Project Setup

Project Setup


The PRESTOplay SDK for Android is delivered as a Maven Repository that can be added to your application build. All required dependencies are either:

  • Contained in the bundle repository

  • Available on a public repository like jcenter or Maven Central

  • Part of the Android Support Repository that can be installed with the Android SDK-Manager.

To work with the PRESTOplay SDK for Android you need to use the Gradle build system for your application builds.

Project Configuration

The SDK bundle contains a repository folder. This folder is a local Maven Repository that is used to find and integrate the PRESTOplay SDK for Android as a dependency within your project.

You can enable the repository for your project in your build.gradle script by adding it as a local Maven repository:

        url '<path/to/castlabs/repository>'

The <path/to/castlabs/repository> needs to be replaced with the actual path to the repository folder that is bundled with the SDK. The repository does not need to be part of your project structure explicitly and you do not need to add it to your version control system. Instead, you can host the repository outside of your project structure. You can for example use a Gradle property to denote the path to the repository folder.

The repository contains all the required pom.xml files to be uploaded to a hosted Maven or Ivy repository.

With the repository added to your build script, you can reference and load the PRESTOplay SDK for Android and its components using:

dependencies {
    compile 'com.castlabs.player:castlabs-sdk:3.0.0'

This will add the SDK and its dependencies to the classpath of your application and you can start referencing classes within the SDK.

After the SDK is added as a dependency, you need to initialize it before you can use it. This is typically done in your Application class using the PlayerSDK.init() method. For example:

public class DemoApp extends Application{
    public void onCreate() {

License Loading

The PRESTOplay SDK for Android requires a license that needs to be distributed with your application. By default, the SDK expects to find the license in your Application Manifest as the castlabs-license meta-data Attribute. For example:

<?xml version="1.0" encoding="utf-8"?>
        <meta-data android:name="castlabs-license"
                   android:value="<your-license-key>" />

The license key is bound to your Applications SHA-1 Fingerprint and Package name. You can generate license keys on the castLabs Download Portal. In the Licenses section, you can create License Keys for your Application.

Depending on how you decide to manage your license file, you might want to load it from a different location or use a different name. For this, you can use an implementation of the LicenseLoader interface. The SDK already comes with an implementation to load the licenses from the application’s Manifest with the ManifestLicenseLoader. This is the default implementation. If you want to use a different loader, you can pass an instance of the LicenseLoader to PlayerSDK.init(). For example:

               new MyLicenseLoader());

Note that in case the license key is invalid the SDK will not be initialized and the error will be sent via the PlayerListener.onError(CastlabsPlayerException). The SDK however can still be re-initialized with a valid key if applicable.

User Id

Your PRESTOplay SDK for Android license might require user tracking for accounting purposes. If this is the case, you must provide a unique user id for each view session.

The value of this parameter must be unique for each end-user. Our backend only needs to identify end users on a cross-session basis, but we don’t use this information to do any correlation.

This means that the provided values should be pseudonymized. One example of this could be hashing a user’s email account.

This value can be informed through the parameter INTENT_USER_ID if using an Intent or with the userId field in PlayerConfig upon playback initialization.


In case your PRESTOplay SDK for Android license requires user identification, you must inform this field.

Without specifying user ID parameter if mandatory, the SDK license check will result in a rejected license and failed playback attempt. If the license check fails due to missing USER_ID, a player exception will be raised:

E/CastlabsPlayerException: [ERROR] [TYPE_USER_ID_NOT_PROVIDED] UserID is required for playback

If you’re using DRMToday, the PRESTOplay SDK for Android will, by default, use the user id informed in the DrmConfiguration, so there’s no obligation to fill in the userId in such scenario. You can still inform the value in the Bundle or the PlayerConfig object and it will take precedence.

As mentioned, there are two ways of providing the end user ID to the SDK: INTENT_USER_ID or PlayerConfig.userId (which can be specified through the Builder). The example for this would be:

// Specify the UserID as an intent bundle parameter
bundle.putString(SdkConsts.INTENT_USER_ID, "unique-user-id");


// Alternatively, set the UserID in PlayerConfig as part of the config
PlayerConfig playerConfig = new PlayerConfig.Builder("<url_to_stream>")

Third party re-signing conflicts

Each license for the PRESTOplay SDK for Android is tied to a unique developer certificate. This link is checked through the certificate’s SHA1 fingerprint. For this reason, some third party processes which introduce re-signing operations may interfere with the PRESTOplay SDK for Android licence check if such re-signing is done with a different key.

Protection tools

Some Android app protection and obfuscation software needs to re-sign the app bundle or apk after the protection and obfuscation actions have taken place. In order for the PRESTOplay SDK for Android license check to succeed, it is necessary that the fingerprint of the key that is used to sign the application is the one indicated upon the PRESTOplay SDK for Android key generation.

If you are experiencing issues with license validation after running protection software, please make sure the third party protection tool is using the same key to re-sign the binary.


If using Licel's DexProtector, you should pay close attention to the signMode element in the configuration. Such should be set to release, alongside the path and information about the keystore to use for signing.

This is the same keystore from which the SHA1 fingerprint should have been extracted in order to generate the license for the PRESTOplay SDK for Android.

Amazon App Store

Please note that the Amazon App store re-signs submitted APKs and hence changes the signature of the Application and the signing key. Since the Castlabs License is bound to the signing key, you need to create a dedicated license using the SHA1 that is exposed on the Amazon Developer console.


Amazon App Store SHA1

OMA Integration

The OMA plugin is bundled in the local repository that ships with the PRESTOplay SDK for Android. You need to add the OMA dependency in your build setup. For example:

dependencies {
    compile 'com.castlabs.player:oma-plugin:3.4.0'

Note that you should keep the base version of the plugin (in the example above 3.5.0) in sync with the version of the SDK you are loading.

Because the OMA integration is delivered as a plugin, you will need to register it before you initialize the PlayerSDK. You can register the plugin using the PlayerSDK.register(PlayerPlugin) method. For example:

PlayerSDK.register(new OmaPlugin());

Variant Builds

The OMA support is typically needed to support DRM protected content playback on devices with Android 4.1 and 4.2. You can leverage the support of the Android build plugin for “build variants” to create different variants of your application and reduce the size of your final APK for Android versions 4.3 and beyond. A detailed discussion of build variants is out of scope for this documentation, but a simple example looks like this:

android {
    defaultConfig {
        minSdkVersion 16
    signingConfigs { ... }
    buildTypes { ... }
    productFlavors {
        modern {
            versionName "1.0-modern"
            versionCode 10020
            minSdkVersion 19
        oma {
            versionName "1.0-oma"
            versionCode 10010
            maxSdkVersion 18
dependencies {
    compile 'com.castlabs.player:castlabs-sdk:3.4.0'
    omaCompile 'com.castlabs.player:oma-plugin:3.4.0'

In this example, we create two variants: “modern” and “oma”. The SDK itself is added using compile as a compile time dependency to all variants. Using omaCompile when referencing the OMA plugin ensures that it is only added to the “oma” variant. In addition to the build setup, you will need to make sure that the “oma” variant of the application has registered the plugin before the SDK is initialized.

Note also that we set the minSdkVersion for the modern variant to 19 while limiting deployment of the maxSdkVersion to API 18 and below. This will separate the target platforms based on the API level. Further note that the Google Play store rules for Multiple APK Support require to provide a higher version code for the modern variant. This allows users who update their phones to get access to the modern build variant.

Split APK Builds

The SDK itself as well as the OMA plugin includes native components for ARM and x86 architectures bundled in their AAR files. Similar to the variant builds (see Variant Builds), you can use the split APK feature of the Android Gradle plugin to generate APK versions specific to ARM and x86 architectures and further reduce the APK size of the final application for a single variant. You can find more information about ABI splits and variant builds in the Android Tools wiki.

Proguard Configuration

The PRESTOplay SDK for Android and all the plugins embed a Proguard configuration in their aar files and there is no need to specify anything specific to the castLabs SDK in your Proguard configuration file.

Protocol buffer dependencies

The PRESTOplay SDK for Android uses Google’s protobuf library some of its components. More precisely, the protobuf-javalite artifact is being used. If you’re using in your project another version of such library, you’ll need to exclude it from the conflicting packages so the build goes through without finding duplicate classes.

Note that this also applies to transitive dependencies. One common example is Google’s play-services-cast-framework used for the Google Cast sender:

// Don't include the transitive protobuf dependency
implementation ('') {
    exclude group: ''
Previous topic: Android SDK documentation
Next topic: Player Basics