Compress video
Video Compressor re-encodes videos to make them smaller or to change their format. It uses FFmpeg, which must be installed on your Linux or Windows computer. It is not available on Android.
If FFmpeg is missing, a red box at the top says FFmpeg was not found with the install command, and the compress button stays greyed out. See Install the helper tools.
Compress a video
On the home screen, select Video Compressor.
Add one or more videos: click the drop box or drag files onto it. It accepts MP4, MKV, MOV, AVI and WEBM.
Set the options (see below). The defaults, MP4 at CRF 26, are a good start.
Select Compress, for example Compress 2 videos.
Videos are processed one after another. Large videos take a while; the button shows Processing… until all are done.
The new file gets _compressed added to its name and the extension of the chosen format, for example clip_compressed.mp4.
Options
| Option | Choices | What it does |
|---|---|---|
| Format | MP4 (default), MKV, MOV, AVI, WEBM | The container of the new file |
| Resolution | Original, 1080p, 720p, 480p, 360p | The new height; the width follows to keep the shape |
| Frame rate | Original, 60 fps, 30 fps, 24 fps | Frames per second |
| Quality | CRF 18 to CRF 40 | Lower CRF means better quality and a bigger file |
| Target size | None, 10 MB, 25 MB (email), 50 MB, 100 MB | Aims for a file of about this size |
| Remove audio | on or off | Drops the sound track |
CRF (constant rate factor) is the video encoder's quality setting. Moving the Quality slider to the right lowers the CRF and raises the quality. The default is 26.
Target size
With a Target size, CompressX reads the video's length and works out the bitrate that fits the size. The Quality slider is then turned off. The result lands close to the target but can be a little over or under. 128 kbps is set aside for the sound unless Remove audio is on.
TIP
For a long video, a small target size gives poor quality. Lower the Resolution as well, for example to 720p or 480p.
How formats are encoded
- MP4, MKV, MOV and AVI use H.264 video and AAC sound at 128 kbps.
- WEBM uses VP9 video and Opus sound at 128 kbps.
Some FFmpeg builds leave out H.264 (for example Fedora's ffmpeg-free). Then MP4, MKV, MOV and AVI fail and only WEBM works.