Differenze tra le versioni di "Conoscere con le funzioni esterne di PortAudio i dispositivi audio presenti nel sistema"
Da Gambas-it.org - Wikipedia.
| Riga 106: | Riga 106: | ||
Print "Default high input latency = "; pdi.defaultHighInputLatency | Print "Default high input latency = "; pdi.defaultHighInputLatency | ||
Print "Default high output latency = "; pdi.defaultHighOutputLatency | Print "Default high output latency = "; pdi.defaultHighOutputLatency | ||
| + | Print "Default sample rate = ", pdi.defaultSampleRate | ||
Next | Next | ||
Versione delle 14:02, 9 lug 2014
La libreria PortAudio è una libreria per la gestione in tempo reale dei dati audio in entrata ed in uscita. Essa fa parte di un assortimento di API e librerie create per la musica e per altri media.
E' possibile con alcune funzioni esterne della libreria PortAudio conoscere i dispositivi audio presenti nel proprio sistema. Sarà necessario avere installata nel proprio sistema la libreria condivisa: libportaudio.so.2.0.0
Mostriamo di seguito un possibile codice:
Public Struct PaDeviceInfo
structVersion As Integer
name As Pointer
maxInputChannels As Integer
maxOutputChannels As Integer
defaultLowInputLatency As Float
defaultLowOutputLatency As Float
defaultHighInputLatency As Float
defaultHighOutputLatency As Float
defaultSampleRate As Float
End Struct
Library "libportaudio:2.0.0"
Private Const paNoError As Integer = 0
' PaError Pa_Initialize(void)
' Library initialization function - call this before using PortAudio.
' This function initializes internal data structures and prepares underlying host APIs for use.
Private Extern Pa_Initialize() As Integer
' PaDeviceIndex Pa_GetDeviceCount(void)
' Retrieve the number of available devices. The number of available devices may be zero.
Private Extern Pa_GetDeviceCount() As Integer
' const PaDeviceInfo * Pa_GetDeviceInfo(PaDeviceIndex device)
' Retrieve a pointer to a PaDeviceInfo structure containing information about the specified device.
Private Extern Pa_GetDeviceInfo(device As Integer) As PaDeviceInfo
' PaDeviceIndex Pa_GetDefaultInputDevice(void)
' Retrieve the index of the default input device.
Private Extern Pa_GetDefaultInputDevice() As Integer
' PaDeviceIndex Pa_GetDefaultOutputDevice(void)
' Retrieve the index of the default output device.
Private Extern Pa_GetDefaultOutputDevice() As Integer
' PaError Pa_Terminate(void)
' Library termination function - call this when finished using PortAudio.
Private Extern Pa_Terminate() As Integer
' const char *Pa_GetErrorText(PaError errnum)
' Translates the supplied PortAudio error number into a human readable message.
Private Extern Pa_GetErrorText(errnum As Integer) As String
Public Sub Main()
Dim err, i, j, numDevices As Integer
Dim pdi As New PaDeviceInfo
Dim defI, defO, ag1, ag2 As String
err = Pa_Initialize()
If err < 0 Then Error.Raise("Impossibile inizializzare la libreria 'PortAudio': " & Pa_GetErrorText(err))
numDevices = Pa_GetDeviceCount()
If numDevices < 0 Then Error.Raise("Impossibile rilevare la presenza di dispositivi audio: " & Pa_GetErrorText(err))
Print "Numbero di dispositivi = "; numDevices
For i = 0 To numDevices - 1
defI = Null
defO = Null
ag1 = Null
ag2 = Null
pdi = Pa_GetDeviceInfo(i)
Print "\n--------------------------------------- dispositivo #"; i
j = 0
If i = Pa_GetDefaultInputDevice() Then
defI = "\n[ Default Input"
j = 1
Endif
If i = Pa_GetDefaultOutputDevice() Then
If j Then
ag1 = ","
Else
ag1 = "["
Endif
defO = " Default Output"
j = 1
Endif
If j = 1 Then ag2 = " ]"
Print defI; ag1; defO; ag2
' Scrive i campi relativi alle informazioni di ciascun dispositivo audio rilevato:
Print "Nome = "; String@(pdi.name)
Print "Max Entrate = "; pdi.maxInputChannels, ", Max Uscite = "; pdi.maxOutputChannels
Print "Default low input latency = "; pdi.defaultLowInputLatency
Print "Default low output latency = "; pdi.defaultLowOutputLatency
Print "Default high input latency = "; pdi.defaultHighInputLatency
Print "Default high output latency = "; pdi.defaultHighOutputLatency
Print "Default sample rate = ", pdi.defaultSampleRate
Next
' Va in chiusura:
Pa_Terminate()
End
