Code Review Vol. 3 - Encode and DRM Audio and Video Content With Windows Media Encoder SDK and VB.Net

Here is a snippet of code I wrote several years ago to encode and DRM content to WMV format. Back when I worked at Music Choice one of my initial tasks was to come up with a DRM solution for all videos on the web. My initial solution was clunky, basically following Microsoft's sample code - what little there actually was for the subject. But over time I revisited the solution and came up with a more elegant solution. Essentially I encapsulated the transcoding and DRMing of raw content to WMVs to a single console application. I exported a DRM profile from our DRM servers and used that to generate the DRM envelope. The console application was included in the automated work flow when new content was distributed to our clients.

Imports WMEncoderLib
Imports System.Windows.Forms
Imports System.IO


Module Module1
    Dim WithEvents Encoder As WMEncoder
    Dim glbQuitBool As Boolean = False
    Dim baseURL As String
    Dim DRMProfilePass As String = "XXX"
    Dim DRMProfile As String = "ExportProfile.drm"


    Sub Main()
       Init()
       SearchDir(baseURL)
    End Sub

    Sub Init()
      Dim sr As StreamReader = New StreamReader("baseLoc.ini")
      Dim line As String
      line = sr.ReadLine()
      sr.Close()
      baseURL = line
    End Sub

    Function DoEncode(ByVal sourceFile As String, ByVal outputFile As String, ByVal thisProfile As WMEncProfile2, ByVal fileType As String) As Boolean
 Try
     Encoder = New WMEncoder
     Dim SrcGrpColl As IWMEncSourceGroupCollection = Encoder.SourceGroupCollection
     Dim SrcGrp As IWMEncSourceGroup = SrcGrpColl.Add("SG_1")
     Dim newFile As IWMEncFile = Encoder.File

     If fileType = "video" Then
      Dim vidFile As IWMEncVideoSource = SrcGrp.AddSource(2)
      vidFile.SetInput(sourceFile)
     End If


     Dim audFile As IWMEncAudioSource = SrcGrp.AddSource(1)

     Dim DRM As IWMDRMContentAuthor
     Dim DRMProColl As IWMDRMProfileCollection
     Dim tempDRMPro As IWMDRMProfile

     DRM = Encoder.EncoderDRMContentAuthor

     ' Retrieve the collection of DRM profiles.
     DRMProColl = DRM.DRMProfileCollection

     'First remove any DRM Profiles that may still linger 
     tempDRMPro = DRMProColl.Item(0)
     DRM.RemoveDRMProfile(tempDRMPro.ID)

     ' Import a DRM profile.
     DRM.ImportDRMProfile(DRMProfilePass, DRMProfile)
     
     DRMProColl = DRM.DRMProfileCollection
     Dim DRMPro As IWMDRMProfile
     DRMPro = DRMProColl.Item(0)

     ' Set the current DRM profile into the encoding session.
     Dim vKeyID As Object = "XXXXX"
     DRM.SetSessionDRMProfile(DRMPro.ID, vKeyID)

     Dim newProfile As WMEncProfile2 = New WMEncProfile2
     audFile.SetInput(sourceFile)
     newFile.LocalFileName = outputFile
     newProfile = thisProfile

     ' newProfile.LoadFromFile(thisProfile)
     SrcGrp.Profile = newProfile
     Encoder.AutoStop = True
     Encoder.RemoteAdmin = True
     Encoder.PrepareToEncode(True)
     Encoder.Start()

     Dim x As Integer
     
     'HACK - needs this to actually work, bug in WM SDK
     For x = 0 To 30
       Application.DoEvents()
       x = x + 1
     Next


     While Encoder.RunState = WMENC_ENCODER_STATE.WMENC_ENCODER_RUNNING
       Dim temp = Encoder.RunState
       Dim y As Integer
       For y = 0 To 300
         y = y + 1
       Next
      Application.DoEvents()
     End While

     Encoder.Stop()
     Return True

 Catch ex As Exception
     Console.WriteLine(ex)
     Dim errFile As String = outputFile + ".error"
     File.Create(errFile)
     File.Delete(outputFile)
     Return False
 End Try

 Encoder = Nothing

    End Function



    Function RetrieveProfile(ByVal nFile) As WMEncProfile2
 Try
     Dim BasicEdit As WMEncBasicEdit
     BasicEdit = New WMEncBasicEdit

     ' Specify the input, output, and configuration files.
     BasicEdit.MediaFile = nFile

     ' Retrieve the duration of the input file, in seconds.
     Dim lFileDur As Long
     lFileDur = BasicEdit.Duration / 1000

     ' Retrieve the profile used by the input file.
     Dim Pro As WMEncProfile2
     Pro = BasicEdit.Profile

     Return Pro
 Catch ex As Exception
     Console.WriteLine(ex)
 End Try


    End Function

    Sub SearchDir(ByVal dir)
    'Environment.CurrentDirectory
     Dim di As New DirectoryInfo(dir)
     ' Create an array representing the files in the current directory.
     Dim fi As FileInfo() = di.GetFiles()
     Dim tempFile As FileInfo
     For Each tempFile In fi
       Dim currentProfile As WMEncProfile2
       Dim currentSourceFile As String = baseURL + "\" + tempFile.Name
       Dim currentOutputFile As String = baseURL + "\DRMed\" + tempFile.Name  
       Dim currentFType As String
       Dim currentFTypeArr = Split(tempFile.Name, ".")
       If currentFTypeArr(1) = "wma" Then
          currentFType = "audio"
       ElseIf currentFTypeArr(1) = "wmv" Then
          currentFType = "video"
       End If

       currentProfile = RetrieveProfile(currentSourceFile)
       DoEncode(currentSourceFile, currentOutputFile, currentProfile, currentFType)
     Next tempFile

    End Sub


End Module