diff --git a/src/mpv_scripts/mpv_cache.lua b/src/mpv_scripts/mpv_cache.lua
index 083339d..fa412c2 100644
--- a/src/mpv_scripts/mpv_cache.lua
+++ b/src/mpv_scripts/mpv_cache.lua
@@ -28,13 +28,13 @@ function make_cache_track(url)
     find_uuid = "%x+-%x+-%x+-%x+-%x+"
     uuid = string.sub(url, string.find(url, find_uuid))
     host = get_url_host(url)
-    cache_path_file = 'cache/' .. host .. '/' .. uuid .. '.webm'
+    cache_path_file = 'cache/' .. host .. '/' .. uuid .. '.mkv'
     if false == file_exists(cache_path_file) then
 	createDir('cache/' .. host .. '/')
 	msg.verbose('Caching ' .. cache_path_file .. '')
 	mp.command('script-message streamsave-title ' .. uuid .. '')
 	mp.set_property('script-opts/media-uuid', uuid)
-	mp.command('script-message streamsave-extension .webm')
+	mp.command('script-message streamsave-extension .mkv')
 	mp.command('script-message streamsave-path cache/' .. host .. '')
 	mp.command('script-message streamsave-rec')
     else
diff --git a/src/mpv_scripts/streamsave.lua b/src/mpv_scripts/streamsave.lua
index 9a77357..fe69b11 100644
--- a/src/mpv_scripts/streamsave.lua
+++ b/src/mpv_scripts/streamsave.lua
@@ -124,7 +124,7 @@ local opts = {
     save_directory = [[.]],         -- output file directory
     dump_mode = "continuous",               -- <ab|current|continuous>
     output_label = "overwrite",     -- <increment|range|timestamp|overwrite>
-    force_extension = ".webm",         -- <no|.ext> extension will be .ext if set
+    force_extension = ".mkv",         -- <no|.ext> extension will be .ext if set
     force_title = "no",             -- <no|title> custom title used for the filename
     range_marks = false,            -- <yes|no> set chapters at A-B loop points?
     autostart = true,              -- <yes|no> automatically dump cache at start?