In my application i have done to record the voice and playing in the device.
Now i want to find the audio frequency of that recorded voice(While recording). How can i find?.I dont have any idea. I have downloaded "aurio Touch" program.But its too difficult to understand me. So is there any tutorials are avilable(in iPhone)?. How can i achieve this?
Please guide me.
Thanks.
This involves math. If that scares you, you should probably get/buy a library to do the analysis for you. If not, Fourier transform is a good place to start to see what's involved. When I did this, I started by poking around Audacity's source code to get an idea of what's involved.
Related
I'm very new to audio programming, but I know this must be possible. (This is an iOS/iPhone related question).
How would I go about changing the tempo of a loaded audio file without changing the pitch, and then playing it back?
I think I need to delve into the CoreAudio framework, but I'm not sure where to begin.
If anyone could let me know what classes I need to look at, or the general process involved, that would help me get started and I'd really appreciate it!
Cheers!
This question is highly related: it relates to pitch shifting, rather than time shifting, but I'd check out the comments and links.
Real-time Pitch Shifting on the iPhone
What you are looking for is a time-pitch modification library. Core Audio on iOS currently does not contain such, but there appear to be some 3rd party libraries available (commercially). There are also time pitch tutorials on the web, such as at dspdimention, which require a large amount of DSP development to get working.
I am developing an app where the user can record their voice, and then alter it in some way. I have implemented OpenAL, and I am able to adjust the pitch to speed up and slow down the audio file. The thing is, I want to add filters like echo, reverb, etc.. I have scoured the internet for hours and have found nothing to help me. I came across a OpenAL called FreeSL, which has a bunch of filters built in, but I cannot get it compile in xcode.
I have also looked into Dirac3, but again all I am seeing is basic pitch/time controls; no echos or anything.
Can anyone point me in the direction a good framework or explain how OpenAL can handle filters like this?
Thanks!
I found a library that is exactly what I am looking for, FMOD:
http://www.fmod.org/index.php/fmod
In my app,i need to generate video with audio. Now i am using Air Play Sample But its contains only generate video only and i need to generate video with audio.Any one help me to solve with problem.
Regards,
First of all, you need to increase your accept rate.
Secondly, this is quite a lot what you are asking for. I'm not familiar with Air Play, but my suggestion would be to start with the SpeakHere project. That will get you familiarised with core-audio and give you a template for accessing the audio input.
As for the visual aspect I highly recommend O'Reilly's 3D Programming book which provides a lot of example code.
It will take a bit of time to assimilate both materials, but you'll end up with a better application.
I am trying to write an iPhone App that should monitor the any incoming sound. I am not sure how can I get the sound recorded by iPhone's Microphone and detect its frequency. If same frequency sound repeated couple of times then I need to take some action. Could anyone please help me here. I went through the How to detect sound frequency / pitch on an iPhone? but I couldn't understood how to use them.
Any documentation or example would be really useful.
Thanks.
You'll appreciate reading this, on how to get the sound "without having to drop down to C", by using AVAudioRecorder...
Then, begin researching FFT...
Checkout this post about FFT for iPhone, which mentions various options, including the possibility of using Apple's Accelerate framework (in which you will need to drop to C) to apparently get "Apple-written FFT functions".
This is probably what you really want to read.
I may be doing an iPhone-based application doing near-real-time sound-processing (filtering, etc). I was wondering the best way to get started. Would I want to create an audio cue for recording and processing sound, as described here?
Edit:
I should be clear. I am not asking how to do signal processing, in general. I know some of that and my team's expert will handle the rest. I asking what the "low level" interfaces to sound data on the iphone are.
Edit2:
My iphone development has been pushed back a week or two so I don't have access to the deve kit right now. Once I have access to the kit, I'll mark one answer or another correct.
Sound processing is a big subject. AudioQueue will get you the raw data. Apple provides two samples that will get you started using AudioQueue: SpeakHere and AurioTouch.
I used SpeakHere as a starting point for some audio processing I wanted to do. It's relatively easy to understand, and has all the pieces to do input and output.