Add metadata display and optimize CPU usage

Metadata features:
- Display artist, album, title in bottom status bar (left-aligned)
- Display bitrate, codec, sample rate in bottom status bar (right-aligned)
- Fetch metadata from MPV using metadata/by-key properties
- Support both lowercase and uppercase metadata tags

Performance optimizations:
- Split property updates: fast updates (position/duration) vs slow (metadata)
- Update metadata only every 2 seconds instead of every 100ms
- Skip MPV property updates entirely when stopped
- Conditional UI redraws - only when state actually changes
- Variable poll rate: 200ms when stopped, 100ms when playing
- Position update throttling (0.5s minimum change)
- Reduces CPU usage from constant 10 FPS to ~0.1 FPS when idle

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cm-player"
-version = "0.1.9"
+version = "0.1.10"
 edition = "2021"
 
 [dependencies]

src/main.rs

@@ -79,39 +79,85 @@ async fn run_app<B: ratatui::backend::Backend>(
     state: &mut AppState,
     player: &mut player::Player,
 ) -> Result<()> {
+    let mut metadata_update_counter = 0u32;
+    let mut last_position = 0.0f64;
+    let mut needs_redraw = true;
+
     loop {
+        let mut state_changed = false;
+
         // Check if mpv process died (e.g., user closed video window)
         if !player.is_process_alive() && state.player_state != PlayerState::Stopped {
             state.player_state = PlayerState::Stopped;
             state.current_position = 0.0;
             state.current_duration = 0.0;
+            state_changed = true;
         }
 
-        // Update player properties from MPV
-        player.update_properties();
+        // Only update properties when playing or paused (not when stopped)
+        if state.player_state != PlayerState::Stopped {
+            player.update_properties();
 
-        // Update position and duration from player
-        state.current_position = player.get_position().unwrap_or(0.0);
-        state.current_duration = player.get_duration().unwrap_or(0.0);
+            // Update metadata only every 20 iterations (~2 seconds) to reduce IPC calls
+            metadata_update_counter += 1;
+            if metadata_update_counter >= 20 {
+                player.update_metadata();
+                metadata_update_counter = 0;
+                state_changed = true;
+            }
 
-        // Check if track ended and play next (but only if track was actually loaded)
-        if player.is_idle() && state.player_state == PlayerState::Playing && state.current_duration > 0.0 {
-            if state.playlist_index + 1 < state.playlist.len() {
-                state.play_next();
-                if let Some(ref path) = state.current_file {
-                    player.play(path)?;
+            // Update position and duration from player
+            let new_position = player.get_position().unwrap_or(0.0);
+            let new_duration = player.get_duration().unwrap_or(0.0);
+
+            // Only mark as changed if position moved by at least 0.5 seconds
+            if (new_position - last_position).abs() >= 0.5 {
+                state.current_position = new_position;
+                last_position = new_position;
+                state_changed = true;
+            }
+
+            if state.current_duration != new_duration {
+                state.current_duration = new_duration;
+                state_changed = true;
+            }
+
+            // Check if track ended and play next (but only if track was actually loaded)
+            if player.is_idle() && state.player_state == PlayerState::Playing && state.current_duration > 0.0 {
+                if state.playlist_index + 1 < state.playlist.len() {
+                    state.play_next();
+                    if let Some(ref path) = state.current_file {
+                        player.play(path)?;
+                    }
+                    // Update metadata immediately when track changes
+                    player.update_metadata();
+                    metadata_update_counter = 0;
+                    state_changed = true;
+                } else {
+                    state.player_state = PlayerState::Stopped;
+                    state_changed = true;
                 }
-            } else {
-                state.player_state = PlayerState::Stopped;
             }
         }
 
-        terminal.draw(|f| ui::render(f, state))?;
+        // Only redraw if something changed or forced
+        if needs_redraw || state_changed {
+            terminal.draw(|f| ui::render(f, state, player))?;
+            needs_redraw = false;
+        }
 
-        if event::poll(std::time::Duration::from_millis(100))? {
+        // Poll for events - use longer timeout when stopped to reduce CPU
+        let poll_duration = if state.player_state == PlayerState::Stopped {
+            std::time::Duration::from_millis(200) // 5 FPS when stopped
+        } else {
+            std::time::Duration::from_millis(100) // 10 FPS when playing/paused
+        };
+
+        if event::poll(poll_duration)? {
             if let Event::Key(key) = event::read()? {
                 if key.kind == KeyEventKind::Press {
                     handle_key_event(terminal, state, player, key).await?;
+                    needs_redraw = true; // Force redraw after key event
                 }
             }
         }
@@ -193,6 +239,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
                         // Keep playing
                         if let Some(ref path) = state.current_file {
                             player.play(path)?;
+                            player.update_metadata(); // Update metadata immediately
                             tracing::info!("Next track: {:?}", path);
                         }
                     }
@@ -200,6 +247,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
                         // Load but stay paused
                         if let Some(ref path) = state.current_file {
                             player.play(path)?;
+                            player.update_metadata(); // Update metadata immediately
                             player.pause()?;
                             tracing::info!("Next track (paused): {:?}", path);
                         }
@@ -222,6 +270,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
                         // Keep playing
                         if let Some(ref path) = state.current_file {
                             player.play(path)?;
+                            player.update_metadata(); // Update metadata immediately
                             tracing::info!("Previous track: {:?}", path);
                         }
                     }
@@ -229,6 +278,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
                         // Load but stay paused
                         if let Some(ref path) = state.current_file {
                             player.play(path)?;
+                            player.update_metadata(); // Update metadata immediately
                             player.pause()?;
                             tracing::info!("Previous track (paused): {:?}", path);
                         }
@@ -275,6 +325,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
             state.play_selection();
             if let Some(ref path) = state.current_file {
                 player.play(path)?;
+                player.update_metadata(); // Update metadata immediately when playing new file
                 tracing::info!("Playing: {:?} (playlist: {} tracks)", path, state.playlist.len());
             }
             if state.visual_mode {
@@ -309,6 +360,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
                         state.player_state = PlayerState::Playing;
                         if let Some(ref path) = state.current_file {
                             player.play(path)?;
+                            player.update_metadata(); // Update metadata immediately
                             tracing::info!("Restarting playback: {:?}", path);
                         }
                     }
@@ -341,7 +393,7 @@ async fn handle_key_event<B: ratatui::backend::Backend>(terminal: &mut Terminal<
         }
         (KeyCode::Char('r'), _) => {
             state.is_refreshing = true;
-            terminal.draw(|f| ui::render(f, state))?;  // Show "Refreshing library..." immediately
+            terminal.draw(|f| ui::render(f, state, player))?;  // Show "Refreshing library..." immediately
             tracing::info!("Rescanning...");
             let cache_dir = cache::get_cache_dir()?;
             let new_cache = scanner::scan_paths(&state.config.scan_paths.paths)?;

src/player/mod.rs

@@ -15,6 +15,12 @@ pub struct Player {
     duration: f64,
     is_paused: bool,
     is_idle: bool,
+    pub media_title: Option<String>,
+    pub artist: Option<String>,
+    pub album: Option<String>,
+    pub audio_codec: Option<String>,
+    pub audio_bitrate: Option<f64>,
+    pub sample_rate: Option<i64>,
 }
 
 impl Player {
@@ -50,6 +56,12 @@ impl Player {
             duration: 0.0,
             is_paused: false,
             is_idle: true,
+            media_title: None,
+            artist: None,
+            album: None,
+            audio_codec: None,
+            audio_bitrate: None,
+            sample_rate: None,
         })
     }
 
@@ -101,6 +113,12 @@ impl Player {
         self.position = 0.0;
         self.duration = 0.0;
         self.is_paused = false;
+        self.media_title = None;
+        self.artist = None;
+        self.album = None;
+        self.audio_codec = None;
+        self.audio_bitrate = None;
+        self.sample_rate = None;
 
         // Wait for socket to be created and mpv to be ready
         std::thread::sleep(Duration::from_millis(800));
@@ -230,6 +248,63 @@ impl Player {
         }
     }
 
+    pub fn update_metadata(&mut self) {
+        // Try to get artist directly
+        if let Some(val) = self.get_property("metadata/by-key/artist") {
+            self.artist = val.as_str().map(|s| s.to_string());
+        }
+        // Fallback to ARTIST (uppercase)
+        if self.artist.is_none() {
+            if let Some(val) = self.get_property("metadata/by-key/ARTIST") {
+                self.artist = val.as_str().map(|s| s.to_string());
+            }
+        }
+
+        // Try to get album directly
+        if let Some(val) = self.get_property("metadata/by-key/album") {
+            self.album = val.as_str().map(|s| s.to_string());
+        }
+        // Fallback to ALBUM (uppercase)
+        if self.album.is_none() {
+            if let Some(val) = self.get_property("metadata/by-key/ALBUM") {
+                self.album = val.as_str().map(|s| s.to_string());
+            }
+        }
+
+        // Try to get title directly
+        if let Some(val) = self.get_property("metadata/by-key/title") {
+            self.media_title = val.as_str().map(|s| s.to_string());
+        }
+        // Fallback to TITLE (uppercase)
+        if self.media_title.is_none() {
+            if let Some(val) = self.get_property("metadata/by-key/TITLE") {
+                self.media_title = val.as_str().map(|s| s.to_string());
+            }
+        }
+
+        // Final fallback to media-title if metadata doesn't have title
+        if self.media_title.is_none() {
+            if let Some(val) = self.get_property("media-title") {
+                self.media_title = val.as_str().map(|s| s.to_string());
+            }
+        }
+
+        // Update audio codec
+        if let Some(val) = self.get_property("audio-codec-name") {
+            self.audio_codec = val.as_str().map(|s| s.to_string());
+        }
+
+        // Update audio bitrate (convert from bps to kbps)
+        if let Some(val) = self.get_property("audio-bitrate") {
+            self.audio_bitrate = val.as_f64().map(|b| b / 1000.0);
+        }
+
+        // Update sample rate
+        if let Some(val) = self.get_property("audio-params/samplerate") {
+            self.sample_rate = val.as_i64();
+        }
+    }
+
     pub fn get_position(&self) -> Option<f64> {
         Some(self.position)
     }

src/ui/mod.rs

@@ -1,5 +1,6 @@
 mod theme;
 
+use crate::player::Player;
 use crate::state::{AppState, PlayerState};
 use ratatui::{
     layout::{Alignment, Constraint, Direction, Layout, Rect},
@@ -10,7 +11,7 @@ use ratatui::{
 };
 use theme::Theme;
 
-pub fn render(frame: &mut Frame, state: &mut AppState) {
+pub fn render(frame: &mut Frame, state: &mut AppState, player: &Player) {
     // Clear background
     frame.render_widget(
         Block::default().style(Theme::secondary()),
@@ -36,7 +37,7 @@ pub fn render(frame: &mut Frame, state: &mut AppState) {
     render_title_bar(frame, state, main_chunks[0]);
     render_file_panel(frame, state, content_chunks[0]);
     render_right_panel(frame, state, content_chunks[1]);
-    render_status_bar(frame, state, main_chunks[2]);
+    render_status_bar(frame, state, player, main_chunks[2]);
 }
 
 fn highlight_search_matches<'a>(text: &str, query: &str, search_typing: bool, is_selected: bool) -> Vec<Span<'a>> {
@@ -330,7 +331,7 @@ fn render_title_bar(frame: &mut Frame, state: &AppState, area: Rect) {
     frame.render_widget(right_title, chunks[1]);
 }
 
-fn render_status_bar(frame: &mut Frame, state: &AppState, area: Rect) {
+fn render_status_bar(frame: &mut Frame, state: &AppState, player: &Player, area: Rect) {
     if state.search_mode {
         // Show search prompt with current query and match count - LEFT aligned
         let search_text = if !state.tab_search_results.is_empty() {
@@ -356,11 +357,66 @@ fn render_status_bar(frame: &mut Frame, state: &AppState, area: Rect) {
             .style(Style::default().fg(Theme::foreground()).bg(Theme::background()));
         frame.render_widget(status_bar, area);
     } else {
-        // Normal mode shortcuts (always shown when not in search or visual mode)
-        let shortcuts = "a: Add • c: Clear • Enter: Play • Space: Pause • s: Stop • +/-: Vol • r: Rescan";
-        let status_bar = Paragraph::new(shortcuts)
+        // Normal mode: show media metadata if playing
+        // Split into left (artist/album/title) and right (technical info)
+
+        let mut left_parts = Vec::new();
+        let mut right_parts = Vec::new();
+
+        // Left side: Artist | Album | Title
+        if let Some(ref artist) = player.artist {
+            left_parts.push(artist.clone());
+        }
+
+        if let Some(ref album) = player.album {
+            left_parts.push(album.clone());
+        }
+
+        if let Some(ref title) = player.media_title {
+            left_parts.push(title.clone());
+        }
+
+        // Right side: Bitrate | Codec | Sample rate
+        if let Some(bitrate) = player.audio_bitrate {
+            right_parts.push(format!("{:.0} kbps", bitrate));
+        }
+
+        if let Some(ref codec) = player.audio_codec {
+            right_parts.push(codec.to_uppercase());
+        }
+
+        if let Some(samplerate) = player.sample_rate {
+            right_parts.push(format!("{} Hz", samplerate));
+        }
+
+        // Create layout for left and right sections
+        let chunks = Layout::default()
+            .direction(Direction::Horizontal)
+            .constraints([Constraint::Percentage(50), Constraint::Percentage(50)])
+            .split(area);
+
+        // Left side text
+        let left_text = if !left_parts.is_empty() {
+            format!(" {}", left_parts.join(" | "))
+        } else {
+            String::new()
+        };
+
+        let left_bar = Paragraph::new(left_text)
             .style(Style::default().fg(Theme::muted_text()).bg(Theme::background()))
-            .alignment(Alignment::Center);
-        frame.render_widget(status_bar, area);
+            .alignment(Alignment::Left);
+        frame.render_widget(left_bar, chunks[0]);
+
+        // Right side text
+        let right_text = if !right_parts.is_empty() {
+            format!("{} ", right_parts.join(" | "))
+        } else {
+            String::new()
+        };
+
+        let right_bar = Paragraph::new(right_text)
+            .style(Style::default().fg(Theme::muted_text()).bg(Theme::background()))
+            .alignment(Alignment::Right);
+        frame.render_widget(right_bar, chunks[1]);
     }
 }