CODEWITHSUNDEEP
vb.netspeech-recognitionspeechsapiaudio-device
FDecker
FDecker

Reputation: 41

How to set the input audio device for Microsoft.Speech recognizer in VB.Net or C# to any audio device

I want to use the Microsoft.Speech namespace in VB.NET to create a telephony application. I need to be able to set the recognizer input to any audio device installed on the system. Microsoft has the recognizer.SetInputToDefaultAudioDevice() method, but I need something like .SetInputToAudioDeviceID. How can I choose another wave audio input from the list of devices installed on my system? In SAPI, I would use MMSystem and SpVoice:

Set MMSysAudioIn1 = New SpMMAudioIn   
MMSysAudioIn1.DeviceId = WindowsAudioDeviceID  'set audio input to audio device Id
MMSysAudioIn1.Format.Type = SAFT11kHz8BitMono  'set wave format, change to 8kHz, 16bit mono for other devices
Dim fmt As New SpeechAudioFormatInfo(1000, AudioBitsPerSample.Eight, AudioChannel.Mono)
Recognizer.SetInputToAudioStream(MMSysAudioIN1, fmt)

How do I do this with Microsoft.Speech?

MORE INFO: I want to take any wave input device in the Windows list of wave drivers and us that as input to speech recognition. Specifically, I may have a Dialogic card with wave input reported by TAPI as deviceID 1-4. In SAPI, I can use the SpMMAudioIn class to create a stream and set which device ID is associated with that stream. You can see some of that code above. Can I directly set Recognizer1.SetInputToAudioStream by the device ID of the device like I can in SAPI? Or do I have to create code that reads bytes and uses buffers, etc. Do I have to create a MemoryStream Object? I can't find any example code anywhere. What do I have to check in .NET to get access to ISpeechMMSysAudio/spMMAudioIn in case something like this would work? But hopefully, there is a way to use MemoryStream or something like it that takes a device ID and lets me pass that stream to the recognizer.

NOTE 2: I added "imports Speechlib" to the VB project and then tried to run the following code. It gives the error listed in the comments below about not being able to set the audio stream to a COM object. 

Dim sre As New SpeechRecognitionEngine
Dim fmt As New SpeechAudioFormatInfo(8000, AudioBitsPerSample.Sixteen, AudioChannel.Mono)
Dim audiosource As ISpeechMMSysAudio
audiosource = New SpMMAudioIn
audiosource.DeviceId = WindowsAudioDeviceID  'set audio input to audio device Id
' audiosource.Format.Type = SpeechAudioFormatType.SAFT11kHz16BitMono 
sre.SetInputToAudioStream(audiosource, fmt) <----- Invalid Cast with COM here

It also appears the SpeechAudioFormatType does not support 8kHz formats. This just gets more and more complicated.

Upvotes: 0

Views: 2556

Answers (1)

Eric Brown
Eric Brown

Reputation: 13942

You would use SpeechRecognitionEngine.SetInputToAudioStream. Note that if you're having problems with streaming input, you may need to wrap the stream, as illustrated here.

Upvotes: 0

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