MJPEG to HEVC Converter

Convert MJPEG to HEVC: What This Tool Actually Produces

This converter decodes a Motion JPEG video and re-encodes the picture with the H.265 (HEVC) codec, writing a raw .hevc elementary stream — just the compressed video, with no container wrapper. The win is real and large: MJPEG stores every frame as a full standalone JPEG with no inter-frame compression, so re-encoding to HEVC (which only stores what changed between frames) typically shrinks the file dramatically. Read the next two cards first, though — a raw .hevc stream carries no audio and won't open in most ordinary players, so if you want a normal playable video, convert to a container instead.

How to Convert MJPEG to HEVC

1. Upload Your MJPEG File: Drag and drop your .mjpeg or .mjpg onto the page or click "+ Add Files." IP / security camera exports, webcam captures, microscope and machine-vision acquisitions, and old digital-camera videos all work as input. Batch is supported.
2. Set the Quality Preset or Constant Quality: The codec is fixed to H.265 for .hevc output. Use the Quality Preset ("Very High (Recommended)" by default) for a one-click result, or open Constant Quality to set an explicit CRF when you're testing encoder behavior.
3. Adjust Video Resolution or Trim (Optional): Under Video Resolution keep original (best for evidence and scientific footage), pick a preset, scale by percentage, or enter a custom width × height. Use Trim to export only a time range.
4. Convert and Download: Click "Convert" and download the .hevc stream. No sign-up, no watermark.

Walk-through: Why the File Shrinks (and What It Can't Do)

The size drop is genuine. A 1-minute 1080p MJPEG clip from an IP camera or microscope routinely lands at 400 MB to 1 GB because each frame is an independent JPEG. HEVC adds temporal (inter-frame) compression — it stores one reference frame and then only the differences — so the same footage can come out a fraction of the size at comparable visual quality.

What it cannot do is add detail back. This is a lossy-to-lossy re-encode: the JPEG frames already discarded high-frequency detail, and HEVC cannot recover what isn't there. You get a much smaller file at similar quality, not a sharper one. To balance the two, pick the rate-control mode that matches your goal:

• Testing or comparing settings: use Constant Quality (CRF). It targets a perceptual level rather than a size, so each clip encodes at consistent quality. Lower CRF means higher quality and a larger stream.
• A predictable bitrate for a downstream pipeline: use Constant Bitrate or Variable Bitrate and enter the target in Mbps.
• Just a smaller result: Specific file size lets you name a target and the encoder scales toward it. Combining an aggressive size target with a resolution downscale is where quality loss shows first — change one variable at a time.

Common Errors and How to Fix Them

• "The file has no sound" — Expected. A raw .hevc stream is video-only. If your source was MJPEG muxed in an AVI/MOV with an audio track and you need that audio, convert to a container instead: MJPEG to MP4 or MJPEG to MKV.
• "My phone / QuickTime / TV won't open the .hevc file" — These players need a container. Mux the stream into MP4 (ffmpeg -f hevc -i in.hevc -c copy out.mp4) or convert to MP4/MKV from the start.
• "VLC opens it but the duration or seeking is wrong" — Raw elementary streams carry no timing index, so players estimate timestamps. Muxing into a container with a proper index fixes seek and duration.
• "Output looks pixelated" — You likely paired an aggressive Specific file size target with a resolution downscale. Raise the size target or keep the original resolution.
• "The HEVC won't play on an older device" — H.265 decoding is patchy on pre-2017 hardware and some browsers, and the codec is patent-encumbered. For universal playback, use MJPEG to MP4 with H.264 instead.

When This Doesn't Work

If your source is a bare elementary MJPEG stream it has no audio to begin with, so a silent .hevc is normal. HEVC also encodes slowly compared to H.264 — expect longer processing on long clips. And if your real goal is a shareable, playable H.265 video for a person or a device rather than an elementary stream for a pipeline, skip this page: convert to MJPEG to MP4 or MJPEG to MKV and select H.265, which keeps any audio and plays far more widely. To shrink an existing HEVC further, see HEVC compressor.

Frequently Asked Questions

Will converting MJPEG to HEVC improve the video quality?

No — it makes the file much smaller, not sharper. MJPEG is already lossy (every frame is a JPEG), and HEVC is another lossy step, so this is a lossy-to-lossy re-encode. HEVC cannot rebuild detail the JPEG frames already threw away. What you gain is efficiency: inter-frame compression replaces MJPEG's frame-by-frame redundancy, so you keep comparable visual quality at a dramatically smaller size.

Why does the converted .hevc file have no audio?

Because .hevc is a raw video elementary stream, not a container. It holds only the H.265-encoded picture data, so there is nowhere for an audio track to live. A bare MJPEG stream usually has no audio anyway; if your source was MJPEG inside an AVI or MOV with sound and you need that sound, convert to a container such as MJPEG to MP4 or MJPEG to MKV instead.

Is HEVC really about half the size of the same H.264?

Roughly, at the same visual quality. The HEVC standard (ITU-T H.265 / ISO/IEC 23008-2, ratified January 2013 and published June 2013) was designed to deliver about 25-50% better compression than H.264/AVC, with larger savings at 4K than at lower resolutions. Against a bloated MJPEG source the reduction is far bigger still, because MJPEG has no inter-frame compression at all.

What can actually play a raw .hevc file?

FFmpeg-based players like VLC can usually decode a raw H.265 stream, and developer tools such as GPAC or an HEVC stream analyzer are built for it. Consumer players — phones, smart TVs, QuickTime, most browsers — generally cannot, because they expect a container. To play the result anywhere, mux it into MP4 with ffmpeg -f hevc -i video.hevc -c copy video.mp4, or convert to MP4/MKV from the start.

Should I output a raw .hevc stream or HEVC inside a container?

Choose the raw .hevc stream only when a downstream tool specifically expects an elementary stream — a muxing step, a hardware-encoder test, or codec conformance work. For anything you'll actually watch or share, convert to MJPEG to MP4 or MJPEG to MKV and pick H.265; you keep any audio and avoid the playback headaches of a bare stream. In our testing, a short 1080p MJPEG clip re-encoded to H.265 at the default preset came out a small fraction of the source size with no visible quality drop, while the equivalent H.264 encode was somewhat larger.

Are my uploaded files kept after conversion?

No. Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion. There is no sign-up, no watermark, and files are never shared or made public.