Compress, convert and trim video

Video Tools has three tabs: Compress, Convert and Trim. On Linux and Windows they need FFmpeg; if it is missing, each tab shows a red box that says FFmpeg was not found on this system. See Install FFmpeg.

The tools read MP4, MOV, MKV, WEBM, AVI, M4V, WMV, FLV, TS, MTS and 3GP files. While a video is processed, its row in Results shows a progress bar and a percentage.

Compress

Re-encodes videos as H.264 MP4, the format almost every site and phone plays.

1. Open Video Tools. The Compress tab is open.

2. Add one or more videos.

3. Choose a Quality:

   Choice	CRF
   High quality	20
   Balanced (default)	26
   Smaller	30
   Smallest	34

   CRF (constant rate factor) is the encoder's quality setting: a lower number keeps more detail and gives a bigger file.

4. Optionally choose a Resolution cap: Original, 1080p, 720p or 480p. Taller videos are scaled down to that height; shorter ones stay as they are.

5. Select Compress video.

The result is always an MP4 with _compressed added to the name. Sound is re-encoded as AAC at 128 kbps.

TIP

Lowering the resolution saves the most space. A phone video recorded in 4K often looks the same on social media at 1080p.

Convert

Changes the format.

1. Open the Convert tab and add videos.

2. Under Output format, choose MP4, MKV, MOV, WEBM or GIF.

3. Select Convert video.

The result keeps the original name with the new extension, for example clip.webm.

• MP4, MKV and MOV use H.264 video and AAC sound.
• WEBM uses VP9 video and Opus sound. VP9 encoding is slow, so expect it to take longer.
• GIF is made at 12 frames per second and 480 pixels wide, with no sound. GIFs get large quickly, so convert short clips only.

Trim

Cuts out part of one video.

1. Open the Trim tab and add one video.

2. Type a Start time. Empty means the beginning.

3. Type an End time. Empty means the end of the video.

   Times can be written as seconds (90), minutes and seconds (1:30), or hours, minutes and seconds (0:01:30). Decimals such as 12.5 work too.

4. Choose how to cut:

   • Frame-accurate cut (re-encode) off (default): the cut is instant and keeps the original quality and format, but it starts at the nearest keyframe, so it can begin a moment earlier or later than the time you typed.
   • Frame-accurate cut (re-encode) on: the cut is exact, but the video is re-encoded, which takes longer, and the result is an MP4.

5. Select Trim video.

The result gets _trimmed added to the name. If the end is not after the start, the app says End time must be after start time.

A keyframe is a complete picture stored every few seconds in a video; the frames in between only store changes, which is why a cut without re-encoding has to start at one.

Next steps

• Convert and compress audio
• Troubleshooting and FAQ