GStreamer xwidget

[Po Lu <luangruo@yahoo.com>]

[-- Attachment #1: Type: text/plain, Size: 506 bytes --]

I would like to install the following change that introduces a
GStreamer-based media widget.

It depends on GStreamer, gst-plugins-base, and gst-plugins-good and is
thus a compile-time option.

Right now, it can only display a test pattern, but getting that to work
and perform decently was a challenge (for instance, offscreen rendering
is not an option, instead the pipeline is dynamically built based on
available xwidget views, utilizing hardware acceleration and video
decoding if available).

WDYT?


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Implement-a-media-xwidget-based-on-GStreamer.patch --]
[-- Type: text/x-patch, Size: 31895 bytes --]

From 39a034aff24b2b64b028345aeae66c7aae6f8820 Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Thu, 18 Nov 2021 18:10:45 +0800
Subject: [PATCH] Implement a media xwidget based on GStreamer

* configure.ac: Add option to use GStreamer for media playback.
* doc/lispref/display.texi (Xwidgets): Document new functions
and xwidget type.

* src/Makefile.in (EMACS_CFLAGS): Add GStreamer cflags.
(LIBES): Add GStreamer linker options.

* etc/NEWS: Announce `media' xwidget.
* etc/xterm.c (x_scroll_run): Don't resize cairo surface
if not a GTK xwidget.
(x_term_init): Initialize GStreamer.

* src/xwidget.c (gst_create_window)
(gst_message_cb, unlink_gst_xwidget_view)
(check_gstreamer_dependencies): New functions.

(Fmake_xwidget): Add support for media xwidgets.
(Fxwidget_perform_lispy_event): Return nil if it doesn't make
sense to perform an event.
(Fxwidget_resize): Add support for media widgets.
(xwidget_button, xwidget_motion_or_crossing): Handle non-GTK
xwidgets.
(xwidget_expose): Handle media xwidgets.
(x_draw_xwidget_glyph_string): Set up GStreamer widgets if
appropriate.
(Fxwidget_size_request): Return nil on widgets that can't
have a size request.
(Fdelete_xwidget_view): Clean up after GStreamer.
(Fxwidget_media_pause, Fxwidget_media_play): New functions.

(syms_of_xwidget): New symbols and subrs.
(kill_xwidget): Clean up after GStreamer.

* src/xwidget.h (struct xwidget, struct xwidget_view): Add
GStreamer specific fields for media xwidgets.
(XWIDGET_VIEW_GTK_P): New macro.
---
 configure.ac             |  13 +
 doc/lispref/display.texi |  12 +
 etc/NEWS                 |   7 +
 src/Makefile.in          |   7 +-
 src/xterm.c              |  16 +-
 src/xwidget.c            | 536 +++++++++++++++++++++++++++++++--------
 src/xwidget.h            |  25 ++
 7 files changed, 508 insertions(+), 108 deletions(-)

diff --git a/configure.ac b/configure.ac
index c231c2ceae..ae3f28f8db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -485,6 +485,7 @@ AC_DEFUN
 OPTION_DEFAULT_ON([zlib],[don't compile with zlib decompression support])
 OPTION_DEFAULT_ON([modules],[don't compile with dynamic modules support])
 OPTION_DEFAULT_ON([threads],[don't compile with elisp threading support])
+OPTION_DEFAULT_OFF([gstreamer],[compile with xwidget video playback support using GStreamer])
 OPTION_DEFAULT_OFF([native-compilation],[compile with Emacs Lisp native compiler support])
 OPTION_DEFAULT_OFF([cygwin32-native-compilation],[use native compilation on 32-bit Cygwin])
 
@@ -2834,6 +2835,18 @@ AC_DEFUN
 fi
 AC_SUBST(XWIDGETS_OBJ)
 
+HAVE_GSTREAMER=no
+if test "$with_gstreamer" != "no" && test "${HAVE_X_WINDOWS}" = "yes" \
+   && test "${HAVE_XWIDGETS}" = "yes"; then
+  EMACS_CHECK_MODULES([GSTREAMER], "gstreamer-1.0 gstreamer-video-1.0")
+  if test "$HAVE_GSTREAMER" = "yes"; then
+    AC_DEFINE(HAVE_GSTREAMER, 1, [Define to 1 if using GStreamer for video support in xwidgets.])
+  fi
+fi
+
+AC_SUBST(GSTREAMER_CFLAGS)
+AC_SUBST(GSTREAMER_LIBS)
+
 CFLAGS=$OLD_CFLAGS
 LIBS=$OLD_LIBS
 
diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index dd2c6e003f..1b4a3d9a22 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -6797,6 +6797,8 @@ Xwidgets
 @table @code
 @item webkit
 The WebKit component.
+@item media
+A media widget that allows to display videos inside Emacs buffers.
 @end table
 
 The @var{width} and @var{height} arguments specify the widget size in
@@ -7004,6 +7006,16 @@ Xwidgets
 be passed as an index to @code{xwidget-webkit-goto-history}.
 @end defun
 
+@defun xwidget-media-pause xwidget
+Suspend playback of @var{xwidget}, a media xwidget.  You can later
+resume playback using @code{xwidget-media-play}.
+@end defun
+
+@defun xwidget-media-pause xwidget
+Start or resume playback of @var{xwidget}, a media xwidget.  You can
+later pause playback using @code{xwidget-media-pause}.
+@end defun
+
 @node Buttons
 @section Buttons
 @cindex buttons in buffers
diff --git a/etc/NEWS b/etc/NEWS
index cee2844be3..8cb5495b4e 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -488,6 +488,13 @@ This is a convenience function to extract the field data from
 
 ** Xwidgets
 
++++
+*** New xwidget type 'media'.
+This xwidget type allows to display video content inside Emacs buffers.
+You must have the GStreamer library installed, along with the plugins
+"xvimagesink", "queue", "videotestsrc" and "tee", and Emacs must be
+built with '--with-gstreamer'.
+
 ---
 *** New user option 'xwidget-webkit-buffer-name-format'.
 Using this option you can control how the xwidget-webkit buffers are
diff --git a/src/Makefile.in b/src/Makefile.in
index 4c5535f8ad..646392c051 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -333,6 +333,9 @@ LIBGMP =
 LIBGCCJIT_LIBS = @LIBGCCJIT_LIBS@
 LIBGCCJIT_CFLAGS = @LIBGCCJIT_CFLAGS@
 
+GSTREAMER_LIBS = @GSTREAMER_LIBS@
+GSTREAMER_CFLAGS = @GSTREAMER_CFLAGS@
+
 ## dynlib.o if necessary, else empty
 DYNLIB_OBJ = @DYNLIB_OBJ@
 
@@ -377,7 +380,7 @@ EMACS_CFLAGS=
   $(WEBKIT_CFLAGS) $(WEBP_CFLAGS) $(LCMS2_CFLAGS) \
   $(SETTINGS_CFLAGS) $(FREETYPE_CFLAGS) $(FONTCONFIG_CFLAGS) \
   $(HARFBUZZ_CFLAGS) $(LIBOTF_CFLAGS) $(M17N_FLT_CFLAGS) $(DEPFLAGS) \
-  $(LIBSYSTEMD_CFLAGS) $(JSON_CFLAGS) \
+  $(LIBSYSTEMD_CFLAGS) $(JSON_CFLAGS) $(GSTREAMER_CFLAGS) \
   $(LIBGNUTLS_CFLAGS) $(NOTIFY_CFLAGS) $(CAIRO_CFLAGS) \
   $(WERROR_CFLAGS)
 ALL_CFLAGS = $(EMACS_CFLAGS) $(WARN_CFLAGS) $(CFLAGS)
@@ -524,7 +527,7 @@ LIBES =
    $(FREETYPE_LIBS) $(FONTCONFIG_LIBS) $(HARFBUZZ_LIBS) $(LIBOTF_LIBS) $(M17N_FLT_LIBS) \
    $(LIBGNUTLS_LIBS) $(LIB_PTHREAD) $(GETADDRINFO_A_LIBS) $(LCMS2_LIBS) \
    $(NOTIFY_LIBS) $(LIB_MATH) $(LIBZ) $(LIBMODULES) $(LIBSYSTEMD_LIBS) \
-   $(JSON_LIBS) $(LIBGMP) $(LIBGCCJIT_LIBS)
+   $(JSON_LIBS) $(LIBGMP) $(LIBGCCJIT_LIBS) $(GSTREAMER_LIBS)
 
 ## FORCE it so that admin/unidata can decide whether this file is
 ## up-to-date.  Although since charprop depends on bootstrap-emacs,
diff --git a/src/xterm.c b/src/xterm.c
index 816b6dc5a8..a7116d9d95 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -4471,9 +4471,11 @@ x_scroll_run (struct window *w, struct run *run)
 					 view->y + view->clip_top,
 					 view->clip_right - view->clip_left,
 					 view->clip_bottom - view->clip_top);
-		      cairo_xlib_surface_set_size (view->cr_surface,
-						   view->clip_right - view->clip_left,
-						   view->clip_bottom - view->clip_top);
+
+		      if (XWIDGET_VIEW_GTK_P (view))
+			cairo_xlib_surface_set_size (view->cr_surface,
+						     view->clip_right - view->clip_left,
+						     view->clip_bottom - view->clip_top);
 		    }
 		  xwidget_expose (view);
 		  XFlush (dpy);
@@ -12940,6 +12942,14 @@ #define NUM_ARGV 10
         gtk_init (&argc, &argv2);
         request_sigio ();
 
+#ifdef HAVE_GSTREAMER
+	unrequest_sigio ();
+	/* gst_init might call XOpenDisplay, which fails if a signal
+	   is received.  */
+	gst_init (&argc, &argv2);
+	request_sigio ();
+#endif
+
         g_log_remove_handler ("GLib", id);
 
         xg_initialize ();
diff --git a/src/xwidget.c b/src/xwidget.c
index e1bf40ea43..ffed743412 100644
--- a/src/xwidget.c
+++ b/src/xwidget.c
@@ -40,6 +40,10 @@ Copyright (C) 2011-2021 Free Software Foundation, Inc.
 #include <JavaScriptCore/JavaScript.h>
 #include <cairo.h>
 #include <X11/Xlib.h>
+#ifdef HAVE_GSTREAMER
+#include <gst/video/videooverlay.h>
+#define XG_WINDOW_HANDLE "xg-window-handle"
+#endif
 #elif defined NS_IMPL_COCOA
 #include "nsxwidget.h"
 #endif
@@ -111,6 +115,12 @@ webkit_decide_policy_cb (WebKitWebView *,
 static void find_widget (GtkWidget *t, struct widget_search_data *);
 static void mouse_target_changed (WebKitWebView *, WebKitHitTestResult *, guint,
 				  gpointer);
+#ifdef HAVE_GSTREAMER
+static GstBusSyncReply gst_create_window (GstBus *, GstMessage *, gpointer);
+static gboolean gst_message_cb (GstBus *, GstMessage *, gpointer);
+static bool check_gstreamer_dependencies (void);
+static void unlink_gst_xwidget_view (struct xwidget_view *);
+#endif
 #endif
 
 
@@ -123,6 +133,7 @@ DEFUN ("make-xwidget",
 TYPE is a symbol which can take one of the following values:
 
 - webkit
+- media
 
 RELATED is nil, or an xwidget.  When constructing a WebKit widget, it
 will share the same settings and internal subprocess as RELATED.
@@ -140,9 +151,18 @@ DEFUN ("make-xwidget",
   CHECK_FIXNAT (width);
   CHECK_FIXNAT (height);
 
-  if (!EQ (type, Qwebkit))
+  if (!EQ (type, Qwebkit) && !EQ (type, Qmedia))
     error ("Bad xwidget type");
 
+#ifdef HAVE_GSTREAMER
+  if (EQ (type, Qmedia)
+      && !check_gstreamer_dependencies ())
+    error ("Your Emacs is missing run-time dependencies required for GStreamer support");
+#else
+  if (EQ (type, Qmedia))
+    error ("Your Emacs was not built with GStreamer support");
+#endif
+
   struct xwidget *xw = allocate_xwidget ();
   Lisp_Object val;
   xw->type = type;
@@ -180,103 +200,142 @@ DEFUN ("make-xwidget",
       gtk_window_resize (GTK_WINDOW (xw->widgetwindow_osr), xw->width,
                          xw->height);
 
-      if (EQ (xw->type, Qwebkit))
-        {
-	  WebKitWebView *related_view;
+      xw->xg_p = true;
+      WebKitWebView *related_view;
+
+      if (NILP (related)
+	  || !XWIDGETP (related)
+	  || !EQ (XXWIDGET (related)->type, Qwebkit))
+	{
+	  xw->widget_osr = webkit_web_view_new ();
+
+	  webkit_web_view_load_uri (WEBKIT_WEB_VIEW (xw->widget_osr),
+				    "about:blank");
+	  /* webkitgtk uses GSubprocess which sets sigaction causing
+	     Emacs to not catch SIGCHLD with its usual handle setup in
+	     'catch_child_signal'.  This resets the SIGCHLD sigaction.  */
+	  catch_child_signal ();
+	}
+      else
+	{
+	  related_view = WEBKIT_WEB_VIEW (XXWIDGET (related)->widget_osr);
+	  xw->widget_osr = webkit_web_view_new_with_related_view (related_view);
+	}
+
+      /* Enable the developer extras.  */
+      settings = webkit_web_view_get_settings (WEBKIT_WEB_VIEW (xw->widget_osr));
+      g_object_set (G_OBJECT (settings), "enable-developer-extras", TRUE, NULL);
+
+      if (xw->xg_p)
+	{
+	  gtk_widget_set_size_request (GTK_WIDGET (xw->widget_osr), xw->width,
+				       xw->height);
 
-	  if (NILP (related)
-	      || !XWIDGETP (related)
-	      || !EQ (XXWIDGET (related)->type, Qwebkit))
+	  if (EQ (xw->type, Qwebkit))
 	    {
-	      xw->widget_osr = webkit_web_view_new ();
-
-	      webkit_web_view_load_uri (WEBKIT_WEB_VIEW (xw->widget_osr),
-					"about:blank");
-	      /* webkitgtk uses GSubprocess which sets sigaction causing
-		 Emacs to not catch SIGCHLD with its usual handle setup in
-		 'catch_child_signal'.  This resets the SIGCHLD sigaction.  */
-	      catch_child_signal ();
+	      gtk_container_add (GTK_CONTAINER (xw->widgetwindow_osr),
+				 GTK_WIDGET (WEBKIT_WEB_VIEW (xw->widget_osr)));
 	    }
 	  else
 	    {
-	      related_view = WEBKIT_WEB_VIEW (XXWIDGET (related)->widget_osr);
-	      xw->widget_osr = webkit_web_view_new_with_related_view (related_view);
+	      gtk_container_add (GTK_CONTAINER (xw->widgetwindow_osr),
+				 xw->widget_osr);
 	    }
 
-	  /* Enable the developer extras.  */
-	  settings = webkit_web_view_get_settings (WEBKIT_WEB_VIEW (xw->widget_osr));
-	  g_object_set (G_OBJECT (settings), "enable-developer-extras", TRUE, NULL);
+	  gtk_widget_show (xw->widget_osr);
+	  gtk_widget_show (xw->widgetwindow_osr);
+	  synthesize_focus_in_event (xw->widgetwindow_osr);
+
+
+	  g_signal_connect (G_OBJECT (gtk_widget_get_window (xw->widgetwindow_osr)),
+			    "from-embedder", G_CALLBACK (from_embedder), NULL);
+	  g_signal_connect (G_OBJECT (gtk_widget_get_window (xw->widgetwindow_osr)),
+			    "to-embedder", G_CALLBACK (to_embedder), NULL);
+
+	  /* Store some xwidget data in the gtk widgets for convenient
+	     retrieval in the event handlers.  */
+	  g_object_set_data (G_OBJECT (xw->widget_osr), XG_XWIDGET, xw);
+	  g_object_set_data (G_OBJECT (xw->widgetwindow_osr), XG_XWIDGET, xw);
+
+	  /* signals */
+	  if (EQ (xw->type, Qwebkit))
+	    {
+	      g_signal_connect (G_OBJECT (xw->widget_osr),
+				"load-changed",
+				G_CALLBACK (webkit_view_load_changed_cb), xw);
+
+	      g_signal_connect (G_OBJECT (webkit_context),
+				"download-started",
+				G_CALLBACK (webkit_download_cb), xw);
+
+	      g_signal_connect (G_OBJECT (xw->widget_osr),
+				"decide-policy",
+				G_CALLBACK
+				(webkit_decide_policy_cb),
+				xw);
+
+	      g_signal_connect (G_OBJECT (xw->widget_osr),
+				"mouse-target-changed",
+				G_CALLBACK (mouse_target_changed),
+				xw);
+	      g_signal_connect (G_OBJECT (xw->widget_osr),
+				"create",
+				G_CALLBACK (webkit_create_cb),
+				xw);
+	      g_signal_connect (G_OBJECT (xw->widget_osr),
+				"script-dialog",
+				G_CALLBACK (webkit_script_dialog_cb),
+				NULL);
+	      g_signal_connect (G_OBJECT (xw->widget_osr),
+				"run-file-chooser",
+			    G_CALLBACK (run_file_chooser_cb),
+				NULL);
+	    }
+
+	  g_signal_connect (G_OBJECT (xw->widgetwindow_osr), "damage-event",
+			    G_CALLBACK (offscreen_damage_event), xw);
 	}
 
-      gtk_widget_set_size_request (GTK_WIDGET (xw->widget_osr), xw->width,
-                                   xw->height);
+      unblock_input ();
+    }
+#ifdef HAVE_GSTREAMER
+  else
+    {
+      xw->xg_p = false;
+      xw->gst_pipeline = gst_pipeline_new (NULL);
+      xw->gst_source = gst_element_factory_make ("videotestsrc", NULL);
+      xw->gst_tee = gst_element_factory_make ("tee", NULL);
 
-      if (EQ (xw->type, Qwebkit))
-        {
-          gtk_container_add (GTK_CONTAINER (xw->widgetwindow_osr),
-                             GTK_WIDGET (WEBKIT_WEB_VIEW (xw->widget_osr)));
-        }
-      else
-        {
-          gtk_container_add (GTK_CONTAINER (xw->widgetwindow_osr),
-                             xw->widget_osr);
-        }
+      GstBus *bus = gst_pipeline_get_bus (GST_PIPELINE (xw->gst_pipeline));
+      GstElement *fakesink = gst_element_factory_make ("fakesink", NULL);
+      GstElement *queue = gst_element_factory_make ("queue", NULL);
 
-      gtk_widget_show (xw->widget_osr);
-      gtk_widget_show (xw->widgetwindow_osr);
-      synthesize_focus_in_event (xw->widgetwindow_osr);
+      g_object_set (G_OBJECT (fakesink), "sync", TRUE, NULL);
 
+      gst_bus_set_sync_handler (bus, gst_create_window, xw->gst_pipeline, NULL);
+      gst_bus_add_signal_watch (bus);
+      g_signal_connect (G_OBJECT (bus), "message",
+			G_CALLBACK (gst_message_cb), xw->gst_pipeline);
 
-      g_signal_connect (G_OBJECT (gtk_widget_get_window (xw->widgetwindow_osr)),
-			"from-embedder", G_CALLBACK (from_embedder), NULL);
-      g_signal_connect (G_OBJECT (gtk_widget_get_window (xw->widgetwindow_osr)),
-			"to-embedder", G_CALLBACK (to_embedder), NULL);
+      xw->gst_fakesink = fakesink;
 
-      /* Store some xwidget data in the gtk widgets for convenient
-         retrieval in the event handlers.  */
-      g_object_set_data (G_OBJECT (xw->widget_osr), XG_XWIDGET, xw);
-      g_object_set_data (G_OBJECT (xw->widgetwindow_osr), XG_XWIDGET, xw);
+      gst_object_ref (xw->gst_pipeline);
+      gst_object_ref (xw->gst_source);
+      gst_object_ref (xw->gst_tee);
+      gst_object_ref (xw->gst_fakesink);
 
-      /* signals */
-      if (EQ (xw->type, Qwebkit))
-        {
-          g_signal_connect (G_OBJECT (xw->widget_osr),
-                            "load-changed",
-                            G_CALLBACK (webkit_view_load_changed_cb), xw);
-
-          g_signal_connect (G_OBJECT (webkit_context),
-                            "download-started",
-                            G_CALLBACK (webkit_download_cb), xw);
-
-          g_signal_connect (G_OBJECT (xw->widget_osr),
-                            "decide-policy",
-                            G_CALLBACK
-                            (webkit_decide_policy_cb),
-                            xw);
-
-	  g_signal_connect (G_OBJECT (xw->widget_osr),
-			    "mouse-target-changed",
-			    G_CALLBACK (mouse_target_changed),
-			    xw);
-	  g_signal_connect (G_OBJECT (xw->widget_osr),
-			    "create",
-			    G_CALLBACK (webkit_create_cb),
-			    xw);
-	  g_signal_connect (G_OBJECT (xw->widget_osr),
-			    "script-dialog",
-			    G_CALLBACK (webkit_script_dialog_cb),
-			    NULL);
-	  g_signal_connect (G_OBJECT (xw->widget_osr),
-			    "run-file-chooser",
-			    G_CALLBACK (run_file_chooser_cb),
-			    NULL);
-        }
+      gst_bin_add_many (GST_BIN (xw->gst_pipeline), xw->gst_source,
+			xw->gst_tee, queue, fakesink, NULL);
 
-      g_signal_connect (G_OBJECT (xw->widgetwindow_osr), "damage-event",
-			G_CALLBACK (offscreen_damage_event), xw);
+      gst_element_link_many (xw->gst_tee, queue, fakesink, NULL);
 
-      unblock_input ();
+      if (!gst_element_link (xw->gst_source, xw->gst_tee))
+	emacs_abort ();
+
+      if (!gst_element_set_state (xw->gst_pipeline, GST_STATE_PAUSED))
+	emacs_abort ();
     }
+#endif
 #elif defined NS_IMPL_COCOA
   nsxwidget_init (xw);
 #endif
@@ -335,6 +394,9 @@ DEFUN ("xwidget-perform-lispy-event",
     f = SELECTED_FRAME ();
 
 #ifdef USE_GTK
+  if (!xw->xg_p)
+    return Qnil;
+
   widget = gtk_window_get_focus (GTK_WINDOW (xw->widgetwindow_osr));
 
   if (!widget)
@@ -888,7 +950,8 @@ xwidget_button (struct xwidget_view *view,
 		bool down_p, int x, int y, int button,
 		int modifier_state, Time time)
 {
-  if (NILP (XXWIDGET (view->model)->buffer))
+  if (NILP (XXWIDGET (view->model)->buffer)
+      || !XWIDGET_VIEW_GTK_P (view))
     return;
 
   record_osr_embedder (view);
@@ -947,7 +1010,7 @@ xwidget_motion_or_crossing (struct xwidget_view *view, const XEvent *event)
   int y;
   GtkWidget *target;
 
-  if (NILP (model->buffer))
+  if (NILP (model->buffer) || !model->xg_p)
     return;
 
   xg_event = gdk_event_new (event->type == MotionNotify
@@ -1117,7 +1180,17 @@ xwidget_expose (struct xwidget_view *xv)
 {
   struct xwidget *xw = XXWIDGET (xv->model);
 
-  xv_do_draw (xv, xw);
+  if (xw->xg_p)
+    xv_do_draw (xv, xw);
+#ifdef HAVE_GSTREAMER
+  else if (EQ (xw->type, Qmedia) && XWIDGET_LIVE_P (xw))
+    {
+      if (xv->wdesc != None)
+	XMoveWindow (xv->dpy, xv->internal_window,
+		     -xv->clip_left, -xv->clip_top);
+      gst_video_overlay_expose (GST_VIDEO_OVERLAY (xv->video_sink));
+    }
+#endif
 }
 #endif /* USE_GTK */
 
@@ -1690,12 +1763,81 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
 				 CopyFromParent, CWEventMask, &a);
       XLowerWindow (xv->dpy, xv->wdesc);
       XDefineCursor (xv->dpy, xv->wdesc, xv->cursor);
-      xv->cr_surface = cairo_xlib_surface_create (xv->dpy,
-						  xv->wdesc,
-						  FRAME_DISPLAY_INFO (s->f)->visual,
-						  clip_right - clip_left,
-						  clip_bottom - clip_top);
-      xv->cr_context = cairo_create (xv->cr_surface);
+
+      if (XWIDGET_VIEW_GTK_P (xv))
+	{
+	  xv->cr_surface = cairo_xlib_surface_create (xv->dpy,
+						      xv->wdesc,
+						      FRAME_DISPLAY_INFO (s->f)->visual,
+						      clip_right - clip_left,
+						      clip_bottom - clip_top);
+	  xv->cr_context = cairo_create (xv->cr_surface);
+	}
+#ifdef HAVE_GSTREAMER
+      else
+	{
+	  XFlush (xv->dpy);
+
+	  if (EQ (xww->type, Qmedia) && XWIDGET_LIVE_P (xww))
+	    {
+	      GstPadTemplate *templ;
+	      GstPad *sinkpad;
+
+	      a.event_mask = ExposureMask;
+	      a.background_pixel = FRAME_BACKGROUND_PIXEL (xv->frame);
+
+	      xv->internal_window = XCreateWindow (xv->dpy, xv->wdesc,
+						   -clip_left, -clip_top,
+						   xww->width, xww->height,
+						   0, CopyFromParent, CopyFromParent,
+						   CopyFromParent,
+						   (CWEventMask | CWBackPixel), &a);
+
+	      XMapWindow (xv->dpy, xv->internal_window);
+	      XFlush (xv->dpy);
+
+	      Fputhash (make_fixnum (xv->internal_window), xvw, x_window_to_xwv_map);
+
+	      templ = gst_element_class_get_pad_template (GST_ELEMENT_GET_CLASS (xww->gst_tee),
+							  "src_%u");
+
+	      xv->teepad = gst_element_request_pad (xww->gst_tee,
+						    templ, NULL, NULL);
+	      xv->video_sink = gst_element_factory_make ("xvimagesink", NULL);
+	      xv->video_queue = gst_element_factory_make ("queue", NULL);
+
+	      gst_object_ref (xv->video_queue);
+	      gst_object_ref (xv->video_sink);
+
+	      g_object_set_data (G_OBJECT (xv->video_sink), XG_WINDOW_HANDLE,
+				 (gpointer) xv->internal_window);
+	      g_object_set (G_OBJECT (xv->video_sink), "display",
+			    FRAME_TERMINAL (xv->frame)->name, NULL);
+
+	      gst_video_overlay_handle_events (GST_VIDEO_OVERLAY (xv->video_sink),
+					       FALSE);
+
+	      gst_bin_add_many (GST_BIN (xww->gst_pipeline), xv->video_queue,
+				xv->video_sink, NULL);
+
+	      if (!gst_element_link (xv->video_queue, xv->video_sink))
+		emacs_abort ();
+
+	      gst_element_sync_state_with_parent (xv->video_queue);
+	      gst_element_sync_state_with_parent (xv->video_sink);
+
+	      sinkpad = gst_element_get_static_pad (xv->video_queue, "sink");
+	      gst_pad_link (xv->teepad, sinkpad);
+	      gst_object_unref (sinkpad);
+
+	      xv->sinkpad = sinkpad;
+
+	      gst_element_sync_state_with_parent (xww->gst_tee);
+
+	      xwidget_expose (xv);
+	    }
+	}
+#endif
       Fputhash (make_fixnum (xv->wdesc), xvw, x_window_to_xwv_map);
 
       moved = false;
@@ -1709,8 +1851,9 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
       XMoveResizeWindow (xv->dpy, xv->wdesc, x + clip_left, y + clip_top,
 			 clip_right - clip_left, clip_bottom - clip_top);
       XFlush (xv->dpy);
-      cairo_xlib_surface_set_size (xv->cr_surface, clip_right - clip_left,
-				   clip_bottom - clip_top);
+      if (XWIDGET_VIEW_GTK_P (xv))
+	cairo_xlib_surface_set_size (xv->cr_surface, clip_right - clip_left,
+				     clip_bottom - clip_top);
 #elif defined NS_IMPL_COCOA
       nsxwidget_move_view (xv, x + clip_left, y + clip_top);
 #endif
@@ -1740,8 +1883,10 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
 			     clip_bottom - clip_top);
 	    }
 	  XFlush (xv->dpy);
-	  cairo_xlib_surface_set_size (xv->cr_surface, clip_right - clip_left,
-				       clip_bottom - clip_top);
+
+	  if (xww->xg_p)
+	    cairo_xlib_surface_set_size (xv->cr_surface, clip_right - clip_left,
+					 clip_bottom - clip_top);
 	}
 #elif defined NS_IMPL_COCOA
       nsxwidget_resize_view (xv, clip_right - clip_left,
@@ -1765,7 +1910,10 @@ x_draw_xwidget_glyph_string (struct glyph_string *s)
       if (!xwidget_hidden (xv))
 	{
 #ifdef USE_GTK
-	  gtk_widget_queue_draw (xww->widget_osr);
+	  if (xww->xg_p)
+	    gtk_widget_queue_draw (xww->widget_osr);
+	  else
+	    xwidget_expose (xv);
 #elif defined NS_IMPL_COCOA
 	  nsxwidget_set_needsdisplay (xv);
 #endif
@@ -1788,6 +1936,12 @@ #define CHECK_WEBKIT_WIDGET(xw)				\
   if (NILP (xw->buffer) || !EQ (xw->type, Qwebkit))	\
     error ("Not a WebKit widget")
 
+#ifdef HAVE_GSTREAMER
+#define CHECK_MEDIA_WIDGET(xw)				\
+  if (NILP (xw->buffer) || !EQ (xw->type, Qmedia))	\
+    error ("Not a WebKit widget")
+#endif
+
 /* Macro that checks xwidget hold webkit web view first.  */
 #define WEBKIT_FN_INIT()						\
   CHECK_LIVE_XWIDGET (xwidget);						\
@@ -1989,6 +2143,14 @@ DEFUN ("xwidget-resize", Fxwidget_resize, Sxwidget_resize, 3, 3, 0,
 #ifdef USE_GTK
 	      xv->just_resized = true;
 	      SET_FRAME_GARBAGED (xv->frame);
+#ifdef HAVE_GSTREAMER
+	      if (EQ (xw->type, Qmedia))
+		{
+		  XResizeWindow (xv->dpy, xv->internal_window,
+				 xw->width, xw->height);
+		}
+#endif
+
 #else
 	      wset_redisplay (XWINDOW (xv->w));
 #endif
@@ -2000,7 +2162,7 @@ DEFUN ("xwidget-resize", Fxwidget_resize, Sxwidget_resize, 3, 3, 0,
 
   /* If there is an offscreen widget resize it first.  */
 #ifdef USE_GTK
-  if (xw->widget_osr)
+  if (xw->xg_p && xw->widget_osr)
     {
       gtk_window_resize (GTK_WINDOW (xw->widgetwindow_osr), xw->width,
                          xw->height);
@@ -2030,9 +2192,14 @@ DEFUN ("xwidget-size-request",
 {
   CHECK_LIVE_XWIDGET (xwidget);
 #ifdef USE_GTK
-  GtkRequisition requisition;
-  gtk_widget_size_request (XXWIDGET (xwidget)->widget_osr, &requisition);
-  return list2i (requisition.width, requisition.height);
+  if (XXWIDGET (xwidget)->xg_p)
+    {
+      GtkRequisition requisition;
+      gtk_widget_size_request (XXWIDGET (xwidget)->widget_osr, &requisition);
+      return list2i (requisition.width, requisition.height);
+    }
+
+  return Qnil;
 #elif defined NS_IMPL_COCOA
   return nsxwidget_get_size (XXWIDGET (xwidget));
 #endif
@@ -2115,18 +2282,29 @@ DEFUN ("delete-xwidget-view",
 #ifdef USE_GTK
   struct xwidget *xw = XXWIDGET (xv->model);
   GdkWindow *w;
-
+#ifdef HAVE_GSTREAMER
+  block_input ();
+  if (XWIDGET_LIVE_P (xw) && EQ (xw->type, Qmedia))
+    unlink_gst_xwidget_view (xv);
+  unblock_input ();
+#endif
   if (xv->wdesc != None)
     {
       block_input ();
-      cairo_destroy (xv->cr_context);
-      cairo_surface_destroy (xv->cr_surface);
+      if (XWIDGET_VIEW_GTK_P (xv))
+	{
+	  cairo_destroy (xv->cr_context);
+	  cairo_surface_destroy (xv->cr_surface);
+	}
       XDestroyWindow (xv->dpy, xv->wdesc);
       Fremhash (make_fixnum (xv->wdesc), x_window_to_xwv_map);
+
+      if (XWIDGET_LIVE_P (xw) && EQ (xw->type, Qmedia))
+	Fremhash (make_fixnum (xv->internal_window), x_window_to_xwv_map);
       unblock_input ();
     }
 
-  if (xw->embedder_view == xv && !NILP (xw->buffer))
+  if (xw->xg_p && xw->embedder_view == xv && !NILP (xw->buffer))
     {
       w = gtk_widget_get_window (xw->widgetwindow_osr);
 
@@ -2555,6 +2733,77 @@ DEFUN ("xwidget-webkit-back-forward-list", Fxwidget_webkit_back_forward_list,
 
   return list3 (back, here, forward);
 }
+
+#ifdef HAVE_GSTREAMER
+DEFUN ("xwidget-media-pause", Fxwidget_media_pause, Sxwidget_media_pause,
+       1, 1, 0, doc: /* Pause specified media XWIDGET.
+This causes playback to stop until you resume it using
+`xwidget-media-play'.  */)
+  (Lisp_Object xwidget)
+{
+  struct xwidget *xw;
+  struct xwidget_view *xv;
+  Lisp_Object tem;
+
+  CHECK_LIVE_XWIDGET (xwidget);
+  xw = XXWIDGET (xwidget);
+  CHECK_MEDIA_WIDGET (xw);
+
+  block_input ();
+  gst_element_set_state (xw->gst_pipeline, GST_STATE_PAUSED);
+  gst_element_sync_state_with_parent (xw->gst_tee);
+  gst_element_sync_state_with_parent (xw->gst_fakesink);
+
+  for (tem = internal_xwidget_view_list; CONSP (tem); tem = XCDR (tem))
+    {
+      xv = XXWIDGET_VIEW (XCAR (tem));
+
+      if (EQ (xv->model, xwidget))
+	{
+	  gst_element_sync_state_with_parent (xv->video_queue);
+	  gst_element_sync_state_with_parent (xv->video_sink);
+	}
+    }
+
+  unblock_input ();
+
+  return Qnil;
+}
+
+DEFUN ("xwidget-media-play", Fxwidget_media_play, Sxwidget_media_play,
+       1, 1, 0, doc: /* Resume playback of specified media XWIDGET.  */)
+  (Lisp_Object xwidget)
+{
+  struct xwidget *xw;
+  struct xwidget_view *xv;
+  Lisp_Object tem;
+
+  CHECK_LIVE_XWIDGET (xwidget);
+  xw = XXWIDGET (xwidget);
+  CHECK_MEDIA_WIDGET (xw);
+
+  block_input ();
+  gst_element_set_state (xw->gst_pipeline, GST_STATE_PLAYING);
+  gst_element_sync_state_with_parent (xw->gst_tee);
+  gst_element_sync_state_with_parent (xw->gst_fakesink);
+
+  for (tem = internal_xwidget_view_list; CONSP (tem); tem = XCDR (tem))
+    {
+      xv = XXWIDGET_VIEW (XCAR (tem));
+
+      if (EQ (xv->model, xwidget))
+	{
+	  gst_element_sync_state_with_parent (xv->video_queue);
+	  gst_element_sync_state_with_parent (xv->video_sink);
+	}
+    }
+
+  gst_element_sync_state_with_parent (xw->gst_tee);
+  unblock_input ();
+
+  return Qnil;
+}
+#endif
 #endif
 
 void
@@ -2584,6 +2833,7 @@ syms_of_xwidget (void)
   defsubr (&Sxwidget_webkit_zoom);
   defsubr (&Sxwidget_webkit_execute_script);
   DEFSYM (Qwebkit, "webkit");
+  DEFSYM (Qmedia, "media");
 
   defsubr (&Sxwidget_size_request);
   defsubr (&Sdelete_xwidget_view);
@@ -2600,6 +2850,10 @@ syms_of_xwidget (void)
 #ifdef USE_GTK
   defsubr (&Sxwidget_webkit_load_html);
   defsubr (&Sxwidget_webkit_back_forward_list);
+#ifdef HAVE_GSTREAMER
+  defsubr (&Sxwidget_media_pause);
+  defsubr (&Sxwidget_media_play);
+#endif
 #endif
   defsubr (&Skill_xwidget);
 
@@ -2862,7 +3116,7 @@ kill_xwidget (struct xwidget *xw)
 #ifdef USE_GTK
   xw->buffer = Qnil;
 
-  if (xw->widget_osr && xw->widgetwindow_osr)
+  if (xw->xg_p && xw->widget_osr && xw->widgetwindow_osr)
     {
       gtk_widget_destroy (xw->widget_osr);
       gtk_widget_destroy (xw->widgetwindow_osr);
@@ -2882,6 +3136,26 @@ kill_xwidget (struct xwidget *xw)
 	}
     }
 
+#ifdef HAVE_GSTREAMER
+  Lisp_Object tem;
+
+  if (EQ (xw->type, Qmedia))
+    {
+      for (tem = internal_xwidget_view_list; CONSP (tem);
+	   tem = XCDR (tem))
+	{
+	  struct xwidget_view *xv = XXWIDGET_VIEW (XCAR (tem));
+
+	  if (XXWIDGET (xv->model) == xw)
+	    unlink_gst_xwidget_view (xv);
+	}
+      gst_object_unref (xw->gst_tee);
+      gst_object_unref (xw->gst_pipeline);
+      gst_object_unref (xw->gst_source);
+      gst_object_unref (xw->gst_fakesink);
+    }
+#endif
+
   xw->widget_osr = NULL;
   xw->widgetwindow_osr = NULL;
   xw->find_text = NULL;
@@ -2908,3 +3182,59 @@ kill_buffer_xwidgets (Lisp_Object buffer)
       }
     }
 }
+
+#ifdef HAVE_GSTREAMER
+static GstBusSyncReply
+gst_create_window (GstBus *bus, GstMessage *msg, gpointer user_data)
+{
+  GstObject *elm;
+  Window wdesc;
+
+  if (!gst_is_video_overlay_prepare_window_handle_message (msg))
+    return GST_BUS_PASS;
+
+  elm = GST_MESSAGE_SRC (msg);
+  wdesc = (Window) g_object_get_data (G_OBJECT (elm), XG_WINDOW_HANDLE);
+
+  gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (elm), wdesc);
+
+  return GST_BUS_DROP;
+}
+
+static gboolean
+gst_message_cb (GstBus *bus, GstMessage *message, gpointer user_data)
+{
+  return TRUE;
+}
+
+static bool
+check_gstreamer_dependencies (void)
+{
+  GstRegistry *registry = gst_registry_get ();
+
+  return (gst_registry_find_feature (registry, "xvimagesink",
+				     GST_TYPE_ELEMENT_FACTORY)
+	  && gst_registry_find_feature (registry, "queue",
+					GST_TYPE_ELEMENT_FACTORY)
+	  && gst_registry_find_feature (registry, "videotestsrc",
+					GST_TYPE_ELEMENT_FACTORY)
+	  && gst_registry_find_feature (registry, "tee",
+					GST_TYPE_ELEMENT_FACTORY));
+}
+
+static void
+unlink_gst_xwidget_view (struct xwidget_view *xv)
+{
+  struct xwidget *xw = XXWIDGET (xv->model);
+
+  gst_pad_unlink (xv->teepad, xv->sinkpad);
+  gst_element_unlink (xv->video_queue, xv->video_sink);
+
+  gst_element_set_state (xv->video_queue, GST_STATE_NULL);
+  gst_element_set_state (xv->video_sink, GST_STATE_NULL);
+  gst_bin_remove_many (GST_BIN (xw->gst_pipeline), xv->video_sink,
+		       xv->video_queue, NULL);
+  gst_object_unref (xv->video_sink);
+  gst_object_unref (xv->video_queue);
+}
+#endif
diff --git a/src/xwidget.h b/src/xwidget.h
index 78fe865dd8..66f7fb2c4c 100644
--- a/src/xwidget.h
+++ b/src/xwidget.h
@@ -39,6 +39,10 @@ #define XWIDGET_H_INCLUDED
 #import "nsxwidget.h"
 #endif
 
+#ifdef HAVE_GSTREAMER
+#include <gst/gst.h>
+#endif
+
 struct xwidget
 {
   union vectorlike_header header;
@@ -65,6 +69,16 @@ #define XWIDGET_H_INCLUDED
   char *find_text;
 
 #if defined (USE_GTK)
+  /* Whether or not the widget is used to display GTK widgets. */
+  bool xg_p;
+
+#ifdef HAVE_GSTREAMER
+  GstElement *gst_tee;
+  GstElement *gst_pipeline;
+  GstElement *gst_source;
+  GstElement *gst_fakesink;
+#endif
+
   /* For offscreen widgets, unused if not osr.  */
   GtkWidget *widget_osr;
   GtkWidget *widgetwindow_osr;
@@ -112,6 +126,14 @@ #define XWIDGET_H_INCLUDED
   Emacs_Cursor cursor;
   struct frame *frame;
 
+#ifdef HAVE_GSTREAMER
+  Window internal_window;
+  GstPad *teepad;
+  GstPad *sinkpad;
+  GstElement *video_sink;
+  GstElement *video_queue;
+#endif
+
   cairo_surface_t *cr_surface;
   cairo_t *cr_context;
   int just_resized;
@@ -159,6 +181,9 @@ #define XXWIDGET_VIEW(a) (eassert (XWIDGET_VIEW_P (a)), \
 #define CHECK_XWIDGET_VIEW(x) \
   CHECK_TYPE (XWIDGET_VIEW_P (x), Qxwidget_view_p, x)
 
+#define XWIDGET_VIEW_GTK_P(x) \
+  XXWIDGET ((x)->model)->xg_p
+
 #define XG_XWIDGET "emacs_xwidget"
 #define XG_XWIDGET_VIEW "emacs_xwidget_view"
 
-- 
2.31.1