pitch

Hello kind people of the audio computing world, I have an array of samples that respresent a recording. Let us say that it is 5 seconds at 44100Hz. How would I play this back at an increased pitch? And is it possible to increase and decrease the pitch dynamically? Like have the pitch slowly increase to double the speed and then back down. In other words I want to take a recording and play it back as if it is being 'scratched' by a d.j. Pseudocode is always welcomed. I will be writing this up in C. Thanks, EDIT 1 Allow me to clarify my intentions. I want to keep the playback at 44100Hz and so

I want to plot the pitch of a sound into a graph. Currently I can plot the amplitude. The graph below is created by the data returned by getUnscaledAmplitude() : AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(new BufferedInputStream(new FileInputStream(file))); byte[] bytes = new byte[(int) (audioInputStream.getFrameLength()) * (audioInputStream.getFormat().getFrameSize())]; audioInputStream.read(bytes); // Get amplitude values for each audio channel in an array. graphData = type.getUnscaledAmplitude(bytes, 1); public int[][] getUnscaledAmplitude(byte[] eightBitByteArray,

I'm looking to extract pitches from a sound signal. Someone on IRC just explained to me how taking a double FFT achieves this. Specifically: take FFT take log of square of absolute value (can be done with lookup table) take another FFT take absolute value I am attempting this using vDSP I can't understand how I didn't come across this technique earlier. I did a lot of hunting and asking questions; several weeks worth. More to the point, I can't understand why I didn't think of it. I am attempting to achieve this with vDSP library. It looks as though it has functions to handle all of these

I have a children's iPhone application that I am writing and I need to be able to shift the pitch of a sound sample using Core Audio. Does anyone have any example code I could look at where this is done. There are many music and game apps in the app store that do this so I know I am not the first one. However, I cannot find any examples of it being done. you can use dirac-2 from dsp dimension for pitch shifting on the iphone. quote: - "DIRAC2 is available as both a commercial object library offering unlimited sample rates and phase locked multichannel support and as a free single channel, 44.1