Video Formats: MP4, WebM, MKV & Codecs
The difference between video containers and compression codecs, plus how to pick the right format for web, mobile, and editing.
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Format Comparison & Technical Specifications
| Output Format | MIME Type | Specification | Type |
|---|---|---|---|
| MP4 Video | video/mp4 | ISO-IEC-14496-14-MP4 | MPEG-4 Part 14 Video |
| WebM Video | video/webm | RFC-6386-VP8 | WebM Open Media Video |
| MOV QuickTime | video/quicktime | APPLE-MOV-SPEC | Apple QuickTime Movie Container |
Technical Specifications & Codec Breakdown
Containers vs. Codecs: The Box vs. The Content
A container (like .mp4 or .webm) is simply a box that bundles video, audio, and subtitles together. The codec (like H.264, VP9, or AV1) is the compression formula used to pack the video inside the box. Two MP4 files can have completely different codecs inside.
MP4 (H.264) vs. WebM (VP9/AV1)
MP4 with H.264 is the undisputed king of compatibility - it plays on literally every device, browser, TV, and phone manufactured in the last 15 years. WebM is an open-source, royalty-free web standard designed for high-efficiency browser streaming.
Why Converting Video Takes More Time & Battery
Video files contain millions of frames. Transcoding requires analyzing frame-to-frame motion vectors to compress repetitive backgrounds. When converting video client-side in the browser, modern WebAssembly decodes frames directly on your CPU/GPU at native hardware speeds.
0 bytes uploaded to external servers. All processing occurred locally in your browser sandbox.