Why large files may fail in browser-based tools
Browser tools are convenient and private, but large files can hit memory, codec, or performance limits.
The browser has limits
A browser tab has less room to work than a dedicated desktop video editor. Large videos can require memory for the original file, temporary working files, decoded frames, and the exported result.
Codec support matters
A file can use a codec that your browser cannot preview directly. FFmpeg may still process some files, but unsupported codecs, unusual audio tracks, or damaged media can cause failures.
What to try
Use a shorter clip, close other heavy tabs, try a modern desktop browser, resize before compressing, or split a long recording into smaller pieces. Processing time depends on file size, device performance, browser, and selected settings.