diff --git a/services/node-agent/index.js b/services/node-agent/index.js
index 04b7526..4d1b842 100644
--- a/services/node-agent/index.js
+++ b/services/node-agent/index.js
@@ -75,6 +75,8 @@ let _dcBridge        = null;   // ChildProcess | null
 let _dcSidecarCount  = 0;      // active deltacast sidecars on this node
 // Map containerId -> sourceType so stop() can decrement the deltacast counter.
 const _containerSourceType = new Map();
+// port -> fmt JSON from bridge stderr (inject into sidecar env)
+const _dcPortFmt = new Map();
 
 function _dcBridgeRunning() {
   return _dcBridge !== null && _dcBridge.exitCode === null && _dcBridge.signalCode === null;
@@ -104,8 +106,12 @@ function startDeltacastBridge() {
       const t = line.trim();
       if (!t) continue;
       // Format JSON lines go to stdout so node-agent can log/forward them.
-      if (t.startsWith('{')) console.log('[dc-bridge] ' + t);
-      else                   console.error('[dc-bridge] ' + t);
+      if (t.startsWith('{')) {
+        console.log('[dc-bridge] ' + t);
+        try { const f = JSON.parse(t); if (typeof f.port === 'number') _dcPortFmt.set(f.port, f); } catch (_) {}
+      } else {
+        console.error('[dc-bridge] ' + t);
+      }
     }
   });
 
@@ -273,6 +279,18 @@ async function handleSidecarStart(body, res) {
     if (sourceType === 'deltacast') {
       _dcSidecarCount++;
       startDeltacastBridge();
+      // Inject per-port signal format so capture-manager uses real dimensions/fps
+      const _srcCfg = (env.find(e => e.startsWith('SOURCE_CONFIG=')) || '').slice(14);
+      let _portNum = NaN;
+      try { _portNum = JSON.parse(_srcCfg).port; } catch (_) {}
+      if (Number.isFinite(_portNum) && _dcPortFmt.has(_portNum)) {
+        const _fmt = _dcPortFmt.get(_portNum);
+        const _fps = (_fmt.fps_den && _fmt.fps_den !== 1) ? `${_fmt.fps_num}/${_fmt.fps_den}` : String(_fmt.fps_num);
+        sidecarEnv.push(`DELTACAST_VIDEO_SIZE=${_fmt.width}x${_fmt.height}`);
+        sidecarEnv.push(`DELTACAST_FRAMERATE=${_fps}`);
+        sidecarEnv.push(`DELTACAST_INTERLACED=${_fmt.interlaced ? '1' : '0'}`);
+        console.log(`[dc-bridge] port ${_portNum} fmt: ${_fmt.width}x${_fmt.height} ${_fps} interlaced=${_fmt.interlaced}`);
+      }
     }
 
     let containerId;