fix(subtitles): guard track-list effect against stale async runs

The track-building effect in VideoContext reruns once api?.basePath and
isCurrentSubImageBased settle. An earlier async run could resolve after a
rerun and overwrite subtitleTracks/audioTracks with setTrack callbacks bound
to a stale `api`, breaking external-subtitle identity matching.

Add a cancellation token and route every state commit through guarded
committers so all six commit points (offline-transcoded audio/subs,
burned-in, and the online audio/subs paths) drop writes from a dead run,
plus bail out right after the awaited getAudioTracks when cancelled.

.github/copilot-instructions.md

@@ -42,7 +42,7 @@ and provides seamless media streaming with offline capabilities and Chromecast s
 
 ## Coding Standards
 
-- Use TypeScript for ALL files (no .js files)
+- Use TypeScript for ALL files (no .js files). Tooling-required exceptions: `babel.config.js`, `metro.config.js`, `react-native.config.js`, `tailwind.config.js` (their loaders cannot parse TypeScript)
 - Use descriptive English names for variables, functions, and components
 - Prefer functional React components with hooks
 - Use Jotai atoms for global state management

.github/workflows/detect-duplicate.yml

@@ -30,7 +30,7 @@ jobs:
           bun-version: "1.3.14"
 
       - name: 🔍 Detect duplicate issues
-        run: bun scripts/detect-duplicate-issue.mjs
+        run: bun scripts/detect-duplicate-issue.ts
         env:
           GH_TOKEN: ${{ github.token }}
           GITHUB_REPOSITORY: ${{ github.repository }}

.gitignore

@@ -12,10 +12,6 @@ web-build/
 # Platform-specific Build Directories
 /ios
 /android
-/iostv
-/iosmobile
-/androidmobile
-/androidtv
 
 # Gradle caches (top-level + per-module native projects)
 **/.gradle/

CLAUDE.md

@@ -152,7 +152,7 @@ import { apiAtom } from "@/providers/JellyfinProvider";
 
 ## Coding Standards
 
-- Use TypeScript for all files (no .js)
+- Use TypeScript for all files (no .js). Tooling-required exceptions: `babel.config.js`, `metro.config.js`, `react-native.config.js`, `tailwind.config.js` (their loaders cannot parse TypeScript)
 - Use functional React components with hooks
 - Use Jotai atoms for global state, React Query for server state
 - Follow BiomeJS formatting rules (2-space indent, semicolons, LF line endings)

app/(auth)/player/direct-player.tsx

@@ -56,8 +56,8 @@ import { getDefaultPlaySettings } from "@/utils/jellyfin/getDefaultPlaySettings"
 import { getPrimaryImageUrl } from "@/utils/jellyfin/image/getPrimaryImageUrl";
 import { getStreamUrl } from "@/utils/jellyfin/media/getStreamUrl";
 import {
+  applyMpvSubtitleSelection,
   getMpvAudioId,
-  getMpvSubtitleId,
 } from "@/utils/jellyfin/subtitleUtils";
 import { writeToLog } from "@/utils/log";
 import { msToTicks, ticksToSeconds } from "@/utils/time";
@@ -639,12 +639,9 @@ export default function DirectPlayerPage() {
       ).map((s) => s.DeliveryUrl!);
     }
 
-    // Calculate track IDs for initial selection
-    const initialSubtitleId = getMpvSubtitleId(
-      mediaSource,
-      subtitleIndex,
-      isTranscoding,
-    );
+    // Audio maps positionally (audio tracks aren't reordered or hidden like
+    // subtitles). The subtitle selection is applied later, once MPV's real track
+    // list is known — see applySubtitleSelection / onTracksReady.
     const initialAudioId = getMpvAudioId(
       mediaSource,
       audioIndex,
@@ -662,7 +659,6 @@ export default function DirectPlayerPage() {
       url: stream.url,
       startPosition: startPos,
       autoplay: true,
-      initialSubtitleId,
       initialAudioId,
       // Pass cache/buffer settings from user preferences
       cacheConfig: {
@@ -710,7 +706,6 @@ export default function DirectPlayerPage() {
     playbackPositionFromUrl,
     api?.basePath,
     api?.accessToken,
-    subtitleIndex,
     audioIndex,
     offline,
     settings.mpvCacheEnabled,
@@ -908,30 +903,41 @@ export default function DirectPlayerPage() {
   );
 
   // TV subtitle track change handler
+  /**
+   * Resolve a Jellyfin subtitle index against MPV's *real* track list and apply
+   * it. Identity-based (external by filename, embedded by language/title) so it
+   * stays correct across external/embedded reordering and server-hidden embedded
+   * subs — unlike positional mapping. Reused for initial selection (onTracksReady,
+   * fired again after each external sub-add) and runtime changes.
+   */
+  const applySubtitleSelection = useCallback(
+    async (jellyfinSubtitleIndex: number) => {
+      const subtitleStreams = stream?.mediaSource?.MediaStreams?.filter(
+        (s) => s.Type === "Subtitle",
+      );
+      await applyMpvSubtitleSelection(videoRef.current, {
+        subtitleStreams,
+        jellyfinSubtitleIndex,
+        // The exact URL each external sub was loaded into MPV with — mirrors the
+        // externalSubtitles array built in videoSource (online: basePath +
+        // DeliveryUrl, offline: local DeliveryUrl).
+        getExpectedExternalUrl: (s) => {
+          if (!s.DeliveryUrl) return undefined;
+          if (offline) return s.DeliveryUrl;
+          return api?.basePath ? `${api.basePath}${s.DeliveryUrl}` : undefined;
+        },
+      });
+    },
+    [stream?.mediaSource, offline, api?.basePath],
+  );
+
+  // TV/mobile subtitle track change handler
   const handleSubtitleIndexChange = useCallback(
     async (index: number) => {
       setCurrentSubtitleIndex(index);
-
-      // Check if we're transcoding
-      const isTranscoding = Boolean(stream?.mediaSource?.TranscodingUrl);
-
-      if (index === -1) {
-        // Disable subtitles
-        await videoRef.current?.disableSubtitles?.();
-      } else {
-        // Convert Jellyfin index to MPV track ID
-        const mpvTrackId = getMpvSubtitleId(
-          stream?.mediaSource,
-          index,
-          isTranscoding,
-        );
-
-        if (mpvTrackId !== undefined && mpvTrackId !== -1) {
-          await videoRef.current?.setSubtitleTrack?.(mpvTrackId);
-        }
-      }
+      await applySubtitleSelection(index);
     },
-    [stream?.mediaSource],
+    [applySubtitleSelection],
   );
 
   // Technical info toggle handler
@@ -1296,6 +1302,10 @@ export default function DirectPlayerPage() {
                 }}
                 onTracksReady={() => {
                   setTracksReady(true);
+                  // Fired after embedded tracks enumerate and again after each
+                  // external sub-add; re-resolve so the final fire (full track
+                  // list) selects the right track by identity.
+                  void applySubtitleSelection(currentSubtitleIndex);
                 }}
               />
               {!hasPlaybackStarted && (

components/ItemContent.tv.tsx

@@ -56,6 +56,7 @@ import { useSettings } from "@/utils/atoms/settings";
 import type { TVOptionItem } from "@/utils/atoms/tvOptionModal";
 import { getLogoImageUrlById } from "@/utils/jellyfin/image/getLogoImageUrlById";
 import { getPrimaryImageUrlById } from "@/utils/jellyfin/image/getPrimaryImageUrlById";
+import { compareTracksForMenu } from "@/utils/jellyfin/subtitleUtils";
 import { formatDuration, runtimeTicksToMinutes } from "@/utils/time";
 
 const { width: SCREEN_WIDTH, height: SCREEN_HEIGHT } = Dimensions.get("window");
@@ -232,12 +233,13 @@ export const ItemContentTV: React.FC<ItemContentTVProps> = React.memo(
       return streams ?? [];
     }, [selectedOptions?.mediaSource]);
 
-    // Get available subtitle tracks (raw MediaStream[] for label lookup)
+    // Get available subtitle tracks (raw MediaStream[] for label lookup),
+    // ordered like jellyfin-web (embedded first, externals last, forced/default up).
     const subtitleStreams = useMemo(() => {
       const streams = selectedOptions?.mediaSource?.MediaStreams?.filter(
         (s) => s.Type === "Subtitle",
       );
-      return streams ?? [];
+      return streams ? [...streams].sort(compareTracksForMenu) : [];
     }, [selectedOptions?.mediaSource]);
 
     // Store handleSubtitleChange in a ref for stable callback reference
@@ -411,11 +413,13 @@ export const ItemContentTV: React.FC<ItemContentTVProps> = React.memo(
             )
           : freshItem.MediaSources?.[0];
 
-        // Get subtitle streams from the fresh data
-        const streams =
-          mediaSource?.MediaStreams?.filter(
+        // Get subtitle streams from the fresh data, ordered like jellyfin-web
+        // (embedded first, externals last) — same as the initial list.
+        const streams = [
+          ...(mediaSource?.MediaStreams?.filter(
             (s: MediaStream) => s.Type === "Subtitle",
-          ) ?? [];
+          ) ?? []),
+        ].sort(compareTracksForMenu);
 
         // Convert to Track[] with setTrack callbacks
         const tracks: Track[] = streams.map((stream) => ({

components/MediaSourceButton.tsx

@@ -7,6 +7,7 @@ import { useCallback, useEffect, useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { ActivityIndicator, TouchableOpacity, View } from "react-native";
 import type { ThemeColors } from "@/hooks/useImageColorsReturn";
+import { compareTracksForMenu } from "@/utils/jellyfin/subtitleUtils";
 import { BITRATES } from "./BitRateSheet";
 import type { SelectedOptions } from "./ItemContent";
 import { type OptionGroup, PlatformDropdown } from "./PlatformDropdown";
@@ -63,9 +64,12 @@ export const MediaSourceButton: React.FC<Props> = ({
 
   const subtitleStreams = useMemo(
     () =>
-      selectedOptions.mediaSource?.MediaStreams?.filter(
-        (x) => x.Type === "Subtitle",
-      ) || [],
+      // Order like jellyfin-web (embedded first, externals last, forced/default up).
+      [
+        ...(selectedOptions.mediaSource?.MediaStreams?.filter(
+          (x) => x.Type === "Subtitle",
+        ) || []),
+      ].sort(compareTracksForMenu),
     [selectedOptions.mediaSource],
   );
 

components/SubtitleTrackSelector.tsx

@@ -2,6 +2,7 @@ import type { MediaSourceInfo } from "@jellyfin/sdk/lib/generated-client/models"
 import { useMemo, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { Platform, TouchableOpacity, View } from "react-native";
+import { compareTracksForMenu } from "@/utils/jellyfin/subtitleUtils";
 import { tc } from "@/utils/textTools";
 import { Text } from "./common/Text";
 import { type OptionGroup, PlatformDropdown } from "./PlatformDropdown";
@@ -22,7 +23,9 @@ export const SubtitleTrackSelector: React.FC<Props> = ({
   const [open, setOpen] = useState(false);
 
   const subtitleStreams = useMemo(() => {
-    return source?.MediaStreams?.filter((x) => x.Type === "Subtitle");
+    const subs = source?.MediaStreams?.filter((x) => x.Type === "Subtitle");
+    // Order like jellyfin-web (embedded first, externals last, forced/default up).
+    return subs ? [...subs].sort(compareTracksForMenu) : subs;
   }, [source]);
 
   const selectedSubtitleSteam = useMemo(

components/video-player/controls/Controls.tv.tsx

@@ -51,6 +51,7 @@ import { useOfflineMode } from "@/providers/OfflineModeProvider";
 import { useSettings } from "@/utils/atoms/settings";
 import type { TVOptionItem } from "@/utils/atoms/tvOptionModal";
 import { getDefaultPlaySettings } from "@/utils/jellyfin/getDefaultPlaySettings";
+import { compareTracksForMenu } from "@/utils/jellyfin/subtitleUtils";
 import { formatTimeString, msToTicks, ticksToMs } from "@/utils/time";
 import { CONTROLS_CONSTANTS } from "./constants";
 import { useVideoContext } from "./contexts/VideoContext";
@@ -317,8 +318,10 @@ export const Controls: FC<Props> = ({
     try {
       const streams = (await onRefreshSubtitleTracks?.()) ?? [];
       // Skip streams without a real index: `?? -1` would alias them to the
-      // "disable subtitles" sentinel and mis-route selection.
-      return streams
+      // "disable subtitles" sentinel and mis-route selection. Order like
+      // jellyfin-web (embedded first, externals last, forced/default up).
+      return [...streams]
+        .sort(compareTracksForMenu)
         .filter((stream) => typeof stream.Index === "number")
         .map((stream) => {
           const index = stream.Index as number;

components/video-player/controls/TVSubtitleSheet.tsx

@@ -33,6 +33,7 @@ import {
   type SubtitleSearchResult,
   useRemoteSubtitles,
 } from "@/hooks/useRemoteSubtitles";
+import { compareTracksForMenu } from "@/utils/jellyfin/subtitleUtils";
 import { COMMON_SUBTITLE_LANGUAGES } from "@/utils/opensubtitles/api";
 
 interface TVSubtitleSheetProps {
@@ -96,13 +97,19 @@ export const TVSubtitleSheet: React.FC<TVSubtitleSheetProps> = ({
   const overlayOpacity = useRef(new Animated.Value(0)).current;
   const sheetTranslateY = useRef(new Animated.Value(300)).current;
 
+  // Order like jellyfin-web (embedded first, externals last, forced/default up).
+  const sortedTracks = useMemo(
+    () => [...subtitleTracks].sort(compareTracksForMenu),
+    [subtitleTracks],
+  );
+
   const initialSelectedTrackIndex = useMemo(() => {
     if (currentSubtitleIndex === -1) return 0;
-    const trackIdx = subtitleTracks.findIndex(
+    const trackIdx = sortedTracks.findIndex(
       (t) => t.Index === currentSubtitleIndex,
     );
     return trackIdx >= 0 ? trackIdx + 1 : 0;
-  }, [subtitleTracks, currentSubtitleIndex]);
+  }, [sortedTracks, currentSubtitleIndex]);
 
   useEffect(() => {
     if (visible) {
@@ -215,7 +222,7 @@ export const TVSubtitleSheet: React.FC<TVSubtitleSheetProps> = ({
       value: -1,
       selected: currentSubtitleIndex === -1,
     };
-    const options = subtitleTracks.map((track) => ({
+    const options = sortedTracks.map((track) => ({
       label:
         track.DisplayTitle || `${track.Language || "Unknown"} (${track.Codec})`,
       sublabel: track.Codec?.toUpperCase(),
@@ -223,7 +230,7 @@ export const TVSubtitleSheet: React.FC<TVSubtitleSheetProps> = ({
       selected: track.Index === currentSubtitleIndex,
     }));
     return [noneOption, ...options];
-  }, [subtitleTracks, currentSubtitleIndex, t]);
+  }, [sortedTracks, currentSubtitleIndex, t]);
 
   if (!visible) return null;
 

components/video-player/controls/contexts/VideoContext.tsx

@@ -23,32 +23,29 @@
  *    - Used to report playback state to Jellyfin server
  *    - Value of -1 means disabled/none
  *
- * 2. MPV INDEX (track.mpvIndex)
- *    - MPV's internal track ID
- *    - MPV orders tracks as: [all embedded, then all external]
- *    - IDs: 1..embeddedCount for embedded, embeddedCount+1.. for external
- *    - Value of -1 means track needs replacePlayer() (e.g., burned-in sub)
+ * 2. PLAYER TRACK (selected by IDENTITY, not position)
+ *    - Selection resolves the server Index against MPV's REAL track list via
+ *      applyMpvSubtitleSelection: externals matched by external-filename,
+ *      embedded by language/title. `track.mpvIndex` is no longer used to select
+ *      (kept -1) — positional mapping mis-selected when externals/embedded were
+ *      reordered or the server hid embedded subs (#954 et al.).
  *
  * ============================================================================
  * SUBTITLE HANDLING
  * ============================================================================
  *
- * Embedded (DeliveryMethod.Embed):
- *   - Already in MPV's track list
- *   - Select via setSubtitleTrack(mpvId)
- *
- * External (DeliveryMethod.External):
- *   - Loaded into MPV on video start
- *   - Select via setSubtitleTrack(embeddedCount + externalPosition + 1)
+ * Embedded & External:
+ *   - Selected via applyMpvSubtitleSelection (identity match against the live
+ *     track list). Menu order matches jellyfin-web (compareTracksForMenu:
+ *     embedded first, externals last, forced/default float up).
  *
  * Image-based during transcoding:
- *   - Burned into video by Jellyfin, not in MPV
- *   - Requires replacePlayer() to change
+ *   - Burned into video by Jellyfin, not in MPV → replacePlayer() to change.
  */
 
-import { SubtitleDeliveryMethod } from "@jellyfin/sdk/lib/generated-client";
 import { File } from "expo-file-system";
 import { useLocalSearchParams } from "expo-router";
+import { useAtomValue } from "jotai";
 import type React from "react";
 import {
   createContext,
@@ -61,9 +58,14 @@ import {
 import { Platform } from "react-native";
 import useRouter from "@/hooks/useAppRouter";
 import type { MpvAudioTrack } from "@/modules";
+import { apiAtom } from "@/providers/JellyfinProvider";
 import { useOfflineMode } from "@/providers/OfflineModeProvider";
 import { getSubtitlesForItem } from "@/utils/atoms/downloadedSubtitles";
-import { isImageBasedSubtitle } from "@/utils/jellyfin/subtitleUtils";
+import {
+  applyMpvSubtitleSelection,
+  compareTracksForMenu,
+  isImageBasedSubtitle,
+} from "@/utils/jellyfin/subtitleUtils";
 import type { Track } from "../types";
 import { usePlayerContext, usePlayerControls } from "./PlayerContext";
 
@@ -87,6 +89,7 @@ export const VideoProvider: React.FC<{ children: ReactNode }> = ({
   const { tracksReady, mediaSource, downloadedItem } = usePlayerContext();
   const playerControls = usePlayerControls();
   const offline = useOfflineMode();
+  const api = useAtomValue(apiAtom);
   const router = useRouter();
 
   const { itemId, audioIndex, bitrateValue, subtitleIndex, playbackPosition } =
@@ -141,6 +144,19 @@ export const VideoProvider: React.FC<{ children: ReactNode }> = ({
   useEffect(() => {
     if (!tracksReady) return;
 
+    // Guard every state commit against stale runs: api?.basePath /
+    // isCurrentSubImageBased can flip mid-run and restart this effect, and an
+    // earlier async run (which captured an old `api`) must not finish later and
+    // overwrite the fresh track list with callbacks bound to stale closures.
+    // The cleanup flips `cancelled`, so any late commit from a dead run is dropped.
+    let cancelled = false;
+    const commitSubtitleTracks = (next: Track[]) => {
+      if (!cancelled) setSubtitleTracks(next);
+    };
+    const commitAudioTracks = (next: Track[]) => {
+      if (!cancelled) setAudioTracks(next);
+    };
+
     const fetchTracks = async () => {
       // Check if this is offline transcoded content
       // For transcoded offline content, only ONE audio track exists in the file
@@ -166,10 +182,10 @@ export const VideoProvider: React.FC<{ children: ReactNode }> = ({
               },
             },
           ];
-          setAudioTracks(audio);
+          commitAudioTracks(audio);
         } else {
           // Fallback: show no audio tracks if the stored track wasn't found
-          setAudioTracks([]);
+          commitAudioTracks([]);
         }
 
         // For subtitles in transcoded offline content:
@@ -179,6 +195,24 @@ export const VideoProvider: React.FC<{ children: ReactNode }> = ({
           downloadedItem.userData.subtitleStreamIndex;
         const subs: Track[] = [];
 
+        // If an IMAGE subtitle was burned into the transcoded download it's in the
+        // video pixels — it can't be turned off or swapped. Show only that entry
+        // instead of advertising "Disable"/text controls that can't affect it.
+        const burnedInSub = allSubs.find(
+          (s) => s.Index === downloadedSubtitleIndex,
+        );
+        if (burnedInSub && isImageBasedSubtitle(burnedInSub)) {
+          commitSubtitleTracks([
+            {
+              name: `${burnedInSub.DisplayTitle || "Unknown"} (burned in)`,
+              index: burnedInSub.Index ?? -1,
+              mpvIndex: -1,
+              setTrack: () => {},
+            },
+          ]);
+          return;
+        }
+
         // Add "Disable" option
         subs.push({
           name: "Disable",
@@ -190,123 +224,82 @@ export const VideoProvider: React.FC<{ children: ReactNode }> = ({
           },
         });
 
-        // For text-based subs, they should still be available in the file
-        let subIdx = 1;
-        for (const sub of allSubs) {
-          if (sub.IsTextSubtitleStream) {
+        // Text subs are muxed into the transcoded file and switchable; resolve by
+        // identity against MPV's real track list (same as online). Order matches web.
+        // Image subs aren't in the transcoded file (only the burned one was, handled
+        // above), so skip them here.
+        for (const sub of [...allSubs].sort(compareTracksForMenu)) {
+          if (!isImageBasedSubtitle(sub)) {
             subs.push({
               name: sub.DisplayTitle || "Unknown",
               index: sub.Index ?? -1,
-              mpvIndex: subIdx,
+              mpvIndex: -1,
               setTrack: () => {
-                playerControls.setSubtitleTrack(subIdx);
-                router.setParams({ subtitleIndex: String(sub.Index) });
-              },
-            });
-            subIdx++;
-          } else if (sub.Index === downloadedSubtitleIndex) {
-            // This image-based sub was burned in - show it but indicate it's active
-            subs.push({
-              name: `${sub.DisplayTitle || "Unknown"} (burned in)`,
-              index: sub.Index ?? -1,
-              mpvIndex: -1, // Can't be changed
-              setTrack: () => {
-                // Already burned in, just update params
                 router.setParams({ subtitleIndex: String(sub.Index) });
+                void applyMpvSubtitleSelection(playerControls, {
+                  subtitleStreams: allSubs,
+                  jellyfinSubtitleIndex: sub.Index ?? -1,
+                  getExpectedExternalUrl: (s) => {
+                    if (!s.DeliveryUrl) return undefined;
+                    if (offline) return s.DeliveryUrl;
+                    return api?.basePath
+                      ? `${api.basePath}${s.DeliveryUrl}`
+                      : undefined;
+                  },
+                });
               },
             });
           }
         }
 
-        setSubtitleTracks(subs.sort((a, b) => a.index - b.index));
+        commitSubtitleTracks(subs);
         return;
       }
 
       // MPV track handling
       const audioData = await playerControls.getAudioTracks().catch(() => null);
+      if (cancelled) return;
       const playerAudio = (audioData as MpvAudioTrack[]) ?? [];
 
-      // Separate embedded vs external subtitles from Jellyfin's list
-      // MPV orders tracks as: [all embedded, then all external]
-      const embeddedSubs = allSubs.filter(
-        (s) => s.DeliveryMethod === SubtitleDeliveryMethod.Embed,
-      );
-      const externalSubs = allSubs.filter(
-        (s) => s.DeliveryMethod === SubtitleDeliveryMethod.External,
-      );
-
-      // Count embedded subs that will be in MPV
-      // (excludes image-based subs during transcoding as they're burned in)
-      const embeddedInPlayer = embeddedSubs.filter(
-        (s) => !isTranscoding || !isImageBasedSubtitle(s),
-      );
-
       const subs: Track[] = [];
 
-      // Process all Jellyfin subtitles
-      for (const sub of allSubs) {
-        const isEmbedded = sub.DeliveryMethod === SubtitleDeliveryMethod.Embed;
-        const isExternal =
-          sub.DeliveryMethod === SubtitleDeliveryMethod.External;
-
-        // For image-based subs during transcoding, need to refresh player
-        if (isTranscoding && isImageBasedSubtitle(sub)) {
-          subs.push({
-            name: sub.DisplayTitle || "Unknown",
-            index: sub.Index ?? -1,
-            mpvIndex: -1,
-            setTrack: () => {
-              replacePlayer({ subtitleIndex: String(sub.Index) });
-            },
-          });
-          continue;
-        }
-
-        // Calculate MPV track ID based on type
-        // MPV IDs: [1..embeddedCount] for embedded, [embeddedCount+1..] for external
-        let mpvId = -1;
-
-        if (isEmbedded) {
-          // Find position among embedded subs that are in player
-          const embeddedPosition = embeddedInPlayer.findIndex(
-            (s) => s.Index === sub.Index,
-          );
-          if (embeddedPosition !== -1) {
-            mpvId = embeddedPosition + 1; // 1-based ID
-          }
-        } else if (isExternal) {
-          // Find position among external subs, offset by embedded count
-          const externalPosition = externalSubs.findIndex(
-            (s) => s.Index === sub.Index,
-          );
-          if (externalPosition !== -1) {
-            mpvId = embeddedInPlayer.length + externalPosition + 1;
-          }
-        }
+      // Process all Jellyfin subtitles. Selection resolves against MPV's real
+      // track list by identity (applyMpvSubtitleSelection) — never positional
+      // index math, which mis-selects across external/embedded reordering and
+      // server-hidden embedded subs (#954/#1690/#618/#1467/#976/#1451).
+      // Order matches jellyfin-web (embedded first, externals last, forced/default up).
+      for (const sub of [...allSubs].sort(compareTracksForMenu)) {
+        // Image-based subs during transcoding are burned into the video by the
+        // server; both switching TO one and switching AWAY from a currently
+        // active one require a player refresh (re-transcode), not a track change.
+        const needsReplace =
+          isTranscoding &&
+          (isImageBasedSubtitle(sub) || isCurrentSubImageBased);
 
         subs.push({
           name: sub.DisplayTitle || "Unknown",
           index: sub.Index ?? -1,
-          mpvIndex: mpvId,
+          mpvIndex: -1,
           setTrack: () => {
-            // Transcoding + switching to/from image-based sub
-            if (
-              isTranscoding &&
-              (isImageBasedSubtitle(sub) || isCurrentSubImageBased)
-            ) {
+            if (needsReplace) {
               replacePlayer({ subtitleIndex: String(sub.Index) });
               return;
             }
-
-            // Direct switch in player
-            if (mpvId !== -1) {
-              playerControls.setSubtitleTrack(mpvId);
-              router.setParams({ subtitleIndex: String(sub.Index) });
-              return;
-            }
-
-            // Fallback - refresh player
-            replacePlayer({ subtitleIndex: String(sub.Index) });
+            router.setParams({ subtitleIndex: String(sub.Index) });
+            void applyMpvSubtitleSelection(playerControls, {
+              subtitleStreams: allSubs,
+              jellyfinSubtitleIndex: sub.Index ?? -1,
+              // Mirror how external subs are loaded into MPV (online: basePath +
+              // DeliveryUrl, offline: local DeliveryUrl) so identity matching by
+              // external-filename lines up.
+              getExpectedExternalUrl: (s) => {
+                if (!s.DeliveryUrl) return undefined;
+                if (offline) return s.DeliveryUrl;
+                return api?.basePath
+                  ? `${api.basePath}${s.DeliveryUrl}`
+                  : undefined;
+              },
+            });
           },
         });
       }
@@ -374,12 +367,29 @@ export const VideoProvider: React.FC<{ children: ReactNode }> = ({
         }
       }
 
-      setSubtitleTracks(subs.sort((a, b) => a.index - b.index));
-      setAudioTracks(audio);
+      // Already in jellyfin-web order (sorted iteration above); "Disable" stays
+      // at the front (unshifted), local downloaded subs at the end.
+      commitSubtitleTracks(subs);
+      commitAudioTracks(audio);
     };
 
     fetchTracks();
-  }, [tracksReady, mediaSource, offline, downloadedItem, itemId]);
+    return () => {
+      cancelled = true;
+    };
+    // api?.basePath: setTrack builds external-sub URLs from it — rebuild once the
+    // API is ready so online externals don't resolve with undefined.
+    // isCurrentSubImageBased: setTrack closes over it for the transcode replacePlayer
+    // decision — rebuild when it flips so we refresh the stream when we should.
+  }, [
+    tracksReady,
+    mediaSource,
+    offline,
+    downloadedItem,
+    itemId,
+    api?.basePath,
+    isCurrentSubImageBased,
+  ]);
 
   return (
     <VideoContext.Provider value={{ subtitleTracks, audioTracks }}>

constants/MediaTypes.ts

@@ -3,9 +3,13 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
-export default {
+const MediaTypes = {
   Audio: "Audio",
   Video: "Video",
   Photo: "Photo",
   Book: "Book",
-};
+} as const;
+
+export type MediaType = (typeof MediaTypes)[keyof typeof MediaTypes];
+
+export default MediaTypes;

modules/mpv-player/android/src/main/java/expo/modules/mpvplayer/MPVLayerRenderer.kt

@@ -532,16 +532,27 @@ class MPVLayerRenderer(private val context: Context) : MPVLib.EventObserver {
             
             val trackId = mpv?.getPropertyInt("track-list/$i/id") ?: continue
             val track = mutableMapOf<String, Any>("id" to trackId)
-            
+
             mpv?.getPropertyString("track-list/$i/title")?.let { track["title"] = it }
             mpv?.getPropertyString("track-list/$i/lang")?.let { track["lang"] = it }
-            
+            mpv?.getPropertyString("track-list/$i/codec")?.let { track["codec"] = it }
+
+            // Identity fields used to map a Jellyfin subtitle to the real track
+            // (instead of fragile positional counting). `external` + `external-filename`
+            // uniquely identify a sub-added sidecar; `ff-index` aids embedded matching.
+            val external = mpv?.getPropertyBoolean("track-list/$i/external") ?: false
+            track["external"] = external
+            mpv?.getPropertyString("track-list/$i/external-filename")?.let {
+                track["externalFilename"] = it
+            }
+            mpv?.getPropertyInt("track-list/$i/ff-index")?.let { track["ffIndex"] = it }
+
             val selected = mpv?.getPropertyBoolean("track-list/$i/selected") ?: false
             track["selected"] = selected
-            
+
             tracks.add(track)
         }
-        
+
         return tracks
     }
     

modules/mpv-player/ios/MPVLayerRenderer.swift

@@ -770,12 +770,32 @@ final class MPVLayerRenderer {
             if let lang = getStringProperty(handle: handle, name: "track-list/\(i)/lang") {
                 track["lang"] = lang
             }
-            
+
+            if let codec = getStringProperty(handle: handle, name: "track-list/\(i)/codec") {
+                track["codec"] = codec
+            }
+
+            // Identity fields used to map a Jellyfin subtitle to the real track
+            // (instead of fragile positional counting). `external` + `external-filename`
+            // uniquely identify a sub-added sidecar; `ff-index` aids embedded matching.
+            var external: Int32 = 0
+            getProperty(handle: handle, name: "track-list/\(i)/external", format: MPV_FORMAT_FLAG, value: &external)
+            track["external"] = external != 0
+
+            if let extFilename = getStringProperty(handle: handle, name: "track-list/\(i)/external-filename") {
+                track["externalFilename"] = extFilename
+            }
+
+            var ffIndex: Int64 = 0
+            if getProperty(handle: handle, name: "track-list/\(i)/ff-index", format: MPV_FORMAT_INT64, value: &ffIndex) >= 0 {
+                track["ffIndex"] = Int(ffIndex)
+            }
+
             var selected: Int32 = 0
             getProperty(handle: handle, name: "track-list/\(i)/selected", format: MPV_FORMAT_FLAG, value: &selected)
             track["selected"] = selected != 0
-            
-            Logger.shared.log("getSubtitleTracks: found sub track id=\(trackId), title=\(track["title"] ?? "none"), lang=\(track["lang"] ?? "none")", type: "Info")
+
+            Logger.shared.log("getSubtitleTracks: found sub track id=\(trackId), title=\(track["title"] ?? "none"), lang=\(track["lang"] ?? "none"), external=\(external != 0)", type: "Info")
             tracks.append(track)
         }
         

modules/mpv-player/src/MpvPlayer.types.ts

@@ -141,6 +141,14 @@ export type SubtitleTrack = {
   id: number;
   title?: string;
   lang?: string;
+  /** Subtitle codec (mpv `codec`), e.g. "subrip", "ass", "hdmv_pgs_subtitle". */
+  codec?: string;
+  /** True if loaded from a separate file via `sub-add` (mpv `external`). */
+  external?: boolean;
+  /** For external tracks: the exact URL/path it was loaded from (mpv `external-filename`). */
+  externalFilename?: string;
+  /** FFmpeg stream index (mpv `ff-index`); not guaranteed for non-lavf demuxers. */
+  ffIndex?: number;
   selected?: boolean;
 };
 

package.json

@@ -17,13 +17,13 @@
     "ios:unsigned-build": "cross-env EXPO_TV=0 bun scripts/ios/build-ios.ts --production",
     "ios:unsigned-build:tv": "cross-env EXPO_TV=1 bun scripts/ios/build-ios.ts --production",
     "prepare": "husky",
-    "typecheck": "node scripts/typecheck.js",
+    "typecheck": "bun scripts/typecheck.ts",
     "check": "biome check . --max-diagnostics 1000",
     "lint": "biome check --write --unsafe --max-diagnostics 1000",
     "format": "biome format --write .",
     "doctor": "expo-doctor",
-    "i18n:check": "bun scripts/check-i18n-keys.mjs",
-    "i18n:fix-unused": "bun scripts/check-i18n-keys.mjs --fix-unused",
+    "i18n:check": "bun scripts/check-i18n-keys.ts",
+    "i18n:fix-unused": "bun scripts/check-i18n-keys.ts --fix-unused",
     "test": "bun run typecheck && bun run lint && bun run format && bun run i18n:check && bun run doctor",
     "postinstall": "patch-package"
   },

scripts/check-i18n-keys.ts

@@ -18,11 +18,11 @@
  *   - Edge cases the static scan cannot see can be allow-listed in the config file.
  *
  * Usage:
- *   bun scripts/check-i18n-keys.mjs                # report + exit 1 on missing OR unused
- *   bun scripts/check-i18n-keys.mjs --unused=warn  # exit 1 only on missing; unused = warning
- *   bun scripts/check-i18n-keys.mjs --unused=off   # ignore unused entirely
- *   bun scripts/check-i18n-keys.mjs --json         # machine-readable output
- *   bun scripts/check-i18n-keys.mjs --fix-unused   # remove dead keys from en.json (Crowdin syncs the rest)
+ *   bun scripts/check-i18n-keys.ts                # report + exit 1 on missing OR unused
+ *   bun scripts/check-i18n-keys.ts --unused=warn  # exit 1 only on missing; unused = warning
+ *   bun scripts/check-i18n-keys.ts --unused=off   # ignore unused entirely
+ *   bun scripts/check-i18n-keys.ts --json         # machine-readable output
+ *   bun scripts/check-i18n-keys.ts --fix-unused   # remove dead keys from en.json (Crowdin syncs the rest)
  */
 
 import {
@@ -34,9 +34,20 @@ import {
 } from "node:fs";
 import { extname, join, relative } from "node:path";
 
+type LocaleTree = { [key: string]: LocaleTree | string };
+
+interface I18nConfig {
+  localesDir: string;
+  sourceLocale: string;
+  srcDirs: string[];
+  srcExtensions: string[];
+  excludeDirs: string[];
+  ignoreUnused: string[];
+}
+
 const ROOT = process.cwd();
 const args = process.argv.slice(2);
-const flag = (name, def) => {
+const flag = (name: string, def: string | boolean): string | boolean => {
   const a = args.find((x) => x === `--${name}` || x.startsWith(`--${name}=`));
   if (!a) return def;
   const [, v] = a.split("=");
@@ -48,7 +59,7 @@ const FIX_UNUSED = !!flag("fix-unused", false);
 
 // ---- config ----
 const CONFIG_PATH = join(ROOT, "scripts", "i18n-keys.config.json");
-const DEFAULT_CONFIG = {
+const DEFAULT_CONFIG: I18nConfig = {
   localesDir: "translations",
   sourceLocale: "en",
   // Scan the whole repo by default so keys referenced outside the obvious dirs
@@ -69,29 +80,36 @@ const DEFAULT_CONFIG = {
   // Keys (or glob-ish prefixes ending with .* or *) known to be used dynamically / externally.
   ignoreUnused: [],
 };
-const config = existsSync(CONFIG_PATH)
-  ? { ...DEFAULT_CONFIG, ...JSON.parse(readFileSync(CONFIG_PATH, "utf8")) }
+const config: I18nConfig = existsSync(CONFIG_PATH)
+  ? {
+      ...DEFAULT_CONFIG,
+      ...(JSON.parse(readFileSync(CONFIG_PATH, "utf8")) as Partial<I18nConfig>),
+    }
   : DEFAULT_CONFIG;
 
 // ---- helpers ----
-const flatten = (obj, prefix = "", out = {}) => {
+const flatten = (
+  obj: LocaleTree,
+  prefix = "",
+  out: Record<string, string> = {},
+): Record<string, string> => {
   for (const [k, v] of Object.entries(obj)) {
     const key = prefix ? `${prefix}.${k}` : k;
     if (v && typeof v === "object" && !Array.isArray(v)) flatten(v, key, out);
-    else out[key] = v;
+    else out[key] = v as string;
   }
   return out;
 };
 
-const globMatch = (key, pattern) => {
+const globMatch = (key: string, pattern: string): boolean => {
   if (pattern.endsWith(".*"))
     return key === pattern.slice(0, -2) || key.startsWith(pattern.slice(0, -1));
   if (pattern.endsWith("*")) return key.startsWith(pattern.slice(0, -1));
   return key === pattern;
 };
 
-const walk = (dir, files = []) => {
-  let entries;
+const walk = (dir: string, files: string[] = []): string[] => {
+  let entries: string[];
   try {
     entries = readdirSync(dir);
   } catch {
@@ -99,7 +117,7 @@ const walk = (dir, files = []) => {
   }
   for (const name of entries) {
     const full = join(dir, name);
-    let st;
+    let st: ReturnType<typeof statSync>;
     try {
       st = statSync(full);
     } catch {
@@ -118,7 +136,7 @@ const walk = (dir, files = []) => {
 // ---- load source keys ----
 const sourcePath = join(ROOT, config.localesDir, `${config.sourceLocale}.json`);
 const sourceKeys = Object.keys(
-  flatten(JSON.parse(readFileSync(sourcePath, "utf8"))),
+  flatten(JSON.parse(readFileSync(sourcePath, "utf8")) as LocaleTree),
 );
 const sourceKeySet = new Set(sourceKeys);
 
@@ -129,16 +147,16 @@ const TPL_DYN_RE = /\bt\(\s*`([^`$]*)\$\{/g; // t(`a.b.${x}`) -> prefix "a.b."
 const I18NKEY_RE = /\bi18nKey\s*=\s*(?:\{\s*)?(['"])((?:\\.|(?!\1).)+?)\1/g; // <Trans i18nKey="a.b">
 const KEY_SHAPE = /^[A-Za-z0-9_]+(\.[A-Za-z0-9_]+)+$/; // dotted key, e.g. home.x.y
 
-const usedStatic = new Set(); // keys passed to t(...) / i18nKey — used for MISSING detection
-const dynamicPrefixes = new Set();
-const fullyDynamic = []; // { file, line }
+const usedStatic = new Set<string>(); // keys passed to t(...) / i18nKey — used for MISSING detection
+const dynamicPrefixes = new Set<string>();
+const fullyDynamic: Array<{ file: string; line: number }> = [];
 let codeBlob = ""; // all (comment-stripped) source text — searched for delimited key literals
 
 // Strip comments so keys mentioned in comments (e.g. `// t("old.key")`) are not counted as
 // usage. Block comments and JSX {/* */} are blanked (preserving newlines for line numbers);
 // line comments are only stripped when `//` follows start/whitespace/punctuation, which keeps
 // `://` inside string URLs intact.
-const stripComments = (src) =>
+const stripComments = (src: string): string =>
   src
     .replace(/\/\*[\s\S]*?\*\//g, (m) => m.replace(/[^\n]/g, " "))
     .replace(/(^|[\s;{}()[\],=>])\/\/[^\n]*/g, (_m, p) => p);
@@ -168,11 +186,11 @@ const prefixList = [...dynamicPrefixes];
 // the code (covers t("k"), <Trans i18nKey>, and keys stored as bare string constants in
 // arrays/config then resolved via t(variable)), or it is reached via a dynamic prefix, or
 // explicitly allow-listed. Delimited search avoids substring false-matches (e.g. a.b vs a.b_c).
-const literalUsed = (key) =>
+const literalUsed = (key: string): boolean =>
   codeBlob.includes(`"${key}"`) ||
   codeBlob.includes(`'${key}'`) ||
   codeBlob.includes(`\`${key}\``);
-const isUsed = (key) =>
+const isUsed = (key: string): boolean =>
   literalUsed(key) ||
   prefixList.some((p) => key.startsWith(p)) ||
   config.ignoreUnused.some((g) => globMatch(key, g));
@@ -191,25 +209,22 @@ const missing = [...usedStatic]
 // keys are static literals in practice; revisit if dynamic key constants become common.
 
 // ---- optional fix: strip dead keys from the source locale (en.json) ----
-const removeKey = (obj, parts) => {
+const removeKey = (obj: LocaleTree, parts: string[]): void => {
   const [head, ...rest] = parts;
   if (!(head in obj)) return;
   if (rest.length === 0) {
     delete obj[head];
     return;
   }
-  removeKey(obj[head], rest);
-  if (
-    obj[head] &&
-    typeof obj[head] === "object" &&
-    Object.keys(obj[head]).length === 0
-  )
-    delete obj[head];
+  const child = obj[head];
+  if (!child || typeof child !== "object") return;
+  removeKey(child, rest);
+  if (Object.keys(child).length === 0) delete obj[head];
 };
 if (FIX_UNUSED && unused.length) {
   // Only edit the SOURCE locale (en.json). Crowdin owns the target locales and removes
   // the keys from them automatically on the next sync once they disappear from the source.
-  const data = JSON.parse(readFileSync(sourcePath, "utf8"));
+  const data = JSON.parse(readFileSync(sourcePath, "utf8")) as LocaleTree;
   for (const key of unused) removeKey(data, key.split("."));
   writeFileSync(sourcePath, `${JSON.stringify(data, null, 2)}\n`);
   console.log(
@@ -259,7 +274,7 @@ if (JSON_OUT) {
       );
       for (const k of unused) console.log(`   - ${k}`);
       console.log(
-        `\n   → remove with: bun scripts/check-i18n-keys.mjs --fix-unused`,
+        `\n   → remove with: bun scripts/check-i18n-keys.ts --fix-unused`,
       );
       console.log(
         `   → or allow-list a dynamic key in scripts/i18n-keys.config.json ("ignoreUnused").`,

scripts/detect-duplicate-issue.ts

@@ -21,8 +21,14 @@
 import { execFileSync } from "node:child_process";
 import { readFileSync } from "node:fs";
 
+interface Issue {
+  number: number;
+  title: string;
+  body: string | null;
+}
+
 // Parse a numeric env var, falling back to `def` only when unset/empty/NaN so an explicit 0 is honoured.
-const numEnv = (name, def) => {
+const numEnv = (name: string, def: number): number => {
   const raw = process.env[name];
   if (raw === undefined || raw === "") return def;
   const n = Number(raw);
@@ -51,9 +57,9 @@ const STOP = new Set(
   ).split(/\s+/),
 );
 
-const stem = (w) => w.replace(/(ing|ed|es|s)$/, "");
+const stem = (w: string): string => w.replace(/(ing|ed|es|s)$/, "");
 
-const tokens = (s) =>
+const tokens = (s: string | null): string[] =>
   (s || "")
     .toLowerCase()
     .replace(/```[\s\S]*?```/g, " ") // drop code blocks
@@ -65,7 +71,7 @@ const tokens = (s) =>
     .map(stem)
     .filter((w) => w.length > 2);
 
-const jaccard = (a, b) => {
+const jaccard = (a: string[], b: string[]): number => {
   const A = new Set(a);
   const B = new Set(b);
   if (!A.size || !B.size) return 0;
@@ -76,14 +82,14 @@ const jaccard = (a, b) => {
 
 const newTitle = tokens(TITLE);
 const newBody = tokens(BODY);
-const score = (o) =>
+const score = (o: Issue): number =>
   0.6 * jaccard(newTitle, tokens(o.title)) +
   0.4 * jaccard(newBody, tokens(o.body));
 
 // fetch open issues (excluding PRs and the new issue itself)
-let issues;
+let issues: Issue[];
 if (process.env.DUP_FIXTURE) {
-  issues = JSON.parse(readFileSync(process.env.DUP_FIXTURE, "utf8"));
+  issues = JSON.parse(readFileSync(process.env.DUP_FIXTURE, "utf8")) as Issue[];
 } else {
   const raw = execFileSync(
     "gh",
@@ -105,7 +111,7 @@ if (process.env.DUP_FIXTURE) {
   issues = raw
     .split("\n")
     .filter(Boolean)
-    .map((l) => JSON.parse(l));
+    .map((l) => JSON.parse(l) as Issue);
 }
 
 const matches = issues
@@ -123,7 +129,7 @@ if (!matches.length) {
 // Neutralise other issues' titles before echoing them back: break @mentions and
 // strip markdown/HTML control chars so a maliciously-named issue can't ping people
 // or inject formatting into our comment. GitHub linkifies "#123" on its own.
-const safeTitle = (t) =>
+const safeTitle = (t: string): string =>
   (t || "")
     .replace(/@/g, "@​")
     .replace(/[`<>|*_~[\]]/g, " ")

scripts/symlink-native-dirs.js

@@ -1,62 +0,0 @@
-#!/usr/bin/env node
-
-const _fs = require("node:fs");
-const path = require("node:path");
-const process = require("node:process");
-const { execSync } = require("node:child_process");
-
-const root = process.cwd();
-// const tvosPath = path.join(root, 'iostv');
-// const iosPath = path.join(root, 'iosmobile');
-// const androidPath = path.join(root, 'androidmobile');
-// const androidTVPath = path.join(root, 'androidtv');
-// const device = process.argv[2];
-// const platform = process.argv[2];
-const isTV = process.env.EXPO_TV || false;
-
-const paths = new Map([
-  ["tvos", path.join(root, "iostv")],
-  ["ios", path.join(root, "iosmobile")],
-  ["android", path.join(root, "androidmobile")],
-  ["androidtv", path.join(root, "androidtv")],
-]);
-
-// const platformPath = paths.get(platform);
-
-if (isTV) {
-  stdout = execSync(
-    `mkdir -p ${paths.get("tvos")}; ln -nsf ${paths.get("tvos")} ios`,
-  );
-  console.log(stdout.toString());
-  stdout = execSync(
-    `mkdir -p ${paths.get("androidtv")}; ln -nsf ${paths.get(
-      "androidtv",
-    )} android`,
-  );
-  console.log(stdout.toString());
-} else {
-  stdout = execSync(
-    `mkdir -p ${paths.get("ios")}; ln -nsf ${paths.get("ios")} ios`,
-  );
-  console.log(stdout.toString());
-  stdout = execSync(
-    `mkdir -p ${paths.get("android")}; ln -nsf ${paths.get("android")} android`,
-  );
-  console.log(stdout.toString());
-}
-
-// target = "";
-// switch (platform) {
-//   case "tvos":
-//     target = "ios";
-//     break;
-//   case "ios":
-//     target = "ios";
-//     break;
-//   case "android":
-//     target = "android";
-//     break;
-//   case "androidtv":
-//     target = "android";
-//     break;
-// }

scripts/typecheck.ts

@@ -1,5 +1,8 @@
-const { execFileSync } = require("node:child_process");
-const process = require("node:process");
+import { execFileSync } from "node:child_process";
+import { createRequire } from "node:module";
+import process from "node:process";
+
+const require = createRequire(import.meta.url);
 
 // Enhanced ANSI color codes and styles
 const colors = {
@@ -32,7 +35,7 @@ const centeredTitle = " ".repeat(titlePadding) + title;
 
 const useColor = process.stdout.isTTY && !process.env.NO_COLOR;
 
-function log(message, color = "") {
+function log(message: string, color = "") {
   if (useColor && color) {
     console.log(`${color}${message}${colors.reset}`);
   } else {
@@ -40,7 +43,7 @@ function log(message, color = "") {
   }
 }
 
-function formatError(errorLine) {
+function formatError(errorLine: string): string {
   if (!useColor) return errorLine;
 
   // Color file paths in cyan
@@ -70,12 +73,15 @@ function formatError(errorLine) {
   return formatted;
 }
 
-function parseErrorsAndCreateSummary(errorOutput) {
+function parseErrorsAndCreateSummary(errorOutput: string): {
+  formattedErrors: string[];
+  errorsByFile: Map<string, number>;
+} {
   const lines = errorOutput.split("\n").filter((line) => line.trim());
-  const errorsByFile = new Map();
-  const formattedErrors = [];
+  const errorsByFile = new Map<string, number>();
+  const formattedErrors: string[] = [];
 
-  let currentError = [];
+  let currentError: string[] = [];
 
   for (const line of lines) {
     const trimmedLine = line.trim();
@@ -96,7 +102,7 @@ function parseErrorsAndCreateSummary(errorOutput) {
       if (!errorsByFile.has(filePath)) {
         errorsByFile.set(filePath, 0);
       }
-      errorsByFile.set(filePath, errorsByFile.get(filePath) + 1);
+      errorsByFile.set(filePath, (errorsByFile.get(filePath) ?? 0) + 1);
 
       // Start new error
       currentError.push(formatError(line));
@@ -119,7 +125,7 @@ function parseErrorsAndCreateSummary(errorOutput) {
   return { formattedErrors, errorsByFile };
 }
 
-function createErrorSummaryTable(errorsByFile) {
+function createErrorSummaryTable(errorsByFile: Map<string, number>): string {
   if (errorsByFile.size === 0) return "";
 
   const sortedFiles = Array.from(errorsByFile.entries()).sort(
@@ -136,7 +142,7 @@ function createErrorSummaryTable(errorsByFile) {
   return table;
 }
 
-function runTypeCheck() {
+function runTypeCheck(): { ok: boolean } {
   const extraArgs = process.argv.slice(2);
 
   // Prefer local TypeScript binary when available
@@ -150,16 +156,13 @@ function runTypeCheck() {
     "false",
     ...extraArgs,
   ];
-  let execArgs = null;
+  let execArgs: { cmd: string; args: string[] };
   try {
     const tscBin = require.resolve("typescript/bin/tsc");
     execArgs = { cmd: process.execPath, args: [tscBin, ...runnerArgs] };
   } catch {
-    // fallback to PATH tsc
-    execArgs = {
-      cmd: "tsc",
-      args: ["-p", "tsconfig.json", "--noEmit", ...extraArgs],
-    };
+    // fallback to PATH tsc (reuse runnerArgs so --pretty false is preserved)
+    execArgs = { cmd: "tsc", args: runnerArgs };
   }
 
   try {
@@ -183,7 +186,21 @@ function runTypeCheck() {
     );
     return { ok: true };
   } catch (error) {
-    const errorOutput = (error && (error.stderr || error.stdout)) || "";
+    const execError = error as { stderr?: string; stdout?: string };
+    const errorOutput = [execError.stdout, execError.stderr]
+      .filter((chunk): chunk is string => Boolean(chunk))
+      .join("\n");
+
+    // No compiler output = tsc never ran (e.g. binary missing). Don't let a
+    // launch failure fall through to the "passed" branch and green-light CI.
+    if (!errorOutput) {
+      const message = error instanceof Error ? error.message : String(error);
+      log(
+        `❌ ${colors.bold}TypeScript check failed to start${colors.reset} ${colors.gray}${message}${colors.reset}`,
+        colors.red,
+      );
+      return { ok: false };
+    }
 
     // Filter out jellyseerr utils errors - this is a third-party git submodule
     // that generates a large volume of known type errors

utils/jellyfin/subtitleUtils.test.ts

@@ -0,0 +1,221 @@
+import { describe, expect, test } from "bun:test";
+import type {
+  MediaStream,
+  SubtitleDeliveryMethod,
+} from "@jellyfin/sdk/lib/generated-client";
+import {
+  compareTracksForMenu,
+  isExternalSubtitle,
+  type PlayerSubtitleTrack,
+  resolveSubtitleTrack,
+} from "@/utils/jellyfin/subtitleUtils";
+
+// String-enum values as typed literals — avoids a runtime SDK import (see subtitleUtils.ts).
+const External = "External" as SubtitleDeliveryMethod;
+const Embed = "Embed" as SubtitleDeliveryMethod;
+
+// --- fixtures --------------------------------------------------------------
+
+const sub = (o: Partial<MediaStream> & { Index: number }): MediaStream =>
+  ({ Type: "Subtitle", ...o }) as MediaStream;
+
+const ext = (Index: number, o: Partial<MediaStream> = {}): MediaStream =>
+  sub({
+    Index,
+    DeliveryMethod: External,
+    IsExternal: true,
+    DeliveryUrl: `/sub/${Index}.srt`,
+    ...o,
+  });
+
+const emb = (Index: number, o: Partial<MediaStream> = {}): MediaStream =>
+  sub({ Index, DeliveryMethod: Embed, ...o });
+
+const track = (o: PlayerSubtitleTrack): PlayerSubtitleTrack => o;
+
+// Mirror direct-player.tsx online URL builder.
+const urlBuilder =
+  (base: string) =>
+  (s: MediaStream): string | undefined =>
+    s.DeliveryUrl ? `${base}${s.DeliveryUrl}` : undefined;
+
+const resolve = (
+  streams: MediaStream[],
+  index: number | undefined,
+  player: PlayerSubtitleTrack[],
+  getExpectedExternalUrl = urlBuilder("http://srv"),
+) =>
+  resolveSubtitleTrack({
+    subtitleStreams: streams,
+    jellyfinSubtitleIndex: index,
+    playerTracks: player,
+    getExpectedExternalUrl,
+  });
+
+// --- tests -----------------------------------------------------------------
+
+describe("isExternalSubtitle", () => {
+  test("true for External delivery or the IsExternal flag, not a bare DeliveryUrl", () => {
+    expect(isExternalSubtitle(ext(0))).toBe(true);
+    expect(isExternalSubtitle(sub({ Index: 1, IsExternal: true }))).toBe(true);
+    expect(isExternalSubtitle(emb(2))).toBe(false);
+    // A DeliveryUrl alone (e.g. an Hls-delivered sub) is NOT a sub-added sidecar.
+    expect(isExternalSubtitle(sub({ Index: 3, DeliveryUrl: "/x.srt" }))).toBe(
+      false,
+    );
+  });
+});
+
+describe("resolveSubtitleTrack — disable / notFound", () => {
+  test("index -1 or undefined disables", () => {
+    expect(resolve([], -1, [])).toEqual({ kind: "disable" });
+    expect(resolve([], undefined, [])).toEqual({ kind: "disable" });
+  });
+
+  test("index not present returns notFound", () => {
+    expect(resolve([emb(0)], 99, [track({ id: 1 })])).toEqual({
+      kind: "notFound",
+    });
+  });
+});
+
+describe("resolveSubtitleTrack — hidden embedded (#954)", () => {
+  // Server hides embedded subs: MediaStreams lists only the 3 externals,
+  // but mpv still demuxes the 3 embedded from the file → externals get ids 4,5,6.
+  const streams = [
+    ext(0, { Language: "por" }),
+    ext(1, { Language: "eng" }),
+    ext(2, { Language: "eng", Title: "SDH" }),
+  ];
+  const player = [
+    track({ id: 1, external: false, language: "eng", title: "CC" }),
+    track({ id: 2, external: false, language: "spa" }),
+    track({ id: 3, external: false, language: "fre" }),
+    track({ id: 4, external: true, externalFilename: "http://srv/sub/0.srt" }),
+    track({ id: 5, external: true, externalFilename: "http://srv/sub/1.srt" }),
+    track({ id: 6, external: true, externalFilename: "http://srv/sub/2.srt" }),
+  ];
+
+  test("each external maps to the right player id by filename (not 1,2,3)", () => {
+    expect(resolve(streams, 0, player)).toEqual({ kind: "select", trackId: 4 });
+    expect(resolve(streams, 1, player)).toEqual({ kind: "select", trackId: 5 });
+    expect(resolve(streams, 2, player)).toEqual({ kind: "select", trackId: 6 });
+  });
+
+  test("falls back to external ordinal when filenames are unavailable", () => {
+    const noNames = player.map((t) =>
+      t.external ? { ...t, externalFilename: undefined } : t,
+    );
+    expect(resolve(streams, 1, noNames)).toEqual({
+      kind: "select",
+      trackId: 5,
+    });
+  });
+});
+
+describe("resolveSubtitleTrack — external/embed reversal (non-hidden)", () => {
+  // Jellyfin lists externals first; mpv lists embedded first then externals.
+  const streams = [
+    ext(0, { Language: "eng" }),
+    emb(1, { Language: "spa" }),
+    emb(2, { Language: "fre" }),
+  ];
+  const player = [
+    track({ id: 1, external: false, language: "spa" }),
+    track({ id: 2, external: false, language: "fre" }),
+    track({ id: 3, external: true, externalFilename: "http://srv/sub/0.srt" }),
+  ];
+
+  test("external resolves by filename, embedded by language", () => {
+    expect(resolve(streams, 0, player)).toEqual({ kind: "select", trackId: 3 });
+    expect(resolve(streams, 1, player)).toEqual({ kind: "select", trackId: 1 });
+    expect(resolve(streams, 2, player)).toEqual({ kind: "select", trackId: 2 });
+  });
+});
+
+describe("resolveSubtitleTrack — external without DeliveryUrl (#1763 CodeRabbit)", () => {
+  // Middle external has no DeliveryUrl → never loaded into the player.
+  const streams = [
+    ext(0, { Language: "eng", DeliveryUrl: "/sub/a.srt" }),
+    sub({ Index: 1, DeliveryMethod: External, IsExternal: true }),
+    ext(2, { Language: "fre", DeliveryUrl: "/sub/c.srt" }),
+  ];
+  const player = [
+    track({ id: 4, external: true, externalFilename: "http://srv/sub/a.srt" }),
+    track({ id: 5, external: true, externalFilename: "http://srv/sub/c.srt" }),
+  ];
+
+  test("loaded externals still map correctly despite the gap", () => {
+    expect(resolve(streams, 0, player)).toEqual({ kind: "select", trackId: 4 });
+    expect(resolve(streams, 2, player)).toEqual({ kind: "select", trackId: 5 });
+  });
+
+  test("selecting the unloaded external returns notFound", () => {
+    expect(resolve(streams, 1, player)).toEqual({ kind: "notFound" });
+  });
+});
+
+describe("resolveSubtitleTrack — embedded matching", () => {
+  test("unique language match wins even when player order differs (not positional)", () => {
+    const streams = [emb(0, { Language: "eng" }), emb(1, { Language: "jpn" })];
+    // Player lists them in the OPPOSITE order — a positional map would mis-pick.
+    const player = [
+      track({ id: 1, external: false, language: "jpn" }),
+      track({ id: 2, external: false, language: "eng" }),
+    ];
+    expect(resolve(streams, 0, player)).toEqual({ kind: "select", trackId: 2 }); // eng
+    expect(resolve(streams, 1, player)).toEqual({ kind: "select", trackId: 1 }); // jpn
+  });
+
+  test("same-language tracks with no distinguishing title fall back to ordinal among matches", () => {
+    const streams = [emb(0, { Language: "eng" }), emb(1, { Language: "eng" })];
+    // Both eng, no title → identity can't disambiguate → ordinal among matches.
+    const player = [
+      track({ id: 5, external: false, language: "eng" }),
+      track({ id: 6, external: false, language: "eng" }),
+    ];
+    expect(resolve(streams, 0, player)).toEqual({ kind: "select", trackId: 5 });
+    expect(resolve(streams, 1, player)).toEqual({ kind: "select", trackId: 6 });
+  });
+
+  test("falls back to embedded ordinal when no language/title info", () => {
+    const streams = [emb(0), emb(1)];
+    const player = [
+      track({ id: 1, external: false }),
+      track({ id: 2, external: false }),
+    ];
+    expect(resolve(streams, 1, player)).toEqual({ kind: "select", trackId: 2 });
+  });
+});
+
+describe("compareTracksForMenu — jellyfin-web order", () => {
+  test("externals sort after embedded despite lower Index", () => {
+    const sorted = [
+      ext(0, { Language: "eng" }),
+      emb(7, { Language: "fra" }),
+    ].sort(compareTracksForMenu);
+    expect(sorted.map((s) => s.Index)).toEqual([7, 0]);
+  });
+
+  test("forced then default float to the top within a group", () => {
+    const sorted = [
+      emb(2, { Language: "eng" }),
+      emb(1, { Language: "eng", IsDefault: true }),
+      emb(0, { Language: "eng", IsForced: true }),
+    ].sort(compareTracksForMenu);
+    expect(sorted.map((s) => s.Index)).toEqual([0, 1, 2]);
+  });
+
+  test("full Okiku order: embedded first, externals last by Index", () => {
+    const streams = [
+      ext(0, { Language: "eng" }),
+      ext(1, { Language: "eng" }),
+      ext(2, { Language: "fra" }),
+      ext(3, { Language: "fra" }),
+      emb(7, { Language: "fra", Title: "French" }),
+    ];
+    expect([...streams].sort(compareTracksForMenu).map((s) => s.Index)).toEqual(
+      [7, 0, 1, 2, 3],
+    );
+  });
+});

utils/jellyfin/subtitleUtils.ts

@@ -1,91 +1,287 @@
 /**
- * Subtitle utility functions for mapping between Jellyfin and MPV track indices.
+ * Subtitle utilities: resolve a Jellyfin subtitle stream to the right track in
+ * the *player's real track list* by identity — never by positional counting.
  *
- * Jellyfin uses server-side indices (e.g., 3, 4, 5 for subtitles in MediaStreams).
- * MPV uses its own track IDs starting from 1, only counting tracks loaded into MPV.
+ * Why: Jellyfin renumbers MediaStreams (externals first); the player enumerates
+ * embedded-from-container first and externals (`sub-add`) last; and a library that
+ * hides embedded subs drops them from MediaStreams while the player still demuxes
+ * them from the file. Positional Index→id mapping therefore mis-selects (e.g.
+ * picking Spanish shows English). See {@link resolveSubtitleTrack}.
  *
  * Image-based subtitles (PGS, VOBSUB) during transcoding are burned into the video
- * and NOT available in MPV's track list.
+ * and absent from the player's track list.
  */
 
-import {
-  type MediaSourceInfo,
-  type MediaStream,
+import type {
+  MediaSourceInfo,
+  MediaStream,
   SubtitleDeliveryMethod,
 } from "@jellyfin/sdk/lib/generated-client";
 
+// "External" is the value of SubtitleDeliveryMethod.External. Compared as a typed
+// literal so this util needs no *runtime* import of the SDK barrel — which pulls in
+// the axios-dependent `/api` modules and breaks unit tests under `bun test`.
+const EXTERNAL_DELIVERY = "External" as SubtitleDeliveryMethod;
+
 /** Check if subtitle is image-based (PGS, VOBSUB, etc.) */
 export const isImageBasedSubtitle = (sub: MediaStream): boolean =>
   sub.IsTextSubtitleStream === false;
 
 /**
- * Determine if a subtitle will be available in MPV's track list.
+ * A Jellyfin subtitle stream is "external" when the server delivers it as a
+ * sub-added sidecar — i.e. `DeliveryMethod === External` (or the `IsExternal`
+ * flag before a device-specific delivery method is assigned).
  *
- * A subtitle is in MPV if:
- * - Delivery is Embed/Hls/External AND not an image-based sub during transcode
+ * Deliberately NOT keyed on `DeliveryUrl`: an Hls-delivered sub also carries a
+ * `DeliveryUrl` but lives inside the player's track list (not `sub-add`-ed), so
+ * it must resolve through the embedded path. Keeping this in lockstep with the
+ * load sites (which only `sub-add` `DeliveryMethod === External`) and with the
+ * menu comparator below avoids a sub being sorted as embedded yet resolved as
+ * external (→ `notFound`).
  */
-export const isSubtitleInMpv = (
-  sub: MediaStream,
-  isTranscoding: boolean,
-): boolean => {
-  // During transcoding, image-based subs are burned in, not in MPV
-  if (isTranscoding && isImageBasedSubtitle(sub)) {
-    return false;
-  }
+export const isExternalSubtitle = (sub: MediaStream): boolean =>
+  sub.DeliveryMethod === EXTERNAL_DELIVERY || sub.IsExternal === true;
 
-  // Embed/Hls/External methods mean the sub is loaded into MPV
-  return (
-    sub.DeliveryMethod === SubtitleDeliveryMethod.Embed ||
-    sub.DeliveryMethod === SubtitleDeliveryMethod.Hls ||
-    sub.DeliveryMethod === SubtitleDeliveryMethod.External
-  );
+/**
+ * Order subtitle MediaStreams for the selection menu exactly like jellyfin-web's
+ * `itemHelper.sortTracks`: in-container tracks first then external, and within
+ * each group forced first, then default, then `Index` ascending. Callers prepend
+ * their own "None/Off" entry separately.
+ *
+ * The Jellyfin server inserts external (sidecar) streams at the FRONT of
+ * `MediaStreams` (low indices), so raw Index order shows externals first — this
+ * comparator flips that to match web (externals last). Uses {@link isExternalSubtitle}
+ * (not the raw `IsExternal` flag) so ordering and resolution agree.
+ */
+export const compareTracksForMenu = (a: MediaStream, b: MediaStream): number =>
+  Number(isExternalSubtitle(a)) - Number(isExternalSubtitle(b)) ||
+  Number(b.IsForced ?? false) - Number(a.IsForced ?? false) ||
+  Number(b.IsDefault ?? false) - Number(a.IsDefault ?? false) ||
+  (a.Index ?? 0) - (b.Index ?? 0);
+
+/**
+ * Identity of a subtitle track as reported by the *player's real track list*
+ * (mpv `track-list`, or a Cast media-track list). Player-agnostic on purpose so
+ * the same resolver can drive the mpv player today and the Chromecast backend later.
+ */
+export type PlayerSubtitleTrack = {
+  /** Player-side id used to actually select the track (mpv `sid`, cast trackId). */
+  id: number;
+  /** True if loaded from a separate file (mpv `external`). */
+  external?: boolean;
+  /** For external tracks: the exact URL/path it was loaded from (mpv `external-filename`). */
+  externalFilename?: string;
+  language?: string;
+  title?: string;
+  codec?: string;
+};
+
+export type SubtitleSelection =
+  | { kind: "select"; trackId: number }
+  | { kind: "disable" }
+  | { kind: "notFound" };
+
+/** Decode percent-encoding and strip a leading `file://` scheme for tolerant comparison. */
+const normalizeUrl = (url: string): string => {
+  let u = url;
+  try {
+    u = decodeURIComponent(u);
+  } catch {
+    // not decodable — compare raw
+  }
+  return u.replace(/^file:\/\//, "");
+};
+
+const externalFilenameMatches = (
+  trackFilename: string | undefined,
+  expectedUrl: string | undefined,
+): boolean => {
+  if (!trackFilename || !expectedUrl) return false;
+  const a = normalizeUrl(trackFilename);
+  const b = normalizeUrl(expectedUrl);
+  return a === b || a.endsWith(b) || b.endsWith(a);
+};
+
+const eq = (a?: string | null, b?: string | null): boolean =>
+  !!a && !!b && a.toLowerCase() === b.toLowerCase();
+
+/** Match an embedded player track to a Jellyfin stream by language/title (codec-agnostic). */
+const embeddedIdentityMatches = (
+  track: PlayerSubtitleTrack,
+  stream: MediaStream,
+): boolean => {
+  if (eq(track.language, stream.Language)) {
+    // When both carry a title it must agree; otherwise language alone is enough.
+    if (track.title && stream.Title) return eq(track.title, stream.Title);
+    return true;
+  }
+  // No language on one side — fall back to a title match.
+  if (!track.language || !stream.Language) return eq(track.title, stream.Title);
+  return false;
 };
 
 /**
- * Calculate the MPV track ID for a given Jellyfin subtitle index.
+ * Resolve the player track id for a given Jellyfin subtitle index by matching
+ * against the player's REAL track list (identity), never by positional counting.
  *
- * MPV track IDs are 1-based and only count subtitles that are actually in MPV.
- * We iterate through all subtitles, counting only those in MPV, until we find
- * the one matching the Jellyfin index.
+ * Why identity, not position: Jellyfin renumbers `MediaStreams` (externals first)
+ * while the player enumerates embedded-from-container first and externals
+ * (`sub-add`) last; and when a library hides embedded subs they vanish from
+ * `MediaStreams` but still physically exist in the file the player demuxes.
+ * Positional Index→id mapping therefore mis-selects (e.g. picking Spanish shows
+ * English — issues #954/#1690/#618/#1467/#976/#1451).
  *
- * @param mediaSource - The media source containing subtitle streams
- * @param jellyfinSubtitleIndex - The Jellyfin server-side subtitle index (-1 = disabled)
- * @param isTranscoding - Whether the stream is being transcoded
- * @returns MPV track ID (1-based), or -1 if disabled, or undefined if not in MPV
+ * Strategy:
+ *  - disabled (-1/undefined) → `disable`
+ *  - external Jellyfin sub → match the player track by `externalFilename`
+ *    (exact identity, immune to hidden-embedded shifts); fall back to the
+ *    ordinal among *loadable* externals (Swiftfin: externals are the list tail).
+ *  - embedded Jellyfin sub → match by language/title among non-external tracks;
+ *    fall back to the embedded ordinal (container order aligns on both sides).
+ *
+ * Player-agnostic: pass any player's track list + a URL builder, so the mpv
+ * player and (later) the Chromecast backend share one source of truth.
  */
-export const getMpvSubtitleId = (
-  mediaSource: MediaSourceInfo | null | undefined,
-  jellyfinSubtitleIndex: number | undefined,
-  isTranscoding: boolean,
-): number | undefined => {
-  // -1 or undefined means disabled
+export const resolveSubtitleTrack = (params: {
+  subtitleStreams: MediaStream[] | undefined;
+  jellyfinSubtitleIndex: number | undefined;
+  playerTracks: PlayerSubtitleTrack[];
+  /** Build the exact URL/path an external Jellyfin sub was loaded into the player with. */
+  getExpectedExternalUrl?: (sub: MediaStream) => string | undefined;
+}): SubtitleSelection => {
+  const { jellyfinSubtitleIndex, playerTracks, getExpectedExternalUrl } =
+    params;
+  const subtitleStreams = params.subtitleStreams ?? [];
+
   if (jellyfinSubtitleIndex === undefined || jellyfinSubtitleIndex === -1) {
-    return -1;
+    return { kind: "disable" };
   }
 
-  const allSubs =
-    mediaSource?.MediaStreams?.filter((s) => s.Type === "Subtitle") || [];
+  const target = subtitleStreams.find((s) => s.Index === jellyfinSubtitleIndex);
+  if (!target) return { kind: "notFound" };
 
-  // Find the subtitle with the matching Jellyfin index
-  const targetSub = allSubs.find((s) => s.Index === jellyfinSubtitleIndex);
+  if (isExternalSubtitle(target)) {
+    const playerExternals = playerTracks.filter((t) => t.external === true);
 
-  // If the target subtitle isn't in MPV (e.g., image-based during transcode), return undefined
-  if (!targetSub || !isSubtitleInMpv(targetSub, isTranscoding)) {
-    return undefined;
-  }
+    // 1) Exact identity by external filename — robust against hidden-embedded offset.
+    const expectedUrl = getExpectedExternalUrl?.(target);
+    const byName = playerExternals.find((t) =>
+      externalFilenameMatches(t.externalFilename, expectedUrl),
+    );
+    if (byName) return { kind: "select", trackId: byName.id };
 
-  // Count MPV track position (1-based)
-  let mpvIndex = 0;
-  for (const sub of allSubs) {
-    if (isSubtitleInMpv(sub, isTranscoding)) {
-      mpvIndex++;
-      if (sub.Index === jellyfinSubtitleIndex) {
-        return mpvIndex;
-      }
+    // 2) Fallback: externals are appended in MediaStreams order → ordinal among
+    //    *loadable* externals (those actually added to the player) stays in lockstep
+    //    with the player's external list, skipping ones with no DeliveryUrl (#1763).
+    const externalStreams = subtitleStreams.filter(isExternalSubtitle);
+    const loadableExternals = getExpectedExternalUrl
+      ? externalStreams.filter((s) => getExpectedExternalUrl(s))
+      : externalStreams;
+    const ordinal = loadableExternals.findIndex(
+      (s) => s.Index === jellyfinSubtitleIndex,
+    );
+    if (ordinal >= 0 && ordinal < playerExternals.length) {
+      return { kind: "select", trackId: playerExternals[ordinal].id };
     }
+    return { kind: "notFound" };
   }
 
-  return undefined;
+  // Embedded / in-container subtitle.
+  const embeddedStreams = subtitleStreams.filter((s) => !isExternalSubtitle(s));
+  const playerEmbedded = playerTracks.filter((t) => t.external !== true);
+
+  // 1) Identity by language/title (unique match wins).
+  const identityMatches = playerEmbedded.filter((t) =>
+    embeddedIdentityMatches(t, target),
+  );
+  if (identityMatches.length === 1) {
+    return { kind: "select", trackId: identityMatches[0].id };
+  }
+
+  // 2) Fallback: embedded order is container order on both sides → ordinal.
+  const ordinal = embeddedStreams.findIndex(
+    (s) => s.Index === jellyfinSubtitleIndex,
+  );
+  if (identityMatches.length > 1 && ordinal >= 0) {
+    // Multiple same-language tracks: pick by position among the matches.
+    const idx = Math.min(ordinal, identityMatches.length - 1);
+    return { kind: "select", trackId: identityMatches[idx].id };
+  }
+  if (ordinal >= 0 && ordinal < playerEmbedded.length) {
+    return { kind: "select", trackId: playerEmbedded[ordinal].id };
+  }
+  return { kind: "notFound" };
+};
+
+/**
+ * A subtitle track as reported by a concrete player's track-list API
+ * (mpv `getSubtitleTracks`, or a Cast track list). `lang` mirrors mpv's field name.
+ */
+export type PlayerSubtitleTrackRaw = {
+  id: number;
+  lang?: string;
+  title?: string;
+  codec?: string;
+  external?: boolean;
+  externalFilename?: string;
+};
+
+/**
+ * Minimal player surface needed to select a subtitle. Satisfied structurally by
+ * the mpv player ref and (later) implementable by the Chromecast backend.
+ */
+export interface SubtitleSelectablePlayer {
+  getSubtitleTracks: () => Promise<PlayerSubtitleTrackRaw[] | null | undefined>;
+  setSubtitleTrack: (trackId: number) => unknown;
+  disableSubtitles: () => unknown;
+}
+
+/**
+ * Read the player's real track list, resolve the Jellyfin subtitle index by
+ * identity ({@link resolveSubtitleTrack}) and apply the result. Single entry point
+ * for both the mobile controls and the player screen, so selection stays
+ * consistent everywhere. Returns the resolution for callers that want to react.
+ */
+export const applyMpvSubtitleSelection = async (
+  player: SubtitleSelectablePlayer | null | undefined,
+  params: {
+    subtitleStreams: MediaStream[] | undefined;
+    jellyfinSubtitleIndex: number;
+    /** Build the exact URL/path an external sub was loaded into the player with. */
+    getExpectedExternalUrl?: (sub: MediaStream) => string | undefined;
+  },
+): Promise<SubtitleSelection> => {
+  if (!player) return { kind: "notFound" };
+
+  // Called fire-and-forget (`void applyMpvSubtitleSelection(...)`), so any native
+  // rejection from getSubtitleTracks/setSubtitleTrack/disableSubtitles must be
+  // swallowed here instead of escaping as an unhandled promise rejection.
+  try {
+    const tracks = (await player.getSubtitleTracks()) ?? [];
+    const selection = resolveSubtitleTrack({
+      subtitleStreams: params.subtitleStreams,
+      jellyfinSubtitleIndex: params.jellyfinSubtitleIndex,
+      playerTracks: tracks.map((t) => ({
+        id: t.id,
+        external: t.external,
+        externalFilename: t.externalFilename,
+        language: t.lang,
+        title: t.title,
+        codec: t.codec,
+      })),
+      getExpectedExternalUrl: params.getExpectedExternalUrl,
+    });
+
+    if (selection.kind === "select") {
+      await player.setSubtitleTrack(selection.trackId);
+    } else if (selection.kind === "disable") {
+      await player.disableSubtitles();
+    }
+    // notFound → leave current selection (e.g. image subs burned in while transcoding)
+    return selection;
+  } catch {
+    return { kind: "notFound" };
+  }
 };
 
 /**

utils/profiles/download.ts

@@ -3,17 +3,17 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
-import { generateDeviceProfile } from "./native";
-
-/**
- * @typedef {"auto" | "stereo" | "5.1" | "passthrough"} AudioTranscodeModeType
- */
+import type {
+  DeviceProfile,
+  SubtitleProfile,
+} from "@jellyfin/sdk/lib/generated-client/models";
+import { type AudioTranscodeModeType, generateDeviceProfile } from "./native";
 
 /**
  * Download-specific subtitle profiles.
  * These are more permissive than streaming profiles since we can embed subtitles.
  */
-const downloadSubtitleProfiles = [
+const downloadSubtitleProfiles: SubtitleProfile[] = [
   // Official formats
   { Format: "vtt", Method: "Encode" },
   { Format: "webvtt", Method: "Encode" },
@@ -46,11 +46,10 @@ const downloadSubtitleProfiles = [
 /**
  * Generates a device profile optimized for downloads.
  * Uses the same audio codec logic as streaming but with download-specific bitrate limits.
- *
- * @param {AudioTranscodeModeType} [audioMode="auto"] - Audio transcoding mode
- * @returns {Object} Jellyfin device profile for downloads
  */
-export const generateDownloadProfile = (audioMode = "auto") => {
+export const generateDownloadProfile = (
+  audioMode: AudioTranscodeModeType = "auto",
+): DeviceProfile => {
   // Get the base profile with proper audio codec configuration
   const baseProfile = generateDeviceProfile({ audioMode });
 

utils/profiles/native.ts

@@ -3,6 +3,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
+import type { DeviceProfile } from "@jellyfin/sdk/lib/generated-client/models";
 import { Platform } from "react-native";
 import MediaTypes from "../../constants/MediaTypes";
 import { getSubtitleProfiles } from "./subtitles";
@@ -193,7 +194,7 @@ export const generateDeviceProfile = (options: ProfileOptions = {}) => {
       },
     ],
     SubtitleProfiles: getSubtitleProfiles(),
-  };
+  } satisfies DeviceProfile;
 
   return profile;
 };

utils/profiles/subtitles.ts

@@ -3,6 +3,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
+import type { SubtitleProfile } from "@jellyfin/sdk/lib/generated-client/models";
 
 // Image-based formats - these need to be burned in by Jellyfin (Encode method)
 // because MPV cannot load them externally over HTTP
@@ -13,7 +14,7 @@ const IMAGE_BASED_FORMATS = [
   "pgssub",
   "teletext",
   "vobsub",
-];
+] as const;
 
 // Text-based formats - these can be loaded externally by MPV
 const TEXT_BASED_FORMATS = [
@@ -37,10 +38,10 @@ const TEXT_BASED_FORMATS = [
   "text",
   "vplayer",
   "xsub",
-];
+] as const;
 
-export const getSubtitleProfiles = () => {
-  const profiles = [];
+export const getSubtitleProfiles = (): SubtitleProfile[] => {
+  const profiles: SubtitleProfile[] = [];
 
   // Image-based formats: Embed or Encode (burn-in), NOT External
   for (const format of IMAGE_BASED_FORMATS) {
@@ -58,4 +59,4 @@ export const getSubtitleProfiles = () => {
 };
 
 // Export for use in player filtering
-export const IMAGE_SUBTITLE_CODECS = IMAGE_BASED_FORMATS;
+export const IMAGE_SUBTITLE_CODECS: readonly string[] = IMAGE_BASED_FORMATS;

utils/profiles/trackplayer.d.ts

@@ -1,19 +0,0 @@
-/**
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/.
- */
-
-export type PlatformType = "ios" | "android";
-
-export interface TrackPlayerProfileOptions {
-  /** Target platform */
-  platform?: PlatformType;
-}
-
-export function generateTrackPlayerProfile(
-  options?: TrackPlayerProfileOptions,
-): any;
-
-declare const _default: any;
-export default _default;

utils/profiles/trackplayer.ts

@@ -3,23 +3,25 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
+import type {
+  CodecProfile,
+  DeviceProfile,
+  DirectPlayProfile,
+} from "@jellyfin/sdk/lib/generated-client/models";
 import { Platform } from "react-native";
 import MediaTypes from "../../constants/MediaTypes";
+import type { PlatformType } from "./native";
 
-/**
- * @typedef {"ios" | "android"} PlatformType
- *
- * @typedef {Object} TrackPlayerProfileOptions
- * @property {PlatformType} [platform] - Target platform
- */
+export interface TrackPlayerProfileOptions {
+  /** Target platform */
+  platform?: PlatformType;
+}
 
 /**
  * Audio direct play profiles for react-native-track-player.
  * iOS uses AVPlayer, Android uses ExoPlayer - each has different codec support.
- *
- * @param {PlatformType} platform
  */
-const getDirectPlayProfile = (platform) => {
+const getDirectPlayProfile = (platform: PlatformType): DirectPlayProfile => {
   if (platform === "ios") {
     // iOS AVPlayer supported formats
     return {
@@ -39,10 +41,8 @@ const getDirectPlayProfile = (platform) => {
 
 /**
  * Audio codec profiles for react-native-track-player.
- *
- * @param {PlatformType} platform
  */
-const getCodecProfile = (platform) => {
+const getCodecProfile = (platform: PlatformType): CodecProfile => {
   if (platform === "ios") {
     // iOS AVPlayer codec constraints
     return {
@@ -64,12 +64,11 @@ const getCodecProfile = (platform) => {
  * This profile is specifically for standalone audio playback using:
  * - AVPlayer on iOS
  * - ExoPlayer on Android
- *
- * @param {TrackPlayerProfileOptions} [options] - Profile configuration options
- * @returns {Object} Jellyfin device profile for track player
  */
-export const generateTrackPlayerProfile = (options = {}) => {
-  const platform = options.platform || Platform.OS;
+export const generateTrackPlayerProfile = (
+  options: TrackPlayerProfileOptions = {},
+): DeviceProfile => {
+  const platform = (options.platform || Platform.OS) as PlatformType;
 
   return {
     Name: "Track Player",