{
  "name": "custom-layout-show",
  "sources": [
    {
      "name": "room_src",
      "type": "livekit",
      "config": {
        "serverUrl": "wss://your-project.livekit.cloud",
        "token": "eyJ..."
      }
    }
  ],
  "nodes": [
    {
      "name": "mix_video",
      "type": "video_mixer",
      "inputs": ["room_src"],
      "config": {
        "canvas": {
          "width": 1920, "height": 1080,
          "bgColor": "#0f0f23",
          "bgImage": { "url": "https://cdn.example.com/show-bg.jpg", "fit": "cover" },
          "coordinateSystem": "ratio"
        },
        "layout": {
          "mode": "custom",
          "common": {
            "defaultFit": "cover",
            "defaultPlaceholder": {
              "image": {
                "url": "https://cdn.example.com/default-avatar.png",
                "borderRadius": 999,
                "width": 0.5,
                "height": 0.5,
                "fit": "cover",
                "position": "center"
              },
              "text": { "content": "{name}", "position": "bottom_center", "fontSize": 14, "color": "#fff" }
            }
          },
          "custom": {
            "regions": [
              {
                "name": "main_view",
                "source": { "match": { "identity": "host" } },
                "width": 0.75, "height": 1,
                "style": { "borderRadius": 16, "borderColor": "#ffd700", "borderWidth": 2 },
                "placeholder": {
                  "image": { "url": "https://cdn.example.com/host-avatar.png", "borderRadius": 999, "width": 0.4, "height": 0.4, "fit": "cover", "position": "center" },
                  "text": { "content": "等待主持人...", "position": "bottom_center", "color": "#888" }
                }
              },
              {
                "name": "guest_1",
                "source": { "slot": { "name": "guest", "index": 0, "filter": { "trackSources": ["camera"] } } },
                "offsetX": 0.75, "width": 0.25, "height": 0.333,
                "style": { "borderRadius": 12, "backgroundColor": "#2d2d44" }
              },
              {
                "name": "guest_2",
                "source": { "slot": { "name": "guest", "index": 1, "filter": { "trackSources": ["camera"] } } },
                "offsetX": 0.75, "offsetY": 0.333, "width": 0.25, "height": 0.334,
                "style": { "borderRadius": 12, "backgroundColor": "#2d2d44" }
              },
              {
                "name": "guest_3",
                "source": { "slot": { "name": "guest", "index": 2, "filter": { "trackSources": ["camera"] } } },
                "offsetX": 0.75, "offsetY": 0.667, "width": 0.25, "height": 0.333,
                "style": { "borderRadius": 12, "backgroundColor": "#2d2d44" }
              }
            ]
          }
        }
      }
    },
    {
      "name": "mix_audio",
      "type": "audio_mixer",
      "inputs": ["room_src"],
      "config": {}
    }
  ],
  "sinks": [
    {
      "name": "rtmp_out",
      "type": "rtmp_push",
      "inputs": ["mix_video", "mix_audio"],
      "config": { "urls": ["rtmp://live.example.com/app/show-key"] }
    }
  ]
}