How the compressor reduces file size
The video is re-encoded with the H.264 codec using constant-quality mode. Instead of targeting a fixed file size, the encoder keeps visual quality consistent and spends fewer bits on simple scenes. Audio is converted to 128 kbps AAC, and the file is optimized so it can start playing before it fully downloads.
Picking the right settings
- High quality keeps the video close to the original. Good for footage you'll edit or archive.
- Balanced is the best choice for most uses — sharing on social media, sending in chat apps, or embedding on a website.
- Smallest file saves the most space. Fine details soften, but speech and screen recordings stay readable.
Lowering the resolution saves even more. A 4K phone video reduced to 1080p often shrinks dramatically with little visible difference on a phone or laptop screen. The tool never upscales: if your video is already smaller than the chosen resolution, it keeps its size.
Why didn't my video get smaller?
Videos exported from editing apps or downloaded from streaming sites are often already compressed efficiently. Re-encoding those at high quality can produce a similar or larger file. The tool always shows you both sizes, so you can keep whichever file is better. Try the “Smallest file” level or a lower resolution for a bigger reduction.
Supported formats and limits
Upload a MP4, MOV, M4V, WEBM, MKV, AVI video up to 500 MB. The compressed file is always an H.264 MP4. Long, high-resolution videos take the longest; if a job runs past the processing time limit, trim the video or choose a lower resolution.
More tools for your video
If you only need the audio, MP4 to MP3 produces a much smaller file than any video compression can. To add captions before you share the video, use the Subtitle Generator, and to get everything that's said as a document, use Video to Text.