diff --git a/src/background/index.ts b/src/background/index.ts
index 20b987b..7053737 100644
--- a/src/background/index.ts
+++ b/src/background/index.ts
@@ -9,12 +9,11 @@ import JSZip from 'jszip';
 
 const logger = new Logger('Main');
 
-// Константы
-const VIDEO_BUFFER_DURATION_MS = 30 * 1000; // 30 секунд
-
 // Состояние
+// videoBuffer is a placeholder array on the SW side; Plan 04 wires it to
+// fetch from the offscreen recorder over the 'video-keepalive' port.
+// Until then it stays empty (the offscreen owns the real buffer per D-16).
 let videoBuffer: VideoChunk[] = [];
-let firstChunkSaved = false; // Флаг что первый чанк уже сохранен
 let isRecording = false;
 let offscreenCreated = false;
 let lastScreenshotTime = 0;
@@ -22,57 +21,9 @@ let cachedScreenshot: Blob | null = null;
 // userEvents хранится только в content script
 // Для архивации получаем его оттуда
 
-// Кольцевой буфер видео
-function addVideoChunkFromBlob(blob: Blob) {
-  logger.log(`Processing video chunk from Blob, size: ${blob.size} bytes, type: ${blob.type}`);
-
-  const chunk: VideoChunk = {
-    data: blob,
-    timestamp: Date.now(),
-    isFirst: !firstChunkSaved // Первый чанк помечаем как isFirst
-  };
-
-  if (!firstChunkSaved) {
-    firstChunkSaved = true;
-    logger.log(`This is the FIRST video chunk (WebM header), size: ${blob.size} bytes`);
-  }
-
-  videoBuffer.push(chunk);
-  logger.log(`Added video chunk, buffer size: ${videoBuffer.length}, chunk size: ${blob.size} bytes, isFirst: ${chunk.isFirst}`);
-
-  // Удаляем старые чанки
-  cleanupVideoBuffer();
-}
-
-function cleanupVideoBuffer() {
-  const now = Date.now();
-  const beforeCount = videoBuffer.length;
-
-  logger.log(`Cleaning up buffer, current size: ${beforeCount}`);
-
-  // Всегда сохраняем первый чанк (WebM заголовок, помечен как isFirst)
-  // Остальные чанки фильтруем по времени (старше 30 секунд удаляем)
-  videoBuffer = videoBuffer.filter(chunk => {
-    // Всегда оставляем первый чанк (заголовок)
-    if (chunk.isFirst) {
-      return true;
-    }
-    // Остальные - только если моложе 30 секунд
-    const age = now - chunk.timestamp;
-    const keep = age < VIDEO_BUFFER_DURATION_MS;
-    if (!keep) {
-      logger.log(`Removing chunk, age: ${age}ms, limit: ${VIDEO_BUFFER_DURATION_MS}ms`);
-    }
-    return keep;
-  });
-
-  const removed = beforeCount - videoBuffer.length;
-  if (removed > 0) {
-    logger.log(`Removed ${removed} old video chunks, buffer: ${videoBuffer.length}`);
-  } else {
-    logger.log(`No chunks removed, buffer: ${videoBuffer.length}`);
-  }
-}
+// addVideoChunkFromBlob / cleanupVideoBuffer / VIDEO_BUFFER_DURATION_MS
+// removed in plan 01-03: the ring buffer now lives in src/offscreen/recorder.ts
+// (D-16). Plan 05 collapses the remaining SW shell further.
 
 // Создание offscreen документа
 async function ensureOffscreen() {
@@ -454,23 +405,13 @@ chrome.runtime.onMessage.addListener((message: Message, _sender, sendResponse) =
       });
       return true;
 
-    case 'VIDEO_CHUNK':
-      const videoData = (message as any).data;
-      const videoTimestamp = (message as any).timestamp;
-      if (videoData && videoData.size > 0) {
-        logger.log(`Received video chunk from offscreen, size: ${videoData.size} bytes, timestamp: ${videoTimestamp}`);
-        addVideoChunkFromBlob(videoData);
-      } else {
-        logger.warn('Received empty or invalid video chunk');
-      }
-      return false;
-
-    case 'VIDEO_CHUNK_SAVED':
-      const chunkId = (message as any).chunkId;
-      const size = (message as any).size;
-      logger.log(`Video chunk ${chunkId} saved, size: ${size} bytes, loading from IndexedDB...`);
-      loadChunkFromIndexedDB(chunkId);
-      return false;
+    // VIDEO_CHUNK and VIDEO_CHUNK_SAVED handlers removed in plan 01-03:
+    //   - the offscreen recorder now owns the buffer (D-16);
+    //   - chunks no longer travel via chrome.runtime.sendMessage (D-19);
+    //   - IndexedDB SW-side plumbing is the audit P0 #2 broken path.
+    // loadChunkFromIndexedDB / openIndexedDB also removed inline (they
+    // were only reachable from the deleted VIDEO_CHUNK_SAVED branch).
+    // Plan 05 collapses the remaining SW dead code further.
 
     default:
       logger.warn('Unknown message type:', message.type);
@@ -478,47 +419,6 @@ chrome.runtime.onMessage.addListener((message: Message, _sender, sendResponse) =
   }
 });
 
-// IndexedDB для загрузки видеочанков
-async function loadChunkFromIndexedDB(chunkId: number) {
-  try {
-    const db = await openIndexedDB();
-    const transaction = db.transaction(['chunks'], 'readonly');
-    const store = transaction.objectStore('chunks');
-    const request = store.get(chunkId);
-
-    request.onsuccess = () => {
-      const record = request.result;
-      if (record) {
-        logger.log(`Loaded chunk ${chunkId} from IndexedDB, size: ${record.data.size} bytes`);
-        addVideoChunkFromBlob(record.data);
-      } else {
-        logger.error(`Chunk ${chunkId} not found in IndexedDB`);
-      }
-    };
-
-    request.onerror = () => {
-      logger.error(`Error loading chunk ${chunkId} from IndexedDB:`, request.error);
-    };
-  } catch (error) {
-    logger.error(`Failed to open IndexedDB:`, error);
-  }
-}
-
-async function openIndexedDB(): Promise<IDBDatabase> {
-  return new Promise((resolve, reject) => {
-    const request = indexedDB.open('VideoRecorderDB', 1);
-
-    request.onerror = () => reject(request.error);
-    request.onsuccess = () => resolve(request.result);
-    request.onupgradeneeded = (event) => {
-      const db = (event.target as IDBOpenDBRequest).result;
-      if (!db.objectStoreNames.contains('chunks')) {
-        db.createObjectStore('chunks', { keyPath: 'id' });
-      }
-    };
-  });
-}
-
 // Инициализация
 function initialize() {
   logger.log('Service Worker initializing');
diff --git a/src/shared/types.ts b/src/shared/types.ts
index 212d905..b6f0ec8 100644
--- a/src/shared/types.ts
+++ b/src/shared/types.ts
@@ -13,8 +13,6 @@ export type MessageType =
   | 'START_RECORDING'
   | 'STOP_RECORDING'
   | 'RECORDING_ERROR'
-  | 'VIDEO_CHUNK'
-  | 'VIDEO_CHUNK_SAVED'
   | 'OFFSCREEN_READY';
 
 export interface Message<T = any> {
@@ -23,6 +21,17 @@ export interface Message<T = any> {
   tabId?: number;
 }
 
+// Типы сообщений в long-lived port (offscreen ↔ SW; D-17 / Plan 04)
+export type PortMessageType =
+  | 'PING'
+  | 'REQUEST_BUFFER'
+  | 'BUFFER';
+
+export interface PortMessage {
+  type: PortMessageType;
+  chunks?: VideoChunk[];
+}
+
 // Видеобуфер
 export interface VideoChunk {
   data: Blob;