Y4M to MP4 converter
Convert Y4M to MP4 in seconds, free and unlimited. No upload, no sign-up, no watermark: your video never leaves your device.
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Quick answer: To convert Y4M to MP4, add the Y4M file to the iHateFiles Y4M to MP4 converter and press Convert. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. Y4M is a format most software has stopped opening. MP4 is not.
Should you convert Y4M to MP4?
Yes, if the Y4M will not play where you need it. MP4 with H.264 plays on essentially everything, which is why nearly every other video format is converted to it.
The picture is re-encoded
A Y4M usually holds completely uncompressed frames with no sound. This writes H.264 video with AAC sound into the MP4. The source is uncompressed, so this is the first and only round of loss.
There is no sound to carry
A Y4M carries no audio track, so the MP4 comes out silent. If the sound exists as a separate file, add it afterwards with the Replace Audio tool.
Expect a smaller MP4
H.264 video is a much more efficient codec than what a Y4M holds, so at the same visual quality the MP4 is usually a third to a half of the size.
Where the MP4 will play
MP4 plays on every phone, laptop, TV, browser and messaging app.
Y4M and MP4 side by side
| Y4M | MP4 | |
|---|---|---|
| Inside the file | completely uncompressed frames with no sound | H.264 video with AAC sound |
| Compression | Lossless | Lossy |
| Carries sound | No | Yes |
| Plays on | Needs converting first | every phone, laptop, TV, browser and messaging app |
| Here | Read only | Read and write |
What usually goes wrong
About the Y4M. A few seconds of Y4M can be larger than a whole film in MP4. That is the format doing its job.
About the MP4. Two MP4 files can behave completely differently depending on the codecs inside. A file that will not play is usually an unusual codec in an ordinary container, not a broken file.
How to convert Y4M to MP4
- Add your Y4M file. It is read from your disk and stays there.
- Check the settings. The output format is already set to MP4.
- Press convert and the MP4 file is saved back to your device.
MP4 converter: everything that converts to MP4
Questions
How do I convert Y4M to MP4?
Open this page, add your Y4M file, and press convert. The file is decoded and re-encoded by your own browser and saved back to your device. Nothing is uploaded.
Is this Y4M to MP4 converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Will converting to MP4 lose quality?
MP4 is a lossy format, so some detail is discarded. The quality control on this page decides how much. The default is set high enough that most people cannot see the difference.
Can I convert several Y4M files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.