--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -598,16 +598,20 @@ pref("media.cubeb.logging_level", "");
 pref("media.cubeb.sandbox", true);
 pref("media.audioipc.pool_size", 2);
 // 64 * 4 kB stack per pool thread.
 pref("media.audioipc.stack_size", 262144);
 #else
 pref("media.cubeb.sandbox", false);
 #endif
 
+#ifdef MOZ_AV1
+pref("media.av1.enabled", false);
+#endif
+
 pref("media.webaudio.audiocontextoptions-samplerate.enabled", true);
 
 // setSinkId expected to be unconditionally enabled in 63. Till then the
 // implementation will remain hidden behind this pref (Bug 1152401, Bug 934425).
 pref("media.setsinkid.enabled", false);
 
 // Weather we allow AMD switchable graphics
 pref("layers.amd-switchable-gfx.enabled", true);