Android Question Human Voice Recognition

Sub Process_Globals
    Private audio As AudioStreamer
    Private timer1 As Timer
    Private bufferList As List
End Sub

Sub Globals
End Sub

Sub Activity_Create(FirstTime As Boolean)
    audio.Initialize("audio", 16000, True, 16, audio.VOLUME_VOICE_CALL)
    bufferList.Initialize
    timer1.Initialize("timer1", 2000)
    timer1.Enabled = True
    audio.StartRecording
End Sub

Sub audio_RecordBuffer(Buffer() As Byte)
    bufferList.Add(Buffer)
End Sub

Sub timer1_Tick
    If bufferList.Size = 0 Then Return

    Dim amplitudes As List
    amplitudes.Initialize

    For Each buf() As Byte In bufferList
        amplitudes.Add(ComputeAmplitude(buf))
    Next

    bufferList.Clear

    Dim avg As Float = Average(amplitudes)
    Dim variance As Float = ComputeVariance(amplitudes, avg)

    Log("Avg: " & avg & "  Var: " & variance)

    If avg > 1000 And variance > 500 Then
        Log("👂 Possible human speech detected!")
        ' You could trigger an alert or record this timestamp
    End If
End Sub

Sub ComputeAmplitude(buffer() As Byte) As Float
    Dim raf As RandomAccessFile
    Dim tmpfile As String = File.DirInternal & "/tmp.raw"
    File.WriteBytes(tmpfile, "", buffer)
    raf.Initialize2(File.DirInternal, "tmp.raw", False, True)

    Dim samples As Int = raf.Size / 2
    Dim total As Long = 0
    For i = 0 To samples - 1
        total = total + Abs(raf.ReadShort(i * 2))
    Next
    raf.Close
    Return total / samples
End Sub

Sub Average(l As List) As Float
    Dim sum As Float = 0
    For Each f As Float In l
        sum = sum + f
    Next
    Return sum / l.Size
End Sub

Sub ComputeVariance(l As List, avg As Float) As Float
    Dim sumSq As Float = 0
    For Each f As Float In l
        sumSq = sumSq + Power(f - avg, 2)
    Next
    Return sumSq / l.Size
End Sub