# LINE channel properties

There are LINE channel-specific properties that can be used when making calls to the Conversation API. These properties can be listed under `channel_properties` in the message request.

For example, below is the code for adding the channel specific property `LINE_VIDEO_TRACKING_ID` to a Conversation API call:


```json
{
  "app_id": "{{APP_ID}}",
  "recipient": {
    "contact_id": "{{CONTACT_ID}}"
  },
  "message": {
    "media_message": {
      "thumbnail_url": "https://url/to/your/thumbnail/image.jpg",
      "url": "https://url/to/yout/video.mp4"
    }
  },
  "channel_properties": {
    "LINE_VIDEO_TRACKING_ID": "my-unique-video-tracking-id"
  }
}
```

The relevant LINE channel properties are detailed in the table below:

| Property name | Property value |
|  --- | --- |
| `LINE_VIDEO_TRACKING_ID` | ID used to identify the video when the video viewing complete event occurs. If you send a video message with `LINE_VIDEO_TRACKING_ID` added, the video viewing complete event occurs when the user finishes watching the video. You can use the same ID in multiple messages. |
| `LINE_OPEN_STATUS` | Optional. User interaction data is aggregated in units defined with this property. During the current month (from the first to the last day of the month), one can send messages with up to 1000 different unit names. Note that when messages are sent with the 1001st or later unit name type, those unit names are treated as if they weren't assigned to the messages. |


Below is an example of using the `LINE_OPEN_STATUS` channel-specific property to mark MT messages with a custom aggregation unit of `promotion_1000`:


```json
{
  "app_id": "{{APP_ID}}",
  "recipient": {
    "contact_id": "{{CONTACT_ID}}"
  },
  "message": {
    "media_message": {
      "thumbnail_url": "https://url/to/your/thumbnail/image.jpg",
      "url": "https://url/to/yout/video.mp4"
    }
  },
  "channel_properties": {
    "LINE_OPEN_STATUS": "promotion_1000"
  }
}
```