6c2f3cc378
* morituri/image/image.py: * morituri/test/test_common_checksum.py: * morituri/common/gstreamer.py (added): Factor out GstException and GstPipelineTask.
101 lines
2.9 KiB
Python
101 lines
2.9 KiB
Python
# -*- Mode: Python; test-case-name: morituri.test.test_common_gstreamer -*-
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# vi:si:et:sw=4:sts=4:ts=4
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# Morituri - for those about to RIP
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# Copyright (C) 2009 Thomas Vander Stichele
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# This file is part of morituri.
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#
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# morituri is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# morituri is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with morituri. If not, see <http://www.gnu.org/licenses/>.
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import os
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import struct
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import zlib
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import gst
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from morituri.common import common, task
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class GstException(Exception):
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def __init__(self, gerror, debug):
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self.args = (gerror, debug, )
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self.gerror = gerror
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self.debug = debug
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class GstPipelineTask(task.Task):
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"""
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I am a base class for tasks that use a GStreamer pipeline.
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I handle errors and raise them appropriately.
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"""
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def start(self, runner):
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task.Task.start(self, runner)
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desc = self.getPipelineDesc()
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self.debug('creating pipeline %r', desc)
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self.pipeline = gst.parse_launch(desc)
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self._bus = self.pipeline.get_bus()
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gst.debug('got bus %r' % self._bus)
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# a signal watch calls callbacks from an idle loop
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# self._bus.add_signal_watch()
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# sync emission triggers sync-message signals which calls callbacks
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# from the thread that signals, but happens immediately
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self._bus.enable_sync_message_emission()
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self._bus.connect('sync-message::eos', self.bus_eos_cb)
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self._bus.connect('sync-message::tag', self.bus_tag_cb)
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self._bus.connect('sync-message::error', self.bus_error_cb)
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self.parsed()
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self.debug('pausing pipeline')
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self.pipeline.set_state(gst.STATE_PAUSED)
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self.pipeline.get_state()
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self.debug('paused pipeline')
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if not self.exception:
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self.paused()
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else:
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raise self.exception
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def getPipelineDesc(self):
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raise NotImplementedError
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def parsed(self):
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"""
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Called after parsing the pipeline but before setting it to paused.
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"""
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pass
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def paused(self):
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"""
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Called after pipeline is paused
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"""
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pass
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def bus_eos_cb(self, bus, message):
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pass
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def bus_tag_cb(self, bus, message):
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pass
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def bus_error_cb(self, bus, message):
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exc = GstException(*message.parse_error())
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self.setAndRaiseException(exc)
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gst.debug('error, scheduling stop')
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#self.runner.schedule(0, self.stop)
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