Convert a video file into an MP4 with H.264 and AAC. When the file is already compatible it is rewrapped in seconds without losing quality, otherwise it is re-encoded. Runs on your device.
How to use
- Add your video. Drop a MOV, WebM, AVI, MKV, FLV or other video file into the tool.
- Choose a mode. Automatic tries a fast copy first. Choose always re-encode if you need the most compatible result.
- Convert. Press the button. A copy finishes in seconds, a re-encode takes about as long as a quarter to a full playing time depending on your device.
- Download the MP4. Preview it, then download. The original file is not changed.
Features
Fast copy when possible
MOV and MP4 files that already contain H.264 and AAC are rewrapped without re-encoding, so there is no quality loss.
H.264 and AAC output
The most widely compatible combination, and the one YouTube recommends for uploads.
Even dimensions and fast start
Output sizes are made even and the index is moved to the front so the file plays and seeks cleanly.
No watermark, no limit
The file never leaves your device, so there is nothing to meter or brand.
Handles phone and screen recordings
iPhone MOV files and screen recordings that use unusual codecs convert without extra software.
What people use it for
- Convert an iPhone MOV into an MP4 that every editor opens.
- Turn a WebM screen recording into an MP4.
- Fix an upload that gets stuck processing or plays without sound.
- Rewrap a file into MP4 without re-encoding, so there is no quality loss.
- Prepare a clip from an old camera or phone in AVI, MKV or 3GP.
- Make a file work in an editor that does not accept its original format.
Does YouTube need MP4?
YouTube accepts many formats, including MOV, MP4, AVI, WMV, FLV, 3GP and WebM, so you do not have to convert. In practice MP4 with H.264 video and AAC audio is the safest choice: it uploads without surprises and tends to finish processing sooner.
Converting also helps when a file refuses to upload, shows no audio, or has odd colours. Re-encoding to standard settings usually removes those problems.
Quality and file size
Copy mode keeps the quality exactly. Re-encoding at the high quality setting is visually close to the original. Do not compress heavily before uploading, because YouTube re-encodes everything again and each pass loses detail. Upload the best version you have.
Copy mode and re-encode mode
A video file is a container holding separate video and audio streams. If those streams are already H.264 and AAC, the container can be swapped for an MP4 in seconds without touching the picture or the sound, which is why copy mode has no quality loss. If the streams use a different codec, such as HEVC from a newer phone or VP9 from a WebM, the video has to be re-encoded to H.264, which takes longer and applies some compression.
Quality settings explained
The quality choices set how aggressively the encoder compresses. High quality is visually very close to the original and makes bigger files. Balanced suits most videos. Smaller file trades some detail for size. Whatever you choose, the output is a normal H.264 and AAC MP4 with a fast-start index, so it begins to play quickly.
Frame rate and colour
The converter keeps your frame rate. Variable frame rate videos from phones and screen recorders can cause audio drift in some editors, and re-encoding with the high setting usually settles that. HDR footage may look flatter when converted to a standard MP4, so if colour matters, upload the original to YouTube instead.
Troubleshooting
The converted file has no sound
The original audio may use a codec that cannot be copied into MP4. Choose always re-encode, which converts the audio to AAC.
It says the file could not be converted
The file may use a rare codec the browser cannot decode, or it may be damaged. Try another source file, or a desktop tool for unusual formats.
The tab runs out of memory
Very large files can exceed browser memory. Files under about 500 MB are the practical limit on most devices.
The colours look different
HDR and some wide-gamut footage changes when converted to a standard MP4. Upload the original when colour accuracy matters.
Limits and good to know
- Files over about 500 MB can run out of browser memory on some devices.
- Re-encoding is slower than copying and uses more battery on a phone.
- A few rare codecs cannot be decoded in the browser. If a file fails, try another source file.
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FAQ
Is this converter free?
Yes. There is no limit, no account and no watermark.
Is my video uploaded?
No. It is converted in your browser.
Will it reduce quality?
Copy mode does not. Re-encoding at the high setting is very close to the original.
Does it download videos from YouTube?
No. It only converts files you already have on your device.
Why is a re-encode slow?
Your device does the work in a browser, which is slower than desktop software. Shorter clips and desktop browsers are faster.
Is MOV to MP4 lossless?
It is when the MOV already holds H.264 and AAC, because the streams are copied. HEVC video has to be re-encoded.
Does YouTube convert my video anyway?
Yes, it makes its own versions. Converting first is mainly to avoid upload and playback problems with unusual files.
Will the file get bigger?
A copy stays almost the same size. A re-encode at high quality can be a little larger or smaller than the original.