Free online WEBM to MJPG converter

Some video editors, cameras, inspection systems, and older playback software require Motion JPEG instead of VP8, VP9, or AV1 video inside a WEBM file. Converting also helps when frame-by-frame editing is more important than the smaller size of the original.

What the WEBM format is

WEBM is an open multimedia container designed mainly for web video. It commonly contains VP8, VP9, or AV1 video and Vorbis or Opus audio. Web browsers, screen recorders, video conferencing tools, and browser-based editors frequently create WEBM files; downloaded browser recordings and captures from services such as OBS Studio are common sources.

The .webm extension identifies the container, not one fixed codec. Check the actual streams with ffprobe input.webm before converting if the source has unusual codecs, variable frame rate, subtitles, or multiple audio tracks.

What the MJPG format is

MJPG, or Motion JPEG, stores each video frame as an independent JPEG image. It is used by some industrial cameras, video capture hardware, medical and inspection systems, older editing applications, and software that needs simple frame-by-frame access.

Independent frames make seeking and editing straightforward and avoid inter-frame decoding. The trade-off is much larger output than WEBM, because JPEG compression is applied separately to every frame. MJPG describes the video encoding; an .avi container is often used when the file must retain audio, while a raw .mjpg stream normally contains video only.

How to convert WEBM to MJPG

Using the built-in online converter

You can convert the file for free on 101convert.com without installing software: select the WEBM file, choose MJPG as the output, start the conversion, and download the result. Use the desktop method below when the file is sensitive, very large, or requires exact codec and audio settings.

Using FFmpeg

FFmpeg is the most controllable desktop option. Install it, open a terminal in the folder containing the source file, and run:

ffmpeg -i input.webm -c:v mjpeg -q:v 3 -pix_fmt yuvj420p -an -f mjpeg output.mjpg

This creates a raw MJPEG video and removes audio because the raw MJPEG output does not provide a dependable audio track. The -q:v value controls JPEG quality: lower values produce better quality and larger files; values around 2 to 5 are typical.

To keep audio in a broadly supported container, create an AVI file instead:

ffmpeg -i input.webm -c:v mjpeg -q:v 3 -pix_fmt yuvj420p -c:a pcm_s16le output.avi

Use -an in the AVI command as well if the receiving application accepts video only. To preserve a selected frame rate, add an explicit setting such as -r 30; otherwise FFmpeg normally follows the source timing.

Quality and compatibility limits

This conversion is normally lossy twice: WEBM is decoded and the resulting frames are JPEG-compressed, so increasing the MJPG quality cannot restore detail already lost in WEBM. Expect a substantially larger file, especially at high resolutions or frame rates.

yuvj420p offers wider compatibility but reduces chroma resolution. If the target hardware accepts 4:2:2 JPEG, use -pix_fmt yuvj422p for better color detail. Verify the result with the target device because some systems accept MJPEG only in AVI, require a particular frame rate or resolution, or reject raw .mjpg streams.