feat(playback): report Embedded MPV file chapters on the timeline (#1771)

apps/electron-backend/native/helper/mpv_frame_helper.cpp

@@ -55,6 +55,12 @@ struct TrackInfo {
     bool forced = false;
 };
 
+/* One entry of mpv's `chapter-list`: start time and optional title. */
+struct ChapterInfo {
+    double timeSeconds = 0;
+    std::string title;
+};
+
 struct SnapshotState {
     std::string status = "idle";
     double positionSeconds = 0;
@@ -118,6 +124,7 @@ struct SnapshotState {
     int64_t selectedAudioTrackId = -1;
     std::vector<TrackInfo> subtitleTracks;
     int64_t selectedSubtitleTrackId = -1;
+    std::vector<ChapterInfo> chapters;
     double playbackSpeed = 1;
     std::string aspectOverride = "no";
     bool recordingActive = false;
@@ -187,6 +194,21 @@ std::string tracksJson(const std::vector<TrackInfo>& tracks,
     return out;
 }
 
+std::string chaptersJson(const std::vector<ChapterInfo>& chapters) {
+    std::string out = "[";
+    bool first = true;
+    for (const ChapterInfo& chapter : chapters) {
+        JsonWriter writer;
+        writer.num("timeSeconds", chapter.timeSeconds);
+        if (!chapter.title.empty()) writer.str("title", chapter.title);
+        if (!first) out += ',';
+        first = false;
+        out += writer.finish();
+    }
+    out += ']';
+    return out;
+}
+
 /* Compose the `stats` object of the snapshot event. Always emitted, even when
  * empty: the adapter merges snapshot events field by field, so an omitted key
  * would leave the previous stream's numbers in place across a channel switch.
@@ -262,6 +284,9 @@ std::string composeSnapshotLocked() {
     } else {
         writer.nullValue("selectedSubtitleTrackId");
     }
+    /* Always emitted: the adapter merges snapshot events field by field, so
+     * an omitted key would keep the previous file's chapters. */
+    writer.raw("chapters", chaptersJson(s.chapters));
     writer.num("playbackSpeed", s.playbackSpeed);
     writer.str("aspectOverride", s.aspectOverride);
     writer.raw("stats", composeStatsJsonLocked());
@@ -383,6 +408,63 @@ void updateTracksFromNode(const mpv_node& trackListNode) {
     g_state.snapshot.subtitleTracks = std::move(subs);
 }
 
+/* Snapshots repeat the chapter list on every emit, so a file with thousands
+ * of chapters or a huge title must not inflate every snapshot. Beyond these
+ * bounds a timeline cannot draw anything useful anyway. */
+constexpr size_t kMaxChapters = 256;
+constexpr size_t kMaxChapterTitleBytes = 256;
+
+/* Cut to at most `maxBytes` without splitting a UTF-8 sequence. */
+std::string truncateUtf8(const char* value, size_t maxBytes) {
+    std::string text = value ? value : "";
+    if (text.size() <= maxBytes) return text;
+    size_t end = maxBytes;
+    while (end > 0 &&
+           (static_cast<unsigned char>(text[end]) & 0xC0) == 0x80) {
+        end--;
+    }
+    text.resize(end);
+    return text;
+}
+
+/* mpv `chapter-list`: an array of { time, title? } maps in file order. */
+void updateChaptersFromNode(const mpv_node& chapterListNode) {
+    std::vector<ChapterInfo> chapters;
+    if (chapterListNode.format == MPV_FORMAT_NODE_ARRAY &&
+        chapterListNode.u.list) {
+        for (int i = 0; i < chapterListNode.u.list->num &&
+                        chapters.size() < kMaxChapters;
+             i++) {
+            const mpv_node& entry = chapterListNode.u.list->values[i];
+            if (entry.format != MPV_FORMAT_NODE_MAP || !entry.u.list) continue;
+            ChapterInfo chapter;
+            bool hasTime = false;
+            const mpv_node_list& map = *entry.u.list;
+            for (int k = 0; k < map.num; k++) {
+                const char* key = map.keys[k];
+                const mpv_node& value = map.values[k];
+                if (!key) continue;
+                if (std::strcmp(key, "time") == 0 &&
+                    value.format == MPV_FORMAT_DOUBLE) {
+                    chapter.timeSeconds = value.u.double_;
+                    hasTime = std::isfinite(chapter.timeSeconds);
+                } else if (std::strcmp(key, "time") == 0 &&
+                           value.format == MPV_FORMAT_INT64) {
+                    chapter.timeSeconds = (double)value.u.int64;
+                    hasTime = true;
+                } else if (std::strcmp(key, "title") == 0 &&
+                           value.format == MPV_FORMAT_STRING &&
+                           value.u.string) {
+                    chapter.title =
+                        truncateUtf8(value.u.string, kMaxChapterTitleBytes);
+                }
+            }
+            if (hasTime) chapters.push_back(std::move(chapter));
+        }
+    }
+    g_state.snapshot.chapters = std::move(chapters);
+}
+
 bool parseTrackSelection(const char* value, int64_t& out) {
     if (!value) return false;
     char* end = nullptr;
@@ -436,6 +518,9 @@ void handlePropertyChange(const mpv_event_property& property) {
     } else if (name == "track-list" && property.format == MPV_FORMAT_NODE &&
                property.data) {
         updateTracksFromNode(*static_cast<mpv_node*>(property.data));
+    } else if (name == "chapter-list" &&
+               property.format == MPV_FORMAT_NODE && property.data) {
+        updateChaptersFromNode(*static_cast<mpv_node*>(property.data));
     } else if (name == "aid" && property.format == MPV_FORMAT_STRING &&
                property.data) {
         int64_t selected = -1;
@@ -536,6 +621,7 @@ void runMpvEventLoop() {
                     s.selectedAudioTrackId = -1;
                     s.subtitleTracks.clear();
                     s.selectedSubtitleTrackId = -1;
+                    s.chapters.clear();
                     g_state.loadedPath = false;
                     markDirtyLocked();
                     break;
@@ -1115,6 +1201,8 @@ int main(int argc, char** argv) {
                          MPV_FORMAT_STRING);
     mpv_observe_property(g_state.mpv, 24, "audio-params/samplerate",
                          MPV_FORMAT_INT64);
+    /* File chapters draw the timeline segments and mark closing credits. */
+    mpv_observe_property(g_state.mpv, 25, "chapter-list", MPV_FORMAT_NODE);
 
     g_state.pipeline.onGenerationChanged = [](const std::string& name,
                                               int width, int height,

apps/electron-backend/native/src/embedded_mpv.mm

@@ -91,6 +91,12 @@ struct AudioTrack {
     bool forced = false;
 };
 
+// One entry of mpv's `chapter-list`: start time and optional title.
+struct Chapter {
+    double timeSeconds = 0.0;
+    std::string title;
+};
+
 struct SessionSnapshot {
     SessionStatus status = SessionStatus::Idle;
     double positionSeconds = 0.0;
@@ -108,6 +114,7 @@ struct SessionSnapshot {
     int64_t selectedAudioTrackId = -1;
     std::vector<AudioTrack> subtitleTracks;
     int64_t selectedSubtitleTrackId = -1;
+    std::vector<Chapter> chapters;
     double playbackSpeed = 1.0;
     std::string aspectOverride = "no";
     // Stream diagnostics for the player's info popover. Sentinels mean "mpv
@@ -1087,6 +1094,67 @@ void updateAudioTracksFromNode(SessionSnapshot& snapshot, const mpv_node& node)
     );
 }
 
+// Snapshots repeat the chapter list on every emit, so a file with thousands
+// of chapters or a huge title must not inflate every snapshot. Beyond these
+// bounds a timeline cannot draw anything useful anyway.
+constexpr size_t kMaxChapters = 256;
+constexpr size_t kMaxChapterTitleBytes = 256;
+
+// Cut to at most `maxBytes` without splitting a UTF-8 sequence.
+std::string truncateUtf8(const std::string& value, size_t maxBytes)
+{
+    std::string text = value;
+    if (text.size() <= maxBytes) return text;
+    size_t end = maxBytes;
+    while (end > 0 &&
+           (static_cast<unsigned char>(text[end]) & 0xC0) == 0x80) {
+        end--;
+    }
+    text.resize(end);
+    return text;
+}
+
+// mpv `chapter-list`: an array of { time, title? } maps in file order.
+void updateChaptersFromNode(SessionSnapshot& snapshot, const mpv_node& node)
+{
+    snapshot.chapters.clear();
+    if (node.format != MPV_FORMAT_NODE_ARRAY ||
+        !node.u.list ||
+        !node.u.list->values) {
+        return;
+    }
+
+    for (int index = 0;
+         index < node.u.list->num && snapshot.chapters.size() < kMaxChapters;
+         index += 1) {
+        const mpv_node& chapterNode = node.u.list->values[index];
+        if (chapterNode.format != MPV_FORMAT_NODE_MAP) {
+            continue;
+        }
+
+        const mpv_node* timeNode = getNodeMapValue(chapterNode, "time");
+        if (!timeNode) {
+            continue;
+        }
+        Chapter chapter;
+        if (timeNode->format == MPV_FORMAT_DOUBLE) {
+            chapter.timeSeconds = timeNode->u.double_;
+        } else if (timeNode->format == MPV_FORMAT_INT64) {
+            chapter.timeSeconds = static_cast<double>(timeNode->u.int64);
+        } else {
+            continue;
+        }
+        if (!std::isfinite(chapter.timeSeconds)) {
+            continue;
+        }
+        if (const mpv_node* titleNode = getNodeMapValue(chapterNode, "title")) {
+            chapter.title =
+                truncateUtf8(readNodeString(*titleNode), kMaxChapterTitleBytes);
+        }
+        snapshot.chapters.push_back(chapter);
+    }
+}
+
 void updateSubtitleTracksFromNode(SessionSnapshot& snapshot, const mpv_node& node)
 {
     updateTracksFromNode(
@@ -1228,6 +1296,7 @@ void runEventLoop(const std::shared_ptr<Session>& session)
                 session->snapshot.selectedAudioTrackId = -1;
                 session->snapshot.subtitleTracks.clear();
                 session->snapshot.selectedSubtitleTrackId = -1;
+                session->snapshot.chapters.clear();
                 session->loadedPath = false;
                 break;
             case MPV_EVENT_FILE_LOADED:
@@ -1354,6 +1423,16 @@ void runEventLoop(const std::shared_ptr<Session>& session)
                     break;
                 }
 
+                if (propertyName == "chapter-list" &&
+                    property->format == MPV_FORMAT_NODE &&
+                    property->data) {
+                    updateChaptersFromNode(
+                        session->snapshot,
+                        *static_cast<mpv_node*>(property->data)
+                    );
+                    break;
+                }
+
                 if (propertyName == "aid" &&
                     property->format == MPV_FORMAT_STRING &&
                     property->data) {
@@ -1993,6 +2072,8 @@ Napi::Value CreateSession(const Napi::CallbackInfo& info)
         "audio-params/samplerate",
         MPV_FORMAT_INT64
     );
+    // File chapters draw the timeline segments and mark closing credits.
+    mpv_observe_property(session->handle, 23, "chapter-list", MPV_FORMAT_NODE);
 
     session->running.store(true);
     session->eventThread = std::thread(runEventLoop, session);
@@ -2818,6 +2899,21 @@ Napi::Value GetSessionSnapshot(const Napi::CallbackInfo& info)
     }
     result.Set("subtitleTracks", subtitleTracks);
 
+    auto chapters = Napi::Array::New(env, snapshot.chapters.size());
+    for (size_t index = 0; index < snapshot.chapters.size(); index += 1) {
+        const Chapter& chapter = snapshot.chapters[index];
+        auto chapterObject = Napi::Object::New(env);
+        chapterObject.Set(
+            "timeSeconds",
+            Napi::Number::New(env, chapter.timeSeconds)
+        );
+        if (!chapter.title.empty()) {
+            chapterObject.Set("title", Napi::String::New(env, chapter.title));
+        }
+        chapters.Set(index, chapterObject);
+    }
+    result.Set("chapters", chapters);
+
     result.Set(
         "playbackSpeed",
         Napi::Number::New(env, snapshot.playbackSpeed)

apps/electron-backend/native/src/embedded_mpv_wid_common.h

@@ -112,6 +112,12 @@ struct AudioTrack {
     bool forced = false;
 };
 
+/** One entry of mpv's `chapter-list`: start time and optional title. */
+struct Chapter {
+    double timeSeconds = 0.0;
+    std::string title;
+};
+
 struct SessionSnapshot {
     SessionStatus status = SessionStatus::Idle;
     double positionSeconds = 0.0;
@@ -125,6 +131,8 @@ struct SessionSnapshot {
     int64_t selectedAudioTrackId = -1;
     std::vector<AudioTrack> subtitleTracks;
     int64_t selectedSubtitleTrackId = -1;
+    /** libmpv backend only; the Linux `--wid` poller does not read it. */
+    std::vector<Chapter> chapters;
     double playbackSpeed = 1.0;
     std::string aspectOverride = "no";
     /** Stream diagnostics for the player's info popover. Sentinels mean "not
@@ -1400,6 +1408,65 @@ void updateAudioTracksFromNode(SessionSnapshot& snapshot, const mpv_node& node)
     }
 }
 
+/* Snapshots repeat the chapter list on every emit, so a file with thousands
+ * of chapters or a huge title must not inflate every snapshot. Beyond these
+ * bounds a timeline cannot draw anything useful anyway. */
+constexpr size_t kMaxChapters = 256;
+constexpr size_t kMaxChapterTitleBytes = 256;
+
+/* Cut to at most `maxBytes` without splitting a UTF-8 sequence. */
+std::string truncateUtf8(const std::string& value, size_t maxBytes)
+{
+    std::string text = value;
+    if (text.size() <= maxBytes) return text;
+    size_t end = maxBytes;
+    while (end > 0 &&
+           (static_cast<unsigned char>(text[end]) & 0xC0) == 0x80) {
+        end--;
+    }
+    text.resize(end);
+    return text;
+}
+
+/** mpv `chapter-list`: an array of { time, title? } maps in file order. */
+void updateChaptersFromNode(SessionSnapshot& snapshot, const mpv_node& node)
+{
+    snapshot.chapters.clear();
+    if (node.format != MPV_FORMAT_NODE_ARRAY || !node.u.list ||
+        !node.u.list->values) {
+        return;
+    }
+
+    for (int index = 0;
+         index < node.u.list->num && snapshot.chapters.size() < kMaxChapters;
+         index += 1) {
+        const mpv_node& chapterNode = node.u.list->values[index];
+        if (chapterNode.format != MPV_FORMAT_NODE_MAP) {
+            continue;
+        }
+        const mpv_node* timeNode = getNodeMapValue(chapterNode, "time");
+        if (!timeNode) {
+            continue;
+        }
+        Chapter chapter;
+        if (timeNode->format == MPV_FORMAT_DOUBLE) {
+            chapter.timeSeconds = timeNode->u.double_;
+        } else if (timeNode->format == MPV_FORMAT_INT64) {
+            chapter.timeSeconds = static_cast<double>(timeNode->u.int64);
+        } else {
+            continue;
+        }
+        if (!std::isfinite(chapter.timeSeconds)) {
+            continue;
+        }
+        if (const mpv_node* titleNode = getNodeMapValue(chapterNode, "title")) {
+            chapter.title =
+                truncateUtf8(readNodeString(*titleNode), kMaxChapterTitleBytes);
+        }
+        snapshot.chapters.push_back(chapter);
+    }
+}
+
 void updateSubtitleTracksFromNode(SessionSnapshot& snapshot, const mpv_node& node)
 {
     snapshot.subtitleTracks = readTracksOfType(node, "sub");
@@ -1498,6 +1565,7 @@ void runEventLoop(std::shared_ptr<Session> session)
                 session->snapshot.status = SessionStatus::Loading;
                 session->snapshot.error.clear();
                 session->snapshot.clearStreamStats();
+                session->snapshot.chapters.clear();
                 break;
             case MPV_EVENT_FILE_LOADED:
                 session->snapshot.status =
@@ -1580,6 +1648,10 @@ void runEventLoop(std::shared_ptr<Session> session)
                         *static_cast<mpv_node*>(property->data);
                     updateAudioTracksFromNode(session->snapshot, node);
                     updateSubtitleTracksFromNode(session->snapshot, node);
+                } else if (name == "chapter-list" && property->format == MPV_FORMAT_NODE) {
+                    updateChaptersFromNode(
+                        session->snapshot,
+                        *static_cast<mpv_node*>(property->data));
                 } else if (name == "aid") {
                     const char* rawValue = property->format == MPV_FORMAT_STRING
                         ? *static_cast<char**>(property->data)
@@ -1918,6 +1990,8 @@ Napi::Value CreateSession(const Napi::CallbackInfo& info)
         session->handle, 21, "audio-params/channels", MPV_FORMAT_STRING);
     mpv_observe_property(
         session->handle, 22, "audio-params/samplerate", MPV_FORMAT_INT64);
+    /* File chapters draw the timeline segments and mark closing credits. */
+    mpv_observe_property(session->handle, 23, "chapter-list", MPV_FORMAT_NODE);
 
     session->running.store(true);
     session->eventThread = std::thread(runEventLoop, session);
@@ -2624,6 +2698,17 @@ Napi::Value GetSessionSnapshot(const Napi::CallbackInfo& info)
         result.Set("selectedSubtitleTrackId", env.Null());
     }
     writeTracks(env, result, "subtitleTracks", snapshot.subtitleTracks);
+    auto chapters = Napi::Array::New(env, snapshot.chapters.size());
+    for (size_t index = 0; index < snapshot.chapters.size(); index += 1) {
+        const Chapter& chapter = snapshot.chapters[index];
+        auto chapterObject = Napi::Object::New(env);
+        chapterObject.Set("timeSeconds", Napi::Number::New(env, chapter.timeSeconds));
+        if (!chapter.title.empty()) {
+            chapterObject.Set("title", Napi::String::New(env, chapter.title));
+        }
+        chapters.Set(index, chapterObject);
+    }
+    result.Set("chapters", chapters);
     result.Set("playbackSpeed", Napi::Number::New(env, snapshot.playbackSpeed));
     result.Set("aspectOverride", Napi::String::New(env, snapshot.aspectOverride));
     writeStreamStats(env, result, snapshot);

apps/electron-backend/src/app/services/embedded-mpv-chapters.util.spec.ts

@@ -0,0 +1,61 @@
+import {
+    MAX_EMBEDDED_MPV_CHAPTERS,
+    MAX_EMBEDDED_MPV_CHAPTER_TITLE_LENGTH,
+    normalizeEmbeddedMpvChapters,
+} from './embedded-mpv-chapters.util';
+
+describe('normalizeEmbeddedMpvChapters', () => {
+    it('keeps valid chapters and trims titles', () => {
+        expect(
+            normalizeEmbeddedMpvChapters([
+                { timeSeconds: 0, title: ' Intro ' },
+                { timeSeconds: 12.5 },
+                { timeSeconds: 40, title: '' },
+            ])
+        ).toEqual([
+            { timeSeconds: 0, title: 'Intro' },
+            { timeSeconds: 12.5 },
+            { timeSeconds: 40 },
+        ]);
+    });
+
+    it('drops malformed entries', () => {
+        expect(
+            normalizeEmbeddedMpvChapters([
+                null,
+                'chapter',
+                { title: 'No time' },
+                { timeSeconds: -1 },
+                { timeSeconds: Number.NaN },
+                { timeSeconds: '10' },
+                { timeSeconds: 5, title: 7 },
+            ])
+        ).toEqual([{ timeSeconds: 5 }]);
+    });
+
+    it('bounds the chapter count and title length', () => {
+        const chapters = normalizeEmbeddedMpvChapters(
+            Array.from({ length: MAX_EMBEDDED_MPV_CHAPTERS + 50 }, (_, i) => ({
+                timeSeconds: i,
+                title: '😀'.repeat(MAX_EMBEDDED_MPV_CHAPTER_TITLE_LENGTH + 5),
+            }))
+        );
+
+        expect(chapters).toHaveLength(MAX_EMBEDDED_MPV_CHAPTERS);
+        expect(chapters.at(-1)?.timeSeconds).toBe(
+            MAX_EMBEDDED_MPV_CHAPTERS - 1
+        );
+        // Cut by code point, so no surrogate pair is split.
+        expect(Array.from(chapters[0].title ?? '')).toHaveLength(
+            MAX_EMBEDDED_MPV_CHAPTER_TITLE_LENGTH
+        );
+        expect(chapters[0].title).toBe(
+            '😀'.repeat(MAX_EMBEDDED_MPV_CHAPTER_TITLE_LENGTH)
+        );
+    });
+
+    it('treats a missing field from an older binary as no chapters', () => {
+        expect(normalizeEmbeddedMpvChapters(undefined)).toEqual([]);
+        expect(normalizeEmbeddedMpvChapters({})).toEqual([]);
+    });
+});

apps/electron-backend/src/app/services/embedded-mpv-chapters.util.ts

@@ -0,0 +1,51 @@
+import type { EmbeddedMpvChapter } from '@iptvnator/shared/interfaces';
+
+/**
+ * Every session update repeats the list, so a chapter-heavy file must not
+ * inflate each IPC payload; the native parsers apply the same bounds.
+ */
+export const MAX_EMBEDDED_MPV_CHAPTERS = 256;
+export const MAX_EMBEDDED_MPV_CHAPTER_TITLE_LENGTH = 256;
+
+/**
+ * Validate the addon's or helper's `chapters` snapshot field before it
+ * reaches the renderer: an older binary omits it, and a malformed entry must
+ * not draw a segment; the list and each title are bounded. Order is left to the renderer's timeline mapping.
+ */
+export function normalizeEmbeddedMpvChapters(
+    value: unknown
+): EmbeddedMpvChapter[] {
+    if (!Array.isArray(value)) {
+        return [];
+    }
+    const chapters: EmbeddedMpvChapter[] = [];
+    for (const entry of value) {
+        if (chapters.length >= MAX_EMBEDDED_MPV_CHAPTERS) {
+            break;
+        }
+        if (!entry || typeof entry !== 'object') {
+            continue;
+        }
+        const { timeSeconds, title } = entry as Record<string, unknown>;
+        if (
+            typeof timeSeconds !== 'number' ||
+            !Number.isFinite(timeSeconds) ||
+            timeSeconds < 0
+        ) {
+            continue;
+        }
+        const trimmedTitle =
+            typeof title === 'string'
+                ? Array.from(title.trim())
+                      .slice(0, MAX_EMBEDDED_MPV_CHAPTER_TITLE_LENGTH)
+                      .join('')
+                      .trim()
+                : '';
+        chapters.push(
+            trimmedTitle
+                ? { timeSeconds, title: trimmedTitle }
+                : { timeSeconds }
+        );
+    }
+    return chapters;
+}

apps/electron-backend/src/app/services/embedded-mpv-frame-copy-protocol.ts

@@ -53,6 +53,7 @@ export function createInitialSnapshot(): NativeEmbeddedMpvSessionSnapshot {
         selectedAudioTrackId: null,
         subtitleTracks: [],
         selectedSubtitleTrackId: null,
+        chapters: [],
         playbackSpeed: 1,
         aspectOverride: 'no',
         recording: { active: false },

apps/electron-backend/src/app/services/embedded-mpv-native.service.spec.ts

@@ -83,6 +83,7 @@ interface MockSnapshot {
     streamUrl: string;
     audioTracks?: never[];
     selectedAudioTrackId?: number | null;
+    chapters?: Array<{ timeSeconds: number; title?: string }>;
     stats?: {
         fps?: number;
         videoBitrateBps?: number;
@@ -580,6 +581,24 @@ describe('EmbeddedMpvNativeService power blocker', () => {
         });
     });
 
+    it('passes validated file chapters through to the renderer session', () => {
+        startSession('s1', snapshot('playing'));
+        addon.getSessionSnapshot.mockReturnValue(
+            snapshot('playing', {
+                chapters: [
+                    { timeSeconds: 0, title: 'Intro' },
+                    { timeSeconds: Number.NaN, title: 'Broken' },
+                    { timeSeconds: 1320, title: 'Credits' },
+                ],
+            })
+        );
+
+        expect(service.setVolume('s1', 1)?.chapters).toEqual([
+            { timeSeconds: 0, title: 'Intro' },
+            { timeSeconds: 1320, title: 'Credits' },
+        ]);
+    });
+
     it('omits the stats key entirely when the engine reports none', () => {
         // An empty object would make the renderer render an empty popover
         // instead of hiding the info button.

apps/electron-backend/src/app/services/embedded-mpv-native.service.ts

@@ -14,6 +14,7 @@ import App from '../app';
 import {
     EmbeddedMpvAudioTrack,
     EmbeddedMpvBounds,
+    EmbeddedMpvChapter,
     EmbeddedMpvCapabilities,
     EmbeddedMpvRecordingStartOptions,
     EmbeddedMpvRecordingState,
@@ -56,6 +57,7 @@ import {
     resolveFrameCopyHelperPath,
 } from './embedded-mpv-frame-copy-platform.util';
 import type { EmbeddedMpvFrameCopyRuntimeMode } from './embedded-mpv-frame-copy-runtime';
+import { normalizeEmbeddedMpvChapters } from './embedded-mpv-chapters.util';
 import {
     EMBEDDED_MPV_EXPERIMENT_ENV,
     isEmbeddedMpvFeatureEnabled,
@@ -71,6 +73,7 @@ export interface NativeEmbeddedMpvSessionSnapshot {
     selectedAudioTrackId?: number | null;
     subtitleTracks?: EmbeddedMpvSubtitleTrack[];
     selectedSubtitleTrackId?: number | null;
+    chapters?: EmbeddedMpvChapter[];
     playbackSpeed?: number;
     aspectOverride?: string;
     videoWidth?: number;
@@ -1237,6 +1240,7 @@ export class EmbeddedMpvNativeService {
                 typeof snapshot.selectedSubtitleTrackId === 'number'
                     ? snapshot.selectedSubtitleTrackId
                     : null,
+            chapters: normalizeEmbeddedMpvChapters(snapshot.chapters),
             playbackSpeed:
                 typeof snapshot.playbackSpeed === 'number'
                     ? snapshot.playbackSpeed