Free online PPSX to WEBM converter

A PPSX slideshow is not directly playable in video players or systems that accept only video files. Converting it to WEBM makes the slides available as a timed video for browser playback or video editing workflows.

What the PPSX format is

PPSX is the PowerPoint Open XML slideshow format. It contains presentation slides and may include transitions, animations, audio, and video; opening it in PowerPoint usually starts the slideshow rather than the editing view. Microsoft PowerPoint creates PPSX files, and compatible presentation software can open them.

What the WEBM format is

WEBM is a video container commonly used for web playback. It can carry VP8 or VP9 video and Vorbis or Opus audio. Browser support and efficient compression make it useful for sharing video on the web, though playback depends on the device and browser’s supported codecs.

How to convert PPSX to WEBM

Online on 101convert.com

1. Upload one or more PPSX files on the converter page. Batch conversion is available; the page shows the per-file size limit.
2. Before converting, set Show each page for to choose how long each slide is displayed.
3. Convert the files to WEBM, then download the converted file or files.

Offline with desktop software

On Windows, Microsoft PowerPoint can export a PPSX slideshow as an MP4 video. Open the file, then use File → Export → Create a Video. Choose the video resolution and whether to use recorded timings and narrations; if timings are not recorded, set the seconds per slide. Export as MP4.

Use FFmpeg, available for Windows, macOS, and Linux, to encode that MP4 as WEBM:

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

Replace presentation.mp4 with the exported video’s filename. The optional audio mapping lets the command work when the MP4 has no audio track.

Quality and timing

PowerPoint’s video export can retain slide timings, transitions, animations, and narration; check the export options because unrecorded timings need a duration per slide. FFmpeg’s VP9 encoding is lossy: a lower -crf value generally gives higher quality and a larger file. The example uses CRF 32; adjust it and check the output on the target browser or device.