These files are usually created asynchronously using tools like ffmpeg to ensure the user can see a low-bandwidth version of the video without loading the entire original file.
To provide more specific context, are you seeing this file name in , on a website's source code , or within a shared cloud folder ? Video preview (transcoded mp4) in the thumbnails folder rendered_preview_6.mp4
If you are seeing this filename in a specific article or technical log, it likely points to a rather than a primary content file intended for direct download. These files are usually created asynchronously using tools
Expected behaviour. We can transcode uploaded movies to smaller size and the correct format and save it in the thumbnails folder ( Nextcloud pdf and video preview - Cloudron Forum Expected behaviour
Systems like Nextcloud and ownCloud often convert original high-resolution uploads into smaller, web-compatible MP4 files stored in a "thumbnails" or "previews" folder.