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Development Team/Almanac/GStreamer: Difference between revisions

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{{Sugar Almanac}}
{{Almanac}}


=== Where can I get additional resources and sample code on using the camera? ===
=== Where can I get additional resources and sample code on using the camera? ===
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=== How can I play back video files in my activity? ===
=== 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.
Sugar, by default, can play back audio (encoded in Vorbis) and video (encoded in Theora) files in ogg containers.


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def setFile(self, path):
def setFile(self, path):
uri = "file://" + str( path )
uri = "file://" + str( path )
if (self.player.get_property('uri') == uri):
if self.player.get_property('uri') == uri:
self.seek(gst.SECOND*0)
self.seek(gst.SECOND*0)
return
return
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self.player.set_property('uri', uri)
self.player.set_property('uri', uri)
ext = uri[len(uri)-3:]
ext = uri[len(uri)-3:]
if (ext == "jpg"):
if ext == "jpg":
self.pause()
self.pause()
else:
else:
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def set_sink(self, sink):
def set_sink(self, sink):
if (self.imagesink != None):
if self.imagesink != None:
assert self.window.xid
assert self.window.xid
self.imagesink = None
self.imagesink = None
Line 143: Line 143:
self.gplayWin.resize( 300, 400 )
self.gplayWin.resize( 300, 400 )
self.gplayWin.show_all( )
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>
</pre>
Retrieved from "https://wiki.sugarlabs.org/go/Development_Team/Almanac/GStreamer"