HighRes von Cam im PC scalen

programs/videoServer.js

@@ -103,14 +103,18 @@ class FFmpegStreamer {
       ...(typeof inChannel === 'number' ? ['-channel', String(inChannel)] : []),
       ...(useWallclock ? ['-use_wallclock_as_timestamps', '1'] : []),
       '-i', this.devicePath,
-      '-fflags', 'nobuffer', '-flags', 'low_delay', '-an', '-sn',
+      //'-fflags', 'nobuffer', '-flags', 'low_delay', '-an', '-sn',
+      '-fflags', 'nobuffer', '-an', '-sn',
     ];
 
     if (inFmt === 'mjpeg' && !scaling) {
       args.push('-vsync', 'passthrough', '-c:v', 'copy', '-f', 'mjpeg', 'pipe:1');
       return args;
     }
-    if (scaling) args.push('-vf', `scale=${Number(this.opts.width)}:${Number(this.opts.height)}`);
+    if (scaling) {
+        args.push('-vf', `scale=${Number(this.opts.width)}:${Number(this.opts.height)}`);
+        args.push('-pix_fmt', 'yuvj422p'); // für mjpeg-Encoder robust
+    }
     if (outFps) args.push('-r', String(outFps));
     args.push('-f', 'mjpeg', '-q:v', String(quality), 'pipe:1');
     return args;
@@ -229,6 +233,53 @@ class FFmpegStreamer {
       try { ws.send(frame, { binary: true }); } catch {}
     }
   }
+
+  /**
+   * Nimmt einen Snapshot in hoher Auflösung auf, unabhängig vom Stream.
+   * Startet kurz einen separaten ffmpeg-Prozess und speichert 1 Frame als JPEG.
+   *
+   * @param {string} toFile - Pfad zur Zieldatei (z.B. '/tmp/snap.jpg')
+   * @param {object} [opts]
+   * @param {string} [opts.size]    - 'WxH' z.B. '1280x960' (Default: opts.input.size)
+   * @param {string} [opts.format]  - z.B. 'mjpeg' | 'yuyv422' (Default: opts.input.format)
+   * @param {number} [opts.quality] - FFmpeg JPEG-Qualität 2..31 (kleiner = besser). Default: 2
+   * @param {number} [opts.timeoutMs] - Abbruch nach ms. Default: 3000
+   */
+  async snapshotHighRes(toFile, { size, format, quality = 2, timeoutMs = 3000 } = {}) {
+    return new Promise((resolve, reject) => {
+      const inFmt = format ?? this.opts.input.format ?? 'mjpeg';
+      const inSize = size ?? this.opts.input.size; // wenn undefined, nimmt ffmpeg die Kamera-Default
+      const fps    = Math.min(5, this.opts.input.fps || 5); // niedrig reicht für Einzelbild
+
+      const args = [
+        '-hide_banner', '-loglevel', 'error',
+        '-f', 'video4linux2',
+        ...(inFmt ? ['-input_format', String(inFmt)] : []),
+        ...(fps ? ['-framerate', String(fps)] : []),
+        ...(inSize ? ['-video_size', String(inSize)] : []),
+        '-i', this.devicePath,
+        '-frames:v', '1',
+        '-q:v', String(quality),
+        '-y', toFile,
+      ];
+
+      const p = spawn('ffmpeg', args, { stdio: ['ignore', 'ignore', 'pipe'] });
+
+      let stderr = '';
+      const t = setTimeout(() => {
+        try { p.kill('SIGKILL'); } catch {}
+        reject(new Error(`snapshotHighRes timeout after ${timeoutMs}ms`));
+      }, timeoutMs);
+
+      p.stderr.on('data', d => { stderr += d.toString(); });
+
+      p.on('close', code => {
+        clearTimeout(t);
+        if (code === 0) resolve(toFile);
+        else reject(new Error(`ffmpeg exited ${code}: ${stderr.trim()}`));
+      });
+    });
+  }
 }
 
 module.exports = { FFmpegStreamer };