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| (11 versioni intermedie di uno stesso utente non sono mostrate) |
| Riga 1: |
Riga 1: |
| − | La libreria '''''[http://sox.sourceforge.net/ Sox]''''' contiene risorse per poter gestire ampiamente i file audio: riproduzione e registrazione, conversione di vari formati audio in altri formati, nonché applicazione di vari effetti. ''Sox'' consente di eseguire numerosissimi [http://sox.sourceforge.net/soxformat.html formati di file audio].
| + | * [[Aggiungere l'effetto Eco ad un file audio WAV con le funzioni esterne del API di Sox]] |
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| − | Per poter utilizzare in Gambas le risorse del API di ''Sox'' bisognerà aver installato e richiamare la libreria dinamica condivisa: ''libsox.so.2.0.1''
| + | * [[Convertire un file audio da un formato audio in un altro con le funzioni esterne del API di Sox]] |
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| | + | * [[Eseguire un file audio mediante le funzioni esterne del API di Sox]] |
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| | + | * [[Estrarre informazioni generali da un file audio con le funzioni esterne del API di Sox]] |
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| − | =Esecuzione di un file audio=
| + | * [[Ridurre a 8-bit la risoluzione di campionamento di un file audio WAV con le funzioni esterne del API di Sox]] |
| − | Nel caso di esecuzione di un file audio bisognerà avere cura di individuare nella funzione ''sox_open_write()'' il dispositivo audio (ad esempio "''Alsa''").
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| − | | + | * [[Variare il volume di un file audio MP3 o WAV con le funzioni esterne del API di Sox]] |
| − | Mostriamo un esempio, il cui codice prevede l'esecuzione di un file audio e la preventiva diminuzione del volume:
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| − | Public Struct sox_signalinfo_t
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| − | rate As Float
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| − | channels As Integer
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| − | precision As Integer
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| − | length As Long
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| − | mult As Pointer
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| − | End Struct
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| − | Public Struct sox_encodinginfo_t
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| − | encoding As Integer
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| − | bits_per_sample As Integer
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| − | compression As Float
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| − | reverse_bytes As Integer
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| − | reverse_nibbles As Integer
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| − | reverse_bits As Integer
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| − | opposite_endian As Integer
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| − | End Struct
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| − | Public Struct sox_effects_globals_t
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| − | plot As Integer
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| − | global_info As Pointer
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| − | End Struct
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| − | Public Struct sox_effects_chain_t
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| − | effects As Pointer
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| − | table_size As Integer
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| − | length As Integer
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| − | ibufc As Pointer
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| − | obufc As Pointer
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| − | global_info As Struct Sox_effects_globals_t
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| − | in_enc As Pointer
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| − | out_enc As Pointer
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| − | End Struct
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| − |
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| − | Public Struct sox_effect_handler_t
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| − | name As Pointer
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| − | usage As Pointer
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| − | flags As Integer
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| − | sox_effect_handler_getopts As Pointer
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| − | sox_effect_handler_start As Pointer
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| − | sox_effect_handler_flow As Pointer
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| − | sox_effect_handler_drain As Pointer
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| − | sox_effect_handler_stop As Pointer
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| − | sox_effect_handler_kill As Pointer
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| − | priv_size As Long
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| − | End Struct
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| − | Public Struct sox_effect_t
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| − | global_info As Pointer
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| − | in_signal As Struct Sox_signalinfo_t
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| − | out_signal As Struct Sox_signalinfo_t
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| − | in_encoding As Pointer
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| − | out_encoding As Pointer
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| − | handler As Struct Sox_effect_handler_t
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| − | obuf As Pointer
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| − | obeg As Long
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| − | oend As Long
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| − | imin As Long
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| − | clips As Long
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| − | flows As Long
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| − | flow As Long
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| − | priv As Pointer
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| − | End Struct
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| − | Library "libsox:2.0.1"
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| − |
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| − | Private Enum SOX_EOF = -1, SOX_SUCCESS, SOX_EHDR = 2000, SOX_EFMT, SOX_ENOMEM, SOX_EPERM, SOX_ENOTSUP, SOX_EINVAL
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| − | <FONT color=gray>' ''int sox_format_init(void)''
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| − | ' ''Client API: Initialize effects library. SOX_SUCCESS if successful.''</font>
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| − | Private Extern sox_init() As Integer
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| − |
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| − | <FONT color=gray>' ''sox_format_t * sox_open_read(char const *path, sox_signalinfo_t const *signal, sox_encodinginfo_t const *encoding, char const *filetype)''
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| − | ' ''Opens a decoding session for a file. returns the handle for the new session, or null on failure.''</font>
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| − | Private Extern sox_open_read(path As String, signalP As Pointer, encoding As Pointer, filetype As String) As Pointer 'Sox_format_t
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| − | <FONT color=gray>' ''sox_format_t * sox_open_write(char const *path, sox_signalinfo_t const *signal, sox_encodinginfo_t const *encoding, char const *filetype, sox_oob_t const *oob, sox_bool(*overwrite_permitted)(const char *filename)
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| − | ' ''Opens a decoding session for a file. returns the handle for the new session, or null on failure.''</font>
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| − | Private Extern sox_open_write(path As String, signal As Pointer, encoding As Pointer, filetype As String, oob As Pointer, filename As String) As Pointer
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| − | <FONT color=gray>' ''sox_effects_chain_t * sox_create_effects_chain(sox_encodinginfo_t const * in_enc, sox_encodinginfo_t const * out_enc)''
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| − | ' ''Initializes an effects chain.''</font>
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| − | Private Extern sox_create_effects_chain(in_enc As Sox_encodinginfo_t, out_enc As Sox_encodinginfo_t) As Sox_effects_chain_t
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| − | <FONT color=gray>' ''sox_effect_t * sox_create_effect(sox_effect_handler_t const * eh)''
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| − | ' ''Creates an effect using the given handler.''</font>
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| − | Private Extern sox_create_effect(eh As Sox_effect_handler_t) As Sox_effect_t
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| − | <FONT color=gray>' ''sox_effect_handler_t const * sox_find_effect(char const * name)''
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| − | ' ''Finds the effect handler with the given name.''</font>
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| − | Private Extern sox_find_effect(name As String) As Pointer
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| − | <FONT color=gray>' ''int sox_effect_options(sox_effect_t *effp, int argc, char * const argv[])''
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| − | ' ''Applies the command-line options to the effect.''</font>
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| − | Private Extern sox_effect_options(effp As Sox_effect_t, argc As Integer, argv As Pointer[]) As Integer
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| − | <FONT color=gray>' ''int sox_add_effect(sox_effects_chain_t * chain, sox_effect_t * effp, sox_signalinfo_t * in, sox_signalinfo_t const * out)''
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| − | ' ''Adds an effect to the effects chain, returns SOX_SUCCESS if successful. Returns SOX_SUCCESS if successful.''</font>
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| − | Private Extern sox_add_effect(chain As Sox_effects_chain_t, effp As Sox_effect_t, inS As Sox_signalinfo_t, ouS As Sox_signalinfo_t) As Integer
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| − | <FONT color=gray>' ''int sox_flow_effects(sox_effects_chain_t * chain, sox_flow_effects_callback callback, void * client_data)''
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| − | ' ''Runs the effects chain, returns SOX_SUCCESS if successful. Returns SOX_SUCCESS if successful.''</font>
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| − | Private Extern sox_flow_effects(chain As Sox_effects_chain_t, callback As Pointer, client_data As Pointer) As Integer
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| − | <FONT color=gray>' ''void sox_delete_effects_chain(sox_effects_chain_t *ecp)''
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| − | ' ''Closes an effects chain.''</font>
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| − | Private Extern sox_delete_effects_chain(chain As Sox_effects_chain_t)
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| − | <FONT color=gray>' ''int sox_close(sox_format_t * ft)''
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| − | ' ''Closes an encoding or decoding session. Returns SOX_SUCCESS if successful.''</font>
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| − | Private Extern sox_close(ft As Pointer)
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| − | <FONT color=gray>' ''sox_quit(void)''
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| − | ' ''Close effects library and unload format handler plugins. Returns SOX_SUCCESS if successful.''</font>
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| − | Private Extern sox_quit()
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| − | '''Public''' Sub Main()
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| − | Dim fileAUDIO As String
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| − | Dim err As Integer
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| − | Dim sfIn, sfOut As Pointer
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| − | Dim sigIn, sigOut As New Sox_signalinfo_t
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| − | Dim encoIn, encoOut As New Sox_encodinginfo_t
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| − | Dim chain As Sox_effects_chain_t
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| − | Dim eff As New Sox_effect_t
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| − | Dim argsP As New Pointer[10]
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| − | fileAUDIO = "<FONT color=gray>''/percorso/del/file/audio''</font>"
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| − | <FONT color=gray>' ''Poiché vogliamo eseguire il file audio, allora scriveremo i dati in ALSA nel modo seguente:''</font>
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| − | sfOut = sox_open_write("default", sigIn, Null, "alsa", 0, Null)
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| − | sigOut = sfOut + 8
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| − | encoIn = sfIn + 40
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| − | encoOut = sfOut + 40
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| − | chain = sox_create_effects_chain(encoIn, encoOut)
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| − | eff = sox_create_effect(sox_find_effect("input"))
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| − | argsP[0] = sfIn
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| − | err = sox_effect_options(eff, 1, argsP)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_effect_options' !")
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| − | err = sox_add_effect(chain, eff, sigIn, sigOut)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_add_effect' !")
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| − | If sigIn.rate <> sigOut.rate Then
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| − | eff = sox_create_effect(sox_find_effect("rate"))
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| − | err = sox_effect_options(eff, 0, Null)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_effect_options' !")
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| − | err = sox_add_effect(chain, eff, sigIn, sigOut)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_add_effect' !")
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| − | Endif
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| − | <FONT color=gray>' ''Crea l'effetto "Volume", lo inizializza con il parametro desiderato:''</font>
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| − | eff = sox_create_effect(sox_find_effect("vol"))
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| − | <FONT color=gray>' ''Diminuisce il volume d'ascolto assegnando il valore "-12dB":''</font>
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| − | argsP[0] = Alloc("-12dB")
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| − | err = sox_effect_options(eff, 1, argsP)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_effect_options' !")
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| − | err = sox_add_effect(chain, eff, sigIn, sigOut)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_add_effect' !")
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| − | eff = sox_create_effect(sox_find_effect("output"))
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| − | argsP[0] = sfOut
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| − | err = sox_effect_options(eff, 1, argsP)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_effect_options' !")
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| − | err = sox_add_effect(chain, eff, sigIn, sigOut)
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| − | If err <> SOX_SUCCESS Then Error.Raise("Errore nella funzione 'sox_add_effect' !")
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| − | <FONT color=gray>' ''Esegue il i dati audio:''</font>
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| − | sox_flow_effects(chain, Null, Null)
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| − | <FONT color=gray>' ''Va in chiusura:''</font>
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| − | Free(argsP.Data)
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| − | sox_delete_effects_chain(chain)
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| − | sox_close(sfOut)
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| − | sox_close(sfIn)
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| − | sox_quit()
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| − | '''End'''
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| − | =Riferimenti=
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| − | [1] [http://sox.sourceforge.net/libsox.html Il sito di Sox]
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| − | [2] [http://fossies.org/dox/sox-14.4.1/index.html Sito del API di Sox]
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| − | [3] [http://sox.sourcearchive.com/documentation/14.3.2-3/index.html Altro sito del API di Sox]
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| − | <FONT Color=red size=4><B>Pagina in costruzione !</b></font>
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