diff --git a/src/cameraSwitch.js b/src/cameraSwitch.js
index 6c435eb..c6c26ef 100644
--- a/src/cameraSwitch.js
+++ b/src/cameraSwitch.js
@@ -232,15 +232,19 @@ class CameraSwitch extends EventEmitter {
       // 1. Live-FFmpeg beenden, auf Prozess-Ende warten (= Device-FD frei)
       await this._killCurrentAndWait();
 
-      // Kurze Pause: v4l2-Buffer der Kamera können noch Frames der alten Live-
-      // Auflösung enthalten (z.B. 640×480-Rest wenn hires 1920×1080 fordert).
-      // 300 ms genügen damit die Kamera den Format-Reset abschliessen kann.
-      await sleep(300);
+      // 2. Kamera resetten: kurz warten, dann zwischenformat öffnen, wieder warten.
+      await sleep(800);
+      const warmupSize = this._chooseWarmupSize();
+      if (warmupSize) {
+        console.log(`[cam ${this.id}] HD: Zwischenformat ${warmupSize} zum Kamera-Reset`);
+        await this._warmupFormat(warmupSize);
+        await sleep(500);
+      }
 
       this.state = 'grabbing';
       console.log(`[cam ${this.id}] HD: Live gestoppt nach ${Date.now() - t0}ms, Gerät frei → ${this.hiresSize}-Grab (minWidth=${minWidth})`);
 
-      // 2. hires-FFmpeg starten, warmlaufen lassen, besten Frame greifen
+      // 3. hires-FFmpeg starten, warmlaufen lassen, besten Frame greifen
       const jpeg = await this._captureHires({ minSize, minWidth, settleFrames, maxWaitMs });
       const gotW = readJpegWidth(jpeg) ?? '?';
       console.log(`[cam ${this.id}] HD OK – ${jpeg.length} bytes, Breite=${gotW}px (Soll: ${hiresW}px, ${Date.now() - t0}ms)`);
@@ -269,10 +273,60 @@ class CameraSwitch extends EventEmitter {
     });
   }
 
+  _chooseWarmupSize() {
+    const liveW = parseInt(this.liveSize.split('x')[0], 10);
+    const hiresW = parseInt(this.hiresSize.split('x')[0], 10);
+    if (Number.isNaN(liveW) || Number.isNaN(hiresW)) return null;
+    if (liveW < 1280 && hiresW >= 1280) return '1280x720';
+    return null;
+  }
+
+  _warmupFormat(size) {
+    return new Promise((resolve) => {
+      const args = [
+        '-hide_banner', '-loglevel', 'warning',
+        '-fflags', 'nobuffer',
+        '-f', 'v4l2', '-input_format', 'mjpeg',
+        '-video_size', size, '-framerate', String(this.hiresFps),
+        '-i', this.device,
+        '-frames:v', '4', '-f', 'null', '-'
+      ];
+      let p;
+      try {
+        p = spawn('ffmpeg', args, { stdio: ['ignore', 'pipe', 'ignore'] });
+      } catch (_e) {
+        return resolve();
+      }
+      this.proc = p;
+      this.stopping = false;
+
+      let finished = false;
+      const done = () => {
+        if (finished) return;
+        finished = true;
+        if (p) {
+          try { p.kill('SIGTERM'); } catch (_e) {}
+        }
+        resolve();
+      };
+
+      p.stderr.on('data', (c) => {
+        const s = c.toString();
+        if (/error|busy|invalid|no such|cannot|denied/i.test(s)) console.error(`[cam ${this.id}] warmup ffmpeg: ${s.trim()}`);
+      });
+      p.on('error', done);
+      p.on('close', done);
+      setTimeout(done, 1600);
+    });
+  }
+
   _captureHires({ minSize, minWidth, settleFrames, maxWaitMs }) {
     return new Promise((resolve, reject) => {
       const args = [
         '-hide_banner', '-loglevel', 'warning',
+        '-fflags', 'nobuffer',
+        '-probesize', '5000000',
+        '-analyzeduration', '1000000',
         '-f', 'v4l2', '-input_format', 'mjpeg',
         '-video_size', this.hiresSize, '-framerate', String(this.hiresFps),
         '-i', this.device,