| import cairo |
| import contextlib |
| import ctypes |
| |
| import gi |
| gi.require_version('Gdk', '3.0') |
| gi.require_version('GObject', '2.0') |
| gi.require_version('Gst', '1.0') |
| gi.require_version('GstBase', '1.0') |
| gi.require_version('GstVideo', '1.0') |
| from gi.repository import Gdk, GObject, Gst, GstBase, GstVideo |
| |
| Gdk.init([]) |
| |
| # Gst.Buffer.map(Gst.MapFlags.WRITE) is broken, this is a workaround. See |
| # http://lifestyletransfer.com/how-to-make-gstreamer-buffer-writable-in-python/ |
| # https://gitlab.gnome.org/GNOME/gobject-introspection/issues/69 |
| class GstMapInfo(ctypes.Structure): |
| _fields_ = [('memory', ctypes.c_void_p), # GstMemory *memory |
| ('flags', ctypes.c_int), # GstMapFlags flags |
| ('data', ctypes.POINTER(ctypes.c_byte)), # guint8 *data |
| ('size', ctypes.c_size_t), # gsize size |
| ('maxsize', ctypes.c_size_t), # gsize maxsize |
| ('user_data', ctypes.c_void_p * 4), # gpointer user_data[4] |
| ('_gst_reserved', ctypes.c_void_p * 4)] # GST_PADDING |
| |
| # ctypes imports for missing or broken introspection APIs. |
| libgst = ctypes.CDLL('libgstreamer-1.0.so.0') |
| libgst.gst_context_writable_structure.restype = ctypes.c_void_p |
| libgst.gst_context_writable_structure.argtypes = [ctypes.c_void_p] |
| libgst.gst_structure_set.restype = ctypes.c_void_p |
| libgst.gst_structure_set.argtypes = [ctypes.c_void_p, ctypes.c_char_p, |
| ctypes.c_int, ctypes.c_void_p, ctypes.c_void_p] |
| GST_MAP_INFO_POINTER = ctypes.POINTER(GstMapInfo) |
| libgst.gst_buffer_map.argtypes = [ctypes.c_void_p, GST_MAP_INFO_POINTER, ctypes.c_int] |
| libgst.gst_buffer_map.restype = ctypes.c_int |
| libgst.gst_buffer_unmap.argtypes = [ctypes.c_void_p, GST_MAP_INFO_POINTER] |
| libgst.gst_buffer_unmap.restype = None |
| libgst.gst_mini_object_is_writable.argtypes = [ctypes.c_void_p] |
| libgst.gst_mini_object_is_writable.restype = ctypes.c_int |
| |
| libgdk = ctypes.CDLL('libgdk-3.so.0') |
| libgdk.gdk_wayland_window_get_wl_surface.restype = ctypes.c_void_p |
| libgdk.gdk_wayland_window_get_wl_surface.argtypes = [ctypes.c_void_p] |
| libgdk.gdk_wayland_display_get_wl_display.restype = ctypes.c_void_p |
| libgdk.gdk_wayland_display_get_wl_display.argtypes = [ctypes.c_void_p] |
| |
| libcairo = ctypes.CDLL('libcairo.so.2') |
| libcairo.cairo_image_surface_create_for_data.restype = ctypes.c_void_p |
| libcairo.cairo_image_surface_create_for_data.argtypes = [ctypes.c_void_p, |
| ctypes.c_int, ctypes.c_int, ctypes.c_int, ctypes.c_int] |
| libcairo.cairo_surface_flush.restype = None |
| libcairo.cairo_surface_flush.argtypes = [ctypes.c_void_p] |
| libcairo.cairo_surface_destroy.restype = None |
| libcairo.cairo_surface_destroy.argtypes = [ctypes.c_void_p] |
| libcairo.cairo_surface_status.restype = ctypes.c_int |
| libcairo.cairo_surface_status.argtypes = [ctypes.c_void_p] |
| libcairo.cairo_format_stride_for_width.restype = ctypes.c_int |
| libcairo.cairo_format_stride_for_width.argtypes = [ctypes.c_int, ctypes.c_int] |
| libcairo.cairo_create.restype = ctypes.c_void_p |
| libcairo.cairo_create.argtypes = [ctypes.c_void_p] |
| libcairo.cairo_destroy.restype = None |
| libcairo.cairo_destroy.argtypes = [ctypes.c_void_p] |
| libcairo.cairo_scale.restype = None |
| libcairo.cairo_scale.argtypes = [ctypes.c_void_p, ctypes.c_double, ctypes.c_double] |
| |
| librsvg = ctypes.CDLL('librsvg-2.so.2') |
| librsvg.rsvg_handle_new_from_data.restype = ctypes.c_void_p |
| librsvg.rsvg_handle_new_from_data.argtypes = [ctypes.c_char_p, ctypes.c_size_t, ctypes.c_void_p] |
| librsvg.rsvg_handle_render_cairo.restype = ctypes.c_bool |
| librsvg.rsvg_handle_render_cairo.argtypes = [ctypes.c_void_p, ctypes.c_void_p] |
| librsvg.rsvg_handle_close.restype = ctypes.c_bool |
| librsvg.rsvg_handle_close.argtypes = [ctypes.c_void_p, ctypes.c_void_p] |
| |
| libgobject = ctypes.CDLL('libgobject-2.0.so.0') |
| libgobject.g_object_unref.restype = None |
| libgobject.g_object_unref.argtypes = [ctypes.c_void_p] |
| |
| def set_display_contexts(sink, widget): |
| handle = libgdk.gdk_wayland_window_get_wl_surface(hash(widget.get_window())) |
| sink.set_window_handle(handle) |
| |
| wl_display = libgdk.gdk_wayland_display_get_wl_display(hash(Gdk.Display.get_default())) |
| context = Gst.Context.new('GstWaylandDisplayHandleContextType', True) |
| structure = libgst.gst_context_writable_structure(hash(context)) |
| libgst.gst_structure_set(structure, ctypes.c_char_p('display'.encode()), |
| hash(GObject.TYPE_POINTER), wl_display, 0) |
| sink.set_context(context) |
| |
| @contextlib.contextmanager |
| def _gst_buffer_map(buffer, flags): |
| ptr = hash(buffer) |
| if flags & Gst.MapFlags.WRITE and libgst.gst_mini_object_is_writable(ptr) == 0: |
| raise ValueError('Buffer not writable') |
| |
| mapping = GstMapInfo() |
| success = libgst.gst_buffer_map(ptr, mapping, flags) |
| if not success: |
| raise RuntimeError('gst_buffer_map failed') |
| try: |
| yield ctypes.cast(mapping.data, ctypes.POINTER(ctypes.c_byte * mapping.size)).contents |
| finally: |
| libgst.gst_buffer_unmap(ptr, mapping) |
| |
| # GStreamer Element that attaches VideoOverlayComposition to buffers passing by. |
| class OverlayInjector(GstBase.BaseTransform): |
| __gstmetadata__ = ('<longname>', '<class>', '<description>', '<author>') |
| __gsttemplates__ = (Gst.PadTemplate.new('src', |
| Gst.PadDirection.SRC, |
| Gst.PadPresence.ALWAYS, |
| Gst.Caps.new_any()), |
| Gst.PadTemplate.new('sink', |
| Gst.PadDirection.SINK, |
| Gst.PadPresence.ALWAYS, |
| Gst.Caps.new_any())) |
| |
| @staticmethod |
| def _plugin_init(plugin): |
| gtype = GObject.type_register(OverlayInjector) |
| Gst.Element.register(plugin, 'overlayinjector', 0, gtype) |
| return True |
| |
| @staticmethod |
| def plugin_register(): |
| version = Gst.version() |
| Gst.Plugin.register_static( |
| version[0], version[1], # GStreamer version |
| '', # name |
| '', # description |
| OverlayInjector._plugin_init, # init_func |
| '', # version |
| 'unknown', # license |
| '', # source |
| '', # package |
| '' # origin |
| ) |
| |
| def __init__(self): |
| GstBase.BaseTransform.__init__(self) |
| GstBase.BaseTransform.set_in_place(self, True) |
| self.render_size = None |
| self.svg = None |
| self.rendered_svg = None |
| self.composition = None |
| self.scale_factor = 0.75 |
| |
| def set_svg(self, svg, render_size): |
| self.svg = svg |
| self.render_size = render_size |
| |
| def do_transform_ip(self, frame_buf): |
| self.render() |
| if self.composition: |
| # Note: Buffer IS writable (ref is 1 in native land). However gst-python |
| # took an additional ref so it's now 2 and gst_buffer_is_writable |
| # returns false. We can't modify the buffer without fiddling with refcount. |
| if frame_buf.mini_object.refcount != 2: |
| return Gst.FlowReturn.ERROR |
| frame_buf.mini_object.refcount -= 1 |
| GstVideo.buffer_add_video_overlay_composition_meta(frame_buf, self.composition) |
| frame_buf.mini_object.refcount += 1 |
| return Gst.FlowReturn.OK |
| |
| |
| def render(self): |
| if not self.svg: |
| self.composition = None |
| self.rendered_svg = None |
| return |
| |
| if self.svg == self.rendered_svg: |
| return |
| |
| overlay_size = self.render_size * self.scale_factor |
| stride = libcairo.cairo_format_stride_for_width( |
| int(cairo.FORMAT_ARGB32), overlay_size.width) |
| overlay_buffer = Gst.Buffer.new_allocate(None, |
| stride * overlay_size.height) |
| with _gst_buffer_map(overlay_buffer, Gst.MapFlags.WRITE) as mapped: |
| # Fill with transparency and create surface from buffer. |
| ctypes.memset(ctypes.addressof(mapped), 0, ctypes.sizeof(mapped)) |
| surface = libcairo.cairo_image_surface_create_for_data( |
| ctypes.addressof(mapped), |
| int(cairo.FORMAT_ARGB32), |
| overlay_size.width, |
| overlay_size.height, |
| stride) |
| |
| # Render the SVG overlay. |
| data = self.svg.encode('utf-8') |
| context = libcairo.cairo_create(surface) |
| libcairo.cairo_scale(context, self.scale_factor, self.scale_factor) |
| handle = librsvg.rsvg_handle_new_from_data(data, len(data), 0) |
| librsvg.rsvg_handle_render_cairo(handle, context) |
| librsvg.rsvg_handle_close(handle, 0) |
| libgobject.g_object_unref(handle) |
| libcairo.cairo_surface_flush(surface) |
| libcairo.cairo_surface_destroy(surface) |
| libcairo.cairo_destroy(context) |
| |
| # Attach overlay to VideoOverlayComposition. |
| GstVideo.buffer_add_video_meta(overlay_buffer, |
| GstVideo.VideoFrameFlags.NONE, GstVideo.VideoFormat.BGRA, |
| overlay_size.width, overlay_size.height) |
| rect = GstVideo.VideoOverlayRectangle.new_raw(overlay_buffer, |
| 0, 0, self.render_size.width, self.render_size.height, |
| GstVideo.VideoOverlayFormatFlags.PREMULTIPLIED_ALPHA) |
| self.composition = GstVideo.VideoOverlayComposition.new(rect) |
| self.rendered_svg = self.svg |
| |
| OverlayInjector.plugin_register() |
