Shrink a video for LINE messaging

Bring a phone clip or screen recording closer to a size LINE can handle. Trim the unneeded parts, drop the resolution, and convert to MP4 — all in the browser, no upload required.

🔒 No files are sent to any server

Open the video compressor

Opens with LINE-friendly defaults (Balanced quality / 720p / MP4). You can adjust everything inside the tool.

Video compressor →

What to check before sending on LINE

Length: Clips longer than ~5 minutes can stall during LINE's send-time re-encoding.
Resolution: 4K and full HD often fail to send off Wi-Fi.
Format: iPhone HEVC (.mov) can fail to play on some recipients' devices. MP4 (H.264) is the most compatible target.

There is no universal "guaranteed to send" size — outcomes depend on LINE's current behaviour, the connection, and the device. The goal of this page is to bring the file closer to a size that sends reliably.

The basics of making a video lighter

Cut what you don't need: The single biggest win, with no quality loss.
Drop the resolution: 720p or 480p typically cuts file size dramatically.
Convert to MP4: Best compatibility for chat recipients.

The tool you'll use

The video compressor outputs H.264 / MP4, lets you pick a resolution, and offers a quality slider (High / Balanced / Small). Everything runs in your browser. If you also need to cut a section first, use the trim tool before compressing.

The FFmpeg command

Prefer the command line? Here's a way to do the same job with FFmpeg directly (the browser tool above uses its own optimized settings, so the output won't be byte-for-byte identical).

ffmpeg -i input.mp4 -vf scale=-2:720 -c:v libx264 -crf 28 -pix_fmt yuv420p -c:a aac -b:a 96k -movflags +faststart output.mp4

This drops the video to 720p and re-encodes it smaller. Here scale=-2:720 sets the height to 720 and the -2 auto-picks a width that keeps the aspect ratio and stays divisible by 2 (H.264 requires even dimensions); -pix_fmt yuv420p and -movflags +faststart improve playback compatibility across devices and players. For an even smaller file, lower the height with -vf scale=-2:480 or raise the quality factor toward -crf 30.

The command runs on a generic input.mp4 and was tested with FFmpeg 8.1.

Steps

Click "Video compressor" above. It opens with Balanced quality, 720p, MP4.
Pick the video file.
If there's a long head or tail you don't need, trim first with the trim tool.
For more shrinkage, slide the quality toward "Small" or drop the resolution to 480p.
Hit "Compress" and download the result.

If your phone struggles to process the file

Files over ~200MB can crash a mobile browser tab due to memory limits. A desktop browser (latest Chrome / Edge / Firefox) handles them much more reliably.

If processing stalls, trim the clip first to shorten the duration — compression becomes far more stable.

FAQ

Q. Is there a hard LINE size limit?

A. It varies by app version and connection, so there is no single guaranteed number. Aim smaller rather than larger, and prefer MP4 / H.264 at around 720p — that combination sends reliably in most cases.

Q. Why does my iPhone .mov file fail to send or play?

A. iPhone clips are often HEVC inside a .mov container, which some recipients' devices can't play. Converting to MP4 / H.264 improves the odds it plays on the other end.

Q. Will compressing reduce the quality?

A. Yes — re-encoding is lossy, so some quality is always lost. Trimming the unneeded parts and dropping the resolution shrink the file far more effectively than crushing the quality, so do those first.