Hello, Sorry to ask a similar question to the one i asked before (FFT Problem (Returns random results)), but i've looked up pitch detection and autocorrelation and have found some code for pitch detection using autocorrelation. Im trying to do pitch detection of a users singing. Problem is, it keeps returning random results. I've got s...
Hello, I'm trying to do real time pitch detection of a users singing, but I'm running into alot of problems. I've tried lots of methods, including FFT (FFT Problem (Returns random results)) and autocorrelation (Autocorrelation pitch detection returns random results with mic input), but I can't seem to get any methods to give a good resu...
Hello, This is not a "programming" question. But I'm sure it's something that is widely known and understood in this community. I have an image, x, and a much smaller image, y, and I need to convolve the two by multiplying their FFTs. But since they are not the same size I don't know how to do the frequency domain multiplication. I ta...
Let's say you had to calculate the sine (cosine or tangent - whatever) where the domain is between 0.01 and 360.01. (using C#) What would be more performant? Using Math.Sin Using a lookup array with precalculated values I would anticpate that given the domain, option 2 would be much faster. At what point in the precision of the dom...
Hello. I would like to write a cross-platform application that can process and play back microphone data in real time. Imagine as a proof of concept a chat room where people can talk to each other and apply filters to their voices. Is OpenAL appropriate for this? If not, can someone provide an alternative? Additionally, if anyone ca...
I want to analyze MIC audio on an ongoing basis (not just a snipper or prerecorded sample), and display frequency graph and filter out certain aspects of the audio. Is the iPhone powerful enough for that? I suspect the answer is a yes, given the Google and iPhone voice recognition, Shazaam and other music recognition apps, and guitar t...
Is there any good c++ source codes or api for handling phone lines like understanding tone signals. For example i like to find out if the person enters 3 (it's likely that this is done using it's tone sound). Do i need a special modem for this purpose or it can be done using only standard modems. ...
I wrote a small software synth for the iPhone. To further tune performance I measured my application with Shark and found that I am loosing a lot of time in float/SInt16 conversions. So I rewrote some parts to get around the conversions by pre-calculating lookup tables that return "ready-to-use" SInt16 samples. This works fine so far. C...
I am going to write some image processing programs for Texas Instruments DaVinci platform. There are tools appropriate for programming in the C language, but I wonder if it is really possible to take full advantage of the DSP processor without resorting to an assembly language. Do you know about any comparisons of speed between programs ...
Hi. With limited resources such as slower CPUs, code size and RAM, how best to detect the pitch of a musical note, similar to what an electronic or software tuner would do? Should I use: Kiss FFT FFTW Discrete Wavelet Transform autocorrelation zero crossing analysis octave-spaced filters other? In a nutshell, what I am trying to d...
Hello, I'm trying to do real-time pitch detection using C++. I'm testing some code from performous (http://performous.org/), because everything else hasn't worked for me. I know for sure that this works, but i just cant get it to work. I've been trying this for a few weeks now, and i haven't been able to get any pitch detection code wor...
Octave appears to assume that a specific sound playing utility will be available on a system but doesn't seem to provide the ability to specify an alternate. In the error below, Octave is looking for ofsndplay, which is not a utility available on all systems. octave:38> sound(beamformed_20) sh: ofsndplay: command not found I...
With a sine input, I tried to modify it's frequency cutting some lower frequencies in the spectrum, shifting the main frequency towards zero. As the signal is not fftshifted I tried to do that by eliminating some samples at the begin and at the end of the fft vector: interval = 1; samplingFrequency = 44100; signalFrequency = 440; sample...
As a follow-up to my previous question, if I want my smartphone application to detect a certain musical note, and I only need to know whether the incoming sound is that musical note or not, with a certain amount of fuzziness, to allow the note to be off-key by x cents. Given that, is there a superior method over others for speed and acc...
I've started developing a simple guitar tuner as a learning project for audio processing programs. Could someone recommend me an adequate library for this? Here's basically what I'm looking for: Microphone input. Real-time processing of the signal. I need to be able to perform note recognition on whatever is being played to the mic. C...
Hi, I've been working on a tool to transcribe recordings of speech with Javascript. Basically I'm hooking up key events to play, pause, and loop a file read in with the audio tag. There are a number of advanced existing desktop apps for doing this sort of thing (such as Transcriber -- here's a screenshot). Most transcription tools have ...
I'm trying to write a filtering function for an image, but I can't seem to wrap my head around (or remember) how to transfer all that math theory into code. Lets say I have the following function, where the ints inside the arrays are integers between 0 and 255 (pretty much grayscale pixels to keep it simple). private int[][] resample(i...
Google returns too much results, although SPUC caught my attention. Is there a standard recommended library like OpenCV for vision? The necessary features would be: Free Open Source filter design (Butterworth, Chebyshev, etc) FFT if possible, some speech processing features, like MFCC computation, although that's secondary, as I could ...
Is there any Java or C# library for signal analysis using the sound card of a PC? I'm not interested in music mixing, rather in general purpose signal analysis - take a look at SIGVIEW - I'm interested in a Java or C# library that can do that. Another example is the scEEG project, striving to build a sound card electroencephalograph, by...
I'm familiar with Computer Vision (Well, know OF it), of which one application can be image recognition, such as Optical Character Recognition, I believe. However, something that I am more interested in is 'computer listening', which I have just learned is considered Digital Signal Processing. The thing that interests me the most about ...