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Here is overview of DAC solution and following video made by ConsultRed at TechSummit2024 nicely explains that bigger picture dac_overview_rdk_tech_summit_2024.mp4

What SW, HW and credentials you need

• Video Accelerator with final RDK6.1 image on it. This can be Raspberry Pi 4 (RPI4) on which you can flash RDK6.1 final release image.   Note that RPIv3B/3B+ is deprecated, not supported by RDK-M anymore. Tool to flash RDK6.1 rpi image to SD card, example is provided with https://www.balena.io/etcher/ tool. Contact RDK-M if you want to test it on more carrier grade Video Accelerator (with amlogic, broadcom or realtek SoC) with RDK6.1 image
• Your application source code with bitbake recipe. Needs to meet the DAC contract for binary compatibility.
• DAC SDK https://github.com/rdkcentral/meta-dac-sdk to cross compile your application, add dependent libraries in AppContainer and package/output your application as oci compliant dac container image.
• As App developer company/entity you will need to request RDK-M DAC support team via support@rdkcentral.com  :
  
  • a login/pswd to register your app and its metadata in RDK-M ASMS instance (ASMS is AppStore Metdata µService and part of DAC cloud setup of RDK-M for Video Accelerators)
  • an associated "Maintainer" identifier (string) to be able to upload/register your app. 
  • credentials for uploading your OCI image to the private RDK OCI container registry. This is not required if you choose to upload it to a public accessible OCI container registry or ask support team to upload it for you.

Above credentials are one time request per App developer entity. Once you have above credentials, you can reuse them for publishing other apps under your entity. At this moment requesting these credentials is still manual process, a point to improve in future 

put RDK6.1 SW image on your RPI4

As an Appdeveloper you want to test and run your DAC Application on a set of real hardware reference devices. RDK-M created the Video Accelerators for that. 

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To get your hands on other Video Accelerator HWs and their RDK6.1 SW images, we refer you to RDK-M

Flash the RDK6.1 image to your RPI

Download and install https://www.balena.io/etcher/ tool

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• Insert the SD card back in the RaspberryPi and power up the Pi. Connect the Raspberry Pi to your network with an ethernet cable, and to your TV with a HDMI cable.
• Make sure you can SSH into the Pi as this is important for later. The default user is root with no password
• You should see the RDK Video Accelerator Resident UI application on your TV at bootup (after following some initial setup questions). In section 4.1 we explain how to use the Video Accelerator Resident UI to install existing DAC apps. But first we explain how you can build and publish dac apps 

use DAC SDK and build your first native DAC app

As part of the DAC project, an SDK has been created to make it easier to develop and build oci and DAC compliant containerized applications. The SDK is public, fully open source and uses standard Yocto 3.1 Dunfel Poky environment.

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• manifest that will download Yocto Poky environment with all required meta-layers, see manifest content in https://github.com/rdkcentral/meta-dac-sdk/blob/master/manifests/dac-dunfell-manifest.xml
• meta-dac-sdk meta-layer specifically developed to make building of DAC application easy for Appdeveloper.
  • It defined some parent classes (dac-image-wayland, dac-image-essos, dac-image-base ) App developer can start from (inherit) to define its DAC AppContainer image as described in 
  • It links the application to DAC GFX abstraction interfaces (gles2, essos, wayland-egl) correctly and configures DAC-RDK abstraction components (eg rialto-client) appropriately.
  • It removes some integration complexity/specific expertise-need from Appdeveloper because:
    • SDK links the application to DAC abstraction interfaces (gles2, essos, wayland-egl, rialto) correctly and configures these appropriately.
    • A c/c++ application typically depends on other standard libraries, The SDK automatically adds the correct application dependency tree into the AppContainer Image
    • At the end of building process an oci compliant AppContainer image is generated. 
  • It comes with various DAC compliant AppContainer examples. see the recipes of example AppContainer images at https://github.com/rdkcentral/meta-dac-sdk/tree/master/recipes-example/images Each one is a yocto image target that you can then ask Yocto to build.  We provided some examples for various Graphics frameworks (Flutter, QT, SDL, directly on wayland, directly on essos). Those also have full opensource reference or hello-world application code provided so App developer can understand how App can use/configure Gfx framework so it will work seamlessly with DAC abstraction interfaces.
• build instructions as per https://github.com/rdkcentral/meta-dac-sdk/blob/master/README.md 

setup of DAC SDK

build instructions as per https://github.com/rdkcentral/meta-dac-sdk/blob/master/README.md They are copies here but it is best to read the instructions there to be sure they are up to date.

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Now you can proceed with building your AppContainer image

build your AppContainer image in SDK

You ask Yocto to build specific DAC AppContainer image by invoking "bitbake <Recipename_AppContainer> "

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Next section explains how you can create your own AppContainer image

AppContainer image recipes, hierarchy, application recipe and appmetadata json 

To create and build your own oci, dobby, dac complaint AppContainer image as Appdeveloper, you need to create the following necessary yocto recipes and files :

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DAC image bbclass to inherit

To ease integration and life of Appdeveloper meta-dac-sdk layer defined several types of dac-image bbclasses 

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Publish your DAC app to RDK-M DAC cloud

Once you have built your oci, dobby, dac compliant AppContainer image with DAC SDK, you can publish it to RDK-M DAC cloud.

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With step2 you will make your DAC native applciation discoverable to Video Accelerators with RDK-M RDK6.1 image but just to be clear and avoid misunderstandings, this will NOT distribute, deploy or make your app available to Appstore of the various RDK operators (Liberty Global, Comcast, Sky). For that you would need to start a discussion with each operator. But this DAC architecture gives you the big benefit that you can now share your Application binary as AppContainer in step1 and when it meets the DAC App  contract for binary compatibility it will be binary compatible and technically much easier/quick for the operator to run and test your app on their boxes for first time, get familiar with it. No significant technical integration work should be needed just to get the app running on the operator box. With the DAC cloud for the RDK-M Video Accelerator you as App developer get staging platform where you and others from RDK community can run, test your same application binary across the various supported RDK SoC reference devices (the VA's) and share it with RDK community.

How to publish the application oci container image to RDK-M oci container registry

You can either publish your oci container image to

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We provide the instructions for Amazon Elastic Container Registry. The private container registry setup RDK-M DAC team is also such type.

instructions for amazon Elastic Container Registry

You need to have the following util programs installed:  aws cli tools and skopeo.

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You have to remember the OCI image URL of your application, which in this example is docker://public.ecr.aws/a0v6o9z7/cobalt:latest. Because you will have to specify it when publishing the DAC app to the ASMS (AppStore Metdata service).

Publish your DAC app to ASMS

 ASMS (AppStore Metadata Service) offers API that allows Application Maintainers to register their app with appropriate metadata. There are various ways to publish a new application to ASMS in DAC Cloud:

1. use the official ASMS REST API to publish the app, is openAPI / swagger API format which we describe in next section
2. using the dactest.py python test tool that in its turn uses the ASMS api
3. using front-end UI that in its turn uses the ASMS api. The latter one is not available yet to App Developers

register App using ASMS REST API

You can access the swagger UI with the API documentation here:

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{
  "header": {
    "icon": "https://280222515084-default-apps-resources.s3.eu-central-1.amazonaws.com/images/apps/com.rdk.app.chocolate-doom.png",
    "name": "Chocolate Doom",
    "description": "Chocolate Doom aims to accurately reproduce the original DOS version of Doom and other games based on the Doom engine in a form that can be run on modern computers.",
    "type": "application/dac.native",
    "size": 10000000,
    "category": "application",
    "localization": [
      {
        "languageCode": "nld",
        "name": "Geweldige applicatie",
        "description": "Dit is een geweldige applicatie"
      }
    ],
    "id": "com.rdk.app.chocolate-doom",
    "version": "1.0.0",
    "visible": true,
    "encryption": false,
    "preferred": false,
    "ociImageUrl": "docker://public.ecr.aws/a0v6o9z7/chocolate-doom:latest"
  },
  "requirements": {
    "dependencies": [
      {
        "id": "com.libertyglobal.service.voice",
        "version": "1.0.0"
      }
    ],
    "platform": {
      "architecture": "arm",
      "variant": "v7",
      "os": "linux"
    },
    "hardware": {
      "ram": "512M",
      "dmips": "2000",
      "persistent": "60M",
      "cache": "200M"
    },
    "features": [
      {
        "name": "rdk.api.awc",
        "version": "2",
        "required": false
      }
    ]
  },
  "maintainer": {
    "code": "rdk",
    "name": "RDK",
    "address": "RDK Management, LLC",
    "homepage": "https://rdkcentral.com",
    "email": "support@rdkcentral.com"
  },
  "versions": [
    {
      "version": "1.0.0",
      "visible": true,
      "preferred": false,
      "encryption": false
    }
  ]
}

Publish the DAC app using dactest.py tool

Among other things, dactest.py can be used list ASMS apps, add entries and remove entries. 

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1. on your development PC/laptop: install dactest.py dependencies. You need python3 and then pip3 install requests colorama websocket-client
2. use ./dactest.py 192.168.0.117 (replace IP address with your RPI IP)
3. it will use the RDK ASMS to list apps available from the cloud. Use "A" to start the procedure to add an app to ASMS
4. you will need to provide an id, name, version, the OCI image URL (see previous step) and a link to an icon to use. When prompted for "encryption" input "false". Unless you really want to test encrypted DAC apps. But for this feature there is a separate wiki page to read. Extra steps are needed for encryption. You can skip that for now and don't use encryption.

Install and run your DAC app on the Video Accelerator

We explain here 2 ways to download your DAC application from Staging RDK-M DAC Appstore and install it on the video Accelerator :

1. via the Resident UI on RDK-Video Accelerator (is the regular, user-friendly way)

   Anchor
   VAUI VAUI

     
2. using the dactest.py test tool  

install and run DAC app using RDK-VA Resident UI

In the resident UI go to the icon with the 9 small squares (left bottom) to navigate to the DAC menu. There you will see three submenu items:

1. My Apps: initially empty. From here you can start installed DAC apps. Use the "Home" key to exit a DAC app.
2. App Catalog: these are the DAC apps from ASMS available for installation. If you published your app to ASMS you should see it here.
3. Manage Apps: here you can uninstall DAC apps from your RPI

Using dactest.py tool

dactest.py can be used list, install, uninstall, start and stop DAC apps. It also connects to RDK ASMS to list available DAC apps in the cloud. The DAC apps downloaded from the cloud are generated to bundles inside that cloud and cached there. Sometimes the download can take a while if the bundle still needs to be generated for a specific platform and/or version.

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