MP4 vs MKV vs WebM vs MOV: Video Formats Explained
People often say "video format" when they mean two different things: the container (the file type, such as MP4) and the codec (how the picture and sound are compressed inside it). Understanding the difference makes every conversion decision easier.
Container vs codec
A container is like a box that holds a video track, an audio track, subtitles and metadata. The codec is how each track inside the box was compressed. A file called .mp4 usually holds H.264 video and AAC audio, but the same container can hold other codecs.
The common containers
| Container | Usually holds | Strengths | Weaknesses |
|---|---|---|---|
| MP4 | H.264 or H.265 video, AAC audio | Plays almost everywhere: phones, browsers, TVs, social platforms | Less flexible with many tracks or subtitle types |
| MOV | Similar to MP4, from Apple | Common from iPhones and Apple software | Fewer players outside Apple's world |
| MKV | Almost any codec, many audio and subtitle tracks | Very flexible, popular for movies and archives | Limited support in browsers and on some devices |
| WebM | VP8, VP9 or AV1 video, Vorbis or Opus audio | Open and designed for the web | Less support on some Apple devices and editing software |
Changing the container vs changing the codec
- Changing only the container (called remuxing) copies the tracks into a new box. It is fast and loses no quality, but works only if the new container supports the codecs inside.
- Changing the codec means decoding and encoding again. It takes much longer, and every lossy re-encode loses some quality.
Which should you choose?
- Sharing with anyone: MP4 with H.264 and AAC.
- Video on your own website: MP4 or WebM.
- Keeping many tracks or subtitles: MKV.
- Editing on a Mac or iPhone: MOV or MP4.
If you only need the sound
Often the real goal is just the audio. The Video to Audio page extracts the sound from a video file as MP3, WAV or another audio format, entirely in your browser. Read how to extract audio from a video for the steps and the limits.
Convert your audio files for free in your browser, without uploading them to any server.
Open the converter