path: root/voctogui/lib/videodisplay.py

import logging
from gi.repository import Gst

class VideoDisplay:
    """ Displays a Voctomix-Video-Stream into a GtkWidget """

    def __init__(self, drawing_area, port, play_audio=False, draw_callback=None, level_callback=None):
        self.log = logging.getLogger('VideoDisplay[%s]' % drawing_area.get_name())

        self.drawing_area = drawing_area
        self.draw_callback = draw_callback
        self.level_callback = level_callback

        # Setup Server-Connection, Demuxing and Decoding
        pipeline = """
            videotestsrc !
            timeoverlay !
            video/x-raw,width=1920,height=1080,framerate=25/1 !
        """.format(
            port=port
        )

        # If an overlay is required, add an cairooverlay-Element into the Video-Path
        if self.draw_callback:
            pipeline += """
                videoconvert !
                cairooverlay name=overlay !
                videoconvert !
            """

        # Video Display
        pipeline += """
            xvimagesink name=v
        """


        # If an Audio-Path is required, add an Audio-Path through a level-Element
        if self.level_callback or play_audio:
            pipeline += """
                audiotestsrc wave=blue-noise !
                audio/x-raw !
                level name=lvl interval=50000000 !
            """

            # If Playback is requested, push fo alsa
            if play_audio:
                pipeline += """
                    alsasink
                """

            # Otherwise just trash the Audio
            else:
                pipeline += """
                    fakesink
                """

        self.log.debug('Creating Display-Pipeline:\n%s', pipeline)
        self.pipeline = Gst.parse_launch(pipeline)

        self.drawing_area.realize()
        self.xid = self.drawing_area.get_property('window').get_xid()
        self.log.debug('Realized Drawing-Area with xid %u', self.xid)

        bus = self.pipeline.get_bus()
        bus.add_signal_watch()
        bus.enable_sync_message_emission()

        bus.connect('message::error', self.on_error)
        bus.connect("sync-message::element", self.on_syncmsg)

        if self.level_callback:
            bus.connect("message::element", self.on_level)

        if self.draw_callback:
            self.pipeline.get_by_name('overlay').connect('draw', self.on_draw)

        self.log.debug('Launching Display-Pipeline')
        self.pipeline.set_state(Gst.State.PLAYING)


    def on_syncmsg(self, bus, msg):
        if msg.get_structure().get_name() == "prepare-window-handle":
                self.log.info('Setting xvimagesink window-handle to %s', self.xid)
                msg.src.set_window_handle(self.xid)

    def on_error(self, bus, message):
        self.log.debug('Received Error-Signal on Display-Pipeline')
        (error, debug) = message.parse_error()
        self.log.debug('Error-Details: #%u: %s', error.code, debug)


    def on_level(self, bus, msg):
        if msg.src.name != 'lvl':
            return

        if msg.type != Gst.MessageType.ELEMENT:
            return

        peaks = msg.get_structure().get_value('peak')
        rms = msg.get_structure().get_value('rms')
        self.level_callback(peaks, rms)

    def on_draw(self, cairooverlay, cr, timestamp, duration):
        self.draw_callback(cr, timestamp, duration)