python - 奇怪的视频间歇性错误 (GStreamer)

Question

我有一个运行 Python 2.7、PyGTK 2.24 和最新版本 PyGST 的项目。

我在以下代码中遇到奇怪的间歇性错误。对于第一个较长的错误，视频可以正常播放，并且只有在我关闭视频窗口后才会出现错误。第二个阻止窗口打开。

import pygtk
pygtk.require('2.0')
import gtk, pango
import pygst
pygst.require('0.10')
import gst
import Trailcrest
import os, sys

class Video:

    def __init__(self):

        def on_message(bus, message): 
            if message.type == gst.MESSAGE_EOS: 
                # End of Stream 
                player.set_state(gst.STATE_NULL) 
            elif message.type == gst.MESSAGE_ERROR: 
                player.set_state(gst.STATE_NULL) 
                (err, debug) = message.parse_error() 
                print "Error: %s" % err, debug

        def on_sync_message(bus, message):
            if message.structure is None: 
                return False 
            if message.structure.get_name() == "prepare-xwindow-id":
                if sys.platform == "win32":
                    win_id = videowidget.window.handle
                else:
                    win_id = videowidget.window.xid
                assert win_id
                imagesink = message.src 
                imagesink.set_property("force-aspect-ratio", True)
                imagesink.set_xwindow_id(win_id) 

        win = gtk.Window()
        win.set_resizable(False)
        win.set_has_frame(False)
        win.set_position(gtk.WIN_POS_CENTER)

        fixed = gtk.Fixed()
        win.add(fixed)
        fixed.show()

        videowidget = gtk.DrawingArea()
        fixed.put(videowidget, 0, 0)
        videowidget.set_size_request(640, 480)
        videowidget.show()

        # Setup GStreamer 
        player = gst.element_factory_make("playbin", "MultimediaPlayer")
        bus = player.get_bus() 
        bus.add_signal_watch() 
        bus.enable_sync_message_emission() 
        #used to get messages that GStreamer emits 
        bus.connect("message", on_message) 
        #used for connecting video to your application 
        bus.connect("sync-message::element", on_sync_message)
        player.set_property("uri", "file://" + os.getcwd() + "/VID/SEQ-GAME-OPEN.ogv") 
        player.set_state(gst.STATE_PLAYING)

        win.show()

def main():
    gtk.gdk.threads_init()
    gtk.main()
    return 0

if __name__ == "__main__":
    Video()
    main()

The program 'Video.py' received an X Window System error. This probably reflects a bug in the program. The error was 'BadIDChoice (invalid resource ID chosen for this connection)'. (Details: serial 373 error_code 14 request_code 1 minor_code 0) (Note to programmers: normally, X errors are reported asynchronously; that is, you will receive the error a while after causing it. To debug your program, run it with the --sync command line option to change this behavior. You can then get a meaningful backtrace from your debugger if you break on the gdk_x_error() function.)

关于此的快速说明...我按照说明在命令行中运行“python Video.py --sync”(我在 Kubuntu 上)，我再次收到该消息。

这是另一个错误 - 完全阻止播放的错误。

python: ../../src/xcb_io.c:221: poll_for_event: Assertion `(((long) (event_sequence) - (long) (dpy->request)) <= 0)' failed. Aborted

这些将逐字交替，但并不完美。我可以获得三个第一，两个第二，一个第一，一个第二，两个第一，等等。它总是不同的。

这到底是怎么回事？

Answer 1

需要与X server同步获取窗口xid。

方法如下:

    def on_sync_message(bus, message):
        if message.structure is None:
            return False
        if message.structure.get_name() == "prepare-xwindow-id":
            gtk.gdk.threads_enter()
            gtk.gdk.display_get_default().sync()
            win_id = videowidget.window.xid
            imagesink = message.src
            imagesink.set_property("force-aspect-ratio", True)
            imagesink.set_xwindow_id(win_id)
            gtk.gdk.threads_leave()