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Diffstat (limited to 'examples/plugins/python/exampleTransform.py')
-rwxr-xr-x | examples/plugins/python/exampleTransform.py | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/examples/plugins/python/exampleTransform.py b/examples/plugins/python/exampleTransform.py new file mode 100755 index 0000000..3d9bdb3 --- /dev/null +++ b/examples/plugins/python/exampleTransform.py @@ -0,0 +1,49 @@ +#!/usr/bin/python3 +# exampleTransform.py +# 2019 Daniel Klamt <graphics@pengutronix.de> + +# Inverts a grayscale image in place, requires numpy. +# +# gst-launch-1.0 videotestsrc ! ExampleTransform ! videoconvert ! xvimagesink + +import gi +gi.require_version('Gst', '1.0') +gi.require_version('GstBase', '1.0') +gi.require_version('GstVideo', '1.0') + +from gi.repository import Gst, GObject, GstBase, GstVideo + +import numpy as np + +Gst.init(None) +FIXED_CAPS = Gst.Caps.from_string('video/x-raw,format=GRAY8,width=[1,2147483647],height=[1,2147483647]') + +class ExampleTransform(GstBase.BaseTransform): + __gstmetadata__ = ('ExampleTransform Python','Transform', + 'example gst-python element that can modify the buffer gst-launch-1.0 videotestsrc ! ExampleTransform ! videoconvert ! xvimagesink', 'dkl') + + __gsttemplates__ = (Gst.PadTemplate.new("src", + Gst.PadDirection.SRC, + Gst.PadPresence.ALWAYS, + FIXED_CAPS), + Gst.PadTemplate.new("sink", + Gst.PadDirection.SINK, + Gst.PadPresence.ALWAYS, + FIXED_CAPS)) + + def do_set_caps(self, incaps, outcaps): + struct = incaps.get_structure(0) + self.width = struct.get_int("width").value + self.height = struct.get_int("height").value + return True + + def do_transform_ip(self, buf): + with buf.map(Gst.MapFlags.READ | Gst.MapFlags.WRITE) as info: + # Create a NumPy ndarray from the memoryview and modify it in place: + A = np.ndarray(shape = (self.height, self.width), dtype = np.uint8, buffer = info.data) + A[:] = np.invert(A) + + return Gst.FlowReturn.OK + +GObject.type_register(ExampleTransform) +__gstelementfactory__ = ("ExampleTransform", Gst.Rank.NONE, ExampleTransform) |