--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mozilla-libavcodec58_91.patch	Thu Jul 23 16:00:58 2020 +0200
@@ -0,0 +1,20 @@
+Index: firefox-78.0.2/dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp
+===================================================================
+--- firefox-78.0.2.orig/dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp
++++ firefox-78.0.2/dom/media/platforms/ffmpeg/FFmpegRuntimeLinker.cpp
+@@ -30,6 +30,7 @@ static FFmpegLibWrapper sLibAV;
+ static const char* sLibs[] = {
+ // clang-format off
+ #if defined(XP_DARWIN)
++  "libavcodec.58.91.dylib",
+   "libavcodec.58.dylib",
+   "libavcodec.57.dylib",
+   "libavcodec.56.dylib",
+@@ -37,6 +38,7 @@ static const char* sLibs[] = {
+   "libavcodec.54.dylib",
+   "libavcodec.53.dylib",
+ #else
++  "libavcodec.so.58.91",
+   "libavcodec.so.58",
+   "libavcodec-ffmpeg.so.58",
+   "libavcodec-ffmpeg.so.57",