AVI to MJPEG Converter

What an AVI to MJPEG Conversion Produces

Motion JPEG stores every frame as its own complete JPEG image, with no prediction between frames. That is why editors love it — any frame can be decoded, scrubbed to, or replaced without touching its neighbours — and why the files are big. This page re-encodes the video stream inside your AVI to MJPEG and writes it with a .mjpeg extension, which is a raw elementary stream rather than a full container. Read the two tables below before you convert: a raw .mjpeg file carries picture only, with no audio and no timing information, and that surprises people who expected a drop-in replacement for their AVI.

Motion JPEG at a Glance

Where the MJPEG Frames Should Live

The codec and the file wrapper are separate decisions. If you want Motion JPEG frames and the sound from your AVI, you need a real container rather than the raw stream.

For the middle row, run AVI to MOV and change the Video Codec to MJPEG — you get the same intraframe JPEG frames with the audio track and proper timing intact. For the bottom row, use AVI to MP4.

How to Convert AVI to MJPEG

1. Upload Your AVI File: Drag and drop your .avi file onto the page, or click "Add Files" to choose it from your computer. Several files can be queued and processed with the same settings.
2. Set the Quality Preset: Open Advanced Options. Under File Compression the Preset starts at "Very High (Recommended)", and Constant Quality is available as the alternative. Because MJPEG compresses each frame independently, this control maps to per-frame JPEG quality rather than to a bitrate.
3. Adjust Video Resolution or Trim: Video resolution offers Keep original, Resolution Percentage, a Preset Resolution, or an exact Width x Height. Trim starts at "Unchanged" and lets you export a single Time Range. Scaling down and trimming are the two reliable ways to stop an MJPEG export from ballooning.
4. Convert and Download: Click Convert and save the .mjpeg file. No sign-up, no watermark.

Why the File Gets So Large

MJPEG has no compression between frames. A locked-off shot where nothing moves still stores the entire scene again on every single frame, whereas H.264 or H.265 would record "same as before" in a handful of bytes. That is the trade: perfect frame independence in exchange for size. A 15-second 426x240 source clip lands at roughly 4.6 MB as raw MJPEG at the default preset — about four times the 1.2 MB the same clip takes as H.264 in a MOV. Scale that up to 1080p and a few minutes of footage and the numbers get uncomfortable quickly. Your three levers are the Quality Preset, a smaller Video resolution (halving both dimensions cuts the per-frame data to roughly a quarter), and Trim.

Frequently Asked Questions

Does the .mjpeg file keep the audio from my AVI?

No. A .mjpeg file is a bare sequence of JPEG frames with no container around it, and there is nowhere in that structure to put an audio stream — the sound from your AVI is not carried into the output. This is a property of the raw format, not something a setting can change. If you need Motion JPEG frames with the audio intact, convert to MOV and set the Video Codec to MJPEG instead; a real container stores the audio track alongside the video.

Why does the MJPEG play at the wrong speed or report an odd frame rate?

Because a raw Motion JPEG stream stores no timestamps. There is no header saying "these frames run at 29.97 fps", so a player or a tool like ffprobe falls back to an assumed rate — commonly 25 fps — regardless of what the source AVI actually ran at. A 30 fps clip written to .mjpeg and then read back will therefore look slightly slow, while the same conversion into a MOV or AVI container reports the original rate correctly. If frame timing matters to your workflow, use a container.

Is the MJPEG file larger than the original AVI?

Usually, and often by a lot. AVI is only a wrapper, so the comparison really depends on what codec was inside it. Most AVIs in circulation hold DivX, Xvid, or MS-MPEG-4, all of which use interframe prediction and are far more space-efficient than storing a full JPEG per frame, so the MJPEG version grows. The exception is a genuinely uncompressed or HuffYUV AVI, where JPEG compression on each frame will make the file smaller.

What software actually opens a .mjpeg file?

Professional editing and inspection tools generally handle it: VLC, ffmpeg-based utilities, and non-linear editors such as Premiere Pro and DaVinci Resolve can read a raw MJPEG stream. Phones, smart TVs, browsers, and general-purpose media apps typically cannot — they expect a container with headers and timing, not a bare frame sequence. If your file needs to open somewhere unpredictable, MJPEG in any form is the wrong target.

Is Motion JPEG a standardized format like MP4?

Not in one place. There is no single ISO or ITU specification titled "Motion JPEG"; the individual frames are ordinary JPEG, but how those frames are framed, timed, and stored is defined separately per transport. IETF RFC 2435 defines the RTP payload format used by IP cameras and streaming devices, and the OpenDML AVI M-JPEG File Format Subcommittee documented how MJPEG lives inside an AVI file. That fragmentation is a large part of why MJPEG playback support varies so much between applications.

Why would I convert to MJPEG instead of MP4?

Choose it when frame independence is the point. Every frame decodes on its own, so scrubbing is instant and exact, an editor can cut on any frame without a re-encode of the surrounding GOP, and a corrupted frame damages only itself instead of propagating through a prediction chain. That is why MJPEG persists in editing intermediates, IP cameras, scientific capture, and machine-vision pipelines. For sharing, streaming, or phone playback, H.264 in an MP4 wins on every axis that matters.

How do I control the quality of each JPEG frame?

Through the Quality Preset under File Compression. MJPEG is driven by a JPEG quantizer scale rather than a target bitrate, which is why the bitrate-style controls you may have seen on other video pages do not apply here — there is no CRF, no constant or variable bitrate, and no two-pass mode. "Very High (Recommended)" keeps frames clean and the file large; stepping down compresses each frame harder and shrinks the output proportionally.

What happens to my file after the conversion?

Your AVI is uploaded over an encrypted connection, converted on our servers, and both the upload and the output are deleted automatically a few hours later. There is no sign-up, no watermark, and files are never shared or made public. The original file on your own machine is untouched. Because MJPEG output is large, the practical constraint on a long clip is upload and download time over your connection rather than any per-file cap.