diff --git a/src/player/state.rs b/src/player/state.rs
new file mode 100644
index 0000000..4c89971
--- /dev/null
+++ b/src/player/state.rs
@@ -0,0 +1,83 @@
+//! Player state management
+
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum PlaybackState {
+    Stopped,
+    Playing,
+    Paused,
+}
+
+impl Default for PlaybackState {
+    fn default() -> Self {
+        Self::Stopped
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct PlayerState {
+    pub playback: PlaybackState,
+    pub current_frame: u64,
+    pub total_frames: u64,
+    pub current_time_ms: u64,
+    pub duration_ms: u64,
+    pub fps: f64,
+    pub volume: f32,
+    pub muted: bool,
+    pub speed: f32,
+    pub show_subtitle: bool,
+    pub show_yolo: bool,
+    pub show_chunks: bool,
+    pub zoom: f32,
+    pub pan_x: f32,
+    pub pan_y: f32,
+}
+
+impl Default for PlayerState {
+    fn default() -> Self {
+        Self {
+            playback: PlaybackState::Stopped,
+            current_frame: 0,
+            total_frames: 0,
+            current_time_ms: 0,
+            duration_ms: 0,
+            fps: 0.0,
+            volume: 1.0,
+            muted: false,
+            speed: 1.0,
+            show_subtitle: false,
+            show_yolo: false,
+            show_chunks: false,
+            zoom: 1.0,
+            pan_x: 0.0,
+            pan_y: 0.0,
+        }
+    }
+}
+
+impl PlayerState {
+    pub fn frame_to_time(frame: u64, fps: f64) -> u64 {
+        if fps > 0.0 {
+            ((frame as f64 / fps) * 1000.0) as u64
+        } else {
+            0
+        }
+    }
+
+    pub fn time_to_frame(time_ms: u64, fps: f64) -> u64 {
+        if fps > 0.0 {
+            ((time_ms as f64 / 1000.0) * fps) as u64
+        } else {
+            0
+        }
+    }
+
+    pub fn format_time(ms: u64) -> String {
+        let total_secs = ms / 1000;
+        let hours = total_secs / 3600;
+        let minutes = (total_secs % 3600) / 60;
+        let seconds = total_secs % 60;
+        format!("{:02}:{:02}:{:02}", hours, minutes, seconds)
+    }
+}