Video streaming with control value¶

Prerequisites¶

Modules

External Ressource

An RTSP video camera

Checkout branches

git checkout origin/osp-web .
git checkout origin/osp-video-configuration .
git checkout origin/osp-scripts .

Description¶

In this tutorial you will learn how to control a video stream with an external variable.

The control will be performed by a script executed every 5 seconds. If the script found a lookup file command with a key named control, he will set the stream controller to true.

In this tutorial you will learn :

How to read a lookup file from scripts
How to set a variable from script
How to create a video dashboard
How to control the stream of a video widget

Structure¶

Steps¶

1. Create the dashboard to visualize the video stream¶

Create a dashboard reading from the controller.

root/dashboard/dashboard.view

{
  "configuration": [
    {
      "type": "VideoPlayer",
      "id": "Obj6KetA",
      "title": "Camera",
      "videoWidgetSettings": {
        "videoId": "root.scripts"
      }
    },
    {
      "type": "ValueSubscription",
      "id": "ormntRfC",
      "title": "",
      "valueSubscriptions": {
        "values": []
      }
    }

  ],
  "layout": {
    "lg": [
      {
        "w": 5,
        "h": 3,
        "x": 0,
        "y": 0,
        "i": "Obj6KetA"
      },
      {
        "w": 7,
        "h": 3,
        "x": 5,
        "y": 0,
        "i": "ormntRfC"
      }
    ]
  },
  "breakpoints": {
    "lg": 1200,
    "md": 996,
    "sm": 768,
    "xs": 480,
    "xxs": 0
  },
  "cols": {
    "lg": 12,
    "md": 10,
    "sm": 6,
    "xs": 4,
    "xxs": 2
  }
}

root/dashboard/dashboard.web

{
    "moduleId": "modules.web.web-1",
    "title": "Example of Camera view",
    "description": "",
    "tags": []
}

2. Write a script reading the command.lookup¶

root/scripts/check-file.js

main();

function main() {
    
    const is_enabled = lookup.get("command", "control", 0);
    log.info("Camera state is {}", is_enabled)
    if (is_enabled == 0)
    {
        return true;
    } 
    else
    {
        return false;
    }
}

root/scripts/owner.scripts

{
    "moduleId": "modules.scripts.scripts-1",
    "scheduledExecutions": ["0/5 * * ? * * *"],
    "accessedValues": [],
    "sourceFile": "root/scripts/check-file.js"
}

root/scripts/value.ospp

{
    "name": "Service status",
    "description": "The status of an external service",
    "type": "BOOLEAN"
}

3. Create a video stream controller¶

This file will link the URL and the value (must be a boolean value)

root/scripts/controller.video

{
    "streamId": "root.url",
    "controllingValue": "root.scripts"
}

4. Create a video stream¶

root/url/owner.video

{
  "networkBufferingTime": {
    "value": 1,
    "unit": "SECONDS"
  },
  "disableStreamEncoding": true,
  "streamType": "STREAM",
  "serverId": "root.video.server-1",
  "urls": [
    "rtsp://user:password@10.10.1.1/axis-media/media.amp?profile=quality_h264&sessiontimeout=60&streamtype=unicast"
  ]
}

root/url/value.ospp

{
    "name" : "Camera 01",
    "description" : "The camera",
    "type" : "BOOLEAN"
}   

5. Open the web view (LOCAL IP:5000)¶

The video should not be displayed yet

6. Set the lookup content to enabled¶

To simulate an external behavior, we will manually create a file inside the scripts container.

Note

This is totally a trick to show this feature. Do not use this in production.

From the command line fetch the container-id

docker container ls | grep scripts

Execute the following command with the previous ID

docker container exec -it [ID] echo "control;1; > /osp/config/lookups/command.lookup"

7. Re-open the web view (LOCAL IP:5000)¶

The video should be displayed (this can take ~1 min depending on the buffering settings of the camera)