA {
    function hello()
        pd.post("hello from OpenScofo")
        pd.send_bang("event-hit")
    end
}

NOTE C4 1
    luacall(hello())

See Score Actions and Lua for Interactive Actions for the score-language side.

Descriptors

Request descriptors by passing their ids as creation arguments:

[openscofo~ rms db centroid mfcc chroma]

When DSP is running, descriptors are output after each analyzed block. Vector descriptors such as mfcc, chroma, logmel, and magnitude output a list of floats. Scalar descriptors output one float.

The full descriptor reference is available in Descriptors.