CODEWITHSUNDEEP
androidaudioaudio-recording
Vinay
Vinay

Reputation: 6322

Android Audio Analysis in Real-time

I have searched for this online, but am still a bit confused (as I'm sure others will be if they think of something like this). I'd like to preface by saying that this is not for homework and/or profit.

I wanted to create an app that could listen to your microwave as you prepare popcorn. It would work by sounding an alarm when there's a certain time interval between pops (say 5-6 seconds). Again, this is simply a project to keep me occupied - not for a class.

Either way, I'm having trouble trying to figure out how to analyze the audio intake in real-time. That is, I need a way to log the time when a "pop" occurs. So that you guys don't think I didn't do any research into the matter, I've checked out this SO question and have extensively searched the AudioRecord function list.

I'm thinking that I will probably have to do something with one of the versions of read() and then compare the recorded audio every 2 seconds or so to the recorded audio of a "pop" (i.e. if 70% or more of the byte[] audioData array is the same as that of a popping sound, then log the time). Can anyone with Android audio input experience let me know if I'm at least on the right track? This is not a question of me wanting you to code anything for me, but a question as to whether I'm on the correct track, and, if not, which direction I should head instead.

Upvotes: 14

Views: 20882

Answers (3)

Andrei
Andrei

Reputation: 2332

this may be a bit overkill, but there is a framework from MIT media labs called funf: http://code.google.com/p/funf-open-sensing-framework/
They already created classes for audio input and some analysis (FFT and the like), also saving to files or uploading is implemented as far as I've seen, and they handle most of the sensors available on the phone. You can also get inspired from the code they wrote, which I think is pretty good.

Upvotes: 5

gregm
gregm

Reputation: 12159

I think I have an easier way.

You could use the MediaRecorder 's getMaxAmplitude method.

Anytime your recorder detects a big jump in amplitude, you have detected a corn pop!

Upvotes: 9

Andrew Packer
Andrew Packer

Reputation: 146

Check out this code (ignore the playback part): Playing back sound coming from microphone in real-time

Basically the idea is that you will have to take the value of each 16-bit sample (which corresponds to the value of the wave at that time). Using the sampling rate, you can calculate the time between peaks in volume. I think that might accomplish what you want.

Upvotes: 6

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