Play Y4M files in your browser
Raw, uncompressed video for codec developers and test suites. Play a Y4M right here, and keep it as a much smaller MP4. Nothing leaves your device.
Or drop it anywhere on this page
What you'll see
Your video starts playing the moment it opens, sized to fit your screen.
- Plays at once, sized to fit
- Play and pause • Drag the timeline
- Step frame by frame • Change the speed
- Export • Save as MP4 or MOV
About Y4M
YUV4MPEG2, or Y4M, is raw video: a line of text with the size and frame rate, then every frame's pixels as they are. It comes from the mjpegtools, and FFmpeg, x264 and codec test suites read and write it.
A Y4M holds 4:2:0, 4:2:2 or 4:4:4 frames at 8 bits or more, with no sound and nothing compressed, so a minute of 1080p at 30 frames a second is about 5.6 GB.
Filepeek reads it a frame at a time with FFmpeg inside your browser, and Export saves an MP4 a small fraction of its size.
YUV4MPEG2 video
.y4m
Format
- MIME type
- video/x-yuv4mpeg
- Made by
- The mjpegtools project
Inside the file
- Video
- Uncompressed YUV
- Audio
- None
- Made by
- FFmpeg, x264 and mjpegtools
- Made for
- Testing video codecs
Opens in every browser
Filepeek plays Y4M with FFmpeg in Chrome, Edge, Firefox and Safari. No browser plays it by itself.
- YouChromePlays through Filepeek
- YouEdgePlays through Filepeek
- YouFirefoxPlays through Filepeek
- YouSafariPlays through Filepeek
Apps that open Y4M
- Windowsmpv, VLC and ffplay
- Macmpv, IINA and VLC
- iPhone and iPadNo app built in plays it
- AndroidNo app built in plays it • An MP4 saved here does
Questions
Why is my Y4M so big?
Every frame is kept whole and uncompressed. Export's Save as MP4 makes a copy a small fraction of the size.
Why is there no sound?
Y4M holds only frames.
Can I convert it to MP4?
Yes. Choose Export, then Save as MP4.