visualize

Visualize octave spectrum

Since R2024b

Syntax

visualize(o)

h = visualize(o)

Description

visualize(o) plots the octave spectrum computed by the octaveSpectrumEstimator System object™. The visualization is updated with the computed spectrum as the simulation progresses.

h = visualize(o) also returns a handle to the visualizer object.

Examples

Measure Octave Spectrum of Streaming Audio

Create a dsp.AudioFileReader to stream an audio file for processing. Create an audioDeviceWriter to play the audio as you stream it.

reader = dsp.AudioFileReader("FunkyDrums-44p1-stereo-25secs.mp3");
player = audioDeviceWriter(SampleRate=reader.SampleRate);

Create an octaveSpectrumEstimator object with the same sample rate as the file reader.

o = octaveSpectrumEstimator(reader.SampleRate)

o = 
  octaveSpectrumEstimator with properties:

            SampleRate: 44100
             Bandwidth: '1/3 octave'
    FrequencyWeighting: 'A-weighting'
         TimeWeighting: 'fast'
        FrequencyRange: [22 22050]
           FilterOrder: 2
    ReferenceFrequency: 1000
       OctaveRatioBase: 10
              ApplyLog: false

Call visualize on the object to open a visualizer to display the spectrum.

visualize(o)

In a streaming loop:

1. Read in a frame of audio data.

2. Compute the octave-band spectrum

3. Play the audio with the device writer.

See the visualizer update with the measured spectrum as the audio plays.

while ~isDone(reader)
    audioIn = reader();
    p = o(audioIn);
    player(audioIn);
end

Tune Octave Spectrum Estimator Properties

Create a dsp.AudioFileReader to stream an audio file for processing. Create an audioDeviceWriter to play the audio as you stream it.

reader = dsp.AudioFileReader("FunkyDrums-44p1-stereo-25secs.mp3");
player = audioDeviceWriter(SampleRate=reader.SampleRate);

Create an octaveSpectrumEstimator object with the same sample rate as the file reader and set the Bandwidth to 1 octave.

o = octaveSpectrumEstimator(reader.SampleRate,Bandwidth="1 octave");

Call visualize on the object to open a visualizer to display the spectrum.

visualize(o)

Call parameterTuner to open a UI to tune parameters of the octaveSpectrumEstimator while streaming.

parameterTuner(o)

In a streaming loop:

1. Read in a frame of audio data.

2. Compute the octave-band spectrum

3. Play the audio with the device writer.

Adjust the properties in the parameterTuner UI while streaming.

while ~isDone(reader)
    audioIn = reader();
    p = o(audioIn);
    player(audioIn);
end

Input Arguments

o — Octave spectrum estimator object

octaveSpectrumEstimator object

Octave spectrum estimator to visualize, specified as an octaveSpectrumEstimator System object.

Output Arguments

h — Handle to visualizer

audio.ui.scope.OctaveSpectrumVisualizer object

Handle to the octave spectrum visualizer, returned as an audio.ui.scope.OctaveSpectrumVisualizer object.

More About

Tuning Properties

Changing the Bandwidth, FrequencyRange, ReferenceFrequency, or OctaveRatioBase properties on the octaveSpectrumEstimator object results in a change of the number of octave bands displayed in the visualizer. In this case, the object resets the scope before continuing to display the spectrum.

Version History

Introduced in R2024b