deck-to-video

Deck to Video (slides + narration → self-playing mp4)

Overview

Turn N slide images (or a PDF) + N per-slide audio clips into one mp4: each slide holds for exactly its narration's length plus a short pause, then hard-cuts to the next. Overlays: a filling progress bar + seconds-remaining countdown (bottom-right) and an "N / M" slide counter (top-right).

The one command (the script ships in this skill's own scripts/ directory — call it by its full path there):

python3 <this-skill-dir>/scripts/build_video.py SLIDES AUDIO_DIR out.mp4
# SLIDES = slides.pdf (rasterized at 200dpi) OR a directory of per-slide images
#          (numeric-aware ordering: s2 before s10; zero-padded names still recommended)
# AUDIO_DIR = slide01.mp3, slide02.mp3, … — count MUST equal slide count
# options: --size 1920x1080 · --pad 0.7 · --no-bar · --no-counter · --bar-color HEX · --crf 20
#          --highlights hl.json · --anim-fps 30   (see "Highlighting elements" below;
#          scripts/make_highlights.py builds hl.json)

On success it prints one line per slide — that per-slide length already includes the pad — and ends with duration matches segment sum (it exits non-zero otherwise).

Getting the inputs right

1. Slides: if starting from a pptx, rasterize from real PowerPoint, not LibreOffice. Export the pptx to PDF via actual PowerPoint (the office-render skill does this on macOS), then hand the PDF to the script — LibreOffice substitutes fonts and re-flows layouts, so the video would not match what the deck's author sees. 200 dpi keeps dense slide text crisp at 1080p. (Already have per-slide images? Use them directly — skip this step.)
2. Audio: one clip per slide, named slideNN.mp3. If the clips came from elevenlabs-tts' generate_tts.py (which narrating-pptx uses), they are already in this exact shape — reuse it so the pptx and the video sound identical.
3. If narration pace was adjusted (e.g. ffmpeg -filter:a atempo=1.1), build the video from the adjusted files.