Common video formats: codecs and containers
MP4, WebM, MOV: the difference between a container and a codec, and which to pick for a given use.
Container vs codec
- The container (the file extension:
.mp4,.mov,.webm) bundles video, audio and metadata together. - The codec (H.264, H.265, VP9, AV1…) is the algorithm that actually compresses the picture and sound inside it.
The same container (.mp4) can hold different codecs, which is why an .mp4 file sometimes plays on one device and not another.
Common formats
| Container | Typical video codec | Typical use |
|---|---|---|
| MP4 | H.264 (most compatible) | Web, sharing, social media |
| MP4 | H.265 / HEVC | Better compression, less compatible with older devices |
| WebM | VP9 / AV1 | Web, open source, heavily used internally by YouTube |
| MOV | H.264 / ProRes | Professional video editing (Apple ecosystem) |
| GIF | — (not a real video codec) | Short, silent animations, heavy files for the quality obtained |
For the general web, H.264 in an MP4 container remains the safest choice for maximum compatibility, optionally offering WebM/AV1 as well to cut file size on browsers that support it.
Resolution and bitrate
A video's file size depends as much on bitrate (in Mbps) as on resolution: a low-bitrate 1080p video can be smaller than a very-high-bitrate 720p one, for sometimes similar perceived quality.
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