ULCKStreamingSubsystem (Unreal)

What Problem Does This Solve?

ULCKStreamingSubsystem is the Blueprint-friendly entry point for live streaming:

Authenticate with LIV’s streaming service via device pairing
Start and stop live streams to YouTube, Twitch, or custom RTMP targets
Monitor stream state, errors, and configuration changes

It implements ILCKStreamingFeature and exposes everything as BlueprintCallable / BlueprintAssignable.

When to Use This

Use ULCKStreamingSubsystem when:

Building a “Go Live” button in your game
Creating a streaming dashboard UI
Integrating streaming into your game flow

Don’t use this directly if: You’re building a custom streaming backend — implement ILCKStreamingFeature instead.

Accessing the Subsystem

ULCKStreamingSubsystem* Streaming =
    GetGameInstance()->GetSubsystem<ULCKStreamingSubsystem>();

Delegates

All delegates are BlueprintAssignable.

Delegate	Signature	Description
`OnPairingCodeReceived`	`FOnLCKPairingCodeReceived(const FString&, Code)`	Pairing code ready for display
`OnAuthenticated`	`FOnLCKAuthenticated()`	User successfully authenticated
`OnStreamingConfigReceived`	`FOnLCKStreamingConfigReceived(ELCKStreamingTargetType, const FLCKUserSubscription&)`	Config loaded from server
`OnStreamStarted`	`FOnLCKStreamStarted()`	Live stream has started
`OnStreamStopped`	`FOnLCKStreamStopped()`	Live stream ended normally
`OnStreamError`	`FOnLCKStreamError(const FString&, ErrorMessage)`	Streaming error occurred
`OnLoggedOut`	`FOnLCKLoggedOut()`	User logged out

Authentication Methods

Method	Return	Description
`StartLogin()`	`void`	Begin device-code login flow (polls every 2.5s)
`CancelLogin()`	`void`	Cancel in-progress login
`GetPairingCode()`	`FString`	Current pairing code (BlueprintPure)
`IsAuthenticated()`	`bool`	Check if authenticated (BlueprintPure)
`Logout()`	`void`	Log out and clear credentials

Configuration Methods

Method	Return	Description
`RefreshStreamingConfig(bool bSilent)`	`void`	Refresh config from server (bSilent suppresses errors)
`HasStreamingTarget()`	`bool`	Has YouTube/Twitch/Manual target? (BlueprintPure)
`HasActiveSubscription()`	`bool`	Has active LIV subscription? (BlueprintPure)
`GetStreamingTargetType()`	`ELCKStreamingTargetType`	Current target type (BlueprintPure)

Streaming Methods

Method	Return	Description
`StartStreaming()`	`bool`	Start live stream (15s timeout)
`StopStreaming()`	`void`	Stop live stream
`IsStreaming()`	`bool`	Is currently streaming? (BlueprintPure)
`IsStartingOrStreaming()`	`bool`	Starting or streaming?

Platform Methods

Method	Return	Description
`LaunchHub()`	`void`	Open LIV Hub (Android only)
`IsHubInstalled()`	`bool`	Is LIV Hub installed?
`GetStreamingTargetName()`	`FString`	Display name (e.g., “YouTube”)
`GetLastLogoutReason()`	`FString`	Reason for last automatic logout

Streaming Bitrate Presets

YouTube

Quality	Video Bitrate	Audio Bitrate
SD	4 Mbps	128 Kbps
HD @30	8 Mbps	128 Kbps
HD @60	12 Mbps	128 Kbps
2K	24 Mbps	128 Kbps
4K	35 Mbps	128 Kbps

Twitch

Quality	Video Bitrate	Audio Bitrate
SD	3 Mbps	96 Kbps
HD @30	4.5 Mbps	96 Kbps
HD @60	6 Mbps	96 Kbps
2K	9 Mbps	96 Kbps
4K	10 Mbps	96 Kbps

Keyframe interval is fixed at 2 seconds. Bitrates are applied automatically based on the streaming target and quality profile.

Timing Constants

Constant	Value	Description
Auth poll interval	2.5s	Pairing confirmation polling
Stream start timeout	15s	Maximum RTMP connection wait
Health check interval	5s	Encoder health monitoring
Health check tolerance	2	Consecutive failures before stopping

Usage Example

UCLASS()
class UStreamingManager : public UActorComponent
{
    GENERATED_BODY()

public:
    virtual void BeginPlay() override
    {
        Super::BeginPlay();

        auto* Streaming = GetWorld()->GetGameInstance()
            ->GetSubsystem<ULCKStreamingSubsystem>();
        if (!Streaming) return;

        Streaming->OnPairingCodeReceived.AddDynamic(
            this, &UStreamingManager::OnCode);
        Streaming->OnAuthenticated.AddDynamic(
            this, &UStreamingManager::OnAuth);
        Streaming->OnStreamStarted.AddDynamic(
            this, &UStreamingManager::OnLive);
        Streaming->OnStreamError.AddDynamic(
            this, &UStreamingManager::OnError);
    }

    UFUNCTION(BlueprintCallable)
    void Login()
    {
        auto* S = GetWorld()->GetGameInstance()
            ->GetSubsystem<ULCKStreamingSubsystem>();
        S->StartLogin();
    }

    UFUNCTION(BlueprintCallable)
    void ToggleStream()
    {
        auto* S = GetWorld()->GetGameInstance()
            ->GetSubsystem<ULCKStreamingSubsystem>();

        if (S->IsStreaming())
            S->StopStreaming();
        else if (S->HasStreamingTarget())
            S->StartStreaming();
    }

private:
    UFUNCTION() void OnCode(const FString& Code) { ShowPairingUI(Code); }
    UFUNCTION() void OnAuth() { ShowStreamControls(); }
    UFUNCTION() void OnLive() { ShowLiveIndicator(); }
    UFUNCTION() void OnError(const FString& E) { ShowError(E); }
};

Key Takeaways

GameInstance subsystem — Available globally, survives level transitions

Blueprint-ready — All methods and delegates are Blueprint accessible

Auth-first flow — Login, configure target, then stream

Check prerequisites — Verify IsAuthenticated() and HasStreamingTarget() before streaming

Streaming Feature Interface — Underlying C++ interface
Streaming Types — Enums and data types
Packet Sink Interface — Custom transport layer
Project Settings — Enable streaming via bEnableStreaming

Core SDK

Tablet Interface

Tablet Customization

Audio

Streaming

API Reference

ULCKStreamingSubsystem (Unreal)

What Problem Does This Solve?

When to Use This

Accessing the Subsystem

Delegates

Authentication Methods

Configuration Methods

Streaming Methods

Platform Methods

Streaming Bitrate Presets

YouTube

Twitch

Timing Constants

Usage Example

Key Takeaways

​What Problem Does This Solve?

​When to Use This

​Accessing the Subsystem

​Delegates

​Authentication Methods

​Configuration Methods

​Streaming Methods

​Platform Methods

​Streaming Bitrate Presets

​YouTube

​Twitch

​Timing Constants

​Usage Example

​Key Takeaways

​Related

What Problem Does This Solve?

When to Use This

Accessing the Subsystem

Delegates

Authentication Methods

Configuration Methods

Streaming Methods

Platform Methods

Streaming Bitrate Presets

YouTube

Twitch

Timing Constants

Usage Example

Key Takeaways

Related