MP4 files from phones and cameras are recorded at high bitrates to capture every detail while filming. Re-encoding them with H.264 at a sensible quality usually makes them much smaller without a visible difference, and lowering the resolution saves even more.
How to compress an MP4
- Upload the MP4 (up to 2 GB).
- Choose A quality level (Balanced looks like the original in most videos) or A file size in MB.
- Keep Maximum resolution: 1080p, or choose 720p for an even smaller file.
- Start and download the compressed MP4. The result shows the size before and after.
What makes the difference
- Resolution: a 4K video has four times the pixels of 1080p. On a phone or laptop screen the difference is hard to see, but the file is far smaller at 1080p.
- Quality level: Balanced keeps the picture close to the original; Small file and Smallest file allow more compression artefacts in fast motion and fine detail.
- Codec: H.264 plays everywhere. H.265, AV1 (both MP4) and VP9 (WebM) reach the same quality with fewer bits, but take longer to encode and need newer devices.
- Frame rate: 60 fps videos can be limited to 30 fps under “More options”.
- Sound: 128 kbps AAC is plenty for most videos; 64 kbps is fine for speech.
When the file doesn't get smaller
If the MP4 is already efficiently compressed (for example a download or a previous export), a higher quality setting can make it larger. The result warns you when that happens; choose Small file or a lower resolution.
Upright phone videos stay upright, HDR videos are converted to standard dynamic range, and the main sound track is kept.
More about what this tool reads and writes: Video Compressor.