--- a/config/external/moz.build
+++ b/config/external/moz.build
@@ -28,16 +28,19 @@ if CONFIG['MOZ_TREMOR']:
     external_dirs += ['media/libtremor']
 
 if CONFIG['MOZ_WEBM_ENCODER']:
     external_dirs += ['media/libmkv']
 
 if not CONFIG['MOZ_SYSTEM_LIBVPX']:
     external_dirs += ['media/libvpx']
 
+if CONFIG['MOZ_AV1']:
+    external_dirs += ['media/libaom']
+
 if not CONFIG['MOZ_SYSTEM_PNG']:
     external_dirs += ['media/libpng']
 
 if CONFIG['CPU_ARCH'] == 'arm':
     external_dirs += ['media/openmax_dl']
 
 if CONFIG['MOZ_WEBSPEECH_POCKETSPHINX']:
     external_dirs += [

--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -400,16 +400,30 @@ def ffmpeg(value, target):
         enabled = target.os not in ('Android', 'WINNT')
     if enabled:
         return True
 
 set_config('MOZ_FFMPEG', ffmpeg)
 set_define('MOZ_FFMPEG', ffmpeg)
 imply_option('--enable-fmp4', ffmpeg, '--enable-ffmpeg')
 
+# Libaom AV1 Video Codec Support
+# ==============================================================
+option('--enable-av1',
+        help='Enable libaom for av1 video support')
+
+@depends('--enable-av1')
+def av1(value):
+    enabled = bool(value)
+    if enabled:
+        return True
+
+set_config('MOZ_AV1', av1)
+set_define('MOZ_AV1', av1)
+
 # Built-in fragmented MP4 support.
 # ==============================================================
 option('--disable-fmp4', env='MOZ_FMP4',
        help='Disable support for in built Fragmented MP4 parsing')
 
 @depends('--disable-fmp4', target, wmf, applemedia)
 def fmp4(value, target, wmf, applemedia):
     enabled = bool(value)