diff --git a/cmd/ffmpeg/README.md b/cmd/ffmpeg/README.md
index 6d19340d..88a91d45 100644
--- a/cmd/ffmpeg/README.md
+++ b/cmd/ffmpeg/README.md
@@ -58,3 +58,4 @@
 - https://github.com/leandromoreira/ffmpeg-libav-tutorial
 - https://www.reddit.com/user/VeritablePornocopium/comments/okw130/ffmpeg_with_libfdk_aac_for_windows_x64/
 - https://slhck.info/video/2017/02/24/vbr-settings.html
+- [HomeKit audio samples problem](https://superuser.com/questions/1290996/non-monotonous-dts-with-igndts-flag)
diff --git a/cmd/ffmpeg/ffmpeg.go b/cmd/ffmpeg/ffmpeg.go
index 7ba5d00d..8dd5cf8b 100644
--- a/cmd/ffmpeg/ffmpeg.go
+++ b/cmd/ffmpeg/ffmpeg.go
@@ -115,6 +115,10 @@ func Init() {
 			input = strings.Replace(tpl["file"], "{input}", s, 1)
 		}
 
+		if _, ok := query["async"]; ok {
+			input = "-use_wallclock_as_timestamps 1 -async 1 " + input
+		}
+
 		s = cmd + input
 
 		if query != nil {