python gstreamer 播放多个视频流

Question

我正在参与一个艺术项目，这个项目需要远程播放视频。我用Python写了一个简单的应用程序，里面有一个HTTP服务器和一个gstreamer视频播放器。我可以接收到HTTP请求并更换正在播放的视频，但我希望能在同一个窗口中添加新视频，并同时播放两个视频。

我使用了playbin2来播放视频，但我觉得它一次只能播放一个视频。我试着找其他方法来同时播放多个视频，但都没成功……

有没有人能给我一个简单的例子，教我怎么同时播放多个视频流，或者给我一些文档或其他资源的建议呢？

提前谢谢大家！！

附注：这是我写的代码：VideoPlayer类初始化了流，playCurrent函数用来切换当前播放的视频——我希望这个函数能直接把新视频添加到流中。

#!/usr/bin/python

import threading
import time
import BaseHTTPServer
from BaseHTTPServer import HTTPServer
from urlparse import urlparse, parse_qs
from os import path
import gst
import gtk



HOST_NAME = 'localhost' # !!!REMEMBER TO CHANGE THIS!!!
PORT_NUMBER = 9000 # Maybe set this to 9000.

#################################################################
# VIDEO DICTIONARY
# Manages the video database
#################################################################

# VideoDictionary class
#################################################################
# This class allows to access the video database
# used by the video player - for best performance, it's a native
# python dictionary
class VideoDictionary():

    # declaring filenames
    filename = path.join(path.dirname(path.abspath(__file__)), 'large.mp4')
    filename_02 = path.join(path.dirname(path.abspath(__file__)), '01.avi')

    # declaring uris
    uri = 'file://' + filename
    uri_02 = 'file://' + filename_02

    # combining it all into a dictionary
    videoDict = {}
    videoDict["01"] = uri
    videoDict["02"] = uri_02

    # setting the current video
    currentVideo = "01"

#################################################################
# VIDEO DICTIONARY END
#################################################################



#################################################################
# VIDEO PLAYER
# Manages all the video playing
#################################################################

# VideoPlayer class
#################################################################
# This class initializes the GST pipe context and it
# handles different events related to video stream playing
class VideoPlayer(object, VideoDictionary):

    VideoDictionary = ""

    def __init__(self, VideoDictionary):
        self.VideoDictionary = VideoDictionary        
        self.window = gtk.Window()
        self.window.connect('destroy', self.quit)
        self.window.set_default_size(1024, 768)

        self.drawingarea = gtk.DrawingArea()
        self.window.add(self.drawingarea)

        # Create GStreamer pipeline
        self.pipeline = gst.Pipeline()

        # Create bus to get events from GStreamer pipeline
        self.bus = self.pipeline.get_bus()

        # This is needed to make the video output in our DrawingArea:
        self.bus.enable_sync_message_emission()
        self.bus.connect('sync-message::element', self.on_sync_message)

        # Create GStreamer elements
        self.playbin = gst.element_factory_make('playbin2')

        # Add playbin2 to the pipeline
        self.pipeline.add(self.playbin)
        self.window.show_all()
        self.xid = self.drawingarea.window.xid
        print('DEBUG INFO: player initialization finished')

    def playCurrent(self):
        print('DEBUG INFO: getting running video ')
        print(self.VideoDictionary.currentVideo)
        self.pipeline.set_state(gst.STATE_READY)
        self.playbin.set_property('uri', self.VideoDictionary.videoDict[self.VideoDictionary.currentVideo])
        self.pipeline.set_state(gst.STATE_PLAYING)

    def quit(self, window):
        print('DEBUG INFO: quitting player')
        self.pipeline.set_state(gst.STATE_NULL)
        gtk.main_quit()

    def on_sync_message(self, bus, msg):
        if msg.structure.get_name() == 'prepare-xwindow-id':
            msg.src.set_property('force-aspect-ratio', True)
            msg.src.set_xwindow_id(self.xid)

    def on_eos(self, bus, msg):
        print('DEBUG INFO: EOS detected')
        print('on_eos(): seeking to start of video')
        self.pipeline.seek_simple(
            gst.FORMAT_TIME,        
            gst.SEEK_FLAG_FLUSH | gst.SEEK_FLAG_KEY_UNIT,
            0L
        )

    def on_error(self, bus, msg):
        print('DEBUG INFO: error detected')
        print('on_error():', msg.parse_error())

#################################################################
# VIDEO PLAYER END
#################################################################




#################################################################
# HTTP SERVER
# implements the http listener in a separate thread
# the listener plays the videos depending on the 
# received parameters in the GET request 
#################################################################

# HttpHandler class
#################################################################
# uses global variables to operate videos
class HttpHandler(BaseHTTPServer.BaseHTTPRequestHandler):

    def do_GET(self):
        # initialize the currently played video
        global VideoDictionary
        print('DEBUG INFO: GET running playCurrent')
        if VideoDictionary.currentVideo == "01":
            VideoDictionary.currentVideo = "02"
        else:
            VideoDictionary.currentVideo = "01"

        # play the video we have just set        
        global player
        player.playCurrent()        

# HttpThread class
#################################################################
# initializes the http listener in a separate thread
class HttpThread (threading.Thread):

    def __init__(self):
        threading.Thread.__init__(self)

    def run(self):
        gtk.gdk.threads_enter()
        server_class = BaseHTTPServer.HTTPServer
        httpd = server_class((HOST_NAME, PORT_NUMBER), HttpHandler)
        print time.asctime(), "Server Starts - %s:%s" % (HOST_NAME, PORT_NUMBER)
        try:
            httpd.serve_forever()
        except KeyboardInterrupt:
            pass
        httpd.server_close()
        print time.asctime(), "Server Stops - %s:%s" % (HOST_NAME, PORT_NUMBER)
        gtk.gdk.threads_leave()
        return

#################################################################
# HTTP SERVER END
#################################################################

if __name__ == '__main__':
    VideoDictionary = VideoDictionary()
    player = VideoPlayer(VideoDictionary)
    gtk.gdk.threads_init()
    thread2 = HttpThread()
    thread2.run()
    gtk.gdk.threads_enter()
    gtk.main()
    gtk.gdk.threads_leave()

http服务器流媒体视频流 GStreamer 视频播放器 playbin2 多媒体播放艺术项目

python gstreamer 播放多个视频流

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