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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Find most dominant audio frequency in sample

I'm trying to create a project that pulls in a live stream audio file from the internet and continuously samples the audio looking for the most dominant frequency for a given time period. The idea is that if it detects a frequency of let's say 440Hz…
Bill
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Convert audio to text

I just want to know if there is any build in libraries or external libraries in Java or C# that allow me to take an audio file and parse it and extract the text from it. I need to make an application to do so, but I don't know from where I can…
Amira Elsayed Ismail
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How to write C++ audio processing applications?

I'm an Electronics and Telecommunications student, next to my graduation. I'm gonna work on a project that involves my knowledge about DSP, music and audio in general. I allready know all the basic mathematic instruments and all the stuff I need to…
Cesko82
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How to add an external audio track to a video file using VLC or FFMPEG command line

I want to add an audio.mp3 soundtrack to a soundless video.mp4 file using a bash script, what is the correct syntax of the "cvlc" "ffmpeg" command line ? I've recorded the video with VLC and --no-audio option so there is no settings such as bit rate…
Jonathan
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Sound recognition API, SDK (Android)

I need to make an Android app that can recognize certain sound files created by me, and do an action on recognition. So something similar to Shazam/Soundhound, but with my own sound files. Is there any API or SDK or something for this? I've read…
KKO
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Library for reading audio files

I want to process audio online/live where I constantly read audio samples from an audio file, process these (e.g. apply some effect), and forward the processed samples to an audio output device like a soundcard. The input files have common formats…
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Python: Change Pitch of Audio File

this is my first post on stack. So far this site has been very helpful, but I am a novice and need a clear explanation to my problem, which is related to pitch-shifting audio in Python. I have the current modules installed: numpy, scipy, pygame, and…
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Adding silent frame to wav file using python

First time posting here, lets see how this goes. I trying to write a script in python which would add a second of silence in the beginning of the wav file, but so far been unsuccessfully in doing so. What I was trying to do is read in the wav header…
Madmax
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Get Video and Audio buffer separately while recording video using front camera

I dug a lot on SO and some nice blog post But seems I am having unique requirement of reading Video and Audio buffer separately for further processing on it while recording going on. My use case is like When the user starts the Video recording, I…
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Find sound effect inside an audio file

I have a load of 3 hour MP3 files, and every ~15 minutes a distinct 1 second sound effect is played, which signals the beginning of a new chapter. Is it possible to identify each time this sound effect is played, so I can note the time offsets? The…
Craig Francis
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How to get & parse the values of ITune's EQ presets

We are trying to implement a music player app with Equalizer presets. We are successful in getting presets from iPod and applying it through audio unit. But, now we need to display sliders and set frequency with respect to the selected preset. But…
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Open source FSK decoder library?

I'm looking for a library or tool to decode FSK in wav files, e.g. caller id. Currently using the tools bundled with vpb-driver for Voicetronix hardware that is available via debian/ubuntu. But this appears to have an error that I'm trying to debug…
bstpierre
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audio comparison with R

I am working in a project where my task deals with speech/audio/voice comparison. This project is used for judging the winner in the competitions(mimicry). Practically I need to capture the user's speech/voice and compare it with the original audio…
Dinesh
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Can I measure distances with sound in an android app?

I've got a number of questions this time, although they all relate to the same problem: I wanted to build a rudimentary sonar in Android, and have no clue as to how possible it is to do such a thing. Is it something that can work reasonably…
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processing an audio wav file with C

I'm working on processing the amplitude of a wav file and scaling it by some decimal factor. I'm trying to wrap my head around how to read and re-write the file in a memory-efficient way while also trying to tackle the nuances of the language (I'm…
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