TechNet Wiki v2

How to change the speed at which you play your wavefile

I have seen this question posted multiple times in the forums and figured I would share here as well.

Please note that this is not perfect, not all wave files can be modified without first modifying other fileformatsubchunk fields.

Create a brand new Visual Basic Winforms project
Replace ALL of Form1's code with the following code:

'Option Strict Is Always Recommended

Option Strict On

Imports System.Text

Public Class


Form1

'Add one button to your form(make sure that the handles clause is still at the end of your
 sub afterwards)=Handles Button1.Click

Private Sub


Button1_Click(

ByVal


sender

As


System.

Object

ByVal

As


System.EventArgs)

Handles Button1.Click

'Create a new instance of the wavefile class(provided in the technet article)

Dim WaveFile As New


Wave

'Create a new openfiledialog

Dim OFD As New


OpenFileDialog

'Set the filter for the openfiledialog

OFD.Filter =

"Wave Files|*.wav"

'make it select single files only

OFD.Multiselect =

False

'Show the dialog

If OFD.ShowDialog = DialogResult.OK Then

'If the user didn't cancel then load the wavefile into its wrapper

WaveFile.LoadFromFile(OFD.FileName)

'Modify the sample rate(not all speeds are compatible without adjusting other properties)

WaveFile.FileFormatSubChunk.SampleRate = Wave.WavSampleRate.hz22050

'Create a new memory stream from the bytes of the wavefile

Dim Stream As New


IO.MemoryStream(WaveFile.GetBytes)

'Play the wavefile

My.Computer.Audio.Play(Stream, AudioPlayMode.Background)

End If

End Sub

End Class

Add a new class to your project
Replace all of that Class's code with the following code:

Option Strict On

Imports System.Text

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/

    'The File's Header

    Public FileHeader As Header

    'Wave File's Format Sub Chunk

    Public FileFormatSubChunk As FormatSubChunk

    'Data Subchunk

    Public FileDataSubChunk As DataSubChunk

    'This structure is an optional parameter for creating a new wave file

    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()

  &nb>As FormatSize

        Public NumberOfSamples As UInt32

        Public Data As End Structure
    'These are the various structures in the wave file and their description     '                                               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. p;   Contains the letters "fmt "(0x666d7420 big-endian form).         Public Property Subchunk1Size As UInt32 '    Dword           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 LoadFromFile(ByVal FileName As String)         If Not My.Computer.FileSystem.FileExists(FileName) Then Exit Sub         Dim FileBytes() As Byte = My.Computer.FileSystem.ReadAllBytes(FileName)         Try              Sub         Dim FileBytes() As Byte = My.Computer.FileSystem.ReadAllBytes(FileName)         Try             Me.FileHeader.ChunkID = GetDataFromByteArray(FileBytes, 0, 0, 4)             Me.FileHeader.ChunkSize = BitConverter.ToUInt32(FileBytes, 4)             Me.FileHeader.Format = GetDataFromByteArray(FileBytes, 0, 8, 4)             Me.FileFormatSubChunk.Subchunk1ID = GetDataFromByteArray(FileBytes, 0, 12, 4)             Me.FileFormatSubChunk.Subchunk1Size = BitConverter.ToUInt32(FileBytes, 16)             Me.FileFormatSubChunk.AudioFormat = BitConverter.ToUInt16(FileBytes, 20)             Me.FileFormatSubChunk.NumChannels = BitConverter.ToUInt16(FileBytes, 22)             Me.FileFormatSubChunk.SampleRate = BitConverter.ToUInt32(FileBytes, 24)             Me.FileFormatSubChunk.ByteRate = BitConverter.ToUInt32(FileBytes, 28)             Me.FileFormatSubChunk.BlockAlign = BitConverter.ToUInt16(FileBytes, 32)             Me.FileFormatSubChunk.BitsPerSample = BitConverter.ToUInt16(FileBytes, 34)             Me.FileDataSubChunk.Subchunk2ID = GetDataFromByteArray(FileBytes, 0, 36, 4)             Me.FileDataSubChunk.Subchunk2Size = BitConverter.ToUInt32(FileBytes, 40)             Me.FileDataSubChunk.Data = GetDataFromByteArray(FileBytes, 0, 44, Me.FileDataSubChunk.Subchunk2Size)         Catch             Throw New Exception("File Is Invalid or corrupt!")         End Try     End             Throw New Exception("File Is Invalid or corrupt!")         EndSub     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(ByVal Array1() As Byte, ByVal 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 ="color:#000000;"> DataLengthAs Long) As Byte()

        On Error Resume Next

       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     count = count + 1             Answer(count) = bt         Next         Return End Function     Sub New(Optional ByVal Options As WaveFileOptions = Nothing)         Try             FileHeader.ChunkID = Encoding.ASCII.GetBytes("RIFF")             FileFormatSubChunk.Subchunk1Size = Options.FormatSize             FileFormatSubChunk.NumChannels = Options.NumberOfChannels             FileFormatSubChunk.BitsPerSample = Options.BitsPerSample             FileDataSubChunk.Subchunk2Size = CUInt(Options.NumberOfSamples * Options.NumberOfChannels * Options.BitsPerSample / 8)             FileHeader.ChunkSize = CUInt(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 = CUInt(Options.SampleRate * Options.NumberOfChannels * Options.BitsPerSample / 8)             FileFormatSubChunk.BlockAlign = CUShort(Options.NumberOfChannels * Options.BitsPerSample / 8)             FileDataSubChunk.Subchunk2ID = Encoding.ASCII.GetBytes("data")             FileDataSubChunk.Data = Options.Data         Catch ex As Exception         End Try     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 Format As UInt16     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


References

https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
MSDN Forums - http://social.msdn.microsoft.com/Forums/en-US/categories

I hope you find this helpful




Please check out my other Technet Wiki articles!

Changing the speed of a wave file In Visual Basic.Net - TechNet Articles - United States (English) - TechNet Wiki

How to change the speed at which you play your wavefile

References