Salve,
Prima di iniziare a postare codice e a parlare della winmm.dll e dei metodi waveInxxx
avrei qualche domanda in generale su come viene gestito l'audio su windows.
Che cos'è un device?
Una scheda audio o un dispositivo hardware esterno qualunque?
Ad esempio quando attacco lo spinotto esterno del mic come faccio a vederlo?
che cos'è una soundcard?
come spieghero dopo nel codice io ottengo come device "sb200" che credo
che stia per "sound blaster" .. che cos'è?
viene rappresentata dal quel mixer nell'applicazione "multimedia" nel pannello di controllo?
questa era la confusione che avevo al riguardo (in quanto newbie del mondo win come di vb)
Ora avrei alcune domande sui metodi waveInxxx della winmm:
--> waveInGetNumDevs
Ritorna il numero dei "dispositivi" waveIn disponibili
cosa vuol dire "dispositivi" in questo caso? una scheda audio o il mic esterno?
[vb]
Private Type WaveInCaps
ManufacturerID As Integer
ProductID As Integer
DriverVersion As Long
ProductName(1 To 32) As Byte
Formats As Long
Channels As Integer
Reserved As Integer
End Type
Private Declare Function waveInGetNumDevs Lib "winmm" () As Long
Private Declare Function waveInGetDevCaps Lib "winmm" Alias "waveInGetDevCapsA" (ByVal uDeviceID As Long, Byval lpCaps As Long, ByVal uSize As Long) As Long
sub InitDevices()
Dim Caps As WaveInCaps, Which As Long, testo As String
For Which = 0 To waveInGetNumDevs - 1
Call waveInGetDevCaps(Which, VarPtr(Caps), Len(Caps))
testo = StrConv(Caps.ProductName, vbUnicode) & Which
msgbox testo
Next
If Which = 0 Then
MsgBox "You have no audio input devices!", vbCritical, "Ack!"
End
End If
End Sub
[/vb]
eseguendo questo codice ottengo SB200 che dovrebbe essere un valido waveIn ...
cos'altro avrei potuto ottenere? waveInGetNumDevs può essere maggiore di 1?
Ora vi posto tutto il codice che ho messo insieme finora per catturare l'audio da mic esterno
anche se ancora non so come e in quale variabile (o descrittore) va a finire l'audio...
[vb]
'
' waveInGetNumDevs(): Determines the number of audio drivers available for input.
' waveInOpen(): Creates an instance of the specified audio device for input.
' waveInPrepareHeader(): Prepares a WAVEHDR and data block for input.
' waveInUnprepareHeader(): Releases a previously prepared WAVEHDR and data block.
' waveInClose(): Closes the specified instance of the audio device.
' waveInReset(): Stops recording and empties the queue.
' waveInStart(): Starts recording to the queued buffer.
' waveInStop(): Stops recording.
' waveInAddBuffer(): Adds a prepared buffer to the record queue.
' waveInGetDevCaps(): Gets the capabilities of the specified device
'
' WAVEINCAPS: Describes the capabilities of an input device.
'
Option Explicit
Private DevHandle As Long
Private InData(0 To 511) As Byte
Private Type WaveFormatEx
FormatTag As Integer
Channels As Integer
SamplesPerSec As Long
AvgBytesPerSec As Long
BlockAlign As Integer
BitsPerSample As Integer
ExtraDataSize As Integer
End Type
Private Type WaveHdr
lpData As Long
dwBufferLength As Long
dwBytesRecorded As Long
dwUser As Long
dwFlags As Long
dwLoops As Long
lpNext As Long
Reserved As Long
End Type
Private Type WaveInCaps
ManufacturerID As Integer
ProductID As Integer
DriverVersion As Long
ProductName(1 To 32) As Byte
Formats As Long
Channels As Integer
Reserved As Integer
End Type
Private Const WAVE_FORMAT_4M16 = &H400& '/* 44.1 kHz, Mono, 6-bit
Private Const WAVE_FORMAT_PCM = 1
Private Declare Function waveInGetNumDevs Lib "winmm" () As Long
Private Declare Function waveInGetDevCaps Lib "winmm" Alias "waveInGetDevCapsA" (ByVal uDeviceID As Long, Byval lpCaps As Long, ByVal uSize As Long) As Long
Private Declare Function waveInAddBuffer Lib "winmm" (ByVal InputDeviceHandle As Long, ByVal WaveHdrPointer As Long, ByVal WaveHdrStructSize As Long) As Long
Private Declare Function waveInPrepareHeader Lib "winmm" (ByVal InputDeviceHandle As Long, ByVal WaveHdrPointer As Long, ByVal WaveHdrStructSize As Long) As Long
Private Declare Function waveInUnprepareHeader Lib "winmm" (ByVal InputDeviceHandle As Long, ByVal WaveHdrPointer As Long, ByVal WaveHdrStructSize As Long) As Long
Private Declare Function waveInOpen Lib "winmm" (WaveDeviceInputHandle As Long, ByVal WhichDevice As Long, ByVal WaveFormatExPointer As Long, ByVal CallBack As Long, ByVal CallBackInstance As Long, ByVal Flags As Long) As Long
Private Declare Function waveInClose Lib "winmm" (ByVal WaveDeviceInputHandle As Long) As Long
Private Declare Function waveInStart Lib "winmm" (ByVal WaveDeviceInputHandle As Long) As Long
Private Declare Function waveInReset Lib "winmm" (ByVal WaveDeviceInputHandle As Long) As Long
Private Declare Function waveInStop Lib "winmm" (ByVal WaveDeviceInputHandle As Long) As Long
sub InitDevices()
Dim Caps As WaveInCaps, Which As Long, testo As String
For Which = 0 To waveInGetNumDevs - 1
Call waveInGetDevCaps(Which, VarPtr(Caps), Len(Caps))
testo = StrConv(Caps.ProductName, vbUnicode) & Which
msgbox testo
Next
If Which = 0 Then
MsgBox "You have no audio input devices!", vbCritical, "Ack!"
End
End If
End Sub
Private Sub Form_Load()
Call InitDevices
End Sub
Private Sub StartButton_Click()
Static WaveFormat As WaveFormatEx
With WaveFormat
.FormatTag = WAVE_FORMAT_PCM
.Channels = 2
.SamplesPerSec = 44100
.BitsPerSample = 8
.BlockAlign = (.Channels * .BitsPerSample) \ 8
.AvgBytesPerSec = .BlockAlign * .SamplesPerSec
.ExtraDataSize = 0
End With
Debug.Print "waveInOpen:"; waveInOpen(DevHandle, 0, VarPtr(WaveFormat), 0, 0, 0)
If DevHandle = 0 Then
Call MsgBox("Wave input device didn't open!", vbExclamation, "Ack!")
Exit Sub
End If
Debug.Print " "; DevHandle
Call waveInStart(DevHandle)
Static Wave As WaveHdr
Wave.lpData = VarPtr(InData(0))
Wave.dwBufferLength = 512 'This is now 512 so there's still 256 samples per channel
Wave.dwFlags = 0
'
' Call waveInPrepareHeader(DevHandle, VarPtr(Wave), Len(Wave))
' Call waveInAddBuffer(DevHandle, VarPtr(Wave), Len(Wave))
'
' Arrivati a questo punto come prendo l'output dal microfono
' per poi redirigerlo ad una convertitore MP3
' o ad un Socket che lo trasmette ad un Client
' o per salvarlo su file ???
'
' Call waveInUnprepareHeader(DevHandle, VarPtr(Wave), Len(Wave))
'
End Sub
Private Sub StopButton_Click()
Call waveInReset(DevHandle)
Call waveInClose(DevHandle)
DevHandle = 0
End Sub
[/vb]
Come ottengo fisicamente l'audio?
Se volessi salvarlo o redirigerlo ad un Socket di tipo server?
(o magari comprimerlo in MP3?)
Grazie a tutti!
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