Free online HEVC to MJPG converter

Legacy video editors, industrial cameras, and playback devices may accept Motion JPEG but reject HEVC/H.265 files. Converting the video creates an MJPEG stream that is easier to decode and edit, although the resulting file is usually much larger.

What the HEVC format is

HEVC, also called H.265, is a video compression codec designed to deliver lower bitrates than H.264 at similar visual quality. Phones, action cameras, screen recorders, CCTV systems, and newer cameras commonly encode HEVC video.

HEVC is often stored inside .mp4, .mov, or .mkv containers; a file named .hevc may contain a raw HEVC video stream. The filename extension therefore does not by itself identify the codec or whether the file has audio. Some older editing applications and hardware decoders cannot open HEVC without additional support.

What the MJPG format is

MJPG, or Motion JPEG, stores video as a sequence of independent JPEG-compressed frames. It is a codec rather than one universal container, so MJPEG video may appear in an .avi file or as a raw .mjpg stream.

Independent frames allow simple frame-accurate editing and low-latency decoding. This makes MJPEG common in older capture hardware, machine-vision systems, video test workflows, and software that does not support interframe codecs. MJPEG requires substantially more storage and bandwidth than HEVC because it does not use motion prediction between frames.

How to convert HEVC to MJPG

FFmpeg is the most flexible desktop method. It reads HEVC from common containers and re-encodes the video with its built-in MJPEG encoder. To create an AVI file with MJPEG video and uncompressed PCM audio, run:

ffmpeg -i input.mp4 -c:v mjpeg -q:v 3 -c:a pcm_s16le output.avi

Replace input.mp4 with the source filename, including its actual extension. The -q:v value controls JPEG quality: lower values produce higher quality and larger files; values around 2 to 5 are common starting points. The command keeps the source resolution and frame rate unless you specify other settings.

For a raw MJPEG stream without audio, use:

ffmpeg -i input.mp4 -an -c:v mjpeg -q:v 3 output.mjpg

A raw .mjpg file has no standard place for audio or container metadata, so use AVI when the target application expects a normal video file or requires sound. If the receiving device requires a particular frame size and pixel format, add filters such as:

ffmpeg -i input.mp4 -vf scale=1280:720,format=yuvj420p -c:v mjpeg -q:v 3 -an output.mjpg

The scale filter changes the dimensions; format=yuvj420p requests JPEG-compatible 4:2:0 pixel format. Remove that filter if the device requires 4:4:4 or another specific pixel format.

To inspect the input before converting, run ffprobe input.mp4. It shows the video codec, dimensions, frame rate, audio streams, and container. A browser-based option is available at 101convert.com, where the file can be converted for free without installing software.

Quality, compatibility, and limitations

The conversion decodes HEVC and encodes every frame as JPEG, so it is a lossy generation even when the source looks clean. MJPEG cannot recover detail already discarded by the HEVC encode. Use a lower -q:v value for better quality, then verify that the output device accepts the resulting file size and bitrate.

MJPEG output is often several times larger than the HEVC source. Raw .mjpg streams may also lack timestamps, duration information, and reliable audio support; AVI is generally more compatible. If the target program only needs a sequence of still images rather than video playback, exporting JPEG frames is a different operation and should use an image-sequence workflow instead.