FastScene user guide

macOS

1. Download the macOS installerFastScene supports Apple Silicon and Intel on macOS 14 or later.
2. Open the DMGDrag FastScene into Applications and open it normally.

Windows

1. Download from fastscene.appChoose Download for Windows. FastScene supports 64-bit Windows 10 and 11.
2. Keep the file in Microsoft EdgeThe Windows build is not yet publisher-verified, so Edge may flag an uncommon download. Open the menu beside the file, choose Keep, then Keep anyway if another confirmation appears.

   

   

3. Open the installerRun FastScene.exe. On Windows protected your PC, choose More info.

   

4. Choose Run anywayConfirm the app name is FastScene and that you downloaded it directly from fastscene.app, then choose Run anyway.

   

5. Finish setupLaunch FastScene and keep a stable connection while the lightweight installer downloads the video engine once.

   

Account and license

• Sign in with the same Google account used to buy or renew FastScene.
• Trial includes 5 successful exports. Your projects stay on your computer afterwards.
• Pro is licensed to one device. Custom projects are a separate one-time add-on.
• A web purchase or renewal normally appears in an open app within about 5 minutes without signing out.

Comparison project

1. Name the projectUse a short, recognizable name. FastScene creates a separate folder and saves edits automatically.
2. Paste the scriptEach line is a reading beat. Break lines where you want the pacing to change.
3. Build comparisonsEach item has labels, colors, left/right media and a starting script line.

Custom project

• Custom projects require the one-time custom-layout add-on.
• Each slide can include titles, multiple text layers, image or video, effects, sound and its own background.
• New slides inherit relevant style choices so you do not need to rebuild every control from scratch.

Comparison editor

• Set the main and secondary labels, colors and label font.
• Replace media or paste an image with Cmd+V on macOS and Ctrl+V on Windows.
• Use zoom, crop/rotate and background removal to frame the subject.
• Add comparisons or a single-image scene, then choose presenter poses and sound cues.

Custom editor

• Drag text, images and subtitles directly on the preview.
• Add multiple text layers, select an effect and sound for each content box, and add more slides.
• Use a color, image or video as the project background.

Upload a complete voiceover

1. Prepare one full audio fileThe recording should follow every script line in order.
2. Choose Voice File/API → Upload fileSelect the MP3, WAV or another supported audio file.
3. Align captionsWord-accurate karaoke needs the ElevenLabs API key with the first 3 Access permissions in the callout above.

ElevenLabs manual or API

• Manual: paste the full script into Text to Speech, choose a voice and model, generate, download, then upload the file to FastScene.
• API: create a restricted API key with the first 3 Access permissions, copy the Voice ID, and save both in FastScene API key management.
• Keep API keys private and use a credit limit to control third-party spend.

Gemini API

1. Create a keyOpen Google AI Studio API Keys and create a new key. Never publish or share it.

   

2. Add it to FastSceneOpen API key management, choose Gemini and add the key. FastScene can rotate multiple keys on permission or quota errors.
3. Set the deliveryChoose voice, style, pace, accent and randomness before rendering. Word-accurate karaoke still needs the ElevenLabs key in the callout above.

Vbee and Edge TTS

• Vbee: add your App ID, Token, voice code and speed, then choose Batch or Realtime.
• Edge TTS needs no API key, but still requires network access to generate speech.
• Enable Regenerate audio cache only when you want to replace an existing generated voiceover.

Single project

1. Select the projectChoose it on the dashboard so it appears in the render panel.
2. Check audio and advanced settingsConfirm the provider, branding, resolution, speed and volume.
3. Start renderKeep the app open and follow the progress log.
4. Open the resultThe final file is output/final_video.mp4 inside the project folder.

Batch render

• Select multiple projects or Select all, then start the queue.
• Batch render cannot use a manually uploaded audio file. Save Gemini, ElevenLabs API, Vbee or Edge TTS settings first.

Publishing copy

• The first caption line becomes the YouTube title.
• The full caption is used for Facebook and the YouTube description, and can be edited before upload.
• Keep the Facebook source URL in the separate Source comment field.
• Choose publish now or a schedule for each platform.

Publish to both platforms

• Connect at least one Facebook Page and one YouTube channel.
• FastScene uploads Facebook first, then YouTube. Keep the app open until both complete.
• For scheduled Facebook Reels, add the source comment after the Reel is actually published.

1. Create the project and enable the API

1. Create or select a projectOpen Google Cloud Console and create a dedicated project, or select one you already use.

   

2. Open API LibraryGo to APIs & Services → Library and search for YouTube Data API v3.

   

3. Enable the APIOpen its Product details page and choose Enable.

   

2. Configure OAuth consent

1. Start the consent screenOpen OAuth consent screen → Get Started, then enter the app name, support email and developer contact email.

   

2. Choose ExternalUse External for regular Google accounts or accounts outside your organization.
3. Add test usersWhile the app is in Testing, add every Google account that needs to connect a channel.
4. Move to In productionOnce setup works, change Publishing status to In production. External apps left in Testing can have refresh tokens limited to about 7 days.

3. Create the OAuth client

1. Open ClientsChoose Clients → Create Client and use Web application as the application type.
2. Add the callbackPaste the exact FastScene URI below into Authorized redirect URIs.
3. Save the credentialsCopy the Client ID and Client Secret and keep both private.

http://localhost:8765/api/social/youtube/callback

4. Connect the channel in FastScene

• Open Upload Center with a project that already has output/final_video.mp4.
• Open OAuth key or Add channel, paste the Client ID and Client Secret, then Save and connect.
• Sign in to the Google account that can upload to the channel and approve the requested YouTube scopes.
• Review title, description, visibility or schedule, then upload.

5. Common OAuth issues

• redirect_uri_mismatch: the Google Cloud URI must exactly match the localhost:8765 callback in FastScene.
• No refresh_token: remove the old app under Google Account → Security → Third-party access, then add the channel again.
• invalid_grant or revoked token: reconnect. If it repeats after about 7 days, move the consent screen out of Testing.
• Another account cannot sign in: add it as a Test user or move the app to In production; Google may require verification depending on distribution and scopes.

1. Create the Meta app

1. Create AppOpen Meta for Developers → My Apps → Create App.
2. Choose the Page use caseFilter Content management and select Manage everything on your Page. This is the use case used to publish Page content and video.

   

3. Choose a Business portfolioSelect the portfolio that manages the Page, or continue without one when appropriate.

   

4. CustomizeFinish app creation, then open Customize/Add use cases if Meta asks for more setup.

   

2. Add Page permissions

1. Add the Page permission setIn Use cases/App Review, add pages_show_list, pages_read_engagement, pages_read_user_content, pages_manage_posts, pages_manage_metadata and pages_manage_engagement. public_profile normally accompanies Meta sign-in.

   

3. Generate and extend the Page token

1. Open Graph API ExplorerOpen Graph API Explorer and select your Meta app at the top of the page.

   

2. Get User Access TokenChoose Get User Access Token, tick the Page permissions, then Generate Access Token.

   

3. Choose the PageIn the permission window, select the Page you want to connect and allow the requested permissions.

   

4. Switch to a Page tokenBack in Graph API Explorer, change User or Page to the Page and generate the access token again.

   

5. Confirm the permissionsThe Explorer permission list should show the full Page permission set.

   

6. Extend the tokenCopy the token into Access Token Debugger, choose Debug, then Extend Access Token. Copy the extended token. About 3 months of expiry is normal; extend it again when it expires.

   

4. Save and publish in FastScene

• Open Add Page, paste the Page ID and extended Page access token, then save. The token stays on this computer and is not shown again.
• Choose Draft, Publish now or a schedule, then review the caption and upload.
• Facebook Reels have no separate title. FastScene keeps the source URL in Source comment and sends it only after the Reel is published.

5. Take the app Live

A Development/Testing app is normally limited to admins, developers and testers. To publish Reels for a real Page, the app must be Live. Watch the video first if you want, then follow the steps below.

1. Create a Privacy Policy URLMeta requires a Privacy Policy URL. You can generate a hosted page, copy the URL, then paste it into Meta.

   

2. Paste it on Go LiveOpen Go Live. Paste the Privacy Policy URL and confirm the Page management use case is on the app.

   

3. Publish while UnpublishedThe Publish sidebar still shows Unpublished. Choose Publish, finish any remaining Meta items, then make the app public.

   

4. Confirm LiveWhen finished, Publish changes to Published. A Live app can publish Reels for Pages outside tester accounts, depending on whether Meta still requires App Review.

   

6. Common errors

• OAuthException or invalid token: the token expired, is for the wrong Page, or is missing permissions; generate or extend a new Page token.
• Cannot publish: confirm the account can create Page content, the app is Live, and the permission set is complete.
• A failed source comment can mean the Reel is still processing; wait until it is published, then retry the comment.

Audio and APIs

• Gemini 401/403/429: check the key, free-tier quota (~10 TTS calls/day), billing and permissions, or add another key.
• Misaligned karaoke: keep the script identical to the speech and add an ElevenLabs key with the first 3 Access permissions (Text to Speech, Forced Alignment, Voice Generation).
• Vbee errors: check App ID, Token, voice code, mode and script length.

YouTube and Facebook

• redirect_uri_mismatch: copy the exact localhost:8765 callback into Google Cloud.
• YouTube invalid_grant: remove the old account permission and connect the channel again.
• Facebook permission errors: confirm the Page, pages_manage_posts permission and the app's Live/tester status.

App and license

• If a web purchase is not visible, confirm both surfaces use the same Google account, leave the app open for about 5 minutes, then refresh.
• Upload Center needs active Pro and a rendered final_video.mp4.
• Wait for autosave before closing the app immediately after an edit.