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GStreamer Windows Audio Thread Priority hack
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| # | |
| # Proof of concept to hack around lack of thread priority in GStreamer on | |
| # Windows. See https://bugzilla.gnome.org/show_bug.cgi?id=781998 | |
| # | |
| from __future__ import print_function | |
| from ctypes.wintypes import BOOL, DWORD, HANDLE, LPCWSTR | |
| import ctypes as C | |
| avrt_dll = C.windll.LoadLibrary("avrt.dll") | |
| AvSetMmThreadCharacteristics = avrt_dll.AvSetMmThreadCharacteristicsW | |
| AvSetMmThreadCharacteristics.argtypes = [LPCWSTR, C.POINTER(DWORD)] | |
| AvSetMmThreadCharacteristics.restype = HANDLE | |
| AvRevertMmThreadCharacteristics = avrt_dll.AvRevertMmThreadCharacteristics | |
| AvRevertMmThreadCharacteristics.argtypes = [HANDLE] | |
| AvRevertMmThreadCharacteristics.restype = BOOL | |
| GetCurrentThreadId = C.windll.LoadLibrary("kernel32.dll").GetCurrentThreadId | |
| GetCurrentThreadId.argtypes = [] | |
| GetCurrentThreadId.restype = DWORD | |
| # | |
| # GST playbin boilerplate | |
| # | |
| from os.path import abspath | |
| import sys | |
| #import os | |
| #os.environ.setdefault('GST_DEBUG_DUMP_DOT_DIR', '.') | |
| from gi.repository import Gst, GObject | |
| def on_stream_status(bus, message): | |
| status = message.parse_stream_status() | |
| # A gstreamer thread starts | |
| if status.type == Gst.StreamStatusType.ENTER: | |
| obj = message.get_stream_status_object() | |
| # note that we use "Pro Audio" because it gives a higher priority, and | |
| # that's what Chrome does anyways... | |
| unused = DWORD() | |
| obj.task_handle = AvSetMmThreadCharacteristics("Pro Audio", C.byref(unused)) | |
| # A gstreamer thread ends | |
| elif status.type == Gst.StreamStatusType.LEAVE: | |
| obj = message.get_stream_status_object() | |
| task_handle = getattr(obj, 'task_handle', None) | |
| if task_handle: | |
| AvRevertMmThreadCharacteristics(task_handle) | |
| if __name__ == '__main__': | |
| Gst.init(None) | |
| player = Gst.ElementFactory.make('playbin') | |
| player.props.uri = 'file:///%s' % abspath(sys.argv[1]).replace('\\', '/') | |
| bus = player.get_bus() | |
| bus.connect('sync-message::stream-status', on_stream_status) | |
| bus.enable_sync_message_emission() | |
| player.set_state(Gst.State.PLAYING) | |
| ml = GObject.MainLoop() | |
| ml.run() | |
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