Castdeck

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Castdeck ヘルプ

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What you can do

Castdeck is a streaming-support app that handles YouTube Live comments, effects, text-to-speech, games, notifications, and OBS display all in one place.

Display comments clearly

Display regular comments, first-timers, members, and Super Chats in an OBS browser source.

  • Standard chat display
  • Chat pinning
  • Super Chat highlighting
  • Placement in the stream layout

Trigger effects

Trigger images, videos, audio, and screen effects based on conditions such as comments and Super Chats.

  • Asset management
  • Trigger conditions
  • Test playback
  • Switching effect sets

Turn your stream into play

Display interactive parts such as slots, roulette, polls, and marble races in OBS.

  • Slot machine
  • Roulette
  • Polls
  • Interactive games

Drive post-stream improvement

Organize information that feeds into the AI Advisor, statistics, inquiries, and future marketing analysis.

  • AI suggestions
  • Stats bar
  • Support inquiries
  • Stream data usage

How to use each screen

Here are the frequently used screens and their roles. Before going live, focus on the Dashboard, Screen Effects, Stream Layout, and Settings.

Dashboard

Connect to YouTube Live and check the status of comments, Super Chats, pins, and text-to-speech.

  • Connect via stream URL or stream ID
  • Check comments and Super Chats
  • Pinning and mark-as-handled actions

Screen Effects

Adjust themes, effects, chat boxes, pins, stats, goals, and asset management.

  • Effect rules
  • Asset management
  • Text-to-speech
  • Appearance of each OBS part

Stream Layout

Arrange chat, pins, stats, goals, effects, games, BGM, sound effects, and more into a single OBS screen.

  • Add parts
  • Adjust position and size
  • Save the layout
  • Check the OBS URL

Settings

Manage external integrations such as Google, AI, emoji, OBS, BASE, Amazon, and updates.

  • Google authentication
  • AI API settings
  • OBS WebSocket integration
  • Purchase/gift notifications

AI API Settings

To use the AI Advisor, set the API key for your AI service or the connection target for your local LLM.

Claude / OpenAI / Gemini

Create an API key in each service's official console and save it in Castdeck Settings.

  • Create a dedicated key for Castdeck
  • Check usage limits and billing status
  • Never show keys on public sites or in OBS

Local LLM

Using an OpenAI-compatible server such as Ollama lets you test without API usage fees.

  • Set the local LLM URL
  • Select a model
  • Check response speed and quality before going live

Cost and safety

AI APIs can be usage-based. Set limits and alerts before going live.

  • Monthly cap
  • Budget alerts
  • Disabling unused keys
  • Watching for excessive calls during streams

Purchase/Gift Notification Guide

Setup steps for displaying BASE orders and Amazon Wish List sync in the notification part of your stream.

What BASE integration can do

Detect new orders from your BASE shop and display them as purchase/gift notifications on your OBS stream.

  • Periodically fetch the order list
  • Notify only for new orders
  • Reflect product name, buyer name, and amount in the notification
  • Buyer names shown as initials

What to prepare on BASE Developers

In the beta, you create your own BASE app and enter the issued Client ID and Client Secret into Castdeck.

  • Create an app on BASE Developers
  • Enable the View shop info and View order info permissions
  • Register http://127.0.0.1:3039/callback as the callback

Setup steps in Castdeck

From External Service Integration in Settings, work through save, authenticate, connection test, and notification test in order.

  • Save the Client ID and Client Secret
  • Authenticate with BASE
  • Connection test
  • Place the purchase/gift notification part
  • Test notification

Amazon Wish List Notifications

Sync your purchased list and display items added since the last sync as purchase/gift notifications.

  • Open the purchased filter
  • Sync with the bookmarklet
  • The first run registers a baseline
  • From the second run on, only differences are notified

OBS WebSocket Integration Guide

An optional setting that automatically controls BGM, sound effects, and video audio in Castdeck layouts as OBS scenes switch.

What OBS integration can do

Automatically mutes BGM, sound effects, and video audio in Castdeck layouts that aren't currently shown.

  • Normal OBS display works without integration
  • Prevents lingering audio across multiple scenes
  • Retrieves the current scene name
  • Mute-controls Castdeck browser sources

Setup steps in OBS

OBS 28 and later include WebSocket support by default.

  • Open OBS
  • Open WebSocket Server Settings from Tools
  • Enable the WebSocket server
  • Check port 4455
  • If authentication is on, check the password

Setup steps in Castdeck

From External Integration in Settings, register the OBS host, port, and password.

  • Enable OBS integration
  • For the same PC, the host is 127.0.0.1
  • The port is 4455
  • Enter the password
  • Turn on audio control
  • Connection test

When you can't connect

If you see ECONNREFUSED or a not-connected status, the WebSocket server in OBS may not be listening.

  • Check that OBS is running
  • Check that the WebSocket server setting is on
  • Check the port number
  • Check the password
  • For another PC, check the IP address and firewall

When there's no sound

Apart from WebSocket integration, also check the audio control setting on the individual OBS browser source.

  • In the OBS browser source properties, turn on "Control audio via OBS"
  • Check the OBS audio mixer
  • Check Castdeck's connection test
  • Check that the current scene contains the /layout browser source
  • Temporarily turn off OBS integration and check

Connecting other platforms

Castdeck can also ingest comments from streaming sites other than YouTube.

How to connect

Twitch, TwitCasting, Kick, Niconico Live, and Whowatch are supported.

  • Open Settings > Streaming accounts and connect from each platform card
  • Twitch / TwitCasting use account linking; Kick connects by channel name
  • Once connected, comments from every platform appear together on the Dashboard

Notes on experimental support

Some platforms are experimental and sensitive to upstream changes.

  • Niconico, Whowatch, and Kick are experimental and may break when the platform changes its behavior
  • If comments stop arriving, disconnect once and reconnect
  • TTS, pinning, and effect rules work the same for comments from any platform

Items within Screen Effects

How to use themes, effects, chat boxes, pins, stats, goals, text-to-speech, and asset management.

Themes & Presets

Unify the color scheme and look shared across chat boxes, pins, the stats bar, goals, and more.

  • Theme selection
  • Sync on/off
  • Individual customization

Effects

Trigger audio, images, video, and effects based on conditions such as comments, Super Chats, subscriptions, and likes.

  • Trigger conditions
  • Asset selection
  • Appearance position
  • Test playback

Asset Management

Register images, audio, and video in the in-app file manager and reference them from each settings screen.

  • Upload to the asset storage location
  • Check the name and type
  • Select from effects or the layout

How to trigger effects

The basic steps for triggering audio, images, video, and screen effects during a stream.

1

In Screen Effects, open Asset Management and register the audio, images, and video you want to use.

2

In the Effects tab, create a trigger rule and set conditions such as comments, Super Chat amount, subscriptions, and likes.

3

Assign the display asset, sound effect, text, and display duration to the rule.

4

Place the effect parts in the stream layout, and paste just the single stream layout URL into OBS.

5

Use test playback to confirm the effect appears in OBS and the sound plays.

6

During the stream, effects fire automatically when an event matches the conditions.

What's new in v0.5

How to use the features added in recent updates.

Per-screen effect rules

Effect rules can apply to all screens or to one layout only.

  • Switch the scope per rule in the Layout Builder effect rules
  • "This screen only" rules fire only while that layout is live in OBS
  • If multiple different layouts are shown at once, only all-screen rules fire

Persistent vs. one-shot media

When adding an image or video part, choose how it appears.

  • "Always visible" keeps it on screen (logos, frames, etc.)
  • "Play once" adds it as an effect rule you can trigger manually or by comment conditions
  • You can change the trigger any time from the effect rule inspector

Part browser

Adding parts and effects is unified into the Add Part browser.

  • Pick individual effects from the Reaction genre and configure trigger & content before adding
  • Slot, poll, BGM, etc. are limited to one per layout (you are guided to edit the existing part)
  • The slot has a Test Spin button that runs without meeting entry conditions

Comment translation (Pro, coming soon)

Automatically translates comments from overseas viewers. Launching soon.

  • Toggle translation on the Dashboard
  • Comments containing Japanese kana skip translation for speed
  • Planned as a Castdeck Pro feature

Voice advice

Transcribes the streamer's voice as input for the AI advisor.

  • Enable voice advice on the AI Advisor page
  • Transcription runs on-device (local Whisper); audio never leaves your computer
  • The first run may take tens of seconds to download the model

TTS with VOICEVOX / COEIROINK

Use character voices as the TTS engine.

  • Start VOICEVOX or COEIROINK on your PC first
  • Pick the engine and speaker in TTS settings, then confirm with test playback
  • If TTS is silent, check that the engine app is running

Troubleshooting

Check common sticking points organized by cause.

Can't connect to YouTube

It may be stuck somewhere in the stream URL, authentication, or API permissions.

  • Check Google login status
  • Check that it's your current live broadcast
  • Check that live chat is enabled
  • Disconnect once and reconnect

Nothing shows up in OBS

Check the URL, source size, and overlay server status.

  • Check the layout URL
  • Set the OBS browser source width/height to your stream resolution
  • Keep the app running and refresh OBS
  • Refresh the browser source cache

Audio or video won't play

Check asset registration, OBS audio settings, and file format.

  • Check that it's registered in the asset manager
  • In the OBS browser source properties, turn on "Control audio via OBS"
  • Check the OBS browser source audio mute
  • If OBS integration is on, check the connection test and current scene
  • Check the volume settings and your PC's output device

Design changes aren't applied

Check the sync setting and reload on the OBS side.

  • Check theme sync
  • Check the custom template
  • Refresh the OBS browser source
  • Re-apply the theme or preset

When you're in trouble

Stay calm and check things in order of least impact on your stream.

First, check these

If display or audio stops during a stream, start by checking the basic state.

  • Whether the app, OBS, and YouTube Studio are running
  • Whether the Dashboard is connected to the stream
  • Whether the layout URL is set in OBS
  • Whether the needed assets are in the asset manager

Basic recovery steps

Refresh the OBS and Castdeck connections in order.

  • Refresh the OBS browser source
  • Disconnect and reconnect the stream in Castdeck
  • Re-save your Google login and API keys
  • Restart the app and check the URL

Pro plan (subscription) cancellation & billing

You can cancel yourself at any time from Paddle's emails — no need to contact support.

Buying & activating Pro

Purchase in the browser (Paddle); activation is automatic via your Google account.

  • Press "Upgrade to Pro" on the upgrade page — the checkout opens in your browser
  • After purchase, return to the app and press "Activate after purchase" (sign in with the same Google account you bought with)
  • If it says the purchase was not found, wait a minute and try again

How to cancel

Castdeck Pro payments are processed by Paddle, our Merchant of Record.

  • Open your purchase confirmation email or a monthly receipt email (sender: Paddle)
  • Open the "Manage subscription" link in the email
  • Choose "Cancel subscription"

Notes on cancelling

Timing and refunds work as follows.

  • Pro features remain available until the end of the current billing period
  • No pro-rated refunds (for duplicate or erroneous charges, contact us on this page)
  • If you cannot find the email, search your spam folder for "paddle"
  • On the Free plan an on-air Castdeck credit (watermark) is shown; Pro can hide it (after official launch)