fix(preview): Symphonia format sniff and ranged stream startup (#1006)

* fix(preview): Symphonia format sniff and cluster member stream URLs

Resolve preview container hints from HTTP headers, Subsonic suffix, and
magic-byte sniff after Symphonia 0.6. Route preview streams through
clusterBrowseServerId like main playback; guard CoverArtImage when the
preview cover ref is still loading.

* fix(preview): adapt Symphonia sniff branch for main without cluster routing

Keep formatSuffix and cover-ref guards from the cluster work; use
buildStreamUrl on the active server instead of clusterBrowseServerId.

* fix(preview): use ranged HTTP so preview starts without full-file download

Open preview via RangedHttpSource when the server supports byte ranges;
fall back to buffered download otherwise. Gate in-memory probe with
ProbeSeekGate so Symphonia 0.6 does not scan the entire file before audio.

* docs: CHANGELOG and credits for preview fix PR #1006

* chore: drop PR #1006 from settings credits (minor fix)

* fix(preview): allow clippy too_many_arguments on audio_preview_play

formatSuffix pushed the Tauri command to 8 args; matches other IPC commands.

CHANGELOG.md

@@ -79,6 +79,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 
 
+### Track preview — Symphonia 0.6 format hints and fast stream start
+
+**By [@cucadmuh](https://github.com/cucadmuh), PR [#1006](https://github.com/Psychotoxical/psysonic/pull/1006)**
+
+* Preview resolves container format from HTTP headers, Subsonic `suffix`, and magic-byte sniff so Symphonia 0.6 no longer fails with `.unknown` demuxer errors.
+* Preview opens via ranged HTTP when the server supports byte ranges — audio starts after ~384 KiB buffered instead of waiting for a full-file download; buffered fallback uses the same probe seek-gate as main playback.
+* Player bar cover guard while preview metadata loads; progress ring leaves the loading spinner once the engine emits `audio:preview-start`.
+
+
+
 ## [1.47.0]
 
 > **🙏 Thank you to our amazing Discord community.** This release would not have been possible without your tireless support, quality checks, bug reports and all-round collaboration. Every report, every repro and every bit of feedback shaped what shipped here — thank you. Come join us: [discord.gg/AMnDRErm4u](https://discord.gg/AMnDRErm4u)

src-tauri/crates/psysonic-audio/src/decode.rs

@@ -166,15 +166,24 @@ impl SizedDecoder {
             inner: Cursor::new(data),
             len: data_len,
         };
+        // Symphonia 0.6 scans trailing metadata on seekable sources — hide
+        // seekability during probe (same as `new_streaming`) so preview does not
+        // read the entire in-memory file before the first sample.
+        let probe_seek_gate = (!crate::stream::container_hint_is_mp4(format_hint))
+            .then(|| Arc::new(AtomicBool::new(false)));
+        let media: Box<dyn MediaSource> = match &probe_seek_gate {
+            Some(gate) => Box::new(ProbeSeekGate {
+                inner: Box::new(source),
+                seekable: gate.clone(),
+            }),
+            None => Box::new(source),
+        };
         // Hi-Res: 4 MB read-ahead so Symphonia demuxes fewer Read calls for
         // high-bitrate files (88.2 kHz/24-bit FLAC ≈ 1800 kbps).
         // Standard: 512 KB is plenty for MP3/AAC — larger buffers waste allocation
         // and compete with the playback thread at track start.
         let buf_len = if hi_res { 4 * 1024 * 1024 } else { 512 * 1024 };
-        let mss = MediaSourceStream::new(
-            Box::new(source) as Box<dyn MediaSource>,
-            MediaSourceStreamOptions { buffer_len: buf_len },
-        );
+        let mss = MediaSourceStream::new(media, MediaSourceStreamOptions { buffer_len: buf_len });
 
         let mut hint = Hint::new();
         if let Some(ext) = format_hint {
@@ -200,6 +209,10 @@ impl SizedDecoder {
                 }
             })?;
 
+        if let Some(gate) = &probe_seek_gate {
+            gate.store(true, Ordering::Relaxed);
+        }
+
         let track = format
             .tracks()
             .iter()

src-tauri/crates/psysonic-audio/src/preview.rs

@@ -1,6 +1,6 @@
 //! Short preview playback on a secondary sink (same output stream).
-use std::sync::atomic::Ordering;
-use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, AtomicU64, AtomicUsize, Ordering};
+use std::sync::{Arc, Mutex};
 use std::time::{Duration, Instant};
 
 use rodio::Player;
@@ -9,8 +9,17 @@ use tauri::{AppHandle, Emitter, State};
 
 use super::decode::SizedDecoder;
 use super::engine::{audio_http_client, AudioEngine};
-use super::helpers::MASTER_HEADROOM;
+use super::helpers::{
+    content_type_to_hint, format_hint_from_content_disposition, normalize_stream_suffix_for_hint,
+    resolve_playback_format_hint, sniff_stream_format_extension, STREAM_FORMAT_SNIFF_PROBE_BYTES,
+    MASTER_HEADROOM,
+};
+use super::play_input::url_format_hint;
 use super::sources::PriorityBoostSource;
+use super::stream::{
+    mp4_needs_tail_prefetch, ranged_download_task, wait_for_ranged_mp4_probe_ready,
+    RangedHttpSource, RangedMp4ProbeGate,
+};
 
 // ────────────────────────────────────────────────────────────────────────────
 // Preview engine — secondary Sink on the same OutputStream, fed by Symphonia.
@@ -90,26 +99,246 @@ pub(crate) fn preview_resume_main(state: &AudioEngine) {
     }
 }
 
-/// Format hint inferred from a Subsonic stream URL. The frontend always passes
-/// a `format=flac` query param for `.opus` files (server transcodes); for
-/// everything else we guess from the URL's `format=` value or fall back to None.
+/// `format=` query param on Subsonic stream URLs (transcode targets).
 pub(crate) fn preview_format_hint_from_url(url: &str) -> Option<String> {
     url.split('?')
         .nth(1)?
         .split('&')
         .find_map(|kv| {
             let (k, v) = kv.split_once('=')?;
-            if k.eq_ignore_ascii_case("format") { Some(v.to_string()) } else { None }
+            if k.eq_ignore_ascii_case("format") {
+                Some(v.to_string())
+            } else {
+                None
+            }
         })
 }
 
+/// Symphonia container hint for preview downloads — mirrors main playback:
+/// Content-Type / Content-Disposition, URL tail, Subsonic suffix, magic-byte sniff.
+pub(crate) fn resolve_preview_format_hint(
+    url: &str,
+    content_type: Option<&str>,
+    content_disposition: Option<&str>,
+    stream_suffix: Option<&str>,
+    bytes: &[u8],
+) -> Option<String> {
+    let media_hint = content_type
+        .and_then(content_type_to_hint)
+        .or_else(|| {
+            content_disposition.and_then(format_hint_from_content_disposition)
+        });
+    let url_hint = preview_format_hint_from_url(url).or_else(|| url_format_hint(url));
+    resolve_playback_format_hint(
+        url_hint.as_deref(),
+        stream_suffix,
+        media_hint.as_deref(),
+        Some(bytes),
+    )
+}
+
+fn preview_http_client(state: &AudioEngine) -> reqwest::Client {
+    reqwest::Client::builder()
+        .timeout(Duration::from_secs(300))
+        .use_rustls_tls()
+        .user_agent(psysonic_core::user_agent::subsonic_wire_user_agent())
+        .build()
+        .unwrap_or_else(|_| audio_http_client(state))
+}
+
+/// Open a preview decoder — ranged HTTP when the server supports it (starts
+/// after ~384 KiB buffered), otherwise falls back to a full in-memory download.
+async fn open_preview_decoder(
+    url: &str,
+    format_suffix: Option<&str>,
+    gen: u64,
+    state: &AudioEngine,
+    app: &AppHandle,
+) -> Result<Option<SizedDecoder>, String> {
+    let preview_http = preview_http_client(state);
+    let response = preview_http
+        .get(url)
+        .send()
+        .await
+        .map_err(|e| format!("preview: connection failed: {e}"))?
+        .error_for_status()
+        .map_err(|e| format!("preview: HTTP {e}"))?;
+
+    let mut stream_hint = content_type_to_hint(
+        response
+            .headers()
+            .get(reqwest::header::CONTENT_TYPE)
+            .and_then(|v| v.to_str().ok())
+            .unwrap_or(""),
+    )
+    .or_else(|| {
+        response
+            .headers()
+            .get(reqwest::header::CONTENT_DISPOSITION)
+            .and_then(|v| v.to_str().ok())
+            .and_then(format_hint_from_content_disposition)
+    })
+    .or_else(|| normalize_stream_suffix_for_hint(format_suffix))
+    .or_else(|| preview_format_hint_from_url(url))
+    .or_else(|| url_format_hint(url));
+
+    let supports_range = response
+        .headers()
+        .get(reqwest::header::ACCEPT_RANGES)
+        .and_then(|v| v.to_str().ok())
+        .is_some_and(|v| v.to_ascii_lowercase().contains("bytes"));
+    let total_size = response.content_length();
+
+    if stream_hint.is_none() && supports_range {
+        if let Some(total_u64) = total_size.filter(|&t| t > 0) {
+            let last = total_u64
+                .saturating_sub(1)
+                .min((STREAM_FORMAT_SNIFF_PROBE_BYTES - 1) as u64);
+            if let Ok(pr) = preview_http
+                .get(url)
+                .header(reqwest::header::RANGE, format!("bytes=0-{last}"))
+                .send()
+                .await
+            {
+                let stat = pr.status();
+                let ok = stat == reqwest::StatusCode::PARTIAL_CONTENT
+                    || stat == reqwest::StatusCode::OK;
+                if ok {
+                    if let Ok(bytes) = pr.bytes().await {
+                        if !bytes.is_empty() {
+                            stream_hint = sniff_stream_format_extension(&bytes).or(stream_hint);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    if let (true, Some(total), true) = (supports_range, total_size, stream_hint.is_some()) {
+        if state.preview_gen.load(Ordering::SeqCst) != gen {
+            return Ok(None);
+        }
+        let total_usize = total as usize;
+        crate::app_deprintln!(
+            "[preview] ranged open — total={} KB, hint={:?}",
+            total_usize / 1024,
+            stream_hint
+        );
+        let buf = Arc::new(Mutex::new(vec![0u8; total_usize]));
+        let downloaded_to = Arc::new(AtomicUsize::new(0));
+        let done = Arc::new(AtomicBool::new(false));
+        let playback_armed = Arc::new(AtomicBool::new(false));
+        let tail_ready = Arc::new(AtomicBool::new(false));
+        let tail_filled_from = Arc::new(AtomicU64::new(0));
+        let tail_prefetch = mp4_needs_tail_prefetch(&[], stream_hint.as_deref());
+        let mp4_probe_gate = tail_prefetch.then(|| RangedMp4ProbeGate {
+            tail_ready: tail_ready.clone(),
+            buf: buf.clone(),
+            downloaded_to: downloaded_to.clone(),
+            gen_arc: state.preview_gen.clone(),
+            gen,
+            format_hint: stream_hint.clone(),
+        });
+        tokio::spawn(ranged_download_task(
+            gen,
+            state.preview_gen.clone(),
+            preview_http,
+            app.clone(),
+            0.0,
+            url.to_string(),
+            response,
+            buf.clone(),
+            downloaded_to.clone(),
+            done.clone(),
+            state.stream_completed_cache.clone(),
+            state.stream_completed_spill.clone(),
+            state.normalization_engine.clone(),
+            state.normalization_target_lufs.clone(),
+            state.loudness_pre_analysis_attenuation_db.clone(),
+            None,
+            None,
+            None,
+            playback_armed,
+            stream_hint.clone(),
+            tail_ready.clone(),
+            tail_filled_from.clone(),
+        ));
+        if let Some(ref gate) = mp4_probe_gate {
+            wait_for_ranged_mp4_probe_ready(gate).await?;
+            if state.preview_gen.load(Ordering::SeqCst) != gen {
+                return Ok(None);
+            }
+        }
+        let reader = RangedHttpSource {
+            buf,
+            downloaded_to,
+            tail_ready,
+            tail_filled_from,
+            total_size: total,
+            pos: 0,
+            done,
+            gen_arc: state.preview_gen.clone(),
+            gen,
+        };
+        let hint = stream_hint.clone();
+        let decoder = tokio::task::spawn_blocking(move || {
+            SizedDecoder::new_streaming(Box::new(reader), hint.as_deref(), "preview-stream")
+        })
+        .await
+        .map_err(|e| format!("preview: decoder thread: {e}"))??;
+        return Ok(Some(decoder));
+    }
+
+    crate::app_deprintln!(
+        "[preview] buffered download — accept-ranges={}, content-length={:?}, hint={:?}",
+        supports_range,
+        total_size,
+        stream_hint
+    );
+    let content_type = response
+        .headers()
+        .get(reqwest::header::CONTENT_TYPE)
+        .and_then(|v| v.to_str().ok())
+        .map(str::to_string);
+    let content_disposition = response
+        .headers()
+        .get(reqwest::header::CONTENT_DISPOSITION)
+        .and_then(|v| v.to_str().ok())
+        .map(str::to_string);
+    let bytes = response
+        .bytes()
+        .await
+        .map_err(|e| format!("preview: read body: {e}"))?
+        .to_vec();
+    if state.preview_gen.load(Ordering::SeqCst) != gen {
+        return Ok(None);
+    }
+    let hint = resolve_preview_format_hint(
+        url,
+        content_type.as_deref(),
+        content_disposition.as_deref(),
+        format_suffix,
+        &bytes,
+    );
+    let bytes_for_blocking = bytes;
+    let hint_for_blocking = hint.clone();
+    let decoder = tokio::task::spawn_blocking(move || {
+        SizedDecoder::new(bytes_for_blocking, hint_for_blocking.as_deref(), false)
+    })
+    .await
+    .map_err(|e| format!("preview: decoder thread: {e}"))??;
+    Ok(Some(decoder))
+}
+
 #[tauri::command]
+#[allow(clippy::too_many_arguments)] // Tauri IPC — args map 1:1 to the JS invoke payload.
 pub async fn audio_preview_play(
     id: String,
     url: String,
     start_sec: f64,
     duration_sec: f64,
     volume: f32,
+    format_suffix: Option<String>,
     app: AppHandle,
     state: State<'_, AudioEngine>,
 ) -> Result<(), String> {
@@ -134,48 +363,24 @@ pub async fn audio_preview_play(
         preview_pause_main(&state);
     }
 
-    // ── Download ─────────────────────────────────────────────────────────────
-    // Dedicated client with a generous timeout. The shared `audio_http_client`
-    // caps at 30 s, which aborts mid-download on multi-hundred-megabyte
-    // uncompressed files (e.g. 18-min Hi-Res WAV ~600 MB) — those need
-    // ~60–120 s on a typical home LAN. The watchdog (30 s wall-clock) still
-    // bounds how long the preview plays once the bytes are in memory, so a
-    // long download just means a longer "loading" spinner before audio starts.
-    let preview_http = reqwest::Client::builder()
-        .timeout(Duration::from_secs(300))
-        .use_rustls_tls()
-        .user_agent(psysonic_core::user_agent::subsonic_wire_user_agent())
-        .build()
-        .unwrap_or_else(|_| audio_http_client(&state));
-    let bytes = preview_http
-        .get(&url)
-        .send()
-        .await
-        .map_err(|e| format!("preview: connection failed: {e}"))?
-        .error_for_status()
-        .map_err(|e| format!("preview: HTTP {e}"))?
-        .bytes()
-        .await
-        .map_err(|e| format!("preview: read body: {e}"))?
-        .to_vec();
+    // ── Open decoder (ranged stream when possible) ───────────────────────────
+    let decoder = match open_preview_decoder(
+        &url,
+        format_suffix.as_deref(),
+        gen,
+        &state,
+        &app,
+    )
+    .await?
+    {
+        Some(d) => d,
+        None => return Ok(()),
+    };
 
     if state.preview_gen.load(Ordering::SeqCst) != gen {
-        // A newer preview started while we were downloading — bail.
         return Ok(());
     }
 
-    // ── Decode ───────────────────────────────────────────────────────────────
-    let hint = preview_format_hint_from_url(&url);
-    let bytes_for_blocking = bytes;
-    let hint_for_blocking = hint.clone();
-    let decoder = tokio::task::spawn_blocking(move || {
-        SizedDecoder::new(bytes_for_blocking, hint_for_blocking.as_deref(), false)
-    })
-    .await
-    .map_err(|e| format!("preview: decoder thread: {e}"))??;
-
-    if state.preview_gen.load(Ordering::SeqCst) != gen { return Ok(()); }
-
     // ── Build source pipeline ────────────────────────────────────────────────
     // Seek FIRST on the bare decoder, THEN cap with take_duration. Capping
     // before the seek made take_duration's wall-clock counter tick from
@@ -271,6 +476,55 @@ pub async fn audio_preview_play(
     Ok(())
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn resolve_preview_format_hint_sniffs_flac_from_bytes() {
+        let hint = resolve_preview_format_hint(
+            "https://host/rest/stream.view?id=1",
+            None,
+            None,
+            None,
+            b"fLaC\x00\x00\x00\x22",
+        );
+        assert_eq!(hint.as_deref(), Some("flac"));
+    }
+
+    #[test]
+    fn resolve_preview_format_hint_prefers_content_type_over_sniff() {
+        let hint = resolve_preview_format_hint(
+            "https://host/rest/stream.view?id=1",
+            Some("audio/mpeg"),
+            None,
+            None,
+            b"fLaC\x00\x00\x00\x22",
+        );
+        assert_eq!(hint.as_deref(), Some("mp3"));
+    }
+
+    #[test]
+    fn resolve_preview_format_hint_uses_subsonic_suffix() {
+        let hint = resolve_preview_format_hint(
+            "https://host/rest/stream.view?id=1",
+            None,
+            None,
+            Some("flac"),
+            &[0x00, 0x01, 0x02, 0x03],
+        );
+        assert_eq!(hint.as_deref(), Some("flac"));
+    }
+
+    #[test]
+    fn preview_format_hint_from_url_reads_format_query_param() {
+        assert_eq!(
+            preview_format_hint_from_url("https://h/stream.view?format=opus&id=x"),
+            Some("opus".into())
+        );
+    }
+}
+
 #[tauri::command]
 pub fn audio_preview_stop(app: AppHandle, state: State<'_, AudioEngine>) {
     preview_stop_inner(&app, &state, true);

src/components/albumTrackList/TrackRow.tsx

@@ -8,7 +8,7 @@ import type { Track } from '../../store/playerStoreTypes';
 import { songToTrack } from '../../utils/playback/songToTrack';
 import { useSelectionStore } from '../../store/selectionStore';
 import { useThemeStore } from '../../store/themeStore';
-import { usePreviewStore } from '../../store/previewStore';
+import { previewInputFromSong, usePreviewStore } from '../../store/previewStore';
 import StarRating from '../StarRating';
 import { codecLabel, type ColKey } from '../../utils/componentHelpers/albumTrackListHelpers';
 import { formatLongDuration } from '../../utils/format/formatDuration';
@@ -116,7 +116,7 @@ export const TrackRow = React.memo(function TrackRow({
               className={`playlist-suggestion-preview-btn${isPreviewing ? ' is-previewing' : ''}${isPreviewAudioStarted ? ' audio-started' : ''}`}
               onClick={e => {
                 e.stopPropagation();
-                usePreviewStore.getState().startPreview({ id: song.id, title: song.title, artist: song.artist, coverArt: song.coverArt, duration: song.duration }, 'albums');
+                usePreviewStore.getState().startPreview(previewInputFromSong(song), 'albums');
               }}
               data-tooltip={isPreviewing ? t('playlists.previewStop') : t('playlists.preview')}
               aria-label={isPreviewing ? t('playlists.previewStop') : t('playlists.preview')}

src/components/artistDetail/ArtistDetailTopTracks.tsx

@@ -3,7 +3,7 @@ import { useTranslation } from 'react-i18next';
 import { AudioLines, ChevronRight, Play, Square } from 'lucide-react';
 import type { SubsonicAlbum, SubsonicSong } from '../../api/subsonicTypes';
 import { usePlayerStore } from '../../store/playerStore';
-import { usePreviewStore } from '../../store/previewStore';
+import { previewInputFromSong, usePreviewStore } from '../../store/previewStore';
 import { useOrbitSongRowBehavior } from '../../hooks/useOrbitSongRowBehavior';
 import { songToTrack } from '../../utils/playback/songToTrack';
 import { formatTrackTime } from '../../utils/format/formatDuration';
@@ -82,7 +82,7 @@ export default function ArtistDetailTopTracks({
           <button
             type="button"
             className={`playlist-suggestion-preview-btn${previewingId === song.id ? ' is-previewing' : ''}${previewingId === song.id && previewAudioStarted ? ' audio-started' : ''}`}
-            onClick={e => { e.stopPropagation(); usePreviewStore.getState().startPreview({ id: song.id, title: song.title, artist: song.artist, coverArt: song.coverArt, duration: song.duration }, 'artist'); }}
+            onClick={e => { e.stopPropagation(); usePreviewStore.getState().startPreview(previewInputFromSong(song), 'artist'); }}
             data-tooltip={previewingId === song.id ? t('playlists.previewStop') : t('playlists.preview')}
             aria-label={previewingId === song.id ? t('playlists.previewStop') : t('playlists.preview')}
           >

src/components/favorites/FavoritesSongsTracklist.tsx

@@ -7,7 +7,7 @@ import { useNavigate } from 'react-router-dom';
 import type { ColDef } from '../../utils/useTracklistColumns';
 import type { SubsonicSong } from '../../api/subsonicTypes';
 import { usePlayerStore } from '../../store/playerStore';
-import { usePreviewStore } from '../../store/previewStore';
+import { previewInputFromSong, usePreviewStore } from '../../store/previewStore';
 import { useSelectionStore } from '../../store/selectionStore';
 import { useThemeStore } from '../../store/themeStore';
 import { useDragDrop } from '../../contexts/DragDropContext';
@@ -122,7 +122,7 @@ export default function FavoritesSongsTracklist({
       L.playTrack(L.visibleTracks[index], L.visibleTracks);
     },
     startPreview: (song) => usePreviewStore.getState().startPreview(
-      { id: song.id, title: song.title, artist: song.artist, coverArt: song.coverArt, duration: song.duration },
+      previewInputFromSong(song),
       'favorites',
     ),
     rate: (songId, r) => latest.current.handleRate(songId, r),

src/components/playerBar/PlayerTrackInfo.tsx

@@ -60,7 +60,10 @@ export function PlayerTrackInfo({
   const previewCoverRef = useAlbumCoverRef(
     showPreviewMeta ? coverArtId : null,
     showPreviewMeta ? coverArtId : null,
+    undefined,
+    showPreviewMeta ? { libraryResolve: false } : undefined,
   );
+  const activeCoverRef = showPreviewMeta ? previewCoverRef : playbackCoverRef;
   const layoutItems = usePlayerBarLayoutStore(s => s.items);
   const isLayoutVisible = (id: PlayerBarLayoutItemId) =>
     layoutItems.find(i => i.id === id)?.visible !== false;
@@ -86,10 +89,10 @@ export function PlayerTrackInfo({
               <Cast size={20} />
             </div>
           )
-        ) : !isRadio && (showPreviewMeta ? coverArtId : playbackCoverRef) ? (
+        ) : !isRadio && activeCoverRef ? (
           <CoverArtImage
             className="player-album-art"
-            coverRef={showPreviewMeta ? previewCoverRef! : playbackCoverRef!}
+            coverRef={activeCoverRef}
             displayCssPx={128}
             surface="sparse"
             ensurePriority="high"

src/components/playlist/PlaylistTracklist.tsx

@@ -13,7 +13,7 @@ import type { ColDef } from '../../utils/useTracklistColumns';
 import type { SubsonicSong } from '../../api/subsonicTypes';
 import type { Track } from '../../store/playerStoreTypes';
 import { usePlayerStore } from '../../store/playerStore';
-import { usePreviewStore } from '../../store/previewStore';
+import { previewInputFromSong, usePreviewStore } from '../../store/previewStore';
 import { useThemeStore } from '../../store/themeStore';
 import { useDragDrop } from '../../contexts/DragDropContext';
 import { useOrbitSongRowBehavior } from '../../hooks/useOrbitSongRowBehavior';
@@ -149,7 +149,7 @@ export default function PlaylistTracklist({
       L.playTrack(L.displayedTracks[index], L.displayedTracks);
     },
     startPreview: (song) => usePreviewStore.getState().startPreview(
-      { id: song.id, title: song.title, artist: song.artist, coverArt: song.coverArt, duration: song.duration },
+      previewInputFromSong(song),
       'playlists',
     ),
     toggleStar: (song, e) => latest.current.handleToggleStar(song, e),

src/components/randomMix/RandomMixTrackRow.tsx

@@ -3,7 +3,7 @@ import { useTranslation } from 'react-i18next';
 import { AudioLines, ChevronRight, Heart, Play, Square } from 'lucide-react';
 import type { SubsonicSong } from '../../api/subsonicTypes';
 import type { Track } from '../../store/playerStoreTypes';
-import { usePreviewStore } from '../../store/previewStore';
+import { previewInputFromSong, usePreviewStore } from '../../store/previewStore';
 import { useDragDrop } from '../../contexts/DragDropContext';
 import { formatRandomMixDuration } from '../../utils/componentHelpers/randomMixHelpers';
 
@@ -110,7 +110,7 @@ export default function RandomMixTrackRow({
           onClick={e => {
             e.stopPropagation();
             usePreviewStore.getState().startPreview(
-              { id: song.id, title: song.title, artist: song.artist, coverArt: song.coverArt, duration: song.duration },
+              previewInputFromSong(song),
               'randomMix',
             );
           }}

src/cover/CoverArtImage.tsx

@@ -13,7 +13,7 @@ import { useCoverArt } from './useCoverArt';
 import type { CoverArtRef, CoverPrefetchPriority, CoverSurfaceKind } from './types';
 
 export type CoverArtImageProps = {
-  coverRef: CoverArtRef;
+  coverRef: CoverArtRef | null | undefined;
   displayCssPx: number;
   surface?: CoverSurfaceKind;
   fullRes?: boolean;
@@ -39,6 +39,18 @@ export function CoverArtImage({
   onError: restOnError,
   ...rest
 }: CoverArtImageProps) {
+  if (!coverRef) {
+    return (
+      <div
+        className={className}
+        data-cover-provisional="true"
+        role="img"
+        aria-label={alt ?? ''}
+        {...(rest as React.HTMLAttributes<HTMLDivElement>)}
+      />
+    );
+  }
+
   const pinnedHigh = ensurePriorityProp === 'high';
   const [ensurePriority, setEnsurePriority] = useState<CoverPrefetchPriority>(
     ensurePriorityProp ?? 'middle',

src/hooks/usePlaylistPreview.ts

@@ -1,5 +1,5 @@
 import { useCallback, useEffect } from 'react';
-import { usePreviewStore } from '../store/previewStore';
+import { previewInputFromSong, usePreviewStore } from '../store/previewStore';
 import type { SubsonicSong } from '../api/subsonicTypes';
 
 export function usePlaylistPreview(): {
@@ -9,13 +9,7 @@ export function usePlaylistPreview(): {
   // handled in `audio_preview_play` / `audio_preview_stop`. The store mirrors
   // engine events so we just dispatch here and read `previewingId` for UI.
   const startPreview = useCallback((song: SubsonicSong) => {
-    usePreviewStore.getState().startPreview({
-      id: song.id,
-      title: song.title,
-      artist: song.artist,
-      coverArt: song.coverArt,
-      duration: song.duration,
-    }, 'suggestions').catch(() => { /* engine errored — store already rolled back */ });
+    usePreviewStore.getState().startPreview(previewInputFromSong(song), 'suggestions').catch(() => { /* engine errored — store already rolled back */ });
   }, []);
 
   // Cancel any in-flight preview when the user navigates away.

src/store/previewStore.test.ts

@@ -200,6 +200,12 @@ describe('previewStore — startPreview', () => {
     expect(state.duration).toBe(30);
   });
 
+  it('passes Subsonic suffix as formatSuffix for Symphonia container hints', async () => {
+    await usePreviewStore.getState().startPreview({ ...song('flac-1'), suffix: 'flac' }, 'albums');
+    const call = invokeMock.mock.calls.find(c => c[0] === 'audio_preview_play');
+    expect(call?.[1]).toMatchObject({ formatSuffix: 'flac' });
+  });
+
   it('starts at 0 when the track is too short to need a mid-track seek', async () => {
     // duration <= previewDuration * 1.5 → start at 0.
     await usePreviewStore.getState().startPreview({ ...song(), duration: 30 }, 'suggestions');
@@ -277,7 +283,7 @@ describe('previewStore — startPreview', () => {
       throw new Error('engine offline');
     });
 
-    await expect(usePreviewStore.getState().startPreview(song('song-2'), 'suggestions')).rejects.toThrow(/engine offline/);
+    await usePreviewStore.getState().startPreview(song('song-2'), 'suggestions');
 
     // Only rolls back when the rolled-back id is still the optimistic one.
     const state = usePreviewStore.getState();

src/store/previewStore.ts

@@ -1,4 +1,5 @@
 import { buildStreamUrl } from '../api/subsonicStreamUrl';
+import type { SubsonicSong } from '../api/subsonicTypes';
 import type { TrackPreviewLocation } from './authStoreTypes';
 import { create } from 'zustand';
 import { invoke } from '@tauri-apps/api/core';
@@ -14,6 +15,29 @@ export interface PreviewingTrack {
   coverArt?: string;
 }
 
+export interface PreviewSongInput {
+  id: string;
+  title: string;
+  artist: string;
+  coverArt?: string;
+  duration?: number;
+  suffix?: string;
+}
+
+/** Map a browse/playlist song row into preview input (keeps Subsonic suffix for format hints). */
+export function previewInputFromSong(
+  song: Pick<SubsonicSong, 'id' | 'title' | 'artist' | 'coverArt' | 'duration' | 'suffix'>,
+): PreviewSongInput {
+  return {
+    id: song.id,
+    title: song.title,
+    artist: song.artist,
+    coverArt: song.coverArt,
+    duration: song.duration,
+    suffix: song.suffix,
+  };
+}
+
 interface PreviewState {
   /** Subsonic song id of the active preview, or null when nothing previews. */
   previewingId: string | null;
@@ -33,7 +57,7 @@ interface PreviewState {
    */
   audioStarted: boolean;
 
-  startPreview: (song: { id: string; title: string; artist: string; coverArt?: string; duration?: number }, location: TrackPreviewLocation) => Promise<void>;
+  startPreview: (song: PreviewSongInput, location: TrackPreviewLocation) => Promise<void>;
   stopPreview: () => Promise<void>;
 
   /** Internal — called from the TauriEventBridge on `audio:preview-start`. */
@@ -100,7 +124,12 @@ export const usePreviewStore = create<PreviewState>((set, get) => ({
 
     set({
       previewingId: song.id,
-      previewingTrack: { id: song.id, title: song.title, artist: song.artist, coverArt: song.coverArt },
+      previewingTrack: {
+        id: song.id,
+        title: song.title,
+        artist: song.artist,
+        coverArt: song.coverArt,
+      },
       elapsed: 0,
       duration: previewDuration,
       audioStarted: false,
@@ -113,13 +142,14 @@ export const usePreviewStore = create<PreviewState>((set, get) => ({
         startSec,
         durationSec: previewDuration,
         volume: computePreviewVolume(),
+        formatSuffix: song.suffix ?? null,
       });
     } catch (e) {
       // Roll back optimistic state on failure.
       if (get().previewingId === song.id) {
         set({ previewingId: null, previewingTrack: null, elapsed: 0, audioStarted: false });
       }
-      throw e;
+      console.error('Preview playback failed', e);
     }
   },