Android Question Need a sound level (dB) example.

[jmeuse2]

I am new and have made countless attempts to get a sample program to show the decibel level of a live microphone but I am utterly unsuccessful. Bugs galore. No need for graphics, I just need the changing numeric value. Thanks

 

[JohnC]

ChatGPT says...

Here's a simple B4A code snippet to measure the microphone volume level in decibels. This example continuously monitors the audio input level from the microphone and displays the volume level as a numeric value.

B4A Code to Measure Microphone Volume​

Sub Process_Globals
    Private Recorder As AudioRecord
    Private Buffer() As Byte
    Private BufferSize As Int
    Private SampleRate As Int = 44100
    Private AudioSource As Int = 1  ' Microphone
    Private ChannelConfig As Int = 16  ' MONO
    Private AudioEncoding As Int = 2  ' PCM 16-bit
    Private Timer1 As Timer
End Sub

Sub Globals
    Private lblVolume As Label
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Main")
    
    BufferSize = AudioRecord.GetMinBufferSize(SampleRate, ChannelConfig, AudioEncoding)
    Recorder.Initialize(AudioSource, SampleRate, ChannelConfig, AudioEncoding, BufferSize)
    Buffer = Array As Byte(BufferSize)
    
    Timer1.Initialize("Timer1", 200) ' Check volume every 200 ms
    Timer1.Enabled = True
    
    Recorder.StartRecording
End Sub

Sub Activity_Resume
    Recorder.StartRecording
End Sub

Sub Activity_Pause (UserClosed As Boolean)
    Recorder.Stop
End Sub

Sub Timer1_Tick
    Dim ReadBytes As Int = Recorder.Read(Buffer, 0, BufferSize)
    If ReadBytes > 0 Then
        Dim Sum As Long = 0
        For i = 0 To ReadBytes - 1 Step 2
            Dim Sample As Short = Bit.Or(Bit.And(0xff, Buffer(i)), Bit.ShiftLeft(Bit.And(0xff, Buffer(i + 1)), 8))
            Sum = Sum + Abs(Sample)
        Next
        
        Dim Amplitude As Float = Sum / ReadBytes
        Dim Decibels As Float = 20 * Log10(Amplitude)
        
        lblVolume.Text = "Volume: " & NumberFormat2(Decibels, 1, 2, 2, False) & " dB"
    End If
End Sub

Explanation:​

1. AudioRecord Initialization: Sets up the microphone for recording with a SampleRate of 44100 Hz, MONO channel, and PCM 16-bit encoding.
2. Buffer Handling: The microphone audio input is read into a buffer for processing.
3. Decibel Calculation: The volume level is calculated based on the amplitude of the recorded audio samples.
4. Timer: Regularly checks the microphone input every 200 ms and displays the decibel value.

Layout (Main.bal)​

You need a simple layout with a label named lblVolume to display the decibel level.

Permissions (AndroidManifest.xml)​

Add these permissions to your AndroidManifest.xml file:

<uses-permission android:name="android.permission.RECORD_AUDIO"/>

Notes:​

• This code works on most Android devices but may require API level 23+ (Android 6.0+) for proper microphone handling.
• Make sure to request runtime permissions if targeting Android 6.0 or higher.

Let me know if you want me to help you enhance this code or make it more efficient.

 

[Alexander Stolte]

Have a look at this, it's not perfect:

[B4X] [XUI] AS AudioVisualizer

This view is an audio visualizer that converts decibel values into simulated FFT data and renders one of three styles (spectrum, waveform, or filled wave) on a canvas. It features noise filtering, Gaussian normalization. The sample project works in B4A and B4I. You need this libs. xFFT...

www.b4x.com

 

[emexes]

There is almost enough in this post to get you going:

https://www.b4x.com/android/forum/threads/noise-detector-by-microphone.143377/#post-909176

If that and/or the previous two responses to your thread don't get you over the line, let me know and I'll bang something up for you.

 

[jmeuse2]

ChatGPT says...

Here's a simple B4A code snippet to measure the microphone volume level in decibels. This example continuously monitors the audio input level from the microphone and displays the volume level as a numeric value.

B4A Code to Measure Microphone Volume​

Sub Process_Globals
    Private Recorder As AudioRecord
    Private Buffer() As Byte
    Private BufferSize As Int
    Private SampleRate As Int = 44100
    Private AudioSource As Int = 1  ' Microphone
    Private ChannelConfig As Int = 16  ' MONO
    Private AudioEncoding As Int = 2  ' PCM 16-bit
    Private Timer1 As Timer
End Sub

Sub Globals
    Private lblVolume As Label
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Main")
   
    BufferSize = AudioRecord.GetMinBufferSize(SampleRate, ChannelConfig, AudioEncoding)
    Recorder.Initialize(AudioSource, SampleRate, ChannelConfig, AudioEncoding, BufferSize)
    Buffer = Array As Byte(BufferSize)
   
    Timer1.Initialize("Timer1", 200) ' Check volume every 200 ms
    Timer1.Enabled = True
   
    Recorder.StartRecording
End Sub

Sub Activity_Resume
    Recorder.StartRecording
End Sub

Sub Activity_Pause (UserClosed As Boolean)
    Recorder.Stop
End Sub

Sub Timer1_Tick
    Dim ReadBytes As Int = Recorder.Read(Buffer, 0, BufferSize)
    If ReadBytes > 0 Then
        Dim Sum As Long = 0
        For i = 0 To ReadBytes - 1 Step 2
            Dim Sample As Short = Bit.Or(Bit.And(0xff, Buffer(i)), Bit.ShiftLeft(Bit.And(0xff, Buffer(i + 1)), 8))
            Sum = Sum + Abs(Sample)
        Next
       
        Dim Amplitude As Float = Sum / ReadBytes
        Dim Decibels As Float = 20 * Log10(Amplitude)
       
        lblVolume.Text = "Volume: " & NumberFormat2(Decibels, 1, 2, 2, False) & " dB"
    End If
End Sub

Explanation:​

1. AudioRecord Initialization: Sets up the microphone for recording with a SampleRate of 44100 Hz, MONO channel, and PCM 16-bit encoding.
2. Buffer Handling: The microphone audio input is read into a buffer for processing.
3. Decibel Calculation: The volume level is calculated based on the amplitude of the recorded audio samples.
4. Timer: Regularly checks the microphone input every 200 ms and displays the decibel value.

Layout (Main.bal)​

You need a simple layout with a label named lblVolume to display the decibel level.

Permissions (AndroidManifest.xml)​

Add these permissions to your AndroidManifest.xml file:

<uses-permission android:name="android.permission.RECORD_AUDIO"/>

Notes:​

• This code works on most Android devices but may require API level 23+ (Android 6.0+) for proper microphone handling.
• Make sure to request runtime permissions if targeting Android 6.0 or higher.

Let me know if you want me to help you enhance this code or make it more efficient.

 

[jmeuse2]

Thanks for the ChatGPT tip, I didn't know about that resource.

 

[jmeuse2]

Have a look at this, it's not perfect:

[B4X] [XUI] AS AudioVisualizer

This view is an audio visualizer that converts decibel values into simulated FFT data and renders one of three styles (spectrum, waveform, or filled wave) on a canvas. It features noise filtering, Gaussian normalization. The sample project works in B4A and B4I. You need this libs. xFFT...

www.b4x.com

Thanks, I downloaded that one, it gave me a lot of trouble but I'm going to go at it again. What Java version do I need?

 

[emexes]

Thanks for the ChatGPT tip, I didn't know about that resource.

Grok is a ripper too. Although ChatGPT might well be better, given its inside link to GitHub.

If you start a request with "I am writing an Android app using B4A dialect of BASIC programming language" then it does a pretty good job of producing runnable code.

 

[Alexander Stolte]

What Java version do I need?

I use jdk-14.0.1