Source Code for Module flumotion.common.gstreamer

  1  # -*- Mode: Python; test-case-name: flumotion.test.test_common_gstreamer -*- 
  2  # vi:si:et:sw=4:sts=4:ts=4 
  3  # 
  4  # Flumotion - a streaming media server 
  5  # Copyright (C) 2004,2005,2006,2007 Fluendo, S.L. (www.fluendo.com). 
  6  # All rights reserved. 
  7   
  8  # This file may be distributed and/or modified under the terms of 
  9  # the GNU General Public License version 2 as published by 
 10  # the Free Software Foundation. 
 11  # This file is distributed without any warranty; without even the implied 
 12  # warranty of merchantability or fitness for a particular purpose. 
 13  # See "LICENSE.GPL" in the source distribution for more information. 
 14   
 15  # Licensees having purchased or holding a valid Flumotion Advanced 
 16  # Streaming Server license may use this file in accordance with the 
 17  # Flumotion Advanced Streaming Server Commercial License Agreement. 
 18  # See "LICENSE.Flumotion" in the source distribution for more information. 
 19   
 20  # Headers in this file shall remain intact. 
 21   
 22  """gstreamer helpers 
 23  """ 
 24   
 25  from twisted.internet import defer 
 26  # moving this down causes havoc when running this file directly for some reason 
 27  from flumotion.common import errors, log 
 28   
 29  import gobject 
 30  import gst 
 31   
 32  __version__ = "$Rev: 6964 $" 
 33   
 34   
 35 -def caps_repr(caps): 
 36      """ 
 37      Represent L{gst.Caps} as a string. 
 38   
 39      @rtype: string 
 40      """ 
 41      value = str(caps) 
 42      pos = value.find('streamheader') 
 43      if pos != -1: 
 44          return 'streamheader=<...>' 
 45      else: 
 46          return value 
 47   
 48 -def verbose_deep_notify_cb(object, orig, pspec, component): 
 49      """ 
 50      A default deep-notify signal handler for pipelines. 
 51      """ 
 52      value = orig.get_property(pspec.name) 
 53      if pspec.value_type == gobject.TYPE_BOOLEAN: 
 54          if value: 
 55              value = 'TRUE' 
 56          else: 
 57              value = 'FALSE' 
 58          output = value 
 59      elif pspec.value_type == gst.Caps.__gtype__: 
 60          output = caps_repr(value) 
 61      else: 
 62          output = value 
 63   
 64      # Filters 
 65      if pspec.name == 'active': 
 66          return 
 67      if pspec.name == 'caps' and output == 'None': 
 68          return 
 69   
 70      component.debug('%s: %s = %r', orig.get_path_string(), pspec.name, output) 
 71   
 72 -def element_factory_has_property(element_factory, property_name): 
 73      """ 
 74      Check if the given element factory has the given property. 
 75   
 76      @rtype: boolean 
 77      """ 
 78      # FIXME: find a better way than instantiating one 
 79      e = gst.element_factory_make(element_factory) 
 80      for pspec in gobject.list_properties(e): 
 81          if pspec.name == property_name: 
 82              return True 
 83      return False 
 84   
 85 -def element_factory_has_property_value(element_factory, property_name, value): 
 86      """ 
 87      Check if the given element factory allows the given value for the given property. 
 88   
 89      @rtype: boolean 
 90      """ 
 91      # FIXME: find a better way than instantiating one 
 92      e = gst.element_factory_make(element_factory) 
 93      try: 
 94          e.set_property(property_name, value) 
 95      except TypeError: 
 96          return False 
 97   
 98      return True 
 99   
100 -def element_factory_exists(name): 
101      """ 
102      Check if the given element factory name exists. 
103   
104      @rtype: boolean 
105      """ 
106      registry = gst.registry_get_default() 
107      factory = registry.find_feature(name, gst.TYPE_ELEMENT_FACTORY) 
108   
109      if factory: 
110          return True 
111   
112      return False 
113   
114 -def get_plugin_version(plugin_name): 
115      """ 
116      Find the version of the given plugin. 
117   
118      @rtype: tuple of (major, minor, micro, nano), or None if it could not be 
119              found or determined 
120      """ 
121      plugin = gst.registry_get_default().find_plugin(plugin_name) 
122   
123      if not plugin: 
124          return None 
125   
126      versionTuple = tuple([int(x) for x in plugin.get_version().split('.')]) 
127      if len(versionTuple) < 4: 
128          versionTuple = versionTuple + (0,) 
129      return versionTuple 
130   
131  # GstPython should have something for this, but doesn't. 
132 -def get_state_change(old, new): 
133      table = {(gst.STATE_NULL, gst.STATE_READY): 
134               gst.STATE_CHANGE_NULL_TO_READY, 
135               (gst.STATE_READY, gst.STATE_PAUSED): 
136               gst.STATE_CHANGE_READY_TO_PAUSED, 
137               (gst.STATE_PAUSED, gst.STATE_PLAYING): 
138               gst.STATE_CHANGE_PAUSED_TO_PLAYING, 
139               (gst.STATE_PLAYING, gst.STATE_PAUSED): 
140               gst.STATE_CHANGE_PLAYING_TO_PAUSED, 
141               (gst.STATE_PAUSED, gst.STATE_READY): 
142               gst.STATE_CHANGE_PAUSED_TO_READY, 
143               (gst.STATE_READY, gst.STATE_NULL): 
144               gst.STATE_CHANGE_READY_TO_NULL} 
145      return table.get((old, new), 0) 
146   
147 -class StateChangeMonitor(dict, log.Loggable): 
148 -    def __init__(self): 
149          # statechange -> [ deferred ] 
150          dict.__init__(self) 
151   
152 -    def add(self, statechange): 
153          if statechange not in self: 
154              self[statechange] = [] 
155   
156          d = defer.Deferred() 
157          self[statechange].append(d) 
158   
159          return d 
160   
161 -    def state_changed(self, old, new): 
162          self.log('state change: pipeline %s->%s', 
163                   old.value_nick, new.value_nick) 
164          change = get_state_change(old, new) 
165          if change in self: 
166              dlist = self[change] 
167              for d in dlist: 
168                  d.callback(None) 
169              del self[change] 
170   
171 -    def have_error(self, curstate, message): 
172          # if we have a state change defer that has not yet 
173          # fired, we should errback it 
174          changes = [gst.STATE_CHANGE_NULL_TO_READY, 
175                     gst.STATE_CHANGE_READY_TO_PAUSED, 
176                     gst.STATE_CHANGE_PAUSED_TO_PLAYING] 
177   
178          extras = ((gst.STATE_PAUSED, gst.STATE_CHANGE_PLAYING_TO_PAUSED), 
179                    (gst.STATE_READY, gst.STATE_CHANGE_PAUSED_TO_READY), 
180                    (gst.STATE_NULL, gst.STATE_CHANGE_READY_TO_NULL)) 
181          for state, change in extras: 
182              if curstate <= state: 
183                  changes.append(change) 
184   
185          for change in changes: 
186              if change in self: 
187                  self.log("We have an error, going to errback pending " 
188                           "state change defers") 
189                  gerror, debug = message.parse_error() 
190                  for d in self[change]: 
191                      d.errback(errors.GStreamerGstError( 
192                          message.src, gerror, debug)) 
193                  del self[change] 
194