Clarify role of connection-map vs input-ports and output-ports

[mtneug]

The connection-map is described as follows:

The array of connection-map object provides a description of the media workflow DAG, i.e. the connection information between different tasks in the graph. (Subclause 8.4.1)

The input-ports and output-ports are described as follows:

The input-ports and output-ports objects specify the endpoints where the data is communicated from NBMP sources to tasks; and between tasks; and from tasks to NBMP sinks. (Subclause 8.2.1)

It's unclear to me what will ultimately define the DAG. My current understanding is that connection-map defines the DAG between tasks and input-ports and output-ports are only used to connect input and output streams to tasks and otherwise only describe available in-/output ports.

Assume the following workflow:

input -> normalize -> transcode720p -> output

Would the following WDD be a proper description (omitting some of the required fields)?

As a side question: Why is the function ID specified as part of the connection-map instead of in the function-restrictions. If one task has multiple connections, the function ID is repeated multiple times with possible inconsistencies.

{
  "general": {
    "name": "Example"
  },
  "input": {
    "media-parameters": [
      {
        "stream-id": "videoIn1",
        "name": "videoIn1",
        "keywords": [
          "master"
        ],
        "mime-type": "video/mp4",
        "protocol": "http",
        "mode": "pull",
        "caching-server-url": "http://example.com/master.mp4"
      }
    ]
  },
  "output": {
    "media-parameters": [
      {
        "stream-id": "videoOut1",
        "name": "videoOut1",
        "keywords": [
          "720p"
        ],
        "mime-type": "video/mp4",
        "protocol": "http",
        "mode": "push",
        "caching-server-url": "http://example.com/720p.mp4"
      }
    ]
  },
  "processing": {
    "connection-map": [
      {
        "connection-id": "normalize -> transcode720p",
        "from": {
          "id": "normalize-function",
          "instance": "normalize",
          "port-name": "normalize-video-output"
        },
        "to": {
          "id": "transcode-function",
          "instance": "transcode720p",
          "port-name": "transcode720p-video-input"
        }
      }
    ],
    "function-restrictions": [
      {
        "instance": "normalize",
        "general": {
          "id": "normalize",
          "name": "normalize",
          "input-ports": [
            {
              "port-name": "normalize-video-input",
              "bind": {
                "stream-id": "videoIn1",
                "name": "normalize-video-input"
              }
            }
          ],
          "output-ports": [
            {
              "port-name": "normalize-video-output",
              "bind": {
                // Do I need to specify `stream-id`?
                "name": "normalize-video-output"
              }
            }
          ]
        }
      },
      {
        "instance": "transcode720p",
        "general": {
          "id": "transcode720p",
          "name": "transcode720p",
          "input-ports": [
            {
              "port-name": "transcode720p-video-input",
              "bind": {
                // Do I need to specify `stream-id`?
                "name": "transcode720p-video-input"
              }
            }
          ],
          "output-ports": [
            {
              "port-name": "transcode720p-video-output",
              "bind": {
                "stream-id": "videoOut1",
                "name": "transcode720p-video-output"
              }
            }
          ]
        }
      }
    ]
  }
}