Y4M to AVI Converter
Processing entirely on your device — large files may take a moment.
Some legacy systems and DVR/camera devices only accept AVI input. If your files are still in Y4M format, this page is the shortcut: Y4M is uncompressed video with a text header — the interchange format of video-filter pipelines (avisynth/vapoursynth) and encoder test suites.
This converter runs entirely in your browser using WebAssembly — your files never leave your device, nothing is uploaded, and there are no watermarks, sign-ups or queues. Drop in several files at once to convert them as a batch.
How Y4M compares to AVI
| Y4M | AVI | |
|---|---|---|
| Compatibility | ffmpeg, x264, vapoursynth | Legacy Windows tooling |
| Best for | Filter-pipeline interchange | Reading old archives |
How to convert Y4M to AVI
- 1
Select your files
Drag & drop your Y4M files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to AVI". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted AVI file individually, or grab everything at once as a ZIP archive.
About the Y4M format
Y4M (YUV4MPEG2) is uncompressed video with a one-line text header: resolution, framerate and color space, then raw YUV frames. It is the lingua franca of video-filter pipelines — AviSynth, Vapoursynth and encoder test suites pass frames around as Y4M because there is nothing to misparse.
A Y4M of any real length is enormous (30MB per second of 1080p), so conversion to MP4/WEBM with H.264 or VP9 is always the destination — the value is in the zero-ambiguity input, not the format itself.
+ Strengths
- ✓Zero-ambiguity pixel format declaration
- ✓Standard between filter frameworks
- ✓Lossless by construction
! Limitations
- −No compression whatsoever
- −Color space variants (limited/full) trip decoders
- −Not natively playable in browsers
About the AVI format
AVI (Microsoft, 1992) is one of the oldest video containers still encountered. It has no native understanding of modern features — variable frame rates, modern codecs, subtitles, chapters — and stores everything through a 32-bit indexing system that caps reliable file sizes around 2 GB (OpenDML extensions patched some of this). Most AVIs you meet today are DivX/Xvid-era rips or old capture-card output.
There is no reason to produce AVI today; the realistic task is converting old libraries into MP4, which typically cuts file size by half or more at equal or better quality.
+ Strengths
- ✓Opens in legacy Windows tooling
- ✓Simple structure, decades of player support
! Limitations
- −Obsolete: no modern codecs or features by design
- −Large overhead, ~2 GB practical ceiling
- −Codec zoo inside — playback is guesswork
Why convert Y4M to AVI?
Converting makes sense where the strengths of AVI meet what Y4M cannot give you. Opens in legacy Windows tooling Meanwhile No compression whatsoever One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this Y4M to AVI converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for Y4M to AVI?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Does converting Y4M to AVI re-encode my video?
Yes. The video is decoded and re-encoded with the settings chosen by the quality slider, which is what allows the format and size to change. For an archival copy, keep higher quality; for sharing, lower quality gives a much smaller file.
Will the audio track be kept?
Yes. The audio is carried over and re-encoded to the standard audio codec of AVI, staying in sync with the video. If your Y4M file has multiple audio tracks, the first one is used.