@@ Line 1: / Line 1: @@
-{{Sugar Almanac}}
+{{Almanac}}
 === Where can I get additional resources and sample code on using the camera? ===
 * [[Programming_the_camera]]
+=== How can I embed video files in my activity? ===
+Sugar, by default, can play back audio (encoded in Vorbis) and video (encoded in Theora) files in ogg containers.
+The following file will be helpful for embedding video or audio files into your activity.  After the code posting is a code snippet showing how to use this.
+<pre>
+import gtk
+import pygtk
+pygtk.require('2.0')
+import sys
+import pygst
+pygst.require('0.10')
+import gst
+import gst.interfaces
+import gobject
+import time
+gobject.threads_init()
+class Gplay:
+	def __init__(self):
+		self.window = None
+		self.playing = False
+		self.player = gst.element_factory_make("playbin", "playbin")
+		xis = gst.element_factory_make("xvimagesink", "xvimagesink")
+		self.player.set_property("video-sink", xis)
+		bus = self.player.get_bus()
+		bus.enable_sync_message_emission()
+		bus.add_signal_watch()
+		self.SYNC_ID = bus.connect('sync-message::element', self._onSyncMessageCb)
+	def _onSyncMessageCb(self, bus, message):
+		if message.structure is None:
+			return True
+		if message.structure.get_name() == 'prepare-xwindow-id':
+			self.window.set_sink(message.src)
+			message.src.set_property('force-aspect-ratio', True)
+			return True
+	def setFile(self, path):
+		uri = "file://" + str( path )
+		if self.player.get_property('uri') == uri:
+			self.seek(gst.SECOND*0)
+			return
+		self.player.set_state(gst.STATE_READY)
+		self.player.set_property('uri', uri)
+		ext = uri[len(uri)-3:]
+		if ext == "jpg":
+			self.pause()
+		else:
+			self.play()
+	def queryPosition(self):
+		#"Returns a (position, duration) tuple"
+		try:
+			position, format = self.player.query_position(gst.FORMAT_TIME)
+		except:
+			position = gst.CLOCK_TIME_NONE
+		try:
+			duration, format = self.player.query_duration(gst.FORMAT_TIME)
+		except:
+			duration = gst.CLOCK_TIME_NONE
+		return (position, duration)
+	def seek(self, time):
+		event = gst.event_new_seek(1.0, gst.FORMAT_TIME, gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_ACCURATE, gst.SEEK_TYPE_SET, time, gst.SEEK_TYPE_NONE, 0)
+		res = self.player.send_event(event)
+		if res:
+			self.player.set_new_stream_time(0L)
+	def pause(self):
+		self.playing = False
+		self.player.set_state(gst.STATE_PAUSED)
+	def play(self):
+		self.playing = True
+		self.player.set_state(gst.STATE_PLAYING)
+	def stop(self):
+		self.playing = False
+		self.player.set_state(gst.STATE_NULL)
+		self.nextMovie()
+	def get_state(self, timeout=1):
+		return self.player.get_state(timeout=timeout)
+	def is_playing(self):
+		return self.playing
+class PlayVideoWindow(gtk.Window):
+	def __init__(self):
+		gtk.Window.__init__(self)
+		self.imagesink = None
+		self.unset_flags(gtk.DOUBLE_BUFFERED)
+		self.set_flags(gtk.APP_PAINTABLE)
+	def set_sink(self, sink):
+		if self.imagesink != None:
+			assert self.window.xid
+			self.imagesink = None
+			del self.imagesink
+		self.imagesink = sink
+		self.imagesink.set_xwindow_id(self.window.xid)
+</pre>
+And here is a code snippet showing how you would use this file to embed media playback in your activity:
+<pre>
+		#this is our video playback window
+		self.gplay = Gplay( )
+		self.gplayWin = PlayVideoWindow( )
+		self.gplay.window = self.gplayWin
+		self.gplayWin.set_type_hint( gtk.gdk.WINDOW_TYPE_HINT_DIALOG )
+		self.gplayWin.set_decorated( False )
+		self.gplayWin.set_transient_for( self ) #activity subclass
+		self.gplayWin.move( 100, 100 )
+		self.gplayWin.resize( 300, 400 )
+		self.gplayWin.show_all( )
+</pre>
+Alternatively, you could embed your video into a gtk.DrawingArea:
+<pre>
+class VideoWidget(gtk.DrawingArea):
+    def __init__(self):
+        gtk.DrawingArea.__init__(self)
+        self.set_events(gtk.gdk.POINTER_MOTION_MASK |
+        gtk.gdk.POINTER_MOTION_HINT_MASK |
+        gtk.gdk.EXPOSURE_MASK |
+        gtk.gdk.KEY_PRESS_MASK |
+        gtk.gdk.KEY_RELEASE_MASK)
+        self.imagesink = None
+        self.unset_flags(gtk.DOUBLE_BUFFERED)
+        self.set_flags(gtk.APP_PAINTABLE)
+    def do_expose_event(self, event):
+        if self.imagesink:
+            self.imagesink.expose()
+            return False
+        else:
+            return True
+    def set_sink(self, sink):
+        assert self.window.xid
+        self.imagesink = sink
+        self.imagesink.set_xwindow_id(self.window.xid)
+</pre>
+=== How can I add play/pause buttons and a scrubber to my audio or video? ===
+The widget below is pre-configured to work with the gplay class above.  This widget takes two gtk.Images in its constructor.
+<pre>
+import gtk
+import pygtk
+pygtk.require('2.0')
+import pygst
+pygst.require('0.10')
+import gst
+import gst.interfaces
+import gobject
+import sugar.graphics.style
+class GScrub(gtk.Window):
+	def __init__(self, gplay, playImg, pauseImg):
+		gtk.Window.__init__(self)
+		self._gplay = gplay
+		self._playImg = playImg
+		self._pauseImg = pauseImg
+		self.UPDATE_INTERVAL = 500
+		self.UPDATE_SCALE_ID = 0
+		self.CHANGED_ID = 0
+		self.was_playing = False
+		self.p_position = gst.CLOCK_TIME_NONE
+		self.p_duration = gst.CLOCK_TIME_NONE
+		self.hbox = gtk.HBox()
+		self.hbox.modify_bg( gtk.STATE_NORMAL, sugar.graphics.style.COLOR_BLACK.get_gdk_color() )
+		self.hbox.modify_bg( gtk.STATE_INSENSITIVE, sugar.graphics.style.COLOR_BLACK.get_gdk_color() )
+		self.add( self.hbox )
+		self.button = gtk.Button()
+		buttBox = gtk.EventBox()
+		buttBox.add(self.button)
+		buttBox.modify_bg( gtk.STATE_NORMAL, sugar.graphics.style.COLOR_BLACK.get_gdk_color() )
+		self.button.set_image( self._playImg )
+		self.button.set_property('can-default', True)
+		self.button.set_relief(gtk.RELIEF_NONE)
+		self.button.set_size_request( 55, 55 )
+		buttBox.set_size_request( 55, 55 )
+		self.button.show()
+		buttBox.modify_bg( gtk.STATE_NORMAL, sugar.graphics.style.COLOR_BLACK.get_gdk_color() )
+		self.button.modify_bg( gtk.STATE_ACTIVE, sugar.graphics.style.COLOR_BLACK.get_gdk_color() )
+		self.button.connect('clicked', self._buttonClickedCb)
+		self.hbox.pack_start(buttBox, expand=False)
+		self.adjustment = gtk.Adjustment(0.0, 0.00, 100.0, 0.1, 1.0, 1.0)
+		self.hscale = gtk.HScale(self.adjustment)
+		self.hscale.set_draw_value(False)
+		self.hscale.set_update_policy(gtk.UPDATE_CONTINUOUS)
+		hscaleBox = gtk.EventBox()
+		hscaleBox.modify_bg( gtk.STATE_NORMAL, sugar.graphics.style.COLOR_BLACK.get_gdk_color() )
+		hscaleBox.add( self.hscale )
+		self.hscale.connect('button-press-event', self._scaleButtonPressCb)
+		self.hscale.connect('button-release-event', self._scaleButtonReleaseCb)
+		self.hbox.pack_start(hscaleBox, expand=True)
+	def removeCallbacks( self ):
+		if self.UPDATE_SCALE_ID != 0:
+			gobject.source_remove(self.UPDATE_SCALE_ID)
+			self.UPDATE_SCALE_ID = 0
+		if self.CHANGED_ID != 0:
+			gobject.source_remove(self.CHANGED_ID)
+			self.CHANGED_ID = 0
+	def reset(self):
+		self.adjustment.set_value(0)
+	def _buttonClickedCb(self, widget):
+		self.play_toggled()
+	def set_button_play(self):
+		self.button.set_image(self._playImg)
+	def set_button_pause(self):
+		self.button.set_image(self._pauseImg)
+	def play_toggled(self):
+		self.p_position, self.p_duration = self._gplay.queryPosition()
+		if self.p_position == self.p_duration:
+			self._gplay.seek(0)
+			self._gplay.pause()
+		if self._gplay.is_playing():
+			self._gplay.pause()
+			self.set_button_play()
+		else:
+			#if self._gplay.error:
+			#	#todo: check if we have "error", and also to disable everything
+			#	self.button.set_disabled()
+			#else:
+			self.doPlay()
+	def doPlay(self):
+		self._gplay.play()
+		if self.UPDATE_SCALE_ID == 0:
+			self.UPDATE_SCALE_ID = gobject.timeout_add(self.UPDATE_INTERVAL, self._updateScaleCb)
+		self.set_button_pause()
+	def _scaleButtonPressCb(self, widget, event):
+		#self.button.set_sensitive(False)
+		self.was_playing = self._gplay.is_playing()
+		if self.was_playing:
+			self._gplay.pause()
+		# don't timeout-update position during seek
+		if self.UPDATE_SCALE_ID != 0:
+			gobject.source_remove(self.UPDATE_SCALE_ID)
+			self.UPDATE_SCALE_ID = 0
+		# make sure we get changed notifies
+		if self.CHANGED_ID == 0:
+			self.CHANGED_ID = self.hscale.connect('value-changed', self._scaleValueChangedCb)
+	def _scaleButtonReleaseCb(self, widget, event):
+		# see seek.cstop_seek
+		widget.disconnect(self.CHANGED_ID)
+		self.CHANGED_ID = 0
+		#self.button.set_sensitive(True)
+		if self.was_playing:
+			self._gplay.play()
+		if self.UPDATE_SCALE_ID != 0:
+			pass
+			#print('Had a previous update timeout id')
+		else:
+			self.UPDATE_SCALE_ID = gobject.timeout_add(self.UPDATE_INTERVAL, self._updateScaleCb)
+	def _scaleValueChangedCb(self, scale):
+		real = long(scale.get_value() * self.p_duration / 100) # in ns
+		self._gplay.seek(real)
+		# allow for a preroll
+		self._gplay.get_state(timeout=50*gst.MSECOND) # 50 ms
+	def _updateScaleCb(self):
+		self.p_position, self.p_duration = self._gplay.queryPosition()
+		if self.p_position != gst.CLOCK_TIME_NONE:
+			value = self.p_position * 100.0 / self.p_duration
+			if value > 99:
+				value = 99
+			elif value < 0:
+				value = 0
+			self.adjustment.set_value(value)
+			if self._gplay.is_playing() and self.p_position == self.p_duration:
+				self._gplay.pause()
+				self.set_button_play()
+		return True
+</pre>

Development Team/Almanac/GStreamer: Difference between revisions