diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index 0934911ec..c7108dbc1 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -826,7 +826,7 @@ def _apply_format_filter(self, format_spec, available_formats):
             '!=': operator.ne,
         }
         operator_rex = re.compile(r'''(?x)\s*\[
-            (?P<key>width|height|tbr|abr|vbr|filesize|fps)
+            (?P<key>width|height|tbr|abr|vbr|asr|filesize|fps)
             \s*(?P<op>%s)(?P<none_inclusive>\s*\?)?\s*
             (?P<value>[0-9.]+(?:[kKmMgGtTpPeEzZyY]i?[Bb]?)?)
             \]$