Differenze tra le versioni di "Eseguire un file WAV con le funzioni esterne del API di LibAo"
Da Gambas-it.org - Wikipedia.
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'''Libao''' è una libreria multi-piattaforma che permette ai programmi di inviare dati audio PCM ai dispositivi audio nativi su una vasta gamma di piattaforme. | '''Libao''' è una libreria multi-piattaforma che permette ai programmi di inviare dati audio PCM ai dispositivi audio nativi su una vasta gamma di piattaforme. | ||
− | + | Possiamo utilizzare due modalità. | |
− | |||
− | |||
− | + | ||
+ | ===1<SUP>a</sup> modalità=== | ||
+ | La prima modalità fa uso delle risorse della sola principale libreria "''libao.so.4.0.0''", che dovrà essere installata nel sistema operativo e debitamente richiamata nell'applicazione gambas. | ||
+ | |||
+ | Mostriamo un esempio: | ||
+ | Public Struct ao_sample_format | ||
+ | bits As Integer <FONT color=gray>' ''bits per sample''</font> | ||
+ | rate As Integer <FONT color=gray>' ''samples per second (in a single channel)''</font> | ||
+ | channels As Integer <FONT color=gray>' ''number of audio channels''</font> | ||
+ | byte_format As Integer <FONT color=gray>' ''Byte ordering in sample, see constants below''</font> | ||
+ | matrix As Pointer <FONT color=gray>' ''input channel location/ordering''</font> | ||
+ | End Struct | ||
+ | |||
+ | Public Struct ao_info | ||
+ | type As Integer | ||
+ | name As Pointer | ||
+ | short_name As Pointer | ||
+ | author As Pointer | ||
+ | comment As Pointer | ||
+ | preferred_byte_format As Integer | ||
+ | priority As Integer | ||
+ | options As Pointer | ||
+ | option_count As Integer | ||
+ | End Struct | ||
+ | |||
+ | Library "libao:4.0.0" | ||
+ | |||
+ | Private Const AO_FMT_LITTLE As Integer = 1 | ||
+ | Private Const AO_FMT_BIG As Integer = 2 | ||
+ | Private Const AO_FMT_NATIVE As Integer = 4 | ||
+ | |||
+ | <FONT color=gray>' ''void ao_initialize(void)'' | ||
+ | ' ''Library setup.''</font> | ||
+ | Private Extern ao_initialize() | ||
+ | |||
+ | <FONT color=gray>' ''int ao_default_driver_id(void)'' | ||
+ | ' ''Driver information.''</font> | ||
+ | Private Extern ao_default_driver_id() As Integer | ||
+ | |||
+ | <FONT color=gray>' ''ao_info *ao_driver_info(int driver_id)'' | ||
+ | ' ''Get information about a particular driver.''</font> | ||
+ | Private Extern ao_driver_info(driver_id As Integer) As Pointer | ||
+ | |||
+ | <FONT color=gray>' ''ao_device * ao_open_live(int driver_id, ao_sample_format *format, ao_option *option)'' | ||
+ | ' ''Open a live playback audio device for output.''</font> | ||
+ | Private Extern ao_open_live(driver_id As Integer, fmt As Ao_sample_format, option As Pointer) As Pointer | ||
+ | |||
+ | <FONT color=gray>' ''int ao_play(ao_device *device, char *output_samples, uint_32 num_bytes)'' | ||
+ | ' ''Play a block of audio data to an open device.''</font> | ||
+ | Private Extern ao_play(device As Pointer, output_samples As Pointer, num_bytes As Integer) As Integer | ||
+ | |||
+ | <FONT color=gray>' ''void ao_shutdown(void)'' | ||
+ | ' ''Unloads all of the plugins and deallocates any internal data structures the library has created.''</font> | ||
+ | Private Extern ao_shutdown() | ||
+ | |||
+ | |||
+ | '''Public''' Sub Main() | ||
+ | |||
+ | Dim device As Pointer | ||
+ | Dim ao_sf As New Ao_sample_format | ||
+ | Dim info As New Ao_info | ||
+ | Dim default_driver, i, err, rbc As Integer | ||
+ | Dim buffer As Byte[] | ||
+ | Dim fileWAV, fmt As String | ||
+ | Dim fl As File | ||
+ | Dim b As Byte | ||
+ | |||
+ | fileWAV = "<FONT color=gray>''/percorso/del/file.wav''</font>" | ||
+ | |||
+ | fl = Open fileWAV For Read | ||
+ | |||
+ | <FONT color=gray>' ''Inizializza la libreria 'libao':''</font> | ||
+ | ao_initialize() | ||
+ | |||
+ | <FONT color=gray>' ''Imposta il driver audio come predefinito:''</font> | ||
+ | default_driver = ao_default_driver_id() | ||
+ | |||
+ | <FONT color=gray>' ''Raccoglie alcune informazioni del dipositivo audio di sistema utilizzato:''</font> | ||
+ | Print "Informazioni sul dispositivo audio utilizzato:" | ||
+ | info = ao_driver_info(default_driver) | ||
+ | With info | ||
+ | Print "Tipo: "; IIf(.type = 1, "Live Output", "File output") | ||
+ | Print "Nome: "; String@(.name) | ||
+ | Print "Abbreviazione: "; String@(.short_name) | ||
+ | Print "Realizzatore: "; String@(.author) | ||
+ | Print "Commento: "; String@(.comment) | ||
+ | Select Case .preferred_byte_format | ||
+ | Case 1 | ||
+ | fmt = "little-endian order" | ||
+ | Case 2 | ||
+ | fmt = "big-endian order" | ||
+ | Case 4 | ||
+ | fmt = "native ordering of the computer" | ||
+ | End Select | ||
+ | Print "Formato byte preferito: "; fmt | ||
+ | Print "Priorità: "; .priority | ||
+ | Print "Opzioni: "; | ||
+ | For b = 1 To .option_count | ||
+ | Print String@(Pointer@(.options + CInt(8 * b))); ", "; | ||
+ | Next | ||
+ | End With | ||
+ | Print "\n____________________________" | ||
+ | |||
+ | <FONT color=gray>' ''Imposta le caratteristiche del file wav caricato, leggendole da esso:''</font> | ||
+ | With ao_sf | ||
+ | Seek #fl, 34 | ||
+ | .bits = Read #fl As Short | ||
+ | Seek #fl, 22 | ||
+ | .channels = Read #fl As Short | ||
+ | .rate = Read #fl As Integer | ||
+ | .byte_format = AO_FMT_LITTLE | ||
+ | <FONT color=gray>' ''Mostra alcune informazioni generali sul file wav caricato:''</font> | ||
+ | Print "File wav: "; fileWAV | ||
+ | Print "Dimensione: "; Lof(fl); " byte" | ||
+ | Print "Risoluzione: "; .bits; " bit" | ||
+ | Print "Canali: "; .channels | ||
+ | Print "Frequenza: "; .rate; " hertz" | ||
+ | rbc = .rate * .bits * .channels | ||
+ | Print "Durata: "; Date(0, 0, 0, 0, 0, 0, ((Lof(fl) * 8) / rbc) * 1000) | ||
+ | Print | ||
+ | End With | ||
+ | |||
+ | <FONT color=gray>' ''Apre il driver:''</font> | ||
+ | device = ao_open_live(default_driver, ao_sf, Null) | ||
+ | If IsNull(device) Then Error.Raise("Errore nell'apertura del dispositivo audio !") | ||
+ | |||
+ | buffer = New Byte[Lof(fl)] | ||
+ | |||
+ | <FONT color=gray>' ''Ciclo per l'elaborazione dell'audio:''</font> | ||
+ | For i = 1 To (buffer.Count) / 1024 | ||
+ | |||
+ | <FONT color=gray>' ''Carica i dati audio nel vettore di tipo "Byte[]":''</font> | ||
+ | buffer.Read(fl, 0, 1024) | ||
+ | |||
+ | <FONT color=gray>' ''Esegue i dati audio:''</font> | ||
+ | err = ao_play(device, buffer.Data, 1024) | ||
+ | If err < 1 Then Error.Raise("Errore nell'esecuzione dei dati audio !") | ||
+ | Write #File.out, "\r" & CStr(Date(0, 0, 0, 0, 0, 0, ((Seek(fl) * 8) / rbc) * 1000)) | ||
+ | |||
+ | Next | ||
+ | |||
+ | |||
+ | <FONT color=gray>' ''Va in chiusura:''</font> | ||
+ | fl.Close | ||
+ | ao_shutdown() | ||
+ | |||
+ | '''End''' | ||
+ | |||
+ | |||
+ | |||
+ | ===2<SUP>a</sup> modalità=== | ||
+ | La seconda modalità fa uso sia della libreria principale "''libao.so.4.0.0''", sia della libreria "''libalsa.so''". | ||
+ | |||
+ | Di seguito un esempio: | ||
Public Struct ao_sample_format | Public Struct ao_sample_format | ||
bits As Integer <FONT color=gray>' ''bits per sample''</font> | bits As Integer <FONT color=gray>' ''bits per sample''</font> | ||
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=Riferimenti= | =Riferimenti= | ||
* http://www.xiph.org/ao/doc/ | * http://www.xiph.org/ao/doc/ | ||
+ | * http://manual.freeshell.org/libao-1.0.0 |
Versione delle 19:38, 6 gen 2016
Libao è una libreria multi-piattaforma che permette ai programmi di inviare dati audio PCM ai dispositivi audio nativi su una vasta gamma di piattaforme.
Possiamo utilizzare due modalità.
1a modalità
La prima modalità fa uso delle risorse della sola principale libreria "libao.so.4.0.0", che dovrà essere installata nel sistema operativo e debitamente richiamata nell'applicazione gambas.
Mostriamo un esempio:
Public Struct ao_sample_format bits As Integer ' bits per sample rate As Integer ' samples per second (in a single channel) channels As Integer ' number of audio channels byte_format As Integer ' Byte ordering in sample, see constants below matrix As Pointer ' input channel location/ordering End Struct Public Struct ao_info type As Integer name As Pointer short_name As Pointer author As Pointer comment As Pointer preferred_byte_format As Integer priority As Integer options As Pointer option_count As Integer End Struct Library "libao:4.0.0" Private Const AO_FMT_LITTLE As Integer = 1 Private Const AO_FMT_BIG As Integer = 2 Private Const AO_FMT_NATIVE As Integer = 4 ' void ao_initialize(void) ' Library setup. Private Extern ao_initialize() ' int ao_default_driver_id(void) ' Driver information. Private Extern ao_default_driver_id() As Integer ' ao_info *ao_driver_info(int driver_id) ' Get information about a particular driver. Private Extern ao_driver_info(driver_id As Integer) As Pointer ' ao_device * ao_open_live(int driver_id, ao_sample_format *format, ao_option *option) ' Open a live playback audio device for output. Private Extern ao_open_live(driver_id As Integer, fmt As Ao_sample_format, option As Pointer) As Pointer ' int ao_play(ao_device *device, char *output_samples, uint_32 num_bytes) ' Play a block of audio data to an open device. Private Extern ao_play(device As Pointer, output_samples As Pointer, num_bytes As Integer) As Integer ' void ao_shutdown(void) ' Unloads all of the plugins and deallocates any internal data structures the library has created. Private Extern ao_shutdown() Public Sub Main() Dim device As Pointer Dim ao_sf As New Ao_sample_format Dim info As New Ao_info Dim default_driver, i, err, rbc As Integer Dim buffer As Byte[] Dim fileWAV, fmt As String Dim fl As File Dim b As Byte fileWAV = "/percorso/del/file.wav" fl = Open fileWAV For Read ' Inizializza la libreria 'libao': ao_initialize() ' Imposta il driver audio come predefinito: default_driver = ao_default_driver_id() ' Raccoglie alcune informazioni del dipositivo audio di sistema utilizzato: Print "Informazioni sul dispositivo audio utilizzato:" info = ao_driver_info(default_driver) With info Print "Tipo: "; IIf(.type = 1, "Live Output", "File output") Print "Nome: "; String@(.name) Print "Abbreviazione: "; String@(.short_name) Print "Realizzatore: "; String@(.author) Print "Commento: "; String@(.comment) Select Case .preferred_byte_format Case 1 fmt = "little-endian order" Case 2 fmt = "big-endian order" Case 4 fmt = "native ordering of the computer" End Select Print "Formato byte preferito: "; fmt Print "Priorità: "; .priority Print "Opzioni: "; For b = 1 To .option_count Print String@(Pointer@(.options + CInt(8 * b))); ", "; Next End With Print "\n____________________________" ' Imposta le caratteristiche del file wav caricato, leggendole da esso: With ao_sf Seek #fl, 34 .bits = Read #fl As Short Seek #fl, 22 .channels = Read #fl As Short .rate = Read #fl As Integer .byte_format = AO_FMT_LITTLE ' Mostra alcune informazioni generali sul file wav caricato: Print "File wav: "; fileWAV Print "Dimensione: "; Lof(fl); " byte" Print "Risoluzione: "; .bits; " bit" Print "Canali: "; .channels Print "Frequenza: "; .rate; " hertz" rbc = .rate * .bits * .channels Print "Durata: "; Date(0, 0, 0, 0, 0, 0, ((Lof(fl) * 8) / rbc) * 1000) Print End With ' Apre il driver: device = ao_open_live(default_driver, ao_sf, Null) If IsNull(device) Then Error.Raise("Errore nell'apertura del dispositivo audio !") buffer = New Byte[Lof(fl)] ' Ciclo per l'elaborazione dell'audio: For i = 1 To (buffer.Count) / 1024 ' Carica i dati audio nel vettore di tipo "Byte[]": buffer.Read(fl, 0, 1024) ' Esegue i dati audio: err = ao_play(device, buffer.Data, 1024) If err < 1 Then Error.Raise("Errore nell'esecuzione dei dati audio !") Write #File.out, "\r" & CStr(Date(0, 0, 0, 0, 0, 0, ((Seek(fl) * 8) / rbc) * 1000)) Next ' Va in chiusura: fl.Close ao_shutdown() End
2a modalità
La seconda modalità fa uso sia della libreria principale "libao.so.4.0.0", sia della libreria "libalsa.so".
Di seguito un esempio:
Public Struct ao_sample_format bits As Integer ' bits per sample rate As Integer ' samples per second (in a single channel) channels As Integer ' number of audio channels byte_format As Integer ' Byte ordering in sample, see constants below matrix As Pointer ' input channel location/ordering End Struct Library "libao:4.0.0" Private Const AO_FMT_LITTLE As Integer = 1 ' void ao_initialize(void) ' Library setup Private Extern ao_initialize() ' int ao_default_driver_id(void) ' Driver information Private Extern ao_default_driver_id() As Integer ' ao_device * ao_open_live(int driver_id, ao_sample_format *format, ao_option *option) ' Driver information Private Extern ao_open_live(driver_id As Integer, fmt As Ao_sample_format, option As Pointer) As Pointer ' void ao_shutdown(void) ' Library teardown Private Extern ao_shutdown() Library "/usr/lib/x86_64-linux-gnu/ao/plugins-4/libalsa" ' int ao_plugin_test() ' Determine if parameters are requires for this particular plugin. Private Extern ao_plugin_test() As Integer ' int ao_plugin_device_init(ao_device *device) ' Initialize internal data structures. Private Extern ao_plugin_device_init(ao_dev As Pointer) As Integer ' int ao_plugin_open(ao_device *device, ao_sample_format *format) ' Prepare the audio device for playback. Private Extern ao_plugin_open(ao_dev As Pointer, fmt As Ao_sample_format) As Integer ' int ao_plugin_play(ao_device *device, const char *output_samples, uint_32 num_bytes) ' Play num_bytes of audio data. Private Extern ao_plugin_play(ao_dev As Pointer, output_samples As Pointer, num_bytes As Integer) As Integer ' int ao_plugin_close(ao_device *device) ' Close the audio device. Private Extern ao_plugin_close(ao_dev As Pointer) As Integer ' void ao_plugin_device_clear(ao_device *device) ' Free the internal data structures. Private Extern ao_plugin_device_clear(ao_dev As Pointer) Public Sub Main() Dim device As Pointer Dim ao_sf As New Ao_sample_format Dim default_driver, i, err, rbc As Integer Dim buffer As Byte[] Dim fileWAV As String Dim fl As File fileWAV = "/percorso/del/file.wav" fl = Open fileWAV For Read ' Inizializza la libreria 'libao': ao_initialize() ' Imposta il driver audio come predefinito: default_driver = ao_default_driver_id() ' Imposta le caratteristiche del file wav caricato, leggendole da esso: With ao_sf Seek #fl, 34 .bits = Read #fl As Short Seek #fl, 22 .channels = Read #fl As Short .rate = Read #fl As Integer .byte_format = AO_FMT_LITTLE ' Mostra alcune informazioni generali sul file wav caricato: Print "File wav: "; fileWAV Print "Dimensione: "; Lof(fl); " byte" Print "Risoluzione: "; .bits; " bit" Print "Canali: "; .channels Print "Frequenza: "; .rate; " hertz" rbc = .rate * .bits * .channels Print "Durata: "; Date(0, 0, 0, 0, 0, 0, ((Lof(fl) * 8) / rbc) * 1000) Print End With ' Apre il driver: device = ao_open_live(default_driver, ao_sf, Null) If IsNull(device) Then Error.Raise("Errore nell'apertura del dispositivo audio !") err = ao_plugin_test() If err = 0 Then Error.Raise("Il driver audio ha bisogno che vengano impostate alcune opzioni !") ao_plugin_device_init(device) ao_plugin_open(device, ao_sf) buffer = New Byte[Lof(fl)] ' Riportiamo il puntatore interno del flusso del file a zero: Seek #fl, 0 ' Ciclo per l'elaborazione dell'audio: For i = 1 To (buffer.Count) / 1024 ' Carica i dati audio nel vettore di tipo "Byte[]": buffer.Read(fl, 0, 1024) ' Esegue i dati audio: err = ao_plugin_play(device, buffer.Data, 1024) If err < 1 Then Error.Raise("Errore nell'esecuzione dei dati audio !") Write #File.out, "\r" & CStr(Date(0, 0, 0, 0, 0, 0, ((Seek(fl) * 8) / rbc) * 1000)) Next ' Va in chiusura: fl.Close ao_plugin_close(device) ao_plugin_device_clear(device) ao_shutdown() End