Differenze tra le versioni di "Visualizzare un oscilloscopio di GStreamer mediante la funzione 'gst parse launch()' durante l'esecuzione di un file Midi"

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(Creata pagina con "Per analogia si potrà utilizzare il codice presente in questa pagina della WIKI, alla quale rinviamo: Visualizzare_un_oscilloscopio_di_GStreamer_mediante_la_funzione_'gst_p...")
 
 
(14 versioni intermedie di uno stesso utente non sono mostrate)
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Per analogia si potrà utilizzare il codice presente in questa pagina della WIKI, alla quale rinviamo:
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La funzione esterna "gst_parse_launch()" della libreria ''GStreamer'' consente di costruire e gestire in modo semplice una pipeline ''GStreamer''. La riga della pipeline gestita dalla funzione esterna "gst_parse_launch()" è un insieme di elementi separati da punti esclamativi (!). Le proprietà possono essere aggiunte agli elementi, sotto forma di: ''proprietà = valore''.
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[[Visualizzare_un_oscilloscopio_di_GStreamer_mediante_la_funzione_'gst_parse_launch()'_durante_l'esecuzione_di_un_file_audio|Visualizzare un oscilloscopio di GStreamer mediante la funzione 'gst parse launch()' durante l'esecuzione di un file audio]]
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Sarà necessario avere installata nel sistema e richiamare nell'applicazione Gambas la libreria condivisa: "''libgstreamer-1.0.so.0.2407.0'' ".
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Usando i plugin "''wavescope''" o "''monoscope''" unitamente a "''autoaudiosink''" all'interno della riga della ''pipeline'' della funzione "gst_parse_launch()", è possibile scegliere la visualizzazione di due tipi diversi di oscilloscopio attivo durante l'esecuzione di un file Midi.
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==Uso del plugin ''wavescope''==
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Mostriamo un esempio pratico usando i plugin "''wavescope''" e "''autoaudiosink''" all'interno della riga della ''pipeline'' della funzione ''gst_parse_launch()'':
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Library "libgstreamer-1.0:0.2407.0"
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Private Enum GST_STATE_VOID_PENDING = 0, GST_STATE_NULL, GST_STATE_READY, GST_STATE_PAUSED, GST_STATE_PLAYING
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Private Const GST_FORMAT_TIME As Integer = 3
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<FONT Color=gray>' ''gst_init (int *argc, char **argv[])''
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' ''Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.''</font>
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Private Extern gst_init(argc As Pointer, argv As Pointer)
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<FONT Color=gray>' ''GstElement * gst_parse_launch (const gchar *pipeline_description, GError **error)''
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' ''Create a new pipeline based on command line syntax.''</font>
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Private Extern gst_parse_launch(description As String, GError As Pointer) As Pointer
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<FONT Color=gray>' ''GstStateChangeReturn gst_element_set_state(GstElement *element, GstState state)''
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' ''Sets the state of the element.''</font>
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Private Extern gst_element_set_state(gstelement As Pointer, state As Integer) As Integer
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<FONT Color=gray>' ''gboolean gst_element_query_duration(GstElement * element, GstFormat format, gint64 * duration)''
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' ''Queries an element For the total stream duration In nanoseconds.''</font>
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Private Extern gst_element_query_duration(gselement As Pointer, formatI As Integer, duration As Pointer) As Boolean
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<FONT color=gray>' ''gboolean gst_element_query_position (GstElement *element, GstFormat format, gint64 *duration)''
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' ''Queries an element for the total stream position in nanoseconds.''</font>
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Private Extern gst_element_query_position(gstelement As Pointer, gstformat As Pointer, position As Pointer) As Boolean
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<FONT Color=gray>' ''void gst_object_unref(gpointer object)''
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' ''Decrements the reference count on object.''</font>
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Private Extern gst_object_unref(gobject As Pointer)
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Public Sub Main()
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  Dim midi As Pointer
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  Dim volume As Float
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  Dim durata, l As Long
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  Dim tm As Date
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  gst_init(0, 0)
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  midi = gst_parse_launch("filesrc location=<FONT Color=darkgreen>''/percorso/del/file.mid''</font> ! midiparse ! fluiddec ! tee name=t " &
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                          "! queue ! audioconvert ! wavescope style=3 ! video/x-raw, width=1000 ! videoconvert ! ximagesink t. " &
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                          "! queue ! audioconvert ! m. t. ! queue ! volume volume=7.0 ! autoaudiosink", 0)
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<FONT Color=gray>' ''Avviamo l'esecuzione del file midi:''</font>
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  gst_element_set_state(midi, GST_STATE_PLAYING)
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  Repeat
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    gst_element_query_duration(midi, GST_FORMAT_TIME, VarPtr(durata))
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    Wait 0.01
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  Until durata > -1
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  tm = Now
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  Repeat
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    l = DateDiff(tm, Now, gb.Millisecond)
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    Write "\r\e[0mDurata: " & Time(0, 0, 0, durata / 1000000) & "      Pos. \e[31m" & Time(0, 0, 0, l)
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    Wait 0.001
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  Until l >= durata / 1000000
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  gst_object_unref(midi)
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  Print "\nEsecuzione terminata."
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End
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==Uso del plugin ''monoscope''==
 +
Mostriamo un esempio pratico usando i plugin "''monoscope''" e "''autoaudiosink''" all'interno della riga della ''pipeline'' della funzione ''gst_parse_launch()'':
 +
Library "libgstreamer-1.0:0.2407.0"
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 +
Private Enum GST_STATE_VOID_PENDING = 0, GST_STATE_NULL, GST_STATE_READY, GST_STATE_PAUSED, GST_STATE_PLAYING
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Private Const GST_FORMAT_TIME As Integer = 3
 +
 
 +
<FONT Color=gray>' ''gst_init (int *argc, char **argv[])''
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' ''Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.''</font>
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Private Extern gst_init(argc As Pointer, argv As Pointer)
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<FONT Color=gray>' ''GstElement * gst_parse_launch (const gchar *pipeline_description, GError **error)''
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' ''Create a new pipeline based on command line syntax.''</font>
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Private Extern gst_parse_launch(description As String, GError As Pointer) As Pointer
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<FONT Color=gray>' ''GstStateChangeReturn gst_element_set_state(GstElement *element, GstState state)''
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' ''Sets the state of the element.''</font>
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Private Extern gst_element_set_state(gstelement As Pointer, state As Integer) As Integer
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<FONT Color=gray>' ''gboolean gst_element_query_duration(GstElement * element, GstFormat format, gint64 * duration)''
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' ''Queries an element For the total stream duration In nanoseconds.''</font>
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Private Extern gst_element_query_duration(gselement As Pointer, formatI As Integer, duration As Pointer) As Boolean
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<FONT color=gray>' ''gboolean gst_element_query_position (GstElement *element, GstFormat format, gint64 *duration)''
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' ''Queries an element for the total stream position in nanoseconds.''</font>
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Private Extern gst_element_query_position(gstelement As Pointer, gstformat As Pointer, position As Pointer) As Boolean
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<FONT Color=gray>' ''void gst_object_unref(gpointer object)''
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' ''Decrements the reference count on object.''</font>
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Private Extern gst_object_unref(gobject As Pointer)
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Public Sub Main()
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  Dim midi As Pointer
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  Dim volume As Float
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  Dim durata, l As Long
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  Dim tm As Date
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  gst_init(0, 0)
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  midi = gst_parse_launch("filesrc location=<FONT Color=darkgreen>''/percorso/del/file.mid''</font> ! midiparse ! fluiddec ! " &
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                          "tee name=t ! queue ! audioconvert ! monoscope ! ximagesink ! queue ! m. t. ! " &
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                          "queue ! volume volume=7.0 ! autoaudiosink", 0)
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<FONT Color=gray>' ''Avviamo l'esecuzione del file Midi:''</font>
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  gst_element_set_state(midi, GST_STATE_PLAYING)
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 +
  Repeat
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    gst_element_query_duration(midi, GST_FORMAT_TIME, VarPtr(durata))
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    Wait 0.01
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  Until durata > -1
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  tm = Now
 +
 +
  Repeat
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    l = DateDiff(tm, Now, gb.Millisecond)
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    Write "\r\e[0mDurata: " & Time(0, 0, 0, durata / 1000000) & "      Pos. \e[31m" & Time(0, 0, 0, l)
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    Wait 0.001
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  Until l >= durata / 1000000
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  gst_object_unref(midi)
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  Print "\nEsecuzione terminata."
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End
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=Riferimenti=
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* http://docs.gstreamer.com/display/GstSDK/gst-launch
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* https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-bad-plugins/html/gst-plugins-bad-plugins-wavescope.html
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* https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-good-plugins/html/gst-plugins-good-plugins-monoscope.html
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* http://gstreamer.freedesktop.org/
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* http://gstreamer.com/

Versione attuale delle 14:33, 2 set 2024

La funzione esterna "gst_parse_launch()" della libreria GStreamer consente di costruire e gestire in modo semplice una pipeline GStreamer. La riga della pipeline gestita dalla funzione esterna "gst_parse_launch()" è un insieme di elementi separati da punti esclamativi (!). Le proprietà possono essere aggiunte agli elementi, sotto forma di: proprietà = valore.

Sarà necessario avere installata nel sistema e richiamare nell'applicazione Gambas la libreria condivisa: "libgstreamer-1.0.so.0.2407.0 ".

Usando i plugin "wavescope" o "monoscope" unitamente a "autoaudiosink" all'interno della riga della pipeline della funzione "gst_parse_launch()", è possibile scegliere la visualizzazione di due tipi diversi di oscilloscopio attivo durante l'esecuzione di un file Midi.


Uso del plugin wavescope

Mostriamo un esempio pratico usando i plugin "wavescope" e "autoaudiosink" all'interno della riga della pipeline della funzione gst_parse_launch(): 

Library "libgstreamer-1.0:0.2407.0"

Private Enum GST_STATE_VOID_PENDING = 0, GST_STATE_NULL, GST_STATE_READY, GST_STATE_PAUSED, GST_STATE_PLAYING
Private Const GST_FORMAT_TIME As Integer = 3
 
' gst_init (int *argc, char **argv[])
' Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.
Private Extern gst_init(argc As Pointer, argv As Pointer)

' GstElement * gst_parse_launch (const gchar *pipeline_description, GError **error)
' Create a new pipeline based on command line syntax.
Private Extern gst_parse_launch(description As String, GError As Pointer) As Pointer

' GstStateChangeReturn gst_element_set_state(GstElement *element, GstState state)
' Sets the state of the element.
Private Extern gst_element_set_state(gstelement As Pointer, state As Integer) As Integer

' gboolean gst_element_query_duration(GstElement * element, GstFormat format, gint64 * duration)
' Queries an element For the total stream duration In nanoseconds.
Private Extern gst_element_query_duration(gselement As Pointer, formatI As Integer, duration As Pointer) As Boolean

' gboolean gst_element_query_position (GstElement *element, GstFormat format, gint64 *duration)
' Queries an element for the total stream position in nanoseconds.
Private Extern gst_element_query_position(gstelement As Pointer, gstformat As Pointer, position As Pointer) As Boolean

' void gst_object_unref(gpointer object)
' Decrements the reference count on object.
Private Extern gst_object_unref(gobject As Pointer)


Public Sub Main()
 
 Dim midi As Pointer
 Dim volume As Float
 Dim durata, l As Long
 Dim tm As Date
     
 gst_init(0, 0)
  
 midi = gst_parse_launch("filesrc location=/percorso/del/file.mid ! midiparse ! fluiddec ! tee name=t " &
                         "! queue ! audioconvert ! wavescope style=3 ! video/x-raw, width=1000 ! videoconvert ! ximagesink t. " &
                         "! queue ! audioconvert ! m. t. ! queue ! volume volume=7.0 ! autoaudiosink", 0)
             
' Avviamo l'esecuzione del file midi:
 gst_element_set_state(midi, GST_STATE_PLAYING)
 
 Repeat
   gst_element_query_duration(midi, GST_FORMAT_TIME, VarPtr(durata))
   Wait 0.01
 Until durata > -1

 tm = Now

 Repeat
   l = DateDiff(tm, Now, gb.Millisecond)
   Write "\r\e[0mDurata: " & Time(0, 0, 0, durata / 1000000) & "      Pos. \e[31m" & Time(0, 0, 0, l)
   Wait 0.001
 Until l >= durata / 1000000

 gst_object_unref(midi)
 Print "\nEsecuzione terminata."
 
End


Uso del plugin monoscope

Mostriamo un esempio pratico usando i plugin "monoscope" e "autoaudiosink" all'interno della riga della pipeline della funzione gst_parse_launch(): 

Library "libgstreamer-1.0:0.2407.0"

Private Enum GST_STATE_VOID_PENDING = 0, GST_STATE_NULL, GST_STATE_READY, GST_STATE_PAUSED, GST_STATE_PLAYING
Private Const GST_FORMAT_TIME As Integer = 3
 
' gst_init (int *argc, char **argv[])
' Initializes the GStreamer library, setting up internal path lists, registering built-in elements, and loading standard plugins.
Private Extern gst_init(argc As Pointer, argv As Pointer)

' GstElement * gst_parse_launch (const gchar *pipeline_description, GError **error)
' Create a new pipeline based on command line syntax.
Private Extern gst_parse_launch(description As String, GError As Pointer) As Pointer

' GstStateChangeReturn gst_element_set_state(GstElement *element, GstState state)
' Sets the state of the element.
Private Extern gst_element_set_state(gstelement As Pointer, state As Integer) As Integer

' gboolean gst_element_query_duration(GstElement * element, GstFormat format, gint64 * duration)
' Queries an element For the total stream duration In nanoseconds.
Private Extern gst_element_query_duration(gselement As Pointer, formatI As Integer, duration As Pointer) As Boolean

' gboolean gst_element_query_position (GstElement *element, GstFormat format, gint64 *duration)
' Queries an element for the total stream position in nanoseconds.
Private Extern gst_element_query_position(gstelement As Pointer, gstformat As Pointer, position As Pointer) As Boolean

' void gst_object_unref(gpointer object)
' Decrements the reference count on object.
Private Extern gst_object_unref(gobject As Pointer)


Public Sub Main()
 
 Dim midi As Pointer
 Dim volume As Float
 Dim durata, l As Long
 Dim tm As Date

 gst_init(0, 0)
  
 midi = gst_parse_launch("filesrc location=/percorso/del/file.mid ! midiparse ! fluiddec ! " &
                         "tee name=t ! queue ! audioconvert ! monoscope ! ximagesink ! queue ! m. t. ! " &
                         "queue ! volume volume=7.0 ! autoaudiosink", 0)
                
' Avviamo l'esecuzione del file Midi:
 gst_element_set_state(midi, GST_STATE_PLAYING)
  
 Repeat
   gst_element_query_duration(midi, GST_FORMAT_TIME, VarPtr(durata))
   Wait 0.01
 Until durata > -1

 tm = Now

 Repeat
   l = DateDiff(tm, Now, gb.Millisecond)
   Write "\r\e[0mDurata: " & Time(0, 0, 0, durata / 1000000) & "      Pos. \e[31m" & Time(0, 0, 0, l)
   Wait 0.001
 Until l >= durata / 1000000

 gst_object_unref(midi)
 Print "\nEsecuzione terminata."
  
End


Riferimenti

Estratto da "https://www.gambas-it.org/wiki/index.php?title=Visualizzare_un_oscilloscopio_di_GStreamer_mediante_la_funzione_%27gst_parse_launch()%27_durante_l%27esecuzione_di_un_file_Midi&oldid=39100"