从 3GP 文件中检测 DTMF 数字

Question

我想知道有没有办法使用 java 从 3GP 文件中检测 DTMF 数字。

Answer 1

您可以使用TarsosDSP 在 Java 中解码 DTMF。在this blogpost 中提供了一个示例实现。

如何解码来自 3GP 的音频取决于其中使用的音频编解码器。

Answer 2

是否可以在我将在此句下方发布的代码上使用此类库“TarsosDSP”？

如果是，怎么做？

如果这个问题很愚蠢，请原谅我，我真的很好奇，我想了解！

 import java.io.IOException;

 import org.JMathStudio.DataStructure.Complex;
 import org.JMathStudio.DataStructure.Cell.Cell;
 import org.JMathStudio.DataStructure.Cell.CellTools;
 import org.JMathStudio.DataStructure.Vector.CVector;
 import org.JMathStudio.DataStructure.Vector.Vector;
 import org.JMathStudio.DataStructure.Vector.VectorStack;
 import org.JMathStudio.Exceptions.DimensionMismatchException;
 import org.JMathStudio.Exceptions.IllegalArgumentException;
 import org.JMathStudio.Exceptions.UnSupportedImageFormatException;
 import org.JMathStudio.SignalToolkit.GeneralTools.SignalUtilities;
 import org.JMathStudio.SignalToolkit.TransformTools.FourierSet.FFT1D;
 import org.JMathStudio.SignalToolkit.Utilities.SignalGenerator;


 public class DTMF_Demo {
static int [] freqTableRow = {
        697, 770, 852, 941  
} ;

static int [] freqTableCol = {
        1209, 1336, 1477
} ;

static char [][] dialKey = {
    {'1', '2', '3'},
    {'4', '5', '6'},
    {'7', '8', '9'},
    {'*', '0', '#'}
} ;

static int fs = 4000 ;              // Sampling Rate
static float noiseLevel = 0.2f ;    // Amplitude of the noise signal before normalization

private String dialKeyString ;      // The dial key sequence generated

// This is the method that generate the dial key sequence signal
public float [] dtmfDial() throws IllegalArgumentException 
{

    VectorStack numberStack = new VectorStack() ;   // A temporary storage for a list of signal vectors
    int totalLength = 0 ;   // Total length of the dial key sequence signal generated
    int row ;               // Row index into the frequency table
    int col ;               // Column index into the frequency table
    int length ;            // Length of a dial key signal
    int numDigit ;          // Number of keys to generate for a dial key sequence
    int pauseLength ;       // Length of pause signal
    int i, j, k ;           // Looping variables
    float normFactor ;      // Normalization factor for dial key sequence

    normFactor = 2.0f + noiseLevel ;
    dialKeyString = new String("") ;



    numDigit = Math.round((float) (5.0f + Math.random() * 11.0f)) ;


    for(i = 0; i < numDigit; i++) 
    {
        row = Math.round((float) (Math.random() * 3.99 - 0.49)) ;


        col = Math.round((float) (Math.random() * 2.99 - 0.49)) ;


        length = Math.round((float) (fs/2 + Math.random() * 1.5 * fs)) ;


        pauseLength = Math.round((float) (fs/4 + Math.random() * 0.75 * fs)) ;



        Vector tone = SignalGenerator.cosine(freqTableRow[row], fs, 0.0f, length+pauseLength) ;



        Vector tone2 = SignalGenerator.cosine(freqTableCol[col], fs, 0.0f, length+pauseLength) ;



        Vector noise = SignalGenerator.random(length+pauseLength) ;





        dialKeyString += dialKey[row][col] ;    // Look up actual key dialed



        totalLength += (length+pauseLength) ;





        // Sum the two sinusoids with addition of noise
        for(j = 0; j < length; j++) 
        {
            tone.accessVectorBuffer()[j] += tone2.accessVectorBuffer()[j] ;
            tone.accessVectorBuffer()[j] += ((2.0f * noiseLevel) * noise.accessVectorBuffer()[j] - noiseLevel);
            tone.accessVectorBuffer()[j] /= normFactor ;

        }


        // Inject pause and noise signals
        for(j = length; j < length + pauseLength; j++) 
        {
            tone.accessVectorBuffer()[j] = ((2.0f * noiseLevel) * noise.accessVectorBuffer()[j] - noiseLevel) ;
            tone.accessVectorBuffer()[j] /= normFactor ;

        }



        numberStack.addVector(tone) ;   // Add the dial key signal into the stack of signal vectors



    }



    float [] dtmfSignal = new float[totalLength] ;  // Array of floats to serve as the output dial key sequence signal
    Vector [] numberVectorArray = numberStack.accessVectorArray();

    // Concatenate the dial key signals to form the output dial key sequence signal
    k = 0 ;
    for(i = 0; i < numberStack.size(); i++) 
    {
        for(j = 0; j < numberVectorArray[i].length(); j++) 
        {
            dtmfSignal[k] = numberVectorArray[i].accessVectorBuffer()[j] ;



            k++ ;
        }
    }


    return dtmfSignal ;
}



public Boolean dialKeyStringMatch(String decodedKeyString) 
{
    return dialKeyString.equals(decodedKeyString) ;
}



public String getDialString() 
{
    return dialKeyString ;
}




public static void main(String[] args) throws IOException, UnSupportedImageFormatException, DimensionMismatchException 
{
    // TODO Auto-generated method stub
    DTMF_Demo demo = new DTMF_Demo() ;
    DTMF_Decode decoder = new DTMF_Decode() ;


    try 
    {
        int correct = 0 ;
        int totalCount = 1 ;

        for(int i = 0; i < totalCount; i++) 
        {
            // Generate Dial Key Sequence Signal
            float [] dtmfSignal = demo.dtmfDial() ;

            // Call your implemented dtmfAnalyse method and obtain decoded key string
            String decodedKeyString = decoder.dtmfAnalyse(dtmfSignal, fs) ;

            // Compare your decoded key sequence with the ground truth
            if(demo.dialKeyStringMatch(decodedKeyString)) 
            {
                correct++ ;
            }
            else 
            {
                // Print out incorrectly decoded dial key sequence
                System.out.println(demo.getDialString() + " (original) != " + decodedKeyString + " (decoded)") ;
            }







        }

        System.out.println(correct + " out of " + totalCount + " are correct.") ;

    } 
    catch (Exception e) 
    {
        e.printStackTrace() ;
    }

}

}