| #!/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_python() | |
| 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): | |
| try: | |
| 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 | |
| except Gst.MapError as e: | |
| Gst.error("Mapping error: %s" % e) | |
| return Gst.FlowReturn.ERROR | |
| GObject.type_register(ExampleTransform) | |
| __gstelementfactory__ = ("ExampleTransform", Gst.Rank.NONE, ExampleTransform) |