Integrating pocketsphinx in .Net project

[David Brandon]

I have been reading through the forums and scouring for information to help me
integrate pocketsphinx in a vb.net project but have found very little
information. I have created a wrapper class using interop services to call the
pocketsphinx methods that I need but I am running into numerous issues. Is
there anyone who has been down this road before who I can beg assistance from?
Is there any sample .Net interface code out there that I can look at to get
ideas from?

[David Brandon]

For your amusement, here is the code for my interface class as it currently
stands. My current issue is that it locks up the process with "vshost32.exe
has stopped working" when it gets to the call to ps_start_utt.

Imports System.Runtime.InteropServices
Imports System.Text

Public Class SphinxInterface
    <DllImport("sphinxbase.dll")> _
    Public Shared Function cmd_ln_init(ByVal inout_cmdln As Object, ByVal defn As Object, ByVal strict As Integer, ByVal ParamArray args() As String) As Integer
    End Function

    'Dim conf = cmd_ln_init(Nothing, Nothing, True, "-hmm", modeldir & "/hmm/en_US/hub4wsj_sc_8k", "-lm", modeldir & "/lm/en/turtle.DMP", "-dict", modeldir & "/lm/en/turtle.dic", Nothing)

    <DllImport("pocketsphinx.dll")> _
    Public Shared Function ps_start_utt(ByRef ps_decoder_t As Object, ByRef uttid As StringBuilder) As Integer
    End Function

    <DllImport("pocketsphinx.dll")> _
    Public Shared Function ps_process_raw(ByRef ps_decoder_t As Object, ByVal buf() As Int16, ByVal len As UInt32, ByVal no_search As Integer, ByVal full_utt As Integer) As Integer
    End Function

    <DllImport("pocketsphinx.dll")> _
    Public Shared Function ps_end_utt(ByRef ps_decoder_t As Object) As Integer
    End Function

    <DllImport("pocketsphinx.dll")> _
    Public Shared Function ps_get_utt(ByRef ps_decoder_t As Object, ByRef score As Integer, ByRef uttid As StringBuilder) As String
    End Function

    Public Function GetText(ByVal buf() As Int16) As String
        Dim config As Object
        Dim returnCode As Integer
        Dim Hyp As String = ""
        Dim ModelDir As String = "D:\CMUSphinx\Source\pocketsphinx\model"
        Dim ps As Object = Nothing
        Dim uttID As New StringBuilder("sphinx")
        Dim tmp() As Int16
        Dim Score As Integer = -1

        returnCode = cmd_ln_init(Nothing, Nothing, True, "-hmm", ModelDir & "/hmm/en_US/hub4wsj_sc_8k", "-lm", ModelDir & "/lm/en/turtle.DMP", "-dict", ModelDir & "/lm/en/turtle.dic", Nothing)
        If returnCode >= 1 Then

           [color=red] returnCode = ps_start_utt(ps, uttID)[/color]

            If returnCode >= 0 Then

                For i As Integer = 0 To buf.GetUpperBound(0) Step 512
                    ReDim tmp(511)
                    Dim len As Integer = IIf(i <= buf.GetUpperBound(0), 512, buf.GetUpperBound(0) - i)

                    Array.Copy(buf, i, tmp, 0, len)

                    returnCode = ps_process_raw(ps, tmp, len, 0, 0)

                Next

                If returnCode >= 0 Then
                    Hyp = ps_get_utt(ps, Score, uttID)
                End If
            End If

        End If

        Return Hyp

    End Function
End Class

[eliasmajic]

Oh Interop fun :)

There is the vc sln file that is a good starting point. You should probably
post the log you see in the console, also, make sure that those paths are
correct.
I refer to /hmm/en_US/hub4wsj_sc_8k

Isnt windows paths \ instead of /?
Make sure also the files are indeed there.

[David Brandon]

I verified that the paths are correct and that the files exist. I also changed
the "/" to "\" as you suggested, good catch there. However, I still get the
same result. What console are you referring to that I should post the log
from?

[eliasmajic]

There should be a console that outputs the log, otherwise we would just be
randomly guessing. I know c# has, vb.net should also. Make sure you have the
console view shown, often it indicates where the error is.

Then paste it here.

[David Brandon]

Thanks so much for being willing to help. I have an Output window but it just
shows the information regarding the managed code but once it calls the
unmanaged library it has nothing. It doesn't show any exception information in
the managed code.

However, I did find a report of the exception in the application event viewer.
It says:

Fault bucket 2900031165, type 5
Event Name: BEX
Response: Not available
Cab Id: 0

Problem signature:
P1: FaceFinder.vshost.exe
P2: 9.0.21022.8
P3: 473168a0
P4: mscorwks.dll
P5: 2.0.50727.5448
P6: 4e154bce
P7: 0028145e
P8: c0000409
P9: 00000000
P10:

From what I have read, BEX is a buffer overlow exception. Do you see anything
that would explain that in my declaration of ps_start_utt?

[David Brandon]

I suspect that it has to do with my declaring the ps_decoder_t parameter as
Object but I'm not sure how else that should be declared in vb.net.

[eliasmajic]

You need to get the unmanaged logs.
Also, I see a possible error:

You are passing in a null ps value to ps_start_utt.
its supposed to be ps=ps_init(returnCode)
then ps_start_utt(ps,whatever)

So one error is your passing in a null ps. Try that, if it doesnt work figure
out how to get logs in unmanaged code.