System.NullReferenceException was unhandled trying to read RIFF file header using FileGetObject()

Question

    Structure RIFFHeader
        <VBFixedString(4)> Public RIFFtag As String ' "RIFF"
        Public Filesize As Long
        <VBFixedString(4)> Public WAVtag As String  ' "WAVE"
        <VBFixedString(4)> Public FMTtag As String  ' "fmt "
        Public FMTsize As Long
        Public CompressType As Integer
        Public Channels As Integer
        Public SampleRate As Long                   ' Samples per sec
        Public BytesPerSecond As Long               ' = SampleRate * BytesPerSample
        Public BytesPerSample As Integer
        Public BitsPerSample As Integer
    End Structure

In a function to read the RIFF header...

   Dim WaveHeader As New RIFFHeader

   FileOpen(1, WaveFile, OpenMode.Binary)

   FileGetObject(1, WaveHeader)

I'm getting an error

System.NullReferenceException was unhandled
  Message=Object reference not set to an instance of an object.
  Source=Microsoft.VisualBasic
  StackTrace:
       at Microsoft.VisualBasic.FileSystem.FileGetObject(Int32 FileNumber, Object& Value, Int64 RecordNumber)
       at Time.Radio.OnTheAir.WavLength(String WaveFile) in C:\Users\jhart\Personal\Time.Radio\Time.Radio\OnTheAir.vb:line 96
       at Time.Radio.OnTheAir.Ticker_Tick(Object sender, EventArgs e) in C:\Users\jhart\Personal\Time.Radio\Time.Radio\OnTheAir.vb:line 45
       at System.Windows.Forms.Timer.OnTick(EventArgs e)
       at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at Time.Radio.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

I don't know how to fix this.

Answer 1

Please try the openfile method in my class I wrote, you can then access the individual structures of the wave file.

Public Class Wave
    'By Paul Ishak
    'WAVE PCM soundfile format 
    'The Canonical WAVE file format
    'As Described Here: https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
    Public FileHeader As Header
    Public FileFormatSubChunk As FormatSubChunk
    Public FileDataSubChunk As DataSubChunk
    Const _Byte As Integer = 1
    Const _word As Integer = 2
    Const _dword As Integer = 4
    Const _qword As Integer = 8
    Public Structure WaveFileOptions
        Public SampleRate As WavSampleRate
        Public AudioFormat As Format
        Public BitsPerSample As BitsPerSample
        Public NumberOfChannels As NumberOfChannels
        Public FormatSize As FormatSize
        Public NumberOfSamples As UInt32
        Public Data As Byte()
    End Structure
    '                                               DATATYPE          OFFSET        Endian           Description
    Structure Header
        Public Property ChunkID As Byte() '          Dword              0             Big            Contains the letters "RIFF" in ASCII form(0x52494646 big-endian form).
        Public Property ChunkSize As UInt32 '        Dword              4             Little         36 + SubChunk2Size, or more precisely: 4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
        Public Property Format As Byte() '           Dword              8             Big            Contains the letters "WAVE" in ASCII form (0x57415645 big-endian form).
    End Structure
    Structure FormatSubChunk
        Public Property Subchunk1ID As Byte() '      Dword              12            Big            Contains the letters "fmt "(0x666d7420 big-endian form).
        Public Property Subchunk1Size As UInt32 '    Dword              16            little         16 for PCM.  This is the size of the rest of the Subchunk which follows this number.
        Public Property AudioFormat As UInt16  '     Word               20            little         PCM = 1 (i.e. Linear quantization)Values other than 1 indicate some form of compression.
        Public Property NumChannels As UInt16 '      Word               22            little         Mono = 1, Stereo = 2, etc.
        Public Property SampleRate As UInt32 '       Dword              24            little         8000, 44100, etc.
        Public Property ByteRate As UInt32 '         Dword              28            little         == SampleRate * NumChannels * BitsPerSample/8
        Public Property BlockAlign As UInt16 '       Word               32            little         == NumChannels * BitsPerSample/8
        Public Property BitsPerSample As UInt16 '    Word               34            little         8 bits = 8, 16 bits = 16, etc.
    End Structure
    Structure DataSubChunk
        Public Property Subchunk2ID As Byte() '      Dword              36            Big            Contains the letters "data"(0x64617461 big-endian form).
        Public Property Subchunk2Size As UInt32 '    Dword              40            little         == NumSamples * NumChannels * BitsPerSample/8     This is the number of bytes in the data.
        Public Property Data As Byte() '             VariableLength     44            little         The actual sound data.
    End Structure
    Public Sub OpenFile(FileName As String)
        Try
            If Not InStr(LCase(FileName), ".wav") Then Throw New Exception("Invalid File Extension Specified!")
            If Not My.Computer.FileSystem.FileExists(FileName) Then Throw New Exception("File Does Not Exist!")
            Dim FileBytes() As Byte = My.Computer.FileSystem.ReadAllBytes(FileName)
            'Get Header
            Me.FileHeader.ChunkID = GetDataFromByteArray(FileBytes, 0, 0, _dword)
            Me.FileHeader.ChunkSize = BitConverter.ToInt32(GetDataFromByteArray(FileBytes, 0, 4, _dword), 0)
            Me.FileHeader.Format = GetDataFromByteArray(FileBytes, 0, 8, _dword)
            'Get FormatSubChunk
            Me.FileFormatSubChunk.Subchunk1ID = GetDataFromByteArray(FileBytes, 0, 12, _dword)
            Me.FileFormatSubChunk.Subchunk1Size = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 16, _dword), 0)
            Me.FileFormatSubChunk.AudioFormat = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 20, _word), 0)
            Me.FileFormatSubChunk.NumChannels = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 22, _word), 0)
            Me.FileFormatSubChunk.SampleRate = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 24, _dword), 0)
            Me.FileFormatSubChunk.ByteRate = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 28, _dword), 0)
            Me.FileFormatSubChunk.BlockAlign = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 32, _word), 0)
            Me.FileFormatSubChunk.BitsPerSample = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 34, _word), 0)
            'Get DataSubChunck
            Me.FileDataSubChunk.Subchunk2ID = GetDataFromByteArray(FileBytes, 0, 36, _dword)
            Me.FileDataSubChunk.Subchunk2Size = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 40, _dword), 0)
            Me.FileDataSubChunk.Data = GetDataFromByteArray(FileBytes, 0, 44, Me.FileDataSubChunk.Subchunk2Size)
        Catch
            Throw New Exception("File Is Invalid or corrupt!")
        End Try
    End Sub
    Public Sub SetDirectBytes(FileBytes() As Byte)
        Try
            'Get Header
            Me.FileHeader.ChunkID = GetDataFromByteArray(FileBytes, 0, 0, _dword)
            Me.FileHeader.ChunkSize = BitConverter.ToInt32(GetDataFromByteArray(FileBytes, 0, 4, _dword), 0)
            Me.FileHeader.Format = GetDataFromByteArray(FileBytes, 0, 8, _dword)
            'Get FormatSubChunk
            Me.FileFormatSubChunk.Subchunk1ID = GetDataFromByteArray(FileBytes, 0, 12, _dword)
            Me.FileFormatSubChunk.Subchunk1Size = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 16, _dword), 0)
            Me.FileFormatSubChunk.AudioFormat = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 20, _word), 0)
            Me.FileFormatSubChunk.NumChannels = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 22, _word), 0)
            Me.FileFormatSubChunk.SampleRate = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 24, _dword), 0)
            Me.FileFormatSubChunk.ByteRate = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 28, _dword), 0)
            Me.FileFormatSubChunk.BlockAlign = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 32, _word), 0)
            Me.FileFormatSubChunk.BitsPerSample = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 34, _word), 0)
            'Get DataSubChunck
            Me.FileDataSubChunk.Subchunk2ID = GetDataFromByteArray(FileBytes, 0, 36, _dword)
            Me.FileDataSubChunk.Subchunk2Size = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 40, _dword), 0)
            Me.FileDataSubChunk.Data = GetDataFromByteArray(FileBytes, 0, 44, Me.FileDataSubChunk.Subchunk2Size)
        Catch ex As Exception
            ' Throw New Exception("File Is Invalid or corrupt!")
            MsgBox(ex.StackTrace)
        End Try
    End Sub
 
    Public Function GetBytes() As Byte()
        Dim Results As Byte() = Nothing
        Results = CombineArrays(FileHeader.ChunkID, BitConverter.GetBytes(FileHeader.ChunkSize))
        Results = CombineArrays(Results, FileHeader.Format)
        Results = CombineArrays(Results, FileFormatSubChunk.Subchunk1ID)
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.Subchunk1Size))
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.AudioFormat))
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.NumChannels))
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.SampleRate))
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.ByteRate))
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.BlockAlign))
        Results = CombineArrays(Results, BitConverter.GetBytes(FileFormatSubChunk.BitsPerSample))
        Results = CombineArrays(Results, FileDataSubChunk.Subchunk2ID)
        Results = CombineArrays(Results, BitConverter.GetBytes(FileDataSubChunk.Subchunk2Size))
        Results = CombineArrays(Results, FileDataSubChunk.Data)
        Return Results
    End Function
    Function CombineArrays(Array1() As Byte, Array2() As Byte) As Byte()
        Dim AllResults(Array1.Length + Array2.Length - 1) As Byte
        Array1.CopyTo(AllResults, 0)
        Array2.CopyTo(AllResults, Array1.Length)
        Return AllResults
    End Function
    Private Function GetDataFromByteArray(ByVal ByteArray As Byte(), ByVal BlockOffset As Long, ByVal RangeStartOffset As Long, ByVal DataLength As Long) As Byte()
        On Error Resume Next
        Dim AnswerL As New List(Of Byte)
        Dim Answer(0 To CInt((DataLength - 1))) As Byte
        Dim CurrentOffset As Long
        For I = 0 To UBound(ByteArray)
            CurrentOffset = BlockOffset + I
            If CurrentOffset >= RangeStartOffset Then
                If CurrentOffset <= RangeStartOffset + DataLength Then
                    AnswerL.Add(ByteArray(I))
                End If
            End If
        Next
        Dim count As Integer = -1
        For Each bt As Byte In AnswerL
            count = count + 1
            Answer(count) = bt
        Next
        Return Answer
    End Function
    Public Function ViewBinary(Optional HexOffsets As Boolean = True) As String
        Dim asc As New StringBuilder
        Dim Hex As New StringBuilder
        Dim result As New StringBuilder
        Dim MB As Byte() = Me.GetBytes
        Select Case HexOffsets
            Case True
                result.Append(" OFFSET " & "    " & "00  01  02  03  04  05  06  07  08  09  0A  0B  0C  0D  0E  0F  " & "    " & "0123456789ABCDEF" & vbCrLf & vbCrLf)
            Case False
                result.Append(" OFFSET " & "    " & "00  01  02  03  04  05  06  07  08  09  10  11  12  13  14  15  " & "    " & "0123456789012345" & vbCrLf & vbCrLf)
        End Select
        Dim Count As Integer = -16
        For Each B As Byte In MB
            Count = Count + 1
            Hex.Append(B.ToString("X2") & "  ")
            If B > 32 And B < 128 Then
                asc.Append(Chr(B))
            Else
                asc.Append(".")
            End If
            If Count Mod 16 = 0 Then
                Select Case HexOffsets
                    Case True
                        result.Append(Count.ToString("X").PadLeft(8, "0") & "    " & Hex.ToString & "    " & asc.ToString & vbCrLf)
                    Case False
                        result.Append(Count.ToString.PadLeft(8, "0") & "    " & Hex.ToString & "    " & asc.ToString & vbCrLf)
                End Select
                Hex.Remove(0, Hex.ToString.Length)
                asc.Remove(0, asc.ToString.Length)
            End If
        Next
        Dim Counts As String = String.Empty
        Select Case HexOffsets
            Case True
                Counts = (Count + (16 - (Count Mod 16))).ToString("X").PadLeft(8, "0").ToString
            Case False
                Counts = (Count + (16 - (Count Mod 16))).ToString.PadLeft(8, "0").ToString
        End Select
        Dim H As Integer = 64 - Hex.ToString.Length
        Dim FinalHex As String = Hex.ToString & Space(H)
        result.Append(Counts & "    " & FinalHex & "    " & asc.ToString & vbCrLf)
        Return result.ToString
    End Function
    Public Shared Function SelectWavData(PictureBox As PictureBox, SelectionColor As Color, Origin As Integer, TextColor As Color, Optional SetLocal As Integer = -1) As SelectedData
        Dim LocalMousePosition As Point = PictureBox.PointToClient(Cursor.Position)
        Dim BM As New Bitmap(PictureBox.Size.Width, PictureBox.Size.Height)
        Dim gr As Graphics = Graphics.FromImage(BM)
        Dim Pen As New Pen(Brushes.Green, 1)
        If SetLocal > -1 Then
            LocalMousePosition.X = SetLocal
        End If
        If LocalMousePosition.X > PictureBox.ClientRectangle.Width Then
            LocalMousePosition.X = PictureBox.ClientRectangle.Width
        End If
        If LocalMousePosition.X < 0 Then
            LocalMousePosition.X = 0
        End If
        Dim Line1point1 As New Point(LocalMousePosition.X, 0)
        Dim Line1point2 As New Point(LocalMousePosition.X, PictureBox.ClientRectangle.Height)
        Dim Line2point1 As New Point(Origin, 0)
        Dim Line2point2 As New Point(Origin, PictureBox.ClientRectangle.Height)
        Dim Poly(3) As Point
        Poly(0) = Line1point1
        Poly(1) = Line2point1
        Poly(2) = Line2point2
        Poly(3) = Line1point2
        If Origin = LocalMousePosition.X = False Then
            gr.FillPolygon(New SolidBrush(SelectionColor), Poly)
            '  gr.DrawPolygon(New Pen(Brushes.Yellow, 2), Poly)
        End If
        PictureBox.Image = BM
        Select Case LocalMousePosition.X > Origin
            Case True
                gr.DrawString("Selected Range(" & Origin & "-" & LocalMousePosition.X & ")", New Font("Consolas", 8), New SolidBrush(TextColor), 1, 1)
                Return New SelectedData(Origin, LocalMousePosition.X)
            Case Else
                gr.DrawString("Selected Range(" & LocalMousePosition.X & "-" & Origin & ")", New Font("Consolas", 8), New SolidBrush(TextColor), 1, 1)
                Return New SelectedData(LocalMousePosition.X, Origin)
        End Select
    End Function
    Public Shared Sub DrawWave(PictureBox As PictureBox, GridSize As Integer, CurrentWaveFile As Wave, GridColor As Color, SineColor As Color)
        Dim Bytes As Byte() = CurrentWaveFile.FileDataSubChunk.Data
        Dim Data(0 To UBound(Bytes)) As UInt16
        Dim Count As Integer = -1
        For Each b As Byte In Bytes
            Count = Count + 1
            Data(Count) = CType(b, UInt16)
        Next
 
        Dim InvertedData(0 To UBound(Bytes)) As UInt32
        For I = 0 To UBound(Data)
            InvertedData(I) = ((255 - Data(I)) \ 2) + ((PictureBox.Height - (255 \ 2)) \ 2)
        Next
        Dim Points As New List(Of Point)
        For I = 0 To UBound(InvertedData)
            Dim Point As New Point(InvertedData(I), I + 1)
            Points.Add(Point)
        Next
        Dim PointsArr() As Point = Points.ToArray
        Dim BM As New Bitmap(PictureBox.Height, PictureBox.Width)
        Dim gr As Graphics = Graphics.FromImage(BM)
        Dim Pen As New Pen(SineColor, 1)
        Dim pen2 As New Pen(Brushes.Red, 3)
        Dim pen3 As New Pen(GridColor, 1)
        For I = 1 To PictureBox.Width Step GridSize
            gr.DrawLine(pen3, New Point(0, I), New Point(PictureBox.Height, I))
            gr.DrawLine(pen3, New Point(I, 0), New Point(I, PictureBox.Width))
        Next
        gr.DrawLines(Pen, PointsArr)
        gr.DrawLine(pen2, New Point(0, PictureBox.ClientRectangle.Width / 2), New Point(PictureBox.Height, PictureBox.ClientRectangle.Width / 2))
        gr.DrawLine(pen3, New Point(0, PictureBox.ClientRectangle.Width / 2), New Point(PictureBox.Height, PictureBox.ClientRectangle.Width / 2))
        BM.RotateFlip(RotateFlipType.Rotate270FlipNone)
        PictureBox.BackgroundImage = BM
    End Sub
    Public Structure SelectedData
        Public SelectionStart As Integer
        Public SelectionEnd As Integer
        Sub New(SelectionStart As Integer, SelectionEnd As Integer)
            Me.SelectionStart = SelectionStart
            Me.SelectionEnd = SelectionEnd
        End Sub
    End Structure
    Sub New(Options As WaveFileOptions)
        FileHeader.ChunkID = Encoding.ASCII.GetBytes("RIFF")
        FileFormatSubChunk.Subchunk1Size = Options.FormatSize
        FileFormatSubChunk.NumChannels = Options.NumberOfChannels
        FileFormatSubChunk.BitsPerSample = Options.BitsPerSample
        FileDataSubChunk.Subchunk2Size = Options.NumberOfSamples * Options.NumberOfChannels * Options.BitsPerSample / 8
        FileHeader.ChunkSize = 4 + (8 + FileFormatSubChunk.Subchunk1Size) + (8 + FileDataSubChunk.Subchunk2Size)
        FileHeader.Format = Encoding.ASCII.GetBytes("WAVE")
        FileFormatSubChunk.Subchunk1ID = Encoding.ASCII.GetBytes("fmt ")
        FileFormatSubChunk.AudioFormat = Options.AudioFormat
        FileFormatSubChunk.SampleRate = Options.SampleRate
        FileFormatSubChunk.ByteRate = Options.SampleRate * Options.NumberOfChannels * Options.BitsPerSample / 8
        FileFormatSubChunk.BlockAlign = Options.NumberOfChannels * Options.BitsPerSample / 8
        FileDataSubChunk.Subchunk2ID = Encoding.ASCII.GetBytes("data")
        FileDataSubChunk.Data = Options.Data
    End Sub
    Public Enum WavSampleRate As UInt32
        hz8000 = 8000
        hz11025 = 11025
        hz16000 = 16000
        hz22050 = 22050
        hz32000 = 32000
        hz44100 = 44100
        hz48000 = 48000
        hz96000 = 96000
        hz192000 = 192000
    End Enum
    Public Enum Format As UInt16
        Standard = 1
    End Enum
    Public Enum BitsPerSample As UInt16
        bps_8 = 8
        bps_16 = 16
        bps_32 = 32
        bps_64 = 64
        bps_128 = 128
        bps_256 = 256
    End Enum
    Public Enum NumberOfChannels As UInt16
        Mono = 1
        Stereo = 2
    End Enum
    Public Enum FormatSize As UInt32
        PCM = 16
    End Enum
End Class

---

If you want something you've never had, you need to do something you've never done.

Answer 2

I don't want to read the entire file, I'm just trying to determine the playing length - as follows.

WavLength = WaveHeader.Filesize \ WaveHeader.BytesPerSecond ' length in seconds

---

Responsibilities first...

Answer 3

I don't want to read the entire file, I'm just trying to determine the playing length - as follows.

WavLength = WaveHeader.Filesize \ WaveHeader.BytesPerSecond ' length in seconds

---

Responsibilities first...

If you use the open file method in my class, you can then access any element of the riff wave header. You can look and see how I am populating that field if you somehow think loading the file will consume too many resources. But the fields you are looking for are populated(individually) when you load my class.

---

If you want something you've never had, you need to do something you've never done.

Answer 4

The code you offered worked... got me past my problem (thanks)

 WavLength = Me.FileDataSubChunk.Subchunk2Size / Me.FileFormatSubChunk.ByteRate ' length in seconds

Yields the length of the audio in seconds

---

Responsibilities first...

Answer 5

The strange thing is that when I used the FileGet() method instead - the NullReferenceException went away and I was able to pull something (admittedly garbage) from the file... Why was FileGetObject upset with me?...

---

Responsibilities first...

Answer 6

Cut down copy of your code for anyone who might follow in my footsteps

Declarations:

    Const _Byte As Integer = 1
    Const _word As Integer = 2
    Const _dword As Integer = 4
    Const _qword As Integer = 8

    Public Enum WavSampleRate As UInt32
        hz8000 = 8000
        hz11025 = 11025
        hz16000 = 16000
        hz22050 = 22050
        hz32000 = 32000
        hz44100 = 44100
        hz48000 = 48000
        hz96000 = 96000
        hz192000 = 192000
    End Enum

    Public Enum Format As UInt16
        Standard = 1
    End Enum

    Public Enum BitsPerSample As UInt16
        bps_8 = 8
        bps_16 = 16
        bps_32 = 32
        bps_64 = 64
        bps_128 = 128
        bps_256 = 256
    End Enum

    Public Enum NumberOfChannels As UInt16
        Mono = 1
        Stereo = 2
    End Enum

    Public Enum FormatSize As UInt32
        PCM = 16
    End Enum

    Public Structure WaveFileOptions
        Public SampleRate As WavSampleRate
        Public AudioFormat As Format
        Public BitsPerSample As BitsPerSample
        Public NumberOfChannels As NumberOfChannels
        Public FormatSize As FormatSize
        Public NumberOfSamples As UInt32
        Public Data As Byte()
    End Structure
    '                                               DATATYPE          OFFSET        Endian           Description
    Public Structure Header
        Public Property ChunkID As Byte() '          Dword              0             Big            Contains the letters "RIFF" in ASCII form(0x52494646 big-endian form).
        Public Property ChunkSize As UInt32 '        Dword              4             Little         36 + SubChunk2Size, or more precisely: 4 + (8 + SubChunk1Size) + (8 + SubChunk2Size)
        Public Property Format As Byte() '           Dword              8             Big            Contains the letters "WAVE" in ASCII form (0x57415645 big-endian form).
    End Structure

    Public Structure FormatSubChunk
        Public Property Subchunk1ID As Byte() '      Dword              12            Big            Contains the letters "fmt "(0x666d7420 big-endian form).
        Public Property Subchunk1Size As UInt32 '    Dword              16            little         16 for PCM.  This is the size of the rest of the Subchunk which follows this number.
        Public Property AudioFormat As UInt16  '     Word               20            little         PCM = 1 (i.e. Linear quantization)Values other than 1 indicate some form of compression.
        Public Property NumChannels As UInt16 '      Word               22            little         Mono = 1, Stereo = 2, etc.
        Public Property SampleRate As UInt32 '       Dword              24            little         8000, 44100, etc.
        Public Property ByteRate As UInt32 '         Dword              28            little         == SampleRate * NumChannels * BitsPerSample/8
        Public Property BlockAlign As UInt16 '       Word               32            little         == NumChannels * BitsPerSample/8
        Public Property BitsPerSample As UInt16 '    Word               34            little         8 bits = 8, 16 bits = 16, etc.
    End Structure

    Public Structure DataSubChunk
        Public Property Subchunk2ID As Byte() '      Dword              36            Big            Contains the letters "data"(0x64617461 big-endian form).
        Public Property Subchunk2Size As UInt32 '    Dword              40            little         == NumSamples * NumChannels * BitsPerSample/8     This is the number of bytes in the data.
        Public Property Data As Byte() '             VariableLength     44            little         The actual sound data.
    End Structure

    Public FileHeader As Header
    Public FileFormatSubChunk As FormatSubChunk
    Public FileDataSubChunk As DataSubChunk

Logic:

Public Sub OpenFile(FileName As String)
        Try
            If Not My.Computer.FileSystem.FileExists(FileName) Then
                Throw New Exception("File Does Not Exist!")
            End If

            Dim FileBytes() As Byte = My.Computer.FileSystem.ReadAllBytes(FileName)

            'Get Header

            Me.FileHeader.ChunkID = GetDataFromByteArray(FileBytes, 0, 0, _dword)
            Me.FileHeader.ChunkSize = BitConverter.ToInt32(GetDataFromByteArray(FileBytes, 0, 4, _dword), 0)
            Me.FileHeader.Format = GetDataFromByteArray(FileBytes, 0, 8, _dword)

            'Get FormatSubChunk

            Me.FileFormatSubChunk.Subchunk1ID = GetDataFromByteArray(FileBytes, 0, 12, _dword)
            Me.FileFormatSubChunk.Subchunk1Size = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 16, _dword), 0)
            Me.FileFormatSubChunk.AudioFormat = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 20, _word), 0)
            Me.FileFormatSubChunk.NumChannels = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 22, _word), 0)
            Me.FileFormatSubChunk.SampleRate = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 24, _dword), 0)
            Me.FileFormatSubChunk.ByteRate = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 28, _dword), 0)
            Me.FileFormatSubChunk.BlockAlign = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 32, _word), 0)
            Me.FileFormatSubChunk.BitsPerSample = BitConverter.ToUInt16(GetDataFromByteArray(FileBytes, 0, 34, _word), 0)

            'Get DataSubChunck

            Me.FileDataSubChunk.Subchunk2ID = GetDataFromByteArray(FileBytes, 0, 36, _dword)
            Me.FileDataSubChunk.Subchunk2Size = BitConverter.ToUInt32(GetDataFromByteArray(FileBytes, 0, 40, _dword), 0)
            Me.FileDataSubChunk.Data = GetDataFromByteArray(FileBytes, 0, 44, Me.FileDataSubChunk.Subchunk2Size)
        Catch
            Throw New Exception("File Is Invalid or corrupt!")
        End Try
    End Sub

    Private Function GetDataFromByteArray(ByVal ByteArray As Byte(), ByVal BlockOffset As Long, ByVal RangeStartOffset As Long, ByVal DataLength As Long) As Byte()
        On Error Resume Next

        Dim AnswerL As New List(Of Byte)
        Dim Answer(0 To CInt((DataLength - 1))) As Byte

        Dim CurrentOffset As Long

        For I = 0 To UBound(ByteArray)
            CurrentOffset = BlockOffset + I

            If CurrentOffset >= RangeStartOffset And CurrentOffset <= RangeStartOffset + DataLength Then
                AnswerL.Add(ByteArray(I))
            End If
        Next

        Dim Count As Integer = 0

        For Each bt As Byte In AnswerL
            Answer(Count) = bt
            Count += 1
        Next

        GetDataFromByteArray = Answer
    End Function

The length of the sound file in seconds:

    Function WavLength(ByVal WaveFile As String) As Long
        OpenFile(WaveFile)

        WavLength = Me.FileDataSubChunk.Subchunk2Size / Me.FileFormatSubChunk.ByteRate ' length in seconds
    End Function

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Responsibilities first...

Answer 7

The strange thing is that when I used the FileGet() method instead - the NullReferenceException went away and I was able to pull something (admittedly garbage) from the file... Why was FileGetObject upset with me?...

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Responsibilities first...

Actually, check this out - Maybe you can retrace your steps?

http://msdn.microsoft.com/en-us/library/y1swwyc4%28v=vs.90%29.aspx

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If you want something you've never had, you need to do something you've never done.

Answer 8

I'm not sure that cutting down my original answer constitutes a unique and different answer. Either way glad my answer solved your poblem.

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If you want something you've never had, you need to do something you've never done.