Add functionality to set a marker when playback is replaced.

events.py

@@ -110,6 +110,7 @@ class Playback(Event):
         self._nextdata = None
         self._nextfs = None
         self._delay = False
+        self._setmark = None
 
         self._stream = sounddevice.OutputStream(
             samplerate=self._fs, device=self._device, channels=self._channels,
@@ -136,6 +137,9 @@ class Playback(Event):
                     raise sounddevice.CallbackStop()
                     self._current_frame += frames
                     frames = 0
+                if self._setmark is not None:
+                    self._eventrunner.activate(self._setmark)
+                    self._setmark = None
 
     def callback_fillchunk(self, outdata, offset, frames):
         chunksize = min(len(self._data) - self._current_frame, frames)
@@ -171,19 +175,20 @@ class Playback(Event):
         self._stream.close(True)
         self._stream = None
 
-    def replace(self, media, delay=False, loop=False):
+    def replace(self, media, delay=False, loop=False, setmark=None):
         self._nextdata, self._nextfs = soundfile.read(media)
         self._delay = delay
         self._nextloop = loop
+        self._setmark = setmark
         # We really should check that the media is the sampe shape as the
         # existing playback. But for now, let's trust the user. *cough*
 
-    def notify(self, message, fadetime=10, db=30, media=None, delay=False, *args, **kwargs):
+    def notify(self, message, fadetime=10, db=30, media=None, delay=False, setmark=None, *args, **kwargs):
         if message == 'fadeout':
             self._fadecurve = np.logspace(0, -db/10, fadetime * self._fs)
             self._fadeframe = 0
         elif message == 'replaceplayback':
-            self.replace(media, delay)
+            self.replace(media, delay, setmark=setmark)
         elif message == 'endloop':
             self._loop = False
 
@@ -215,18 +220,23 @@ class EndLoop(Event):
 
 
 class PlaybackNext(Event):
-    def __init__(self, media, delay=False, loop=False, *args, **kwargs):
+    def __init__(self, media, delay=False, loop=False, setmark=None, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._media = media
         self._delay = delay
         self._loop = loop
+        self._setmark = setmark
 
     def __repr__(self):
-        return '{}(at={}, media={}, delay={}, loop={})'.format(type(self).__name__, self._at, self._media, self._delay, self._loop)
+        return '{}(at={}, media={}, delay={}, loop={}, setmark={})'.format(type(self).__name__, self._at, self._media, self._delay, self._loop, self._setmark)
+
+    def prepare(self):
+        if self._setmark is not None:
+            self._at._timings.register_mark(self._setmark, None)
 
     def start(self):
         print("Replacing playback")
-        self._eventrunner.notify('replaceplayback', media=self._media, delay=self._delay, loop=self._loop)
+        self._eventrunner.notify('replaceplayback', media=self._media, delay=self._delay, loop=self._loop, setmark=self._setmark)
         self._eventrunner.finished(self)
 
 class SetTempo(Event):