IWMEncAudioSource.PreProcessPass
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The PreProcessPass property specifies and retrieves the preprocess pass count.
Syntax
IWMEncAudioSource.PreProcessPass = Integer
Integer = IWMEncAudioSource.PreProcessPass
Parameters
This property takes no parameters.
Property Value
An Integer that indicates the number of passes to make (0 or 1) for preprocessing.
Remarks
During one-pass encoding (where the PreProcessPass property is 0), audio content is analyzed and compressed at the same time.
During two-pass encoding (where the PreProcessPass property is 1), audio content is analyzed in the first pass, and then the best combinations of bit rate, frame rate, buffer size, and image quality are applied during the second pass. Two-pass encoding produces a better-quality result but the process takes longer. To use two-pass encoding, the input cannot be a live source and the output cannot be a broadcast.
Example Code
' Create a WMEncoder object.
Dim Encoder As WMEncoder
Set Encoder = New WMEncoder
' Create a source group.
Dim SrcGrpColl As IWMEncSourceGroupCollection
Dim SrcGrp As IWMEncSourceGroup
Set SrcGrpColl = Encoder.SourceGroupCollection
Set SrcGrp = SrcGrpColl.Add("SG_1")
' Add an audio source to the source group and specify an input file.
Dim SrcAud As IWMEncAudioSource
Set SrcAud = SrcGrp.AddSource(WMENC_AUDIO)
SrcAud.SetInput "C:\InputFile.avi" ' REPLACE THIS.
' Use two-pass encoding.
SrcAud.PreProcessPass = 1
Requirements
Reference: Windows Media Encoder
Library: wmenc.exe
See Also
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