Modified from upstream commit:
https://github.com/ankitects/anki/commit/ccd715013609133c55e83924734efa78abc03326
Fixes mpv argument syntax (support for old syntax removed in mpv 0.31):
https://anki.tenderapp.com/discussions/ankidesktop/38186-mpvprocesserror-unable-to-start-process
Necessary because we are currently unable to upgrade anki to the
latest version in guix (NPM dependencies currently unpackaged).
---
 anki/mpv.py   | 4 ++--
 anki/sound.py | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/anki/mpv.py b/anki/mpv.py
index f53d9d0..563fddc 100644
--- a/anki/mpv.py
+++ b/anki/mpv.py
@@ -104,9 +104,9 @@ class MPVBase:
         """
         self.argv = [self.executable]
         self.argv += self.default_argv
-        self.argv += ["--input-ipc-server", self._sock_filename]
+        self.argv += ["--input-ipc-server="+self._sock_filename]
         if self.window_id is not None:
-            self.argv += ["--wid", str(self.window_id)]
+  </td></tr></table>
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