如何在PyQt4 Phonon应用程序中使用GStreamer1.0？

Question

我有一个使用PyQt4和Phonon（带有gstreamer0.1后端）的音乐应用程序。我想用一些GStreamer代码添加一些音频分析。这两组代码独立运行良好，但是当我尝试将它们组合在同一个应用程序中时，出现以下错误并且应用程序挂起。测试代码如下。有任何想法吗？

> (python3:11922): GStreamer-WARNING **: Element factory metadata for 'bin' has no valid long-name field 

> phonon_gstreamer.py:110: Warning: cannot register existing type `GstObject'        
    self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self) 

> phonon_gstreamer.py:110: Warning: g_once_init_leave: assertion `result != 0' failed 
    self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self) 

> phonon_gstreamer.py:110: Warning: g_type_register_static: assertion `parent_type > 0' failed 
    self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self) 

> phonon_gstreamer.py:110: Warning: g_object_newv: assertion `G_TYPE_IS_OBJECT (object_type)' failed 
    self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self) 


from PyQt4 import QtGui 
from PyQt4.phonon import Phonon 

import gi 
gi.require_version('Gst', '1.0') 
from gi.repository import GObject, Gst 

class AudioAnalysis(Gst.Bin): 
    def __init__(self): 
     super().__init__() 

     # Create elements 
     q1 = Gst.ElementFactory.make('queue', None)   

     convert = Gst.ElementFactory.make("audioconvert", None) 
     resample = Gst.ElementFactory.make("audioresample", None)   
     self.analysis = Gst.ElementFactory.make("rganalysis", None) 
     self.analysis.set_property("num-tracks", 1) 

     q2 = Gst.ElementFactory.make('queue', None) 

     # Add elements to Bin 
     self.add(q1) 
     self.add(convert) 
     self.add(resample) 
     self.add(self.analysis) 
     self.add(q2) 

     # Link elements 
     q1.link(convert) 
     convert.link(resample) 
     resample.link(self.analysis) 
     self.analysis.link(q2) 

     # Add Ghost Pads 
     self.add_pad(
      Gst.GhostPad.new('sink', q1.get_static_pad('sink')) 
     ) 
     self.add_pad(
      Gst.GhostPad.new('src', q2.get_static_pad('src')) 
     ) 

    def bus_message_tag(self, bus, message): 
     pass 

class Example: 
    def __init__(self):   
     self.mainloop = GObject.MainLoop() 
     self.pipeline = Gst.Pipeline() 

     # Create elements 
     self.src = Gst.ElementFactory.make('filesrc', None) 
     self.dec = Gst.ElementFactory.make('decodebin', None) 
     self.audio = AudioAnalysis()   
     self.sink = Gst.ElementFactory.make('fakesink', None) 

     # Add elements to pipeline  
     self.pipeline.add(self.src) 
     self.pipeline.add(self.dec) 
     self.pipeline.add(self.audio) 
     self.pipeline.add(self.sink) 

     # Set properties 
     self.src.set_property('location', 'foo.mp3') 

     # Connect signal handlers 
     self.dec.connect('pad-added', self.on_pad_added) 
     self.dec.connect('pad-removed', self.removed_decoded_pad) 

     # Link elements 
     self.src.link(self.dec) 
     self.audio.link(self.sink) 

     self.bus = self.pipeline.get_bus() 
     self.bus.add_signal_watch() 
     self.bus.connect('message::eos', self.on_eos) 
     self.bus.connect('message::error', self.on_error) 
     self.bus.connect("message::tag", self.audio.bus_message_tag)  

    def run(self): 
     self.pipeline.set_state(Gst.State.PLAYING) 
     self.mainloop.run() 

    def kill(self): 
     self.pipeline.set_state(Gst.State.NULL) 
     self.mainloop.quit() 

    def removed_decoded_pad(self, dbin, pad): 
     pad.unlink(self.audio.get_static_pad("sink")) 

    def on_pad_added(self, element, pad): 
     string = pad.query_caps(None).to_string() 
     if string.startswith('audio/'): 
      pad.link(self.audio.get_static_pad('sink')) 

    def on_eos(self, bus, msg): 
     self.kill() 

    def on_error(self, bus, msg): 
     print('on_error():', msg.parse_error()) 
     self.kill() 

#example = Example() 
#example.run() 

class Window(QtGui.QPushButton): 
    def __init__(self): 
     QtGui.QPushButton.__init__(self, '') 
     self.mediaObject = Phonon.MediaObject(self) 
     self.audioOutput = Phonon.AudioOutput(Phonon.MusicCategory, self) 
     Phonon.createPath(self.mediaObject, self.audioOutput) 
     self.mediaObject.stateChanged.connect(self.handleStateChanged) 
     self.mediaObject.setCurrentSource(Phonon.MediaSource(sys.argv[1])) 
     self.mediaObject.play() 

    def handleStateChanged(self, newstate, oldstate): 
     if newstate == Phonon.PlayingState: 
      self.setText('Playing') 
     elif newstate == Phonon.StoppedState: 
      self.setText('Stopped') 
     elif newstate == Phonon.ErrorState: 
      source = self.mediaObject.currentSource().fileName() 
      print('ERROR: could not play:', source.toLocal8Bit().data()) 

if __name__ == '__main__': 

    GObject.threads_init() 
    Gst.init(None) 

    import sys 
    app = QtGui.QApplication(sys.argv) 
    app.setApplicationName('Phonon') 
    win = Window() 
    win.resize(200, 100) 
    win.show() 
    sys.exit(app.exec_()) 

Answer 1

这是不可能的。 Gstreamer 0.10和1.x不是平行链接的。

要么尝试使用这个分支：https://projects.kde.org/projects/kdesupport/phonon/phonon-gstreamer/repository/show?rev=1.0-porting（不稳定据我所知）

或者使用非声的GStreamer后端。或者您可以在分离过程中实施分析代码，而不要直接调用它。