File formats
CS2 Demo Formats: .dem, .dem.zst & .dem.bz2
Demos may arrive as raw .dem files or compressed archives. Compression reduces the file size; the contents are still game replay data, not video.
Updated
What each extension means
- .dem is the raw replay file used by CS2 and supported demo tools.
- .dem.zst is a demo compressed with Zstandard.
- .dem.bz2 is a demo compressed with bzip2.
- .mp4 is an encoded video output and cannot be parsed as a match demo.
Which file to upload
Select .dem or .dem.bz2, up to 1 GiB. Extract other archive formats to .dem before selecting them. The service uses Zstandard internally for transfer, but the file picker does not accept .dem.zst.
What stays after upload
- A previously analyzed demo may open faster while its local result is still available.
- The demo is kept only while it is needed to create videos.
- If the uploaded demo has been removed, upload it again to make another video.
- Finished videos remain in your library until you delete them.
Frequently asked questions
Should I extract a .dem.bz2 before uploading?
It is not required when the upload flow supports that compressed demo format. Keeping it compressed can save transfer time.
Can I rename a video to .dem?
No. Renaming the extension does not convert encoded video into game replay data.