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AI VTuber Broadcast

This guide shows how to run an AI VTuber-style YouTube live stream from the ProjectP client.

The basic flow is:

  1. Prepare YouTube OAuth.
  2. Add the Broadcast Console HUD item to your character and prepare a target NPC.
  3. Log in to YouTube from the console.
  4. Use Go Live and copy the RTMP values to OBS.
  5. Start streaming from OBS.
  6. Let the console relay live chat to the NPC.

Prerequisites​

Before using the Broadcast Console HUD item, prepare:

  • a YouTube channel that is allowed to go live
  • YouTube Data API v3 enabled in Google Cloud Console
  • an OAuth 2.0 desktop client
  • the OAuth Client ID
  • the OAuth Client Secret
  • OBS
  • a loaded ProjectP world with at least one NPC

Notes:

  • Some desktop OAuth flows can work without a secret, but the current ProjectP sample expects both values.
  • If the OAuth consent screen is still in testing mode, add the intended Google account as a test user.

1. Prepare The HUD Item​

  1. Load a world with at least one NPC.
  2. Add the Broadcast Console HUD item to your character.
  3. Open the console UI.
  4. Enter Google Client ID.
  5. Enter Google Client Secret.
  6. Choose Broadcast, or leave it as Auto (Recommended).
  7. Choose Target NPC.

Target selection behavior:

  • Auto uses the first NPC found in the loaded world.
  • An explicit NPC name uses the selected NPC.

2. Log In To YouTube​

  1. Click Login YouTube.
  2. Sign in with the Google account that owns the YouTube channel.
  3. Approve access.
  4. Return to ProjectP and check that the console is connected.

The console stores token state locally, so repeated login is usually unnecessary while the refresh token remains valid.

3. Go Live​

  1. Click Go Live.
  2. Wait while the console creates or reuses the YouTube live stream.
  3. Wait while the console creates or refreshes the broadcast session.
  4. Check that the console displays:
    • Watch
    • RTMP
    • Key

Keep the console open while setting up OBS.

If the button changes to Enter Live Mode, click it to open the live view.

4. Configure OBS​

  1. Create a new OBS scene.
  2. Add the ProjectP client as a source.
  3. Open Settings -> Stream.
  4. Choose Custom.
  5. Paste RTMP from the console.
  6. Paste Key from the console.
  7. Start streaming in OBS.
  8. Wait for the console to detect that the stream is live.

Recommended capture order:

  • Game Capture
  • Window Capture
  • Display Capture

5. Test Live Chat​

After OBS starts streaming and the console reports that the stream is live, send a test message in YouTube live chat.

The selected NPC should receive the message and reply through its AI chat and speech setup.

Troubleshooting​

  • If login fails, check the OAuth Client ID, Client Secret, consent-screen test users, and YouTube live access for the channel.
  • If the NPC list is empty, make sure an NPC is loaded in the current world.
  • If chat appears on YouTube but the NPC does not answer, check Target NPC, the NPC's AI chat setup, and the console state after Go Live.
  • If OBS is streaming but YouTube does not become live, recheck RTMP and Key in OBS.