[RESOLVED] Concatenate .wav files via byte array

[Españolita]

I want to concatenate two .wav files. The file format for a .wav is bytes 0 to 39 file details, bytes 40 to 43 length of the data chunk, 44 onwards is the data.
The method I have chosen is:
1. load two wavs as byte arrays (byt1 and byt2)
2. copy the header from byt1 and store it
3. copy the data portion of byt1 to another byte array (finalData)
4. copy the data from byt2 and add it to the end if FinalData.
5. Create a final finished byte array representation of the wav (Output)
6. Copy the previously saved header to Output.
7. store the length of FinalData.
8. Add FinalData to the end of Output
9. Convert the previously saved length (int32=4 bytes) to byte array
10. Overwrite bytes 40-43 of Output with the new length
11. Save the final file to disk.

When I run the program, there are no errors until it tries to play the file, then it says the header is corrupt. Since both wav files are created in exactly the same way, things like sample rate etc are the same, the only thing that should change is the length and therefore I should have no problem retaining the information in the header. Giving a corrupt header error probably means that the length is wrong but I have checked and checked and can't find a mistake in my maths.
this is my first foray into Byte arrays so I need another pair of more experienced eyes to look over my code please.

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        Dim Byt1() As Byte = IO.File.ReadAllBytes("h.wav")
        Dim Byt2() As Byte = IO.File.ReadAllBytes("e.wav")
        Join(Byt1, Byt2)
        Byt1 = IO.File.ReadAllBytes("temp.wav")
        Byt2 = IO.File.ReadAllBytes("l.wav")
        Join(Byt1, Byt2)
        Byt1 = IO.File.ReadAllBytes("temp.wav")
        Byt2 = IO.File.ReadAllBytes("ow.wav")
        Join(Byt1, Byt2)
        Dim snd As New System.Media.SoundPlayer("temp.wav")
        snd.Play()
    End Sub
 
    Private Sub Join(ByRef byt1() As Byte, byt2() As Byte)
 
        Dim Lgth As Integer
        Dim SaveHeader(43) As Byte
 
        'Save the header
        System.Array.Copy(Byt1, 0, SaveHeader, 0, 43)
        Dim FinalData(byt1.Length - 44) As Byte
 
        'Save the data from the first file
        System.Array.Copy(Byt1, 44, FinalData, 0, Byt1.Length - 44)
 
        'Save the data from the second file
        ReDim Preserve FinalData(byt1.Length + byt2.Length - 44)
        System.Array.Copy(byt2, 44, FinalData, byt1.Length - 44, byt2.Length - 44)
 
        'save length of new data
        Lgth = FinalData.Length
 
        'create array to hold final output
        Dim Output() As Byte
        ReDim Output(FinalData.Length + 43)
 
        'add header
        System.Array.Copy(SaveHeader, Output, 43)
 
        'add data
        System.Array.Copy(FinalData, 0, Output, 44, FinalData.Length)
 
        'adjust data length
        Dim bytes() As Byte = BitConverter.GetBytes(Lgth)
        System.Array.Copy(bytes, 0, Output, 40, 4)
        ByteArrayToFile("temp.wav", Output)
 
    End Sub
 
    ' <summary>
    ' Function to save byte array to a file
    ' </summary>
    ' <param name="_FileName">File name to save byte array</param>
    ' <param name="_ByteArray">Byte array to save to external file</param>
    ' <returns>Return true if byte array save successfully, if not return false</returns>
    Public Sub ByteArrayToFile(ByVal _FileName As String, ByVal _ByteArray() As Byte)
        Try
            'Dim myInt As Int32
            'myint = BitConverter.ToInt32(_ByteArray, 40)
            'MsgBox("Length of file " & BitConverter.ToString(BitConverter.GetBytes(_ByteArray.Length)) & ". Length stored in header " & BitConverter.ToString(BitConverter.GetBytes(myInt)))
            '' Open file for readin
            Dim _FileStream As New System.IO.FileStream(_FileName, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Write)
            ' Writes a block of bytes to this stream using data from a byte array.
            _FileStream.Write(_ByteArray, 0, _ByteArray.Length)
            ' close file stream
            _FileStream.Close()
 
        Catch _Exception As Exception
            ' Error
            Console.WriteLine("Exception caught in process: {0}", _Exception.ToString())
        End Try
        ' error occured, return false
 
    End Sub

[Inferrd]

Hey Españolita,

I think you may have a couple of problems there.

You seem to be doing what I typically do; getting confused over array upper bounds and array lengths. By this I mean that an array with a Length of 44 (44 elements) has an upper bound of 43 (the highest index value you can access). Zero indexing can be a pain in the bum at times.

Also, looking at the .wav format as explained here, I think you may need to alter two length fields in the final file Header (at offsets 4 and 40).

So your join sub should look like:

Private Sub Join(ByRef byt1() As Byte, byt2() As Byte)

    Dim Lgth As Integer
    Dim SaveHeader(43) As Byte

    'Save the header
    System.Array.Copy(byt1, 0, SaveHeader, 0, 44)
    Dim FinalData(byt1.Length - 44 - 1) As Byte 

    'Save the data from the first file
    System.Array.Copy(byt1, 44, FinalData, 0, byt1.Length - 44)

    'Save the data from the second file
    ReDim Preserve FinalData(byt1.Length - 44 + byt2.Length - 44 - 1)
    System.Array.Copy(byt2, 44, FinalData, byt1.Length - 44, byt2.Length - 44)

    'save length of new data
    Lgth = FinalData.Length

    'create array to hold final output
    Dim Output() As Byte
    ReDim Output(FinalData.Length + 44 - 1)

    'add header
    System.Array.Copy(SaveHeader, Output, 44)

    'add data
    System.Array.Copy(FinalData, 0, Output, 44, FinalData.Length)


    Dim bytes() As Byte
    'adjust data length (Subchunk2Size)
    bytes = BitConverter.GetBytes(Lgth)
    System.Array.Copy(bytes, 0, Output, 40, 4)

    'adjust data length (ChunkSize)
    bytes = BitConverter.GetBytes(Lgth + 36)
    System.Array.Copy(bytes, 0, Output, 4, 4)


    ByteArrayToFile("temp.wav", Output)

    End Sub

That said, would you not consider using Lists, (and also avoid writing temporary files)?

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
 
 
    Dim wav1 As List(Of Byte) = IO.File.ReadAllBytes("h.wav").ToList
    Dim wav2 As List(Of Byte) = IO.File.ReadAllBytes("e.wav").ToList
 
    wav1 = Join(wav1, wav2)
    wav1 = Join(wav1, IO.File.ReadAllBytes("l.wav").ToList)
    wav1 = Join(wav1, IO.File.ReadAllBytes("ow.wav").ToList)
 
 
    File.WriteAllBytes("test.wav", wav1.ToArray)
 
    Dim snd As New System.Media.SoundPlayer("test.wav")
    snd.Play()
 
End Sub
 
 
Private Function Join(ByVal wavBytes As List(Of Byte), ByVal wav2 As List(Of Byte)) As List(Of Byte)
 
    '   add on the second file excluding its header bytes
    wavBytes.AddRange(wav2.Skip(44).Take(wav2.Count - 44))
 
 
    '   rewrite the ChunkSize and Subchunk2Size fields of the Header
    Dim chunkSize As Integer = wavBytes.Count - 8
    Dim subChunk2Size As Integer = wavBytes.Count - 44
 
    Dim chunkSizeBytes() As Byte = BitConverter.GetBytes(chunkSize)
    Dim subChunk2SizeBytes() As Byte = BitConverter.GetBytes(subChunk2Size)
    For i = 0 To 3
        wavBytes(4 + i) = chunkSizeBytes(i)
        wavBytes(40 + i) = subChunk2SizeBytes(i)
    Next
 
    Return wavBytes
End Function

You could also avoid saving the combined .wav to file by replacing

File.WriteAllBytes("test.wav", wav1.ToArray)

Dim snd As New System.Media.SoundPlayer("test.wav")
snd.Play()

with

Using ms As New MemoryStream(wav1.ToArray)
    Using snd As New System.Media.SoundPlayer(ms)
        snd.Play()
    End Using
End Using

[Españolita]

What an absolute star!!! Thank you so much. After creating this thread, I saw another which mentioned using lists and it was on my "Upgrade list" after I got the basics of this sorted out. You were absolutely right about confusing UpperBounds and Array Lengths. I'm afraid I simply copied and pasted your code and it works brilliantly. But rest assured, I will analyse the code because that first part (chunks length at index 4) really confuses me.
Also you must be a mindreader, because that last little bit about playing directly from memory was also on my "Upgrade list". This is my first foray into this kind of thing and I found it a bit overwhelming.
I would have given you some more rep but I need to spread it around a bit first

[psiva74]

What an absolute star!!! Thank you so much. After creating this thread, I saw another which mentioned using lists and it was on my "Upgrade list" after I got the basics of this sorted out. You were absolutely right about confusing UpperBounds and Array Lengths. I'm afraid I simply copied and pasted your code and it works brilliantly. But rest assured, I will analyse the code because that first part (chunks length at index 4) really confuses me.
Also you must be a mindreader, because that last little bit about playing directly from memory was also on my "Upgrade list". This is my first foray into this kind of thing and I found it a bit overwhelming.
I would have given you some more rep but I need to spread it around a bit first

I have set of wav files in a folder with different length. I want to join as single file. kindly provide code for this