Fix buffering UX when transitioning from local to Qobuz tracks

- Stop playback immediately when starting a Qobuz track to prevent
  previous track from continuing during download
- Show buffering toast while downloading Qobuz audio
- Skip buffering UI for local tracks since they load instantly
- Add is_local field to QueueTrack for prefetch optimization
- Update prefetch to skip local tracks (no network needed)
- Update all queue track builders to include is_local flag

src-tauri/src/commands/playback.rs

@@ -215,6 +215,12 @@ fn spawn_prefetch(
         let track_id = track.id;
         let track_title = track.title.clone();
 
+        // Skip local tracks - they don't need prefetching from Qobuz
+        if track.is_local {
+            log::debug!("Skipping prefetch for local track: {} - {}", track_id, track_title);
+            continue;
+        }
+
         // Check if already cached or being fetched
         if cache.contains(track_id) {
             log::debug!("Track {} already cached", track_id);

src-tauri/src/queue/mod.rs

@@ -23,6 +23,9 @@ pub struct QueueTrack {
     pub hires: bool,
     pub bit_depth: Option<u32>,
     pub sample_rate: Option<f64>,
+    /// Whether this is a local library track (not from Qobuz)
+    #[serde(default)]
+    pub is_local: bool,
 }
 
 /// Repeat mode options

src/lib/components/views/PlaylistDetailView.svelte

@@ -586,6 +586,7 @@
       hires: t.hires ?? false,
       bit_depth: t.bitDepth ?? null,
       sample_rate: t.samplingRate != null ? (t.isLocal ? t.samplingRate * 1000 : t.samplingRate) : null,
+      is_local: t.isLocal ?? false,
     }));
 
     // Collect local track IDs (original positive IDs)
@@ -667,6 +668,7 @@
             hires: t.hires ?? false,
             bit_depth: t.bitDepth ?? null,
             sample_rate: t.samplingRate != null ? (t.isLocal ? t.samplingRate * 1000 : t.samplingRate) : null,
+            is_local: t.isLocal ?? false,
           }
         });
       } catch (err) {
@@ -694,6 +696,7 @@
       hires: t.hires ?? false,
       bit_depth: t.bitDepth ?? null,
       sample_rate: t.samplingRate != null ? (t.isLocal ? t.samplingRate * 1000 : t.samplingRate) : null,
+      is_local: t.isLocal ?? false,
     }));
 
     // Collect local track IDs

src/lib/services/playbackService.ts

@@ -81,7 +81,21 @@ export async function playTrack(
   setCurrentTrack(track);
 
   try {
-    if (showLoadingToast) {
+    // For Qobuz tracks: stop current playback immediately and show buffering
+    // This prevents the previous track from continuing while we download
+    // Local tracks load instantly so they don't need this
+    if (!isLocal && !isCasting()) {
+      // Stop current playback immediately
+      try {
+        await invoke('stop_playback');
+      } catch {
+        // Ignore errors - player might not be playing
+      }
+      // Show buffering indicator
+      if (showLoadingToast) {
+        showToast(track.title, 'buffering');
+      }
+    } else if (showLoadingToast && !isLocal) {
       showToast(track.title, 'buffering');
     }
 

src/lib/services/trackActions.ts

@@ -36,7 +36,8 @@ export function buildQueueTrackFromQobuz(track: QobuzTrack): BackendQueueTrack {
     artwork_url: artwork || null,
     hires: track.hires_streamable ?? false,
     bit_depth: track.maximum_bit_depth ?? null,
-    sample_rate: track.maximum_sampling_rate ?? null
+    sample_rate: track.maximum_sampling_rate ?? null,
+    is_local: false
   };
 }
 
@@ -50,7 +51,8 @@ export function buildQueueTrackFromAlbumTrack(track: Track, albumArtwork: string
     artwork_url: albumArtwork || null,
     hires: track.hires ?? false,
     bit_depth: track.bitDepth ?? null,
-    sample_rate: track.samplingRate ?? null
+    sample_rate: track.samplingRate ?? null,
+    is_local: false
   };
 }
 
@@ -64,7 +66,8 @@ export function buildQueueTrackFromPlaylistTrack(track: PlaylistTrack): BackendQ
     artwork_url: track.albumArt || null,
     hires: track.hires ?? false,
     bit_depth: track.bitDepth ?? null,
-    sample_rate: track.samplingRate ?? null
+    sample_rate: track.samplingRate ?? null,
+    is_local: false
   };
 }
 
@@ -81,7 +84,8 @@ export function buildQueueTrackFromLocalTrack(track: LocalLibraryTrack): Backend
     artwork_url: artwork,
     hires: isHires,
     bit_depth: track.bit_depth ?? null,
-    sample_rate: track.sample_rate ?? null
+    sample_rate: track.sample_rate ?? null,
+    is_local: true
   };
 }
 

src/lib/stores/queueStore.ts

@@ -27,6 +27,7 @@ export interface BackendQueueTrack {
   hires: boolean;
   bit_depth: number | null;
   sample_rate: number | null;
+  is_local?: boolean;
 }
 
 interface BackendQueueState {

src/routes/+page.svelte

@@ -433,7 +433,8 @@
       artwork_url: artwork || null,
       hires: t.hires ?? false,
       bit_depth: t.bitDepth ?? null,
-      sample_rate: t.samplingRate ?? null
+      sample_rate: t.samplingRate ?? null,
+      is_local: false
     }));
 
     await setQueue(queueTracks, 0, true);
@@ -475,7 +476,8 @@
         artwork_url: artwork || null,
         hires: t.hires ?? false,
         bit_depth: t.bitDepth ?? null,
-        sample_rate: t.samplingRate ?? null
+        sample_rate: t.samplingRate ?? null,
+        is_local: false
       });
     }
     showToast(`Playing ${album.tracks.length} tracks next`, 'success');
@@ -495,7 +497,8 @@
       artwork_url: artwork || null,
       hires: t.hires ?? false,
       bit_depth: t.bitDepth ?? null,
-      sample_rate: t.samplingRate ?? null
+      sample_rate: t.samplingRate ?? null,
+      is_local: false
     }));
 
     const success = await addTracksToQueue(queueTracks);
@@ -603,7 +606,8 @@
         artwork_url: artwork || null,
         hires: t.hires ?? false,
         bit_depth: t.bitDepth ?? null,
-        sample_rate: t.samplingRate ?? null
+        sample_rate: t.samplingRate ?? null,
+        is_local: false
       }));
 
       // Set the queue starting at the clicked track
@@ -923,7 +927,8 @@
         artwork_url: artwork || null,
         hires: t.hires ?? false,
         bit_depth: t.bitDepth ?? null,
-        sample_rate: t.samplingRate ?? null
+        sample_rate: t.samplingRate ?? null,
+        is_local: false
       });
     }
     showToast(`Playing ${selectedAlbum.tracks.length} tracks next`, 'success');
@@ -943,7 +948,8 @@
       artwork_url: artwork || null,
       hires: t.hires ?? false,
       bit_depth: t.bitDepth ?? null,
-      sample_rate: t.samplingRate ?? null
+      sample_rate: t.samplingRate ?? null,
+      is_local: false
     }));
 
     const success = await addTracksToQueue(queueTracks);
@@ -1295,7 +1301,8 @@
           artwork_url: t.artwork_url,
           hires: t.hires ?? false,
           bit_depth: t.bit_depth ?? null,
-          sample_rate: t.sample_rate ?? null
+          sample_rate: t.sample_rate ?? null,
+          is_local: t.is_local ?? false
         }));
 
         await setQueue(tracks, session.current_index ?? 0, true);