diff --git a/libs/hbb_common/protos/message.proto b/libs/hbb_common/protos/message.proto
index 273e7a6c5..f6c57b1e4 100644
--- a/libs/hbb_common/protos/message.proto
+++ b/libs/hbb_common/protos/message.proto
@@ -447,9 +447,9 @@ message PermissionInfo {
 
 enum ImageQuality {
   NotSet = 0;
-  Low = 50;
-  Balanced = 66;
-  Best = 100;
+  Low = 2;
+  Balanced = 3;
+  Best = 4;
 }
 
 message VideoCodecState {
diff --git a/src/client.rs b/src/client.rs
index ca5352ae4..d4cd44351 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -1005,17 +1005,17 @@ impl LoginConfigHandler {
         msg_out
     }
 
-    pub fn save_custom_image_quality(&mut self, custom_image_quality: i32) -> Message {
+    pub fn save_custom_image_quality(&mut self, image_quality: i32) -> Message {
         let mut misc = Misc::new();
         misc.set_option(OptionMessage {
-            custom_image_quality,
+            custom_image_quality: image_quality << 8,
             ..Default::default()
         });
         let mut msg_out = Message::new();
         msg_out.set_misc(misc);
         let mut config = self.load_config();
         config.image_quality = "custom".to_owned();
-        config.custom_image_quality = vec![custom_image_quality as _];
+        config.custom_image_quality = vec![image_quality as _];
         self.save_config(config);
         msg_out
     }
diff --git a/src/server/connection.rs b/src/server/connection.rs
index 77d41d4e0..46c730092 100644
--- a/src/server/connection.rs
+++ b/src/server/connection.rs
@@ -1114,13 +1114,15 @@ impl Connection {
     async fn update_option(&mut self, o: &OptionMessage) {
         log::info!("Option update: {:?}", o);
         if let Ok(q) = o.image_quality.enum_value() {
-            let mut image_quality = None;
+            let image_quality;
             if let ImageQuality::NotSet = q {
                 if o.custom_image_quality > 0 {
-                    image_quality = Some(o.custom_image_quality as _);
+                    image_quality = o.custom_image_quality;
+                } else {
+                    image_quality = ImageQuality::Balanced.value();
                 }
             } else {
-                image_quality = Some(q.value() as _)
+                image_quality = q.value();
             }
             video_service::VIDEO_QOS
                 .lock()
diff --git a/src/server/video_service.rs b/src/server/video_service.rs
index 8113ffee3..abc13a54c 100644
--- a/src/server/video_service.rs
+++ b/src/server/video_service.rs
@@ -52,55 +52,75 @@ lazy_static::lazy_static! {
     pub static ref VIDEO_QOS: Arc<Mutex<VideoQoS>> = Default::default();
 }
 
+trait Percent {
+    fn as_percent(&self) -> u32;
+}
+
+impl Percent for ImageQuality {
+    fn as_percent(&self) -> u32 {
+        match self {
+            ImageQuality::NotSet => 0,
+            ImageQuality::Low => 50,
+            ImageQuality::Balanced => 66,
+            ImageQuality::Best => 100,
+        }
+    }
+}
+
 pub struct VideoQoS {
     width: u32,
     height: u32,
     user_image_quality: u32,
     current_image_quality: u32,
-    enable_abr: bool,
 
     pub current_delay: u32,
     pub fps: u8,             // abr
     pub target_bitrate: u32, // abr
-    updated: bool,
 
-    state: AdaptiveState,
-    last_delay: u32,
-    count: u32,
+    updated: bool,
+    state: DelayState,
+    debounce_count: u32,
 }
 
-#[derive(Debug)]
-enum AdaptiveState {
-    Normal,
-    LowDelay,
-    HeightDelay,
+#[derive(PartialEq, Debug)]
+enum DelayState {
+    Normal = 0,
+    LowDelay = 200,
+    HighDelay = 500,
+    Broken = 1000,
+}
+
+impl DelayState {
+    fn from_delay(delay: u32) -> Self {
+        if delay > DelayState::Broken as u32 {
+            DelayState::Broken
+        } else if delay > DelayState::HighDelay as u32 {
+            DelayState::HighDelay
+        } else if delay > DelayState::LowDelay as u32 {
+            DelayState::LowDelay
+        } else {
+            DelayState::Normal
+        }
+    }
 }
 
 impl Default for VideoQoS {
     fn default() -> Self {
         VideoQoS {
             fps: FPS,
-            user_image_quality: ImageQuality::Balanced.value() as _,
-            current_image_quality: ImageQuality::Balanced.value() as _,
-            enable_abr: false,
+            user_image_quality: ImageQuality::Balanced.as_percent(),
+            current_image_quality: ImageQuality::Balanced.as_percent(),
             width: 0,
             height: 0,
             current_delay: 0,
             target_bitrate: 0,
             updated: false,
-            state: AdaptiveState::Normal,
-            last_delay: 0,
-            count: 0,
+            state: DelayState::Normal,
+            debounce_count: 0,
         }
     }
 }
 
-const MAX: f32 = 1.2;
-const MIN: f32 = 0.8;
-const MAX_COUNT: u32 = 3;
-const MAX_DELAY: u32 = 500;
-const MIN_DELAY: u32 = 50;
-
 impl VideoQoS {
     pub fn set_size(&mut self, width: u32, height: u32) {
         if width == 0 || height == 0 {
@@ -117,131 +137,69 @@ impl VideoQoS {
         time::Duration::from_secs_f32(1. / (self.fps as f32))
     }
 
-    // abr
     pub fn update_network_delay(&mut self, delay: u32) {
         if self.current_delay.eq(&0) {
             self.current_delay = delay;
             return;
         }
-        let current_delay = self.current_delay as f32;
 
         self.current_delay = delay / 2 + self.current_delay / 2;
-        log::debug!(
-            "update_network_delay:{}, {}, state:{:?},count:{}",
+        log::trace!(
+            "VideoQoS update_network_delay:{}, {}, state:{:?},count:{}",
             self.current_delay,
             delay,
             self.state,
-            self.count
+            self.debounce_count
         );
 
-        if self.current_delay < MIN_DELAY {
-            if self.fps != 30 && self.current_image_quality != self.user_image_quality {
-                log::debug!("current_delay is normal, set to user_image_quality");
-                self.fps = 30;
+        // ABR
+        let current_state = DelayState::from_delay(self.current_delay);
+        if current_state != self.state && self.debounce_count > 5 {
+            log::debug!(
+                "VideoQoS state changed:{:?} -> {:?}",
+                self.state,
+                current_state
+            );
+            self.state = current_state;
+            self.debounce_count = 0;
+            self.refresh_quality();
+        } else {
+            self.debounce_count += 1;
+        }
+    }
+
+    fn refresh_quality(&mut self) {
+        match self.state {
+            DelayState::Normal => {
+                self.fps = FPS;
                 self.current_image_quality = self.user_image_quality;
-                let _ = self.generate_bitrate().ok();
-                self.updated = true;
             }
-            self.state = AdaptiveState::Normal;
-        } else if self.current_delay > MAX_DELAY {
-            if self.fps != 5 && self.current_image_quality != 25 {
-                log::debug!("current_delay is very height, set fps to 5, image_quality to 25");
-                self.fps = 5;
-                self.current_image_quality = 25;
-                let _ = self.generate_bitrate().ok();
-                self.updated = true;
+            DelayState::LowDelay => {
+                self.fps = FPS;
+                self.current_image_quality = std::cmp::min(self.user_image_quality, 50);
             }
-        } else {
-            let delay = delay as f32;
-            let last_delay = self.last_delay as f32;
-            match self.state {
-                AdaptiveState::Normal => {
-                    if delay > current_delay * MAX {
-                        self.state = AdaptiveState::HeightDelay;
-                    } else if delay < current_delay * MIN
-                        && self.current_image_quality < self.user_image_quality
-                    {
-                        self.state = AdaptiveState::LowDelay;
-                    }
-                    self.count = 1;
-                    self.last_delay = self.current_delay
-                }
-                AdaptiveState::HeightDelay => {
-                    if delay > last_delay {
-                        if self.count > MAX_COUNT {
-                            self.decrease_quality();
-                            self.reset_state();
-                            return;
-                        }
-                        self.count += 1;
-                    } else {
-                        self.reset_state();
-                    }
-                }
-                AdaptiveState::LowDelay => {
-                    if delay < last_delay * MIN {
-                        if self.count > MAX_COUNT {
-                            self.increase_quality();
-                            self.reset_state();
-                            return;
-                        }
-                        self.count += 1;
-                    } else {
-                        self.reset_state();
-                    }
-                }
+            DelayState::HighDelay => {
+                self.fps = FPS / 2;
+                self.current_image_quality = std::cmp::min(self.user_image_quality, 25);
+            }
+            DelayState::Broken => {
+                self.fps = FPS / 4;
+                self.current_image_quality = 10;
             }
         }
-    }
-
-    fn reset_state(&mut self) {
-        self.count = 0;
-        self.state = AdaptiveState::Normal;
-    }
-
-    fn increase_quality(&mut self) {
-        log::debug!("Adaptive increase quality");
-        if self.fps < FPS {
-            log::debug!("increase fps {} -> {}", self.fps, FPS);
-            self.fps = FPS;
-        } else {
-            self.current_image_quality += self.current_image_quality / 2;
-            let _ = self.generate_bitrate().ok();
-            log::debug!("increase quality:{}", self.current_image_quality);
-        }
+        let _ = self.generate_bitrate().ok();
         self.updated = true;
     }
 
-    fn decrease_quality(&mut self) {
-        log::debug!("Adaptive decrease quality");
-        if self.fps < 15 {
-            log::debug!("fps is low enough :{}", self.fps);
-            return;
-        }
-        if self.current_image_quality < ImageQuality::Low.value() as _ {
-            self.fps = self.fps / 2;
-            log::debug!("decrease fps:{}", self.fps);
-        } else {
-            self.current_image_quality -= self.current_image_quality / 2;
+    pub fn update_image_quality(&mut self, image_quality: i32) {
+        let image_quality = Self::convert_quality(image_quality) as _;
+        log::debug!("VideoQoS update_image_quality{}", image_quality);
+        if self.current_image_quality != image_quality {
+            self.current_image_quality = image_quality;
             let _ = self.generate_bitrate().ok();
-            log::debug!("decrease quality:{}", self.current_image_quality);
-        };
-        self.updated = true;
-    }
-
-    pub fn update_image_quality(&mut self, image_quality: Option<u32>) {
-        if let Some(image_quality) = image_quality {
-            if image_quality < 10 || image_quality > 200 {
-                self.current_image_quality = ImageQuality::Balanced.value() as _;
-            }
-            if self.current_image_quality != image_quality {
-                self.current_image_quality = image_quality;
-                let _ = self.generate_bitrate().ok();
-                self.updated = true;
-            }
-        } else {
-            self.current_image_quality = ImageQuality::Balanced.value() as _;
+            self.updated = true;
         }
+
         self.user_image_quality = self.current_image_quality;
     }
 
@@ -251,7 +209,7 @@ impl VideoQoS {
             bail!("Fail to generate_bitrate, width or height is not set");
         }
         if self.current_image_quality == 0 {
-            self.current_image_quality = ImageQuality::Balanced.value() as _;
+            self.current_image_quality = ImageQuality::Balanced.as_percent();
         }
 
         let base_bitrate = ((self.width * self.height) / 800) as u32;
@@ -280,6 +238,18 @@ impl VideoQoS {
     pub fn reset(&mut self) {
         *self = Default::default();
     }
+
+    pub fn convert_quality(q: i32) -> i32 {
+        if q == ImageQuality::Balanced.value() {
+            100 * 2 / 3
+        } else if q == ImageQuality::Low.value() {
+            100 / 2
+        } else if q == ImageQuality::Best.value() {
+            100
+        } else {
+            (q >> 8 & 0xFF) * 2
+        }
+    }
 }
 
 fn is_capturer_mag_supported() -> bool {
diff --git a/src/ui/header.tis b/src/ui/header.tis
index 88ee8b6e6..35a132c90 100644
--- a/src/ui/header.tis
+++ b/src/ui/header.tis
@@ -335,13 +335,14 @@ class Header: Reactor.Component {
 }
 
 function handle_custom_image_quality() {
-    var bitrate = handler.get_custom_image_quality()[0] / 2;
+    var tmp = handler.get_custom_image_quality();
+    var bitrate = (tmp[0] || 50);
     msgbox("custom", "Custom Image Quality", "<div .form> \
           <div><input type=\"hslider\" style=\"width: 50%\" name=\"bitrate\" max=\"100\" min=\"10\" value=\"" + bitrate + "\"/ buddy=\"bitrate-buddy\"><b #bitrate-buddy>x</b>% Bitrate</div> \
       </div>", function(res=null) {
         if (!res) return;
         if (!res.bitrate) return;
-        handler.save_custom_image_quality(res.bitrate * 2);
+        handler.save_custom_image_quality(res.bitrate);
         toggleMenuState();
       });
 }