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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Audio processing library for android

Does anyone know a library for audio processing on android? I need to extract pitch and speech power (intensity).
Hassan Pezeshk
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Retrieving Data from AudioKit's FFT Plot

I'm working on a project that involves recording audio from the microphone of the iPhone, then feeds it through a Fast Fourier Transform (FFT). I've found AudioKit.io has a demo in which it actively monitors microphone input and can display a plot…
gh0st
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Audio processing libraries for Ruby?

Any recommendation on libraries to do audio processing in Ruby. I need to do the following two tasks: Find silences, for which I'm happy to just be able to iterate over each sample in the wave. Cut and paste pieces of wav files to form a new wav…
Pablo Fernandez
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How to analyze the BPM of AAC file or any library for converting AAC to MP3

I am iphone developer and developing one mac application now. This is my first project ever in mac platform. I have to analyze the BPM of the songs files. I have done this work for MP3 using FMOD and SoundTouch library. But i have to analyze for AAC…
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Voice changer for audio files

I have some audio files in different voices (only spoken words there is no music or noise). I am aiming to change all that audios for a one standard voice "man" voice for example For example: Input : audio file say "Hello World" in Woman/man…
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Changing tempo (speed) of audio

I want to change the tempo of a stereo audio stream in near realtime - the audio is loaded from a file and the buffer should not be longer than 1 second. I tried SoundTouch (http://www.surina.net/soundtouch/) but the quality when decreasing the…
Hyndrix
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Controlling audio volume in real time

I'm currently using libsndfile in combination with PortAudio V19 to read audio data from a file and play it back. (Please note I am doing this on a Raspberry Pi running Raspbian.) The problem I'm encountering is that I need to dynamically control…
Chris Hayes
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Can't import audiolab in python

I installed audiolab from this source: http://www.lfd.uci.edu/~gohlke/pythonlibs/#scikits.audiolab Those are the only windows binaries for python 2.7 I was able to find. When I call from scikits import audiolab I get the following error: Traceback…
Flavian Hautbois
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detect sound level in raw pcm data

I writing small program which need to detect sound level and write it if level higher than set in settings, i done sound capturing via portaudio, compressing via libvorbis, but one part of program has unfinished and i stuck on it, i need to detect…
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Calculating the difference between two sound samples

I have two sound samples (.WAV) and I want to find the difference between them. I've read about this subject and I know that I should use FFT to do such a thing. Unfortunately, I can't find a way to do the actual calculation. I am searching for a…
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Which API: JavaFX or JMF is better for audio processing in Java?

I am doing a project in which I have to transform the audio data (which would be most probably in mp3, wav or wma format) into a waveform and also get the FFT and pitch for it along with the time in milliseconds at which the pitch change. I am just…
Soul Enrapturer
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Python does not detect soundtouch elements (bpmdetect and pitch) in gst-plugins-bad

I have installed gstreamer, gst-plugins-bad and its python bindings. The following code selects a song from a given directory and plays it. import pygst pygst.require("0.10") import gst import pygtk import gtk import os class Main: def…
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Detect beat and play (wav) file in a synchronised manner

I am trying my hands at Audio Processing in python with this Beat Detection algorithm. I have implemented the first (non-optimized version) from the aforementioned article. While it prints some results, I have no way to detect whether it works with…
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C#/.net audio noise reduction

I'm developing a class library, that allows to do some manipulations with streamed audio (it is working with buffered samples, retrieved from recording device - so basically I've got an bytes array) for researsh purposes. The problem is that i need…
danyloid
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How to crop an audio file based on the timestamps present in a list

So, I have an audio file which is very long in duration. I have manual annotations (start and end duration in seconds) of the important parts which I need from the whole audio in a text file. I have converted this text file into a nested list where…
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