MP4 Converter
Convert almost any video file into MP4 with H.264 video and AAC audio: the combination that plays on phones, televisions and browsers.
Convert with this tool
or choose a file from your device — it is processed in this tab and never uploaded
Accepted: MKV, MOV, AVI, WebM, M4V, MPEG-TS, FLV, WMV, 3GP, MPEG-2
Files stay on your device. There is no upload, no queue and no watermark, so a conversion works even with the network switched off after the page has loaded.
Supported formats & processing
| Accepted input | MKV, MOV, AVI, WebM, M4V, MPEG-TS, FLV, WMV, 3GP, MPEG-2 |
|---|---|
| Produced output | MP4 with H.264 video and AAC audio |
| Processing | FFmpeg.wasm (video engine, downloaded on first use) |
| Upload required | No — the file is read locally and never transmitted |
How to use this tool
- Add the video fileAny container the FFmpeg engine can read is accepted.
- Leave the defaults unless you have a reasonH.264, CRF 23, veryfast, AAC 192 kbps plays everywhere.
- Downscale if the file is large1280 px wide is enough for most screens and cuts the size substantially.
- ConvertProgress is reported from the encoder log, with the timestamp being processed.
- Preview and downloadThe result plays in the built-in player before you save it.
About this tool
MP4 is the format to choose when you do not know what will play the file. With H.264 video and AAC audio inside it, the answer is essentially everything made in the last fifteen years — phones, smart televisions, game consoles, browsers and editing software.
This page sets the sensible defaults for you: H.264 with a veryfast preset, CRF 23 for quality, yuv420p pixel format for maximum compatibility, and AAC at 192 kbps. Every one of those can be changed, but if you just want a file that plays, the defaults are already correct.
Features
- Correct yuv420p pixel format for maximum player compatibility
- H.264 baseline-friendly encoding that phones and televisions accept
- AAC audio at a bitrate you choose, or audio removed entirely
- Optional resolution and frame-rate conversion in the same pass
- Trimming to a time range without a separate step
- Works from MKV, MOV, AVI, WebM, FLV and WMV sources
Frequently asked questions
Why will my television not play the MP4?
Usually the pixel format or the profile. H.264 High profile at level 4.1 with yuv420p is the safest combination, and it is what this tool produces by default. 10-bit sources should be converted to 8-bit.
How long does a conversion take?
Roughly one to three times the length of the video on a modern laptop, depending on resolution. A five-minute 1080p clip typically takes three to eight minutes.
Can I convert without re-encoding?
Only if the source is already H.264 and AAC inside a compatible container. In that case a stream copy would be possible; with other codecs the video must be re-encoded.
Is the file uploaded anywhere?
No. FFmpeg runs inside your browser as WebAssembly, so the video stays on your device for the entire conversion.