Loop video

A looping video is a specific content asset distinct from a regular video. Landing page background videos loop silently. Waiting screen animations loop indefinitely. Digital signage in retail environments runs the same 15-second clip hundreds of times per day. Social media profiles and animated banners on platforms that support video loops need a file that is prebuilt to loop rather than relying on the player's loop attribute.

Building a loop into the file itself (rather than using a player loop flag) is also more reliable in embedded contexts where you do not control the player settings.

Looping uses the concat demuxer, the same mechanism as the merge tool. A text file listing the input file N times (one path per line) is written to the in-browser filesystem and passed to FFmpeg as a concat list. The fast path uses -c copy to stream-copy without re-encoding. If the fast path produces an invalid output (which can happen with some containers), the fallback re-encodes with libx264 and the ultrafast preset and AAC audio.

The number of times the file appears in the concat list equals the number of loops you specified. A 5-second clip with 4 loops produces a 20-second output. The tool validates the output size (must be over 1000 bytes) to detect silent fast-path failures before attempting the re-encode fallback.

For seamless loops, the clip's last frame and first frame must be visually continuous. If the subject moves or the scene changes between the end and the start, the loop seam will be visible. Design or select footage specifically for looping: slow pans, abstract motion, or sequences where the end state matches the start state.

The output file size grows linearly with the loop count. Four loops of a 10 MB clip produces a roughly 40 MB output. For large loop counts, this can approach browser memory limits. If you need a 100-loop output, build a 10-loop file and then loop that, which is faster and uses less working memory.

Creating a looped video with a desktop editor requires duplicating the clip on a timeline, which is conceptually simple but produces a large project file. Command-line FFmpeg with a concat list does the same thing efficiently but requires knowing the syntax. This tool writes the concat list automatically, handles the fast path and re-encode fallback, and downloads the result directly.