Windows: README update; use d3d11 as default videosink

README.md

@@ -846,16 +846,25 @@ downloads, "UxPlay" for "git clone" downloads) and build/install with
 
 3.  [MSYS2 packages](https://packages.msys2.org/package/) are installed
     with a variant of the "pacman" package manager used by Arch Linux.
-    Open a "MSYS2 MINGW64" terminal from the MSYS2 tab in the Windows
+    Open a "MSYS2" terminal from the MSYS2 tab in the Windows
     Start menu, and update the new MSYS2 installation with "pacman
-    -Syu". Then install the **MinGW-64** compiler and **cmake**
+    -Syu". 
 
-        pacman -S mingw-w64-x86_64-cmake mingw-w64-x86_64-gcc
+    * _NEW: MSYS2 now recommends using the newer UCRT64 terminal environment (which uses the newer Microsoft
+    UCRT "Universal C RunTime Library", included as part of the Windows OS since Windows 10)
+    rather than the MINGW64 terminal environment
+    (which uses the older Microsoft MSVCRT C library, which has "legacy" status, but is available on all Windows systems).
+    If you wish to use the legacy MSVCRT library, to support older Windows versions, modify the instructions below as follows:
+    (1) change the MSYS2 terminal type from UCRT64 to MINGW64; (2)  modify mingw-w64-ucrt-x86_64-* package names to mingw-w64-x86_64-*, (just omit "-ucrt");
+    (3) replace `ucrt64` by ``mingw64`` in directory names._
 
-    The compiler with all required dependencies will be installed in the
-    msys64 directory, with default path `C:/msys64/mingw64`. Here we
-    will simply build UxPlay from the command line in the MSYS2
-    environment (this uses "`ninja`" in place of "`make`" for the build
+
+    Open a new MSYS2 UCRT64 terminal, and install the gcc compiler and cmake:
+
+       `pacman -S mingw-w64-ucrt-x86_64-cmake mingw-w64-ucrt-x86_64-gcc`
+
+    We will simply build UxPlay from the command line in the MSYS2
+    environment (using "`ninja`" in place of "`make`" for the build
     system).
 
 4.  Download the latest UxPlay from github **(to use `git`, install it
@@ -863,7 +872,7 @@ downloads, "UxPlay" for "git clone" downloads) and build/install with
     "`git clone https://github.com/FDH2/UxPlay`")**, then install UxPlay
     dependencies (openssl is already installed with MSYS2):
 
-    `pacman -S mingw-w64-x86_64-libplist mingw-w64-x86_64-gstreamer mingw-w64-x86_64-gst-plugins-base`
+        `pacman -S mingw-w64-ucrt-x86_64-libplist mingw-w64-ucrt-x86_64-gstreamer mingw-w64-ucrt-x86_64-gst-plugins-base`
 
     If you are trying a different Windows build system, MSVC versions of
     GStreamer for Windows are available from the [official GStreamer
@@ -883,18 +892,23 @@ downloads, "UxPlay" for "git clone" downloads) and build/install with
 6.  Assuming no error in either of these, you will have built the uxplay
     executable **uxplay.exe** in the current ("build") directory. The
     "sudo make install" and "sudo make uninstall" features offered in
-    the other builds are not available on Windows; instead, the MSYS2
-    environment has `/mingw64/...` available, and you can install the
-    uxplay.exe executable in `C:/msys64/mingw64/bin` (plus manpage and
-    documentation in `C:/msys64/mingw64/share/...`) with
+    the other builds are not available on Windows; instead, you can install the
+    uxplay.exe executable in `C:/msys64/ucrt64/bin` (plus manpage and
+    documentation in `C:/msys64/ucrt64/share/...`) with
 
-    `cmake --install . --prefix /mingw64`
+    `cmake --install . --prefix $HOME/../../ucrt64`
+
+    You can later uninstall uxplay by returning to the build directory and running
+
+    `ninja uninstall`
+
+    (This assumes that certain files in the build directory were not deleted since building UxPlay). 
 
     To be able to view the manpage, you need to install the manpage
     viewer with "`pacman -S man`".
 
 To run **uxplay.exe** you need to install some gstreamer plugin packages
-with `pacman -S mingw-w64-x86_64-gst-<plugin>`, where the required ones
+with `pacman -S mingw-w64-ucrt-x86_64-gst-<plugin>`, where the required ones
 have `<plugin>` given by
 
 1.  **libav**
@@ -913,7 +927,7 @@ app through firewall**. If your virus protection flags uxplay.exe as
 "suspicious" (but without a true malware signature) you may need to give
 it an exception.
 
-Now test by running "`uxplay`" (in a MSYS2 terminal window). If you need
+Now test by running "`uxplay`" (in a MSYS2 UCRT64 terminal window.  If you need
 to specify the audiosink, there are two main choices on Windows: the
 older DirectSound plugin "`-as directsoundsink`", and the more modern
 Windows Audio Session API (wasapi) plugin "`-as wasapisink`", which
@@ -929,23 +943,20 @@ like `\{0.0.0.00000000\}.\{98e35b2b-8eba-412e-b840-fd2c2492cf44\}`. If
 "`device`" is not specified, the default audio device is used.
 
 If you wish to specify the videosink using the `-vs <videosink>` option,
-some choices for `<videosink>` are `d3d11videosink`, `d3dvideosink`,
-`glimagesink`, `gtksink`.
+some choices for `<videosink>` are  `d3d12videosink`, ``d3d11videosink``, ```d3dvideosink```,
+`glimagesink`, ``gtksink``, ```autovideosink```.   If you do not specify the videosink,
+the d3d11videosink will be used (users have reported segfaults of the newer d3d12  videodecoder
+on certain older Nvidia cards when the image resolution changes:
+d3d11 will used by default until this is fixed).
 
--   With Direct3D 11.0 or greater, you can either always be in
-    fullscreen mode using option
-    `-vs "d3d11videosink fullscreen-toggle-mode=property fullscreen=true"`,
-    or get the ability to toggle into and out of fullscreen mode using
-    the Alt-Enter key combination with option
-    `-vs "d3d11videosink fullscreen-toggle-mode=alt-enter"`. For
-    convenience, these options will be added if just
-    `-vs d3d11videosink` with or without the fullscreen option "-fs" is
-    used. *(Windows users may wish to add "`vs d3d11videosink`" (no
-    initial "`-`") to the UxPlay startup options file; see "man uxplay"
-    or "uxplay -h".)*
+-   With Direct3D 11.0 or greater, various options can be set
+    using  e.g. `-vs "d3d11videosink <options>"` (see the gstreamer videosink
+    documentation for these videosinks).
+    For convenience, if no `<options>` are set, the option to
+    toggle in and out of fullscreen mode with the Alt-Enter key combination is added.
 
 The executable uxplay.exe can also be run without the MSYS2 environment,
-in the Windows Terminal, with `C:\msys64\mingw64\bin\uxplay`.
+in the Windows Terminal, with `C:\msys64\ucrt64\bin\uxplay`.
 
 # Usage