-#Source0Download: http://downloads.webmproject.org/releases/webm/index.html
-Source0: https://github.com/webmproject/libvpx/archive/v%{version}.tar.gz?/%{name}-%{version}.tar.gz
+# original download URL: http://downloads.webmproject.org/releases/webm/index.html
+# ...but use github mirror to get consistent tarballs
+#Source0Download: https://github.com/webmproject/libvpx/releases
+Source0: https://github.com/webmproject/libvpx/archive/v%{version}/%{name}-%{version}.tar.gz