One tool, four containers
The dedicated pages on Tinyvert cover the common pairs; this one is for everything else. Drop any mix of .mp4, .mov, .mkv, .webm, .ts or .m4v files, choose MP4, WebM, MOV or MKV from the Output format menu, and each file is rewritten into that container. The guiding rule is simple: copy the streams if the target allows them, encode only if it does not, and say which happened.
Copy when possible, encode when required
A video file is a container holding compressed streams. Changing the container does not require touching the streams, provided the new wrapper is allowed to hold them, and that is true far more often than people expect.
| Output | Accepts | Sources that copy losslessly |
|---|---|---|
| MP4 | H.264, HEVC, AV1, VP9, VP8; AAC, MP3, Opus, FLAC | MOV, MKV, TS, WebM |
| MOV | Much the same as MP4 | MP4, MKV |
| MKV | Much the same as MP4 | MP4, MOV, WebM, TS |
| WebM | VP8, VP9, AV1; Opus, Vorbis | MKV or MP4 files already holding VP9 or AV1 with Opus; H.264 and AAC are always re-encoded |
When a stream does not fit, Tinyvert decodes it and encodes it with the browser's WebCodecs encoders, hardware-accelerated where the device allows: H.264 for MP4, MOV and MKV when the browser can produce it, otherwise AV1 or VP9; VP9 for WebM; and AAC or Opus for audio, or a copy when the container permits. Audio in codecs outside these lists, such as AC-3 from a camcorder, is re-encoded as well, provided the browser can decode it.
Choosing a format
- MP4 when the video must play on phones, TVs, in PowerPoint or on social platforms. It is the safe default.
- MOV for Final Cut Pro, iMovie and other Apple workflows that prefer QuickTime files.
- MKV for archiving and for media servers such as Plex and Jellyfin, which handle it natively.
- WebM for self-hosted web video and open-source platforms; expect a re-encode and a longer wait.
Quality and Max resolution
Both fields are ignored during a copy. They take effect when a re-encode is unavoidable, or when you choose a Max resolution (1080p, 720p, 480p or 360p) smaller than the source, which forces one; Quality then sets the trade-off between size and detail. Videos are never upscaled, and rotation flags from phone clips survive a copy, so portrait footage stays upright.
Where it runs
Entirely on your device, in Chrome, Edge, Brave or Opera (desktop and Android), Safari 17 or newer, or Firefox 130 or newer. No upload, no queue, no watermark, and the page works offline after the first visit. Large files are limited by your device's memory. When size rather than format is the problem, Compress Video is the better tool, and MOV to MP4 covers the single most common job with its own guide.