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Questions tagged [spectrogram]

A spectrogram, or sonogram, is a visual representation of the spectrum of frequencies in a sound, at each time. Spectrograms are also called spectral waterfalls, voiceprints, or voicegrams. Spectrograms are used extensively in the development of the fields of music, sonar, radar, and speech processing, seismology, etc.

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Why spectrogram from librosa library have twice the time duration of the actual audio track?

I am using the following code to obtain Mel spectrogram from a recorded audio signal of about 30 s: spectrogram = librosa.feature.melspectrogram(y=self.RawSamples,sr=self.SamplingFrequency, n_mels=128, fmax=8000) if show: …
LiukPet
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how to convert audio data to fourier on jupyter notebook?

I want to convert mp3 files using courier's transform and export as spectrogram.Then I need to save as PNG file containing all frequencies of my mp3. How can I do that by using jupyter notebook?
pinkdolphin
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python - spectrogram divide by zero encountered in log10 warning

i tried to generate a spectrogram for each axis in my dataset here what i tried dataset = np.loadtxt("trainingdataset.txt", delimiter=",", dtype = np.int32) fake_size = 1415684 time = np.arange(fake_size)/1415684 # 1kHz base_freq = 2 * np.pi *…
Hadeer El-Zayat
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scipy.signal.spectrogram nfft parameter

What does nfft parameter mean in this function? Please refer to this link for the documentation https://docs.scipy.org/doc/scipy-0.19.0/reference/generated/scipy.signal.spectrogram.html
Chaine
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Spectrograms generated using Librosa don't look consistent with Kaldi?

I generated spectrogram of a "seven" utterance using the "egs/tidigits" code from Kaldi, using 23 bins, 20kHz sampling rate, 25ms window, and 10ms shift. Spectrogram appears as below visualized via MATLAB imagesc function: I am experimenting with…
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Spectrogram of two audio files (Added together)

Assume for a moment I have two input signals f1 and f2. I could add these signals to produce a third signal f3 = f1 + f2. I would then compute the spectrogram of f3 as log(|stft(f3)|^2). Unfortunately I don't have the original signals f1 and f2. I…
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matlab spectrum returns more FRAME than expected

I'm using the following code to get specgram2D from np array: specgram2D, freq, time = mlab.specgram(samples, Fs=11025, NFFT=1024, window=mlab.window_hanning, noverlap=int(1024 * 0.5)) Then I print out specgram2D like print len(specgram2D) #…
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Draw spectrogram graph of audio file in android

I'm developing an Android application in which I need to create a graph of spectrogram (which is a visual representation of the spectrum of frequencies in a sound as they vary with time). I had an audio file and use FFT to have signal in frequency…
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Create a spectrogram in python (without drawing)

I'm trying to create a spectrogram object for audio analysis. I'm using Snack Library. This library, create the spectrogram as a canvas object but I should use the spectrogram as a numerical object (every 10 ms I should extract the vector of…
elviuz
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2D plot of a matrix with colors like in a spectrogram

How to plot, with Python, a 2D matrix A[i,j] like this: i is the x-axis j is the y-axis A[i,j] is a value between 0 and 100 that has to be drawn by a colour (ex: 0=blue, 100=red) Is there a Python function for that? (NB: I don't want a function…
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Save Spectrogram as an Image in MATLAB

I'm analyzing some sound clips using the spectrogram() function in MATLAB. I would like to save the spectrogram as an image (jpg, png, etc). But regardless of what image format I save the figure in, the resulting image always looks different…
shapeshifter
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Map a value [0.0-1.0] to color gain

I need to translate values from 0.0 to 1.0 to their color representations (each value is a pixel). I am making a spectrogram, so the higher the value the brightest the pixel should be (as in the below image). How can I do this? I am working in C#…
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How to calculate the phases after a pitch shift on the STFT?

I use torch.stft() to generate a spectrogram. I want to perform a pitch shift on the audio. The end result should be an STFT of the pitch-shifted audio. I can't phase_vocoder -> istft -> resample -> stft because that's too slow. Instead, I wrote…
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Mel-spectrogram vs MFCC for Automatic Speech Recognition

I am trying to do Automatic Speech Recognition using CNN. For the feature extraction I am using MFCC. I have read many articles, some of them say with lot of data and classifiers like CNN, mel spectorgram are better while others say MFCC is…
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Normalize a melspectrogram to (0, 255) with or without frequency scaling

I am converting multiple log-mel spectrograms from .wav files to images. I want to destroy as little information as possible as I plan to use the resulting images for a computer vision task. To convert the data to an image format, I currently use a…
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