ffmpeg: add some more scripts

modules/programs/ffmpeg.nix

@@ -55,6 +55,11 @@ let
         exit 1
       fi
 
+      # do it stereo
+      # -ac 2
+      # do it sample rate 44100
+      # -ar 44100
+
       exec ${pkgs.ffmpeg}/bin/ffmpeg \
         -i "$input" \
         -filter:v scale=h='min(720\,ih)':w='min(1280\,iw)' \
@@ -63,6 +68,8 @@ let
         -profile:v ${profile} \
         ${optionalString (tune != null) "-tune ${tune}"} \
         -acodec aac \
+        -ac 2 \
+        -ar 44100 \
         "$output" \
         -hide_banner
     '';