Turn a PowerPoint deck into a narrated video, fully offline. Each slide's speaker notes are read aloud in your own cloned voice (Chatterbox-Turbo), and the slides and narration are encoded into a single AV1 or HEVC video with subtitles.

Built for long lecture decks - a series of 90-minute lectures is the everyday workload. Finished work is kept, so after editing the notes of three slides, only those three are recorded again.

What it does

• Your voice from a short sample. 10-20 seconds of clean speech is enough to clone a voice. Audition a test phrase before processing a whole lecture.
• Animations, transitions and embedded videos are kept when Microsoft PowerPoint is installed: every slide is rendered the way PowerPoint plays it. A video with its own sound waits until the narration has finished; a silent video or GIF keeps looping for as long as the slide is on screen. Without PowerPoint, slides become still images.
• One button. Make video goes from the deck to the finished file: slides, narration, encoding.
• Whole folders at once. Point it at a folder of decks (subfolders included) and it processes every one with a single model load, skipping decks whose video is already up to date.
• Edit the narration in the app. Change a slide's notes, exclude slides, re-record just one slide, and listen to each slide's audio before encoding.
• Clean sound. Silence trimming, smooth joins, and the whole track evened out to a steady loudness.
• Subtitles included. Every video comes with .srt and .vtt subtitles timed to the narration.
• Pause and resume any long run; finished slides are never lost, even when cancelling.
• Nothing leaves your PC. After the one-time model download, everything runs offline.

What you need

• Windows 10 or 11, 64-bit.
• An NVIDIA graphics card with 3 GB of video memory or more and a recent driver. Without one Slidecast still works, just much more slowly.
• About 15 GB of free disk space and an internet connection for the installation.
• Microsoft PowerPoint (optional) - only needed to keep animations, transitions and videos that are embedded in slides. Without it, slides become still images.

Everything else - LibreOffice, ffmpeg and the voice model - is installed for you.

Install

1. Download Slidecast-<version>.zip from the Releases page (the newest is at the top).
2. Unpack it to a folder whose path has no spaces or non-Latin letters, e.g. C:\Slidecast.
3. Double-click Install.cmd. It downloads everything Slidecast needs (about 10 GB, so it takes a while), checks your graphics card and adds a Slidecast shortcut to the Desktop and the Start menu. At the end it lists what it found, each line marked [ok].

Then open Slidecast from the Desktop or the Start menu. After the installation it works offline.

If the installation stops with an error, check the internet connection and run Install.cmd again - it continues where it stopped. Running it again later also repairs the installation.

To uninstall, delete the Slidecast folder and the two shortcuts. LibreOffice and ffmpeg stay installed; remove them in Settings > Apps if you do not need them.

How to use it

The steps on the left go top to bottom:

1. Decks - drop a .pptx into the window or press Browse for deck. You get a table of slides with a preview, the notes, the expected length and the state of each slide. Double-click a slide to edit its narration; right-click for more (re-record, play, include/exclude, reset notes). Switch to Folder (batch) to process a whole folder of decks.
2. Voice - choose the reference recording of your voice, then press Synthesize test phrase to hear how it sounds. Expressiveness and the pauses between sentences and slides can be tuned here.
3. Synthesis - see how much of the narration is ready and preview how each slide's notes will be read, split into parts.
4. Export - video quality and size, codec, audio, and the output folder, with a live estimate of the file size.
5. Rebuild - redo just one part of a video (slides, narration, the final video) or free disk space. Enter slide numbers such as 3, 7, 12-15 to re-record only those slides.

Press Make video in the Decks step to do everything in one go. The status bar shows progress and the time left, with Pause and Cancel.

The settings in Voice, Synthesis and Export can be changed with no deck open: they then become the defaults for new decks and for folder runs.

Where the files go

Slidecast creates a folder next to each deck, <deck name>_slidecast. The finished video is in its output folder (or in the output folder you chose in Export), together with the subtitles.

Keep this folder: it holds the narration that is already recorded, which is what makes a second run fast. To free disk space, use the Rebuild step rather than deleting files by hand.

Writing the speaker notes

• Bullets, numbering and formatting are removed; each line is read as a sentence.
• Web addresses are read aloud ("example dot com") or skipped - your choice in Synthesis.
• Common abbreviations (e.g., mg, GPU) are expanded - can be switched off in Synthesis.
• [laugh], [chuckle] and [cough] in the notes are performed by the voice.
• Slides without notes stay on screen silently for a few seconds (adjustable in Voice).
• Hidden slides are left out.

Troubleshooting

• "LibreOffice was not found" or "ffmpeg was not found" - run Install.cmd again; it installs whatever is missing. If you installed them yourself somewhere unusual, show Slidecast where they are via File → Set LibreOffice path / Set ffmpeg path.
• The window stays blank or does not open - Slidecast needs the Microsoft Edge WebView2 runtime, which Windows 11 already has; on Windows 10 install it from microsoft.com.
• "Access is denied" while saving audio - OneDrive, Dropbox or an antivirus is holding the file. Slidecast retries automatically; if a slide still fails, run again and it is picked up. It is best to keep decks outside synced folders and only put the finished video there.
• A slide's video talks over the narration - turn on Play slide videos after the narration in Export (it is on by default).
• An embedded video has no sound - it is muted in the deck itself (PowerPoint → Playback → Volume).
• Animations are missing - PowerPoint is not installed, so slides were made as still images.
• Out of graphics memory - close other programs using the GPU, lower the chunk size in Synthesis, or set Processor to cpu in Voice.
• Reference clip rejected - it must be longer than 5 seconds; only the first 10 seconds are used. Use clean speech without music or noise.
• The MP4 plays without sound in some players - choose AAC audio in Export (the MP4 default), or use the MKV container.
• The first run of an animated deck is slow - PowerPoint renders every slide in real time. This happens once; later runs reuse the result.
• Every run writes a log to <deck name>_slidecast/logs/slidecast.log; the Log button in the window shows it too.

License

MIT. © 2026 Edgars Edelmers. Chatterbox-Turbo is MIT-licensed by Resemble AI; LibreOffice and ffmpeg carry their own licenses.

Contact

Edgars Edelmers – [email protected], or open an issue.