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53 lines
2.1 KiB
Python
Executable file
53 lines
2.1 KiB
Python
Executable file
#!/usr/bin/python3
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# exampleTransform.py
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# 2019 Daniel Klamt <graphics@pengutronix.de>
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# Inverts a grayscale image in place, requires numpy.
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#
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# gst-launch-1.0 videotestsrc ! ExampleTransform ! videoconvert ! xvimagesink
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import gi
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gi.require_version('Gst', '1.0')
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gi.require_version('GstBase', '1.0')
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gi.require_version('GstVideo', '1.0')
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from gi.repository import Gst, GObject, GstBase, GstVideo
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import numpy as np
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Gst.init(None)
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FIXED_CAPS = Gst.Caps.from_string('video/x-raw,format=GRAY8,width=[1,2147483647],height=[1,2147483647]')
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class ExampleTransform(GstBase.BaseTransform):
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__gstmetadata__ = ('ExampleTransform Python','Transform',
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'example gst-python element that can modify the buffer gst-launch-1.0 videotestsrc ! ExampleTransform ! videoconvert ! xvimagesink', 'dkl')
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__gsttemplates__ = (Gst.PadTemplate.new("src",
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Gst.PadDirection.SRC,
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Gst.PadPresence.ALWAYS,
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FIXED_CAPS),
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Gst.PadTemplate.new("sink",
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Gst.PadDirection.SINK,
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Gst.PadPresence.ALWAYS,
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FIXED_CAPS))
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def do_set_caps(self, incaps, outcaps):
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struct = incaps.get_structure(0)
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self.width = struct.get_int("width").value
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self.height = struct.get_int("height").value
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return True
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def do_transform_ip(self, buf):
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try:
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with buf.map(Gst.MapFlags.READ | Gst.MapFlags.WRITE) as info:
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# Create a NumPy ndarray from the memoryview and modify it in place:
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A = np.ndarray(shape = (self.height, self.width), dtype = np.uint8, buffer = info.data)
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A[:] = np.invert(A)
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return Gst.FlowReturn.OK
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except Gst.MapError as e:
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Gst.error("Mapping error: %s" % e)
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return Gst.FlowReturn.ERROR
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GObject.type_register(ExampleTransform)
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__gstelementfactory__ = ("ExampleTransform", Gst.Rank.NONE, ExampleTransform)
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