diff --git a/src/features/viewer/VideoPlayer.tsx b/src/features/viewer/VideoPlayer.tsx
index e63d936..beb699b 100644
--- a/src/features/viewer/VideoPlayer.tsx
+++ b/src/features/viewer/VideoPlayer.tsx
@@ -52,11 +52,23 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
   const [rate, setRate] = createSignal(1);
   const [fullscreen, setFullscreen] = createSignal(false);
   const [controlsShown, setControlsShown] = createSignal(true);
+  // <video> 요소가 보고한 길이 (직접 재생 시 메타데이터보다 정확·항상 존재)
+  const [elDuration, setElDuration] = createSignal(0);
+  // 스트림 시크 중 표시 위치 고정용 (null이면 실제 재생 위치 사용)
+  const [seekingTo, setSeekingTo] = createSignal<number | null>(null);
   let jobId: number | undefined;
   let hideTimer: ReturnType<typeof setTimeout> | undefined;
+  let streamSeekTimer: ReturnType<typeof setTimeout> | undefined;
 
-  const durationSec = () => (pb()?.durationMs ?? 0) / 1000;
   const isStream = () => plan()?.mode === "stream";
+  // 재생 길이: 직접 모드는 요소 duration이 진실(메타 없어도 시크바 동작),
+  // 스트림 모드는 -ss로 잘린 요소 duration이 부정확하므로 메타데이터 우선.
+  const durationSec = () => {
+    const meta = (pb()?.durationMs ?? 0) / 1000;
+    const ed = elDuration();
+    if (isStream()) return meta > 0 ? meta : ed;
+    return ed > 0 ? ed : meta;
+  };
 
   const cleanupJob = () => {
     if (jobId != null) {
@@ -80,9 +92,12 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
     const app = appInfoSig();
     if (!p || !app) return;
     cleanupJob();
+    clearTimeout(streamSeekTimer);
     setSeekBase(0);
     setCurrent(0);
     setBuffered(0);
+    setSeekingTo(null);
+    setElDuration(0);
     const decided = decidePlayback(p);
     setPlan(decided);
     if (decided.mode === "direct") {
@@ -106,6 +121,7 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
   onCleanup(() => {
     cleanupJob();
     clearTimeout(hideTimer);
+    clearTimeout(streamSeekTimer);
   });
 
   // ── 재생 제어 ──
@@ -119,12 +135,15 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
     const p = plan();
     if (!p) return;
     const clamped = Math.max(0, Math.min(durationSec() || t, t));
+    setCurrent(clamped);
     if (p.mode === "direct") {
+      setSeekingTo(null);
       if (videoRef) videoRef.currentTime = clamped;
-      setCurrent(clamped);
     } else if (p.mode === "stream") {
-      setCurrent(clamped);
-      void startStreamAt(clamped, p.video, p.audio);
+      // ffmpeg 재시작은 비싸다 — 연속 시크(드래그·연타)는 마지막 위치로 합쳐 한 번만 재시작.
+      setSeekingTo(clamped);
+      clearTimeout(streamSeekTimer);
+      streamSeekTimer = setTimeout(() => void startStreamAt(clamped, p.video, p.audio), 250);
     }
   };
 
@@ -162,17 +181,19 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
   };
 
   // ── 시크바 상호작용 ──
-  const seekFromPointer = (clientX: number) => {
-    if (!barRef) return;
+  const posToTime = (clientX: number): number => {
+    if (!barRef) return 0;
     const rect = barRef.getBoundingClientRect();
     const ratio = Math.max(0, Math.min(1, (clientX - rect.left) / rect.width));
-    seekTo(ratio * (durationSec() || 0));
+    return ratio * (durationSec() || 0);
   };
 
   const onBarPointerDown = (e: PointerEvent) => {
+    if (durationSec() <= 0) return; // 길이 미상이면 시크 불가
     e.preventDefault();
-    seekFromPointer(e.clientX);
-    const move = (me: PointerEvent) => seekFromPointer(me.clientX);
+    // 드래그 중엔 표시 위치만 즉시 갱신(seekTo가 setCurrent). 스트림은 손 뗄 때 한 번만 재시작.
+    seekTo(posToTime(e.clientX));
+    const move = (me: PointerEvent) => seekTo(posToTime(me.clientX));
     const up = () => {
       window.removeEventListener("pointermove", move);
       window.removeEventListener("pointerup", up);
@@ -263,13 +284,21 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
   });
 
   const onTimeUpdate = () => {
-    setCurrent(seekBase() + (videoRef?.currentTime ?? 0));
+    // 스트림 시크가 예정된 동안(재시작 전)엔 표시 위치를 고정 — 옛 스트림이 되돌리지 않게.
+    if (seekingTo() == null) {
+      setCurrent(seekBase() + (videoRef?.currentTime ?? 0));
+    }
     // 버퍼 끝(직접 모드)
     if (videoRef && videoRef.buffered.length > 0 && !isStream()) {
       setBuffered(videoRef.buffered.end(videoRef.buffered.length - 1));
     }
   };
 
+  const onLoadedMeta = () => {
+    const d = videoRef?.duration ?? 0;
+    setElDuration(Number.isFinite(d) && d > 0 ? d : 0);
+  };
+
   const rateLabel = () => (rate() === 1 ? "1x" : `${rate()}x`);
 
   return (
@@ -296,6 +325,8 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
           playsinline
           onTimeUpdate={onTimeUpdate}
           onProgress={onTimeUpdate}
+          onLoadedMetadata={onLoadedMeta}
+          onDurationChange={onLoadedMeta}
           onPlay={() => {
             setPlaying(true);
             showControls();
@@ -306,7 +337,10 @@ export const VideoPlayer: Component<{ fileId: number }> = (props) => {
             clearTimeout(hideTimer);
           }}
           onWaiting={() => setWaiting(true)}
-          onPlaying={() => setWaiting(false)}
+          onPlaying={() => {
+            setWaiting(false);
+            setSeekingTo(null); // 시크 후 새 스트림 재생 시작 → 표시 위치 고정 해제
+          }}
           onCanPlay={() => setWaiting(false)}
           onEnded={onEnded}
           onClick={togglePlay}