Containers and codecs
MP4, MOV and WebM are containers: files that hold a video stream, an audio stream and some information about them. The codec inside decides the quality and size. The same H.264 video can sit in an MP4 or a MOV file and look identical.
The three formats
- MP4: the safe choice. Usually H.264 or H.265 video with AAC audio, and it plays on almost every phone, computer, TV and website.
- MOV: Apple's QuickTime format, what iPhones and Macs record. iPhones often record H.265 (HEVC), which some older Windows computers and editors cannot open without an extra codec.
- WebM: an open format from Google with VP9 or AV1 video and Opus audio. It plays in every modern browser, but older phones, TVs and Apple apps may not open it.
Which to use
- Sending to someone or uploading: MP4 with H.264.
- Editing on a Mac: MOV is fine.
- On your own website: MP4, with WebM as a smaller alternative if you want.
Converting and shrinking
Compress Video takes any of the three and makes a smaller H.264 video, at a quality or a target size you choose. Cut it down first with Trim Video, pull out the sound with Video to MP3, or make a short clip into a GIF with Video to GIF. All of them run in your browser, so the video is not uploaded.