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Got an MKV your TV won't play, or a MOV that a website rejects? Add one or several videos, pick the format you need, and they're converted on your computer. When the codecs already fit, the tool simply rewraps them, which takes seconds and loses nothing.
Processing locally on your device
Overview
A video file has two layers: the container (MP4, MOV, MKV, WebM, AVI) and the codecs inside it (for example H.264 video and AAC audio). Many “conversions” only need a new container. An MKV holding H.264 and AAC can become an MP4 without touching a single frame. The converter reads each file's codecs with FFmpeg first and shows a badge per file: Fast remux when the streams can be copied as they are, or Re-encode when they can't.
Fast remux copies the video and audio into the new container. It is lossless and usually finishes in seconds, even for long files. Re-encoding decodes every frame and compresses it again, which is needed when the target format doesn't support the source codec, for example VP9 to MP4, or H.264 to WebM. You can turn fast remux off to force a re-encode, which is useful when an H.265 file must become plain H.264 for an older device.
The output formats each serve a purpose. MP4 (H.264 + AAC) is the universal choice. WebM (VP8 + Opus) is an open web format. MOV (H.264 + AAC) suits Apple workflows and editors. MKV holds almost anything and is popular for archives and media servers. AVI (MPEG-4 Part 2 with MP3 audio, tagged as Xvid) exists for old players and legacy software. MP4 with H.265/HEVC is typically 30–50% smaller than H.264 at the same quality, but encodes several times slower and isn't supported by every browser or PC.
Re-encodes use a quality slider (CRF 18–32, where lower means better quality and a bigger file); the value is mapped sensibly for VP8, H.265 and MPEG-4. Everything runs in FFmpeg compiled to WebAssembly, a one-time download of about 31 MB that is cached afterwards. Remuxing is near-instant, but re-encoding in a browser is slower than desktop software, so allow a few minutes per minute of HD footage. Several files are processed one after another and can be downloaded together as a ZIP.
| Format | Codecs | Best for |
|---|---|---|
| MP4 | H.264 + AAC | Everything: phones, web, social, editors |
| WebM | VP8 + Opus | Open web video |
| MOV | H.264 + AAC | Apple apps and editing software |
| MKV | H.264 + AAC (or copied streams) | Archives and media servers |
| AVI | MPEG-4 Part 2 (Xvid) + MP3 | Legacy players and software |
| MP4 (H.265) | HEVC + AAC | Smaller files on HEVC-capable devices |
Drop one or more videos into the converter. MP4, MOV, WebM, MKV, AVI, FLV, WMV, TS and MTS are accepted.
Wait a moment while each file's codecs are read; each file shows Fast remux or Re-encode.
Choose the output format: MP4, WebM, MOV, MKV, AVI or MP4 (H.265).
Keep fast remux on for lossless conversion where possible, and set the re-encode quality.
Click Convert and download each file, or all of them as a ZIP.
Use cases
Many smart TVs, iPhones and editors refuse MKV, even though the H.264 video inside is perfectly compatible. A fast remux to MP4 fixes this in seconds without any quality loss.
Need an open-format version of a clip for a website or a project that prefers WebM? Convert from MP4 to VP8 + Opus and serve it alongside the MP4.
Old car head units, DVD players with USB ports and some classroom software still expect AVI. The AVI target produces an Xvid-compatible MPEG-4 file with MP3 audio.
For footage you're keeping rather than sharing, the H.265 target produces noticeably smaller files at similar quality, provided your players support HEVC.
Pro tips
Answers to common questions about the video converter.
Remuxing copies the existing video and audio streams into a new container without changing them, so it's lossless and fast. Re-encoding decodes and compresses every frame again, which is slower and slightly lossy, but required when the target format can't hold the original codecs.
Its codecs aren't compatible with the chosen container. For example, WebM can only hold VP8/VP9 video, and MP4 doesn't accept VP9 here, so those combinations must be re-encoded.
Yes. Add as many files as you like; they're converted one after another to the same format, and you can download them individually or together as a ZIP.
HEVC playback depends on your browser, operating system and hardware. Safari and recent Edge versions on supported hardware play it, while many other setups don't. Use the regular MP4 (H.264) target for maximum compatibility.
Remuxing takes seconds regardless of length. Re-encoding runs in your browser's CPU and is slower than desktop software, typically a few minutes per minute of 1080p, and H.265 is several times slower than H.264.
No. ToolEnhancer processes files on your own device inside the browser. They are never sent to, stored on or seen by our servers.
Yes. The video converter is free to use with no sign-up, no watermarks and no daily limits.