Sound convertion to frequency in android [duplicate]

问题

Possible Duplicate:
Real time pitch detection
Determine the audio frequency of sound received via the microphone

I'm developing my own android guitar tuner. Here I will have to use the guitar note frequency. Therefore, I want to know how to convert the sound coming through the mic port into its frequency in android?

回答1:

EDIT: link dead ---This problem is already solved here---

I shall summarize the paper :

Record stuff :

    int minSize = AudioRecord.getMinBufferSize(sampleRate,AudioFormat.
    CHANNEL_CONFIGURATION_MONO,
    AudioFormat.ENCODING_PCM_16BIT);
    AudioRecord audioInput = new AudioRecord(MediaRecorder.AudioSource.MIC, sampleRate,
    AudioFormat.CHANNEL_CONFIGURATION_MONO,
    AudioFormat.ENCODING_PCM_16BIT);
    minSize);
    ...
    short[] buffer = new short[readSize];
    audioInput.startRecording();
    audioInput.read(buffer, index, readSize); // record data from mic into buffer

Anayze the frequency using FFT.

I'd say you record about 4 seconds of apply FFT on it. Like hotpaw2 says you have to use pitch estimation algorithms to determine the range of frequencies in recorded sound from the strum.

回答2:

You will need a pitch estimation algorithm (there have been many published, such as autocorrelation, ASDF/AMDF, cepstral processing, harmonic product spectrum, RAPT, YAAPT, etc.). Frequency estimation alone is not suitable for guitar tuning, as note pitch is different from spectral frequency.

来源：https://stackoverflow.com/questions/8928695/sound-convertion-to-frequency-in-android

标签

android

signal-processing