For optimal results set the camera vertical FOV data in:

YOUR_PROJECT_PATH\Binaries\Win64\mediapipe\graphs\face_mesh\multi_face_landmarks.pbtxt

node {
  calculator: "FaceGeometryEnvGeneratorCalculator"
  output_side_packet: "ENVIRONMENT:environment"
  node_options: {
    [type.googleapis.com/mediapipe.FaceGeometryEnvGeneratorCalculatorOptions] {
      environment: {
        origin_point_location: TOP_LEFT_CORNER
        perspective_camera: {
          vertical_fov_degrees: 59.0
          near: 1.0 # 1cm
          far: 10000.0 # 100m
        }
      }
    }
  }
}