Free online PPTM to WEBM converter

A browser player or video-editing workflow may require WebM rather than a macro-enabled PowerPoint deck. Converting the slides produces a video, but slide timing and interactive features may not carry over.

What the PPTM format is

.pptm is the macro-enabled presentation format used by Microsoft PowerPoint. It stores slides and can include VBA macros, animations, transitions, and embedded media. PowerPoint creates PPTM files; LibreOffice Impress can also open them, though compatibility with advanced formatting and macros can vary.

What the WEBM format is

WebM is a video container commonly used for web playback. It typically contains VP8 or VP9 video, with Vorbis or Opus audio. It suits browser players and video workflows that accept WebM, but it does not preserve editable slides or runnable macros.

How to convert

Online on 101convert.com

1. Upload the PPTM file on the converter page. You can add several files for batch conversion; the page shows the per-file size limit.
2. Set show each page for to choose how long each page is displayed.
3. Start the conversion, then download the WEBM file.

Offline with desktop software

Free route: LibreOffice, Poppler, and FFmpeg. LibreOffice runs on Windows, macOS, and Linux. Open the PPTM in Impress and export it as a PDF using File → Export As → Export as PDF. Then use Poppler’s pdftoppm and FFmpeg to render the pages as a video; install both command-line tools first.

mkdir slides
pdftoppm -png -r 150 presentation.pdf slides/slide
ffmpeg -framerate 1/5 -i slides/slide-%d.png -vf "fps=30,format=yuv420p" -c:v libvpx-vp9 -crf 32 -b:v 0 presentation.webm

Replace presentation.pdf with the exported PDF’s name. This command displays each page for five seconds; change 1/5 to another rate to adjust the duration. Rendering the PDF as images retains slide appearance but not PowerPoint animations, transitions, narration, or macros.

PowerPoint route: In desktop PowerPoint for Windows, use File → Export → Create a Video, choose a resolution and whether to use recorded timings and narrations, then create an MP4. Convert that file with FFmpeg:

ffmpeg -i presentation.mp4 -c:v libvpx-vp9 -crf 32 -b:v 0 -c:a libopus -b:a 128k presentation.webm

Quality and compatibility

The PDF route turns each slide into a still image, so increasing -r 150 improves image detail but can increase processing time and output size. PowerPoint’s video export is preferable when you need recorded timings, narration, or animations. Check the finished WebM in the intended player because WebM codec support varies by device and application.