diff --git a/server/plugin/plg_video_transcoder/index.go b/server/plugin/plg_video_transcoder/index.go
index e461155c..34404cfa 100644
--- a/server/plugin/plg_video_transcoder/index.go
+++ b/server/plugin/plg_video_transcoder/index.go
@@ -19,7 +19,7 @@ import (
 )
 
 const (
-	HLS_SEGMENT_LENGTH = 10
+	HLS_SEGMENT_LENGTH = 25
 	CLEAR_CACHE_AFTER  = 12
 	VideoCachePath     = "data/cache/video/"
 )
@@ -192,6 +192,7 @@ func hls_transcode(ctx *App, res http.ResponseWriter, req *http.Request) {
 		"-vcodec", "libx264",
 		"-preset", "veryfast",
 		"-acodec", "aac",
+		"-ac", "2",
 		"-pix_fmt", "yuv420p",
 		"-x264opts:0", "subme=0:me_range=4:rc_lookahead=10:me=dia:no_chroma_me:8x8dct=0:partitions=none",
 		"-force_key_frames", fmt.Sprintf("expr:gte(t,n_forced*%d.000)", HLS_SEGMENT_LENGTH),