Questions tagged [audio-processing]

Audio processing involves the study of mathematical and signal processing techniques to understand or alter the nature of audio signals. The different kind of audio signals under study include speech, music, environmental audio and computer audio. Audio is analyzed in the temporal or spectral domain by applying various filters.

Key concept is to transform the audio into PCM format so you have access to the raw audio curve. Each channel will have its own curve.

Digital audio is represented by a series of points on this curve. Each point is called an audio sample. Numerical value of each sample can be represented in either integer or floating point.

Be aware to map each audio sample numerical value to memory typically requires several bytes of storage. One byte can store only 2^8 distinct values (256) which will result in noticeable distortion. High quality audio is typically stored using at least two bytes of storage per audio sample. When we use two bytes this gives us 2^16 possible values of the raw audio curve height as the audio wobbles up and down. The more bytes we use for storage the higher fidelity we gain as this reduces the gap between each distinct curve height measurement. This called bit depth. CD quality audio uses two bytes per audio sample per channel. The other fundamental aspect of digital audio is Sample Rate with determines the number of samples per second of time.

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implementing FftPitchDetector in C#

I've added FftPitchDetector.cs into my project, but I'm not sure how to use it. My code: private void sourceStream_DataAvailable(object sender, NAudio.Wave.WaveInEventArgs e) { if (waveWriter == null) return; byte[]…
Jeff Tung
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matlab to android conversion to calculate energy

I have to convert a matlab code into Android. This matlab code contains energy calculation as shown below: first I read the audio file into matrix x, and the sample frequency into fs, and then calculate the energy for each window: [x, fs] =…
Mardini
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How to modify a recorded voice to playback and sound "funny" in iOS?

I am creating one application which requires recording voice and then funny voice will play. Is there any library to use this work function better?
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Downsample a wave file

I need to downsample a 16000 hz PCM 16 bit wave file to 8000 hz. I dont have much knowledge(almost no) on audio processing, i just understand bits, bytes, shifting etc as all programmers understand. It is a Windows Phone application. What do you…
mehmet6parmak
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Transfer and extract message by Audio signal in Android

I do research about audio processing and have a big problem to solve. Is it possible to transfer a text message or binary stream(10101010) by embedding it into audio signal, broadcasting it so that other android devices can record that sound and…
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Generating a sound using two channel in MATLAB

I am trying to create a sound using two channels. I send two signals with different frequencies. I am trying to do it without the Data Acquisition Toolbox. It is possible to do it?
Fred
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Is real time communication in matlab possible?

I am doing audio steganography using dsk TMSC6713. i want to send the message using dsk in real time to a PC, then do all processing and serial communication between the sender and receiver PC in real time using matlab and listen to the sent message…
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Applying LFO on a signal in Matlab

I want a LFO to be a 6Hz sine wave that will modify the amplitude of the original signal by +/- 2db. [y, Fs] = wavread('input.wav'); t = 0:1/Fs:(length(y)-1)/Fs; y1 = y .* 1.584893.*sin(2*pi*6*t); wavwrite(y1,Fs,'output.wav'); is that going to do…
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Preprocessing audio in android Speech Input recognizer

I'm doing some basic command recognition and using Google Search Input API for that. However I want to capture audio myself, preprocess the audio (denoise, boost amplitude, etc), send those modified audio to the recognizer and obtaining results. Is…
pzo
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Configure buffer list to store non-interleaved audio data?

I've got a callback from which I am attempting to capture audio from a remote I/O unit in an audio graph. Inside of my callback I have an AudioBufferList in an AudioUnitRender function that I need to store non-interleaved data from two…
Orpheus Mercury
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Splitting an audio file into different plots and datasets when a sound plays

I am learning some python audio processing and was wondering how I could split an audio file into different amplitude time plots when a sound plays. For example if the audio file is a guitar that plays four notes and different times I would like to…
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Install essentia on Windows

I still have issues to install essentia on windows. Could you guide me step by step, please? I have tried to install using pip install. But I got following errors. note: This error originates from a subprocess, and is likely not a problem with…
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Why does this code for calculating total harmonic distortion give me wrong values?

I am trying to calculate total harmonic distortion plus noise in python. When I input the same waveform to my code and another closed source total harmonic distortion plus noise calculator, I get different answers. What’s wrong with my code? #…
PetSven
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How to get frequency at every 50ms interval of an audio file?

Like the title says I need the frequency (pitch) of an audio file every 50 ms. Does anyone know how to do this?
bezzoon
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Audio processing: How to obtain similar data from audio records that are recorded by different microphones, by the same person

I am currently developing a speaker recognition program which should recognize the speaker by listening the microphone. I'm a newbie at audio processing and machine learning, but I trained a neural network classifier for this project which only…