#!/usr/bin/env python3 # Demonstration of using compositor and the samples-selected # signal to do frame-by-frame updates and animation by # udpating compositor pad properties and the GstVideoConverter # config. # # Supply a URI argument to use a video file in the example, # or omit it to just animate a videotestsrc. import gi import math import sys gi.require_version('Gst', '1.0') gi.require_version('GstVideo', '1.0') gi.require_version('GLib', '2.0') gi.require_version('GObject', '2.0') from gi.repository import GLib, GObject, Gst, GstVideo def bus_call(bus, message, loop): t = message.type if t == Gst.MessageType.EOS: sys.stdout.write("End-of-stream\n") loop.quit() elif t == Gst.MessageType.ERROR: err, debug = message.parse_error() sys.stderr.write("Error: %s: %s\n" % (err, debug)) loop.quit() return True def update_compositor(comp, seg, pts, dts, duration, info): sink = comp.get_static_pad("sink_1") # Can peek at the input sample(s) here to get the real video input caps sample = comp.peek_next_sample(sink) caps = sample.get_caps() in_w = caps[0]['width'] in_h = caps[0]['height'] dest_w = 160 + in_w * math.fabs(math.sin(pts / (10 * Gst.SECOND) * math.pi)) dest_h = 120 + in_h * math.fabs(math.sin(pts / (11 * Gst.SECOND) * math.pi)) x = (1920 - dest_w) * math.fabs(math.sin(pts / (5 * Gst.SECOND) * math.pi)) y = (1080 - dest_h) * math.fabs(math.sin(pts / (7 * Gst.SECOND) * math.pi)) sink.set_property("xpos", x) sink.set_property("ypos", y) sink.set_property("width", dest_w) sink.set_property("height", dest_h) # Update video-converter settings cfg = Gst.Structure.new_empty("GstVideoConverter") # When scaling down, switch to nearest-neighbour scaling, otherwise use bilinear if in_w < dest_w or in_h < dest_h: cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_RESAMPLER_METHOD, GstVideo.VideoResamplerMethod.NEAREST) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_CHROMA_RESAMPLER_METHOD, GstVideo.VideoResamplerMethod.NEAREST) else: cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_RESAMPLER_METHOD, GstVideo.VideoResamplerMethod.LINEAR) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_CHROMA_RESAMPLER_METHOD, GstVideo.VideoResamplerMethod.LINEAR) # Crop some from the top and bottom or sides of the source image crop = 64 * math.cos(pts / (4 * Gst.SECOND) * math.pi) if crop < 0: crop = min(in_w / 2, -crop) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_SRC_X, int(crop)) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_SRC_WIDTH, int(in_w - 2 * crop)) else: crop = min(in_h / 2, crop) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_SRC_Y, int(crop)) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_SRC_HEIGHT, int(in_h - 2 * crop)) # Add add some borders to the result by not filling the destination rect border = 64 * math.sin(pts / (4 * Gst.SECOND) * math.pi) if border < 0: border = min(in_w / 2, -border) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DEST_X, int(border)) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DEST_WIDTH, int(dest_w - 2 * border)) else: border = min(in_h / 2, border) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DEST_Y, int(border)) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DEST_HEIGHT, int(dest_h - 2 * border)) # Set the border colour. Need to set this into a GValue explicitly to ensure it's a uint argb = GObject.Value() argb.init(GObject.TYPE_UINT) argb.set_uint(0x80FF80FF) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_BORDER_ARGB, argb) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_FILL_BORDER, True) # When things get wide, do some dithering why not if dest_w > in_w: # Dither quantization must also be a uint dither = GObject.Value() dither.init(GObject.TYPE_UINT) dither.set_uint(64) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DITHER_METHOD, GstVideo.VideoDitherMethod.FLOYD_STEINBERG) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DITHER_QUANTIZATION, dither) else: dither = GObject.Value() dither.init(GObject.TYPE_UINT) dither.set_uint(1) # cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DITHER_METHOD, GstVideo.VideoDitherMethod.NONE) cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_DITHER_QUANTIZATION, dither) # and fade it in and out every 13 seconds alpha = 0.25 + 0.75 * math.fabs(math.sin(pts / (13 * Gst.SECOND) * math.pi)) # Use the video-converter to render alpha # cfg.set_value(GstVideo.VIDEO_CONVERTER_OPT_ALPHA_VALUE, alpha) # or use the pad's alpha setting is better because compositor can use it to skip rendering sink.set_property("alpha", alpha) # print(f"Setting config {cfg}") sink.set_property("converter-config", cfg) if __name__ == "__main__": Gst.init(sys.argv) pipeline = Gst.ElementFactory.make('pipeline', None) compositor = Gst.ElementFactory.make("compositor", None) compositor.set_property("emit-signals", True) compositor.set_property("background", "black") compositor.connect("samples-selected", update_compositor) cf = Gst.ElementFactory.make("capsfilter", None) # Need to make sure the output has RGBA or AYUV, or we can't do alpha blending / fades: caps = Gst.Caps.from_string("video/x-raw,width=1920,height=1080,framerate=25/1,format=RGBA") cf.set_property("caps", caps) conv = Gst.ElementFactory.make("videoconvert", None) sink = Gst.ElementFactory.make("autovideosink", None) pipeline.add(compositor, cf, conv, sink) Gst.Element.link_many(compositor, cf, conv, sink) bgsource = Gst.parse_bin_from_description("videotestsrc pattern=circular ! capsfilter name=cf", False) cfsrc = bgsource.get_by_name("cf") caps = Gst.Caps.from_string("video/x-raw,width=320,height=180,framerate=1/1,format=RGB") cfsrc.set_property("caps", caps) src = cfsrc.get_static_pad("src") bgsource.add_pad(Gst.GhostPad.new("src", src)) pipeline.add(bgsource) bgsource.link(compositor) pad = compositor.get_static_pad("sink_0") pad.set_property("width", 1920) pad.set_property("height", 1080) if len(sys.argv) > 1: source = Gst.parse_bin_from_description("uridecodebin name=u ! capsfilter name=cf caps=video/x-raw", False) u = source.get_by_name("u") u.set_property("uri", sys.argv[1]) cfsrc = source.get_by_name("cf") caps = Gst.Caps.from_string("video/x-raw") cfsrc.set_property("caps", caps) # Expose the capsfilter source pad as a ghost pad src = cfsrc.get_static_pad("src") source.add_pad(Gst.GhostPad.new("src", src)) else: source = Gst.parse_bin_from_description("videotestsrc ! capsfilter name=cf", False) cfsrc = source.get_by_name("cf") caps = Gst.Caps.from_string("video/x-raw,width=320,height=240,framerate=30/1,format=I420") cfsrc.set_property("caps", caps) src = cfsrc.get_static_pad("src") source.add_pad(Gst.GhostPad.new("src", src)) pipeline.add(source) source.link(compositor) pipeline.set_state(Gst.State.PLAYING) bus = pipeline.get_bus() bus.add_signal_watch() loop = GLib.MainLoop() bus.connect("message", bus_call, loop) loop.run() pipeline.set_state(Gst.State.NULL) pipeline.get_state(Gst.CLOCK_TIME_NONE)