Cut MJPEG

How to Cut MJPEG Files Online

1. Upload Your MJPEG File: Drag and drop one or more .mjpeg, .mjpg, or MJPEG-in-AVI / MOV files onto the dropzone, or click "+ Add Files" to browse. Batch processing is supported, so several dashcam or surveillance clips can be queued together.
2. Set Time Range: Enter the start time and duration in HH:MM:SS.ms (e.g., start 00:01:12.500, duration 00:00:18.000). Because every MJPEG frame is a self-contained JPEG, cut points snap to exact frame boundaries — no leading freeze or trailing artifact like you would see when cutting between I-frames in H.264.
3. Choose Output Settings (Optional): Keep MJPEG to preserve the intraframe stream, or pick a different codec under Quality Preset (Highest → Lowest), Target file size (%), Specific file size, Constant Bitrate, Variable Bitrate, Constant Quality (CRF), or Constraint Quality. Use Video resolution to keep original or downscale to a 1080p / 720p / 480p preset.
4. Cut and Download: Click "Cut" to process. Each clip downloads individually or as a ZIP for batches. Files are processed inside your XConvert session — no account, no watermark, no upload to a third party.

Why Cut MJPEG?

Motion JPEG (M-JPEG) stores every frame as an independent JPEG image, with no inter-frame prediction. That intraframe-only design makes MJPEG the easiest video codec to cut accurately — any frame can be the new in or out point without re-rendering a GOP. It also explains why the files are so large (typical compression of roughly 10:1 to 20:1 versus 50:1+ for H.264), which is usually the reason people are trimming them in the first place.

• Trim dashcam footage before sharing — Many dashcams (Garmin, BlackVue, older Mio units, and the budget AVI-based cameras common on Amazon) record in MJPEG so individual frames survive an accident-triggered shutdown. A 5-minute 1080p loop can easily hit 1.5–2 GB; cutting out the 30 seconds you actually need for an insurance claim drops it to under 100 MB.
• Extract incident clips from IP cameras — Axis, Mobotix, and many older Hikvision / Dahua streams default to MJPEG for low-latency viewing and frame-perfect evidence. Cutting a 6-hour MJPEG archive down to a 45-second event clip keeps the original frames intact for chain-of-custody work.
• Isolate findings in medical and microscopy video — Endoscopy, ultrasound, and slide-scanner systems often record MJPEG so each frame is diagnostic on its own. Cutting lets clinicians share only the relevant 10 seconds without recompressing the source.
• Pull a clip from older DSLR / camcorder recordings — Nikon D90 (the first DSLR with video, 2008), Pentax K-7, Canon EOS 5D Mark IV (4K Motion JPEG up to ~500 Mbit/s), and many Apple QuickTime camcorders wrote MJPEG. Cutting in-browser avoids opening a full NLE.
• Prep machine-vision and robotics logs — Industrial cameras and ROS / OpenCV pipelines often stream MJPEG over HTTP because of its low CPU cost and per-frame indexing. Cutting a 20-minute test run down to the failure window makes bug reports actually reviewable.
• Shrink the file at the same time — Combine the cut with a codec change to MP4 (H.264) or HEVC and the same footage typically lands at 5–15% of the MJPEG size with little visible loss.

MJPEG vs Modern Codecs — When Cutting Matters

Property	MJPEG	H.264 (MP4)	HEVC (MP4)
Frame structure	Every frame independent JPEG	I + P + B frames in a GOP	I + P + B frames in a GOP
Frame-accurate cut without re-encode	Trivial — any frame is a key frame	Only possible on I-frames (~1/sec)	Only possible on I-frames
Typical compression ratio	~10:1 to 20:1	~50:1 to 100:1	~100:1 to 200:1
1080p30 bitrate (good quality)	50–100 Mbps	8–15 Mbps	4–8 Mbps
CPU to decode	Very low (single-frame JPEG decode)	Moderate	High without HW
Standardized container?	No single spec; AVI / MOV / MKV all in use	MP4 standard	MP4 standard
Best for	IP cams, dashcams, frame-accurate editing	Sharing, streaming, storage	Maximum compression, modern hardware

Output Quality Quick Guide

Output	Quality Preset / CRF	Roughly what you get on a 60-second 1080p clip
MJPEG (re-mux only)	Unchanged	Identical bytes, just cut to time range
MJPEG re-encoded	Quality Preset = High	~30–60% of original size, visually lossless
MP4 / H.264	CRF 18 (Constant Quality)	~8–15% of original size, archival quality
MP4 / H.264	CRF 23 (default)	~3–6% of original size, web-share quality
MP4 / HEVC	CRF 23	~2–4% of original size, modern devices only
WebM / VP9	Constant Quality preset	~3–5% of original size, browser-friendly

Frequently Asked Questions

Will cutting MJPEG re-encode the video and reduce quality?

Not if you leave the output codec as MJPEG. XConvert performs a stream-copy / re-mux when input and output codecs match, so the cut clip contains the exact original JPEG frames — no generational loss. Quality loss only occurs if you also change codec, resolution, or bitrate.

My dashcam records .mp4 files but the codec is MJPEG. Does this tool still work?

Yes. The "MJPEG" here refers to the video codec, not the file extension. Many dashcams and IP cameras wrap MJPEG inside .avi, .mov, or even .mp4 containers. Upload the file as-is — the tool detects the inner codec. If you want a more universal output, switch the codec to H.264 in the same step.

Why is my MJPEG file so much larger than an H.264 file of the same length?

Because MJPEG has no inter-frame compression — every single frame is a full JPEG. H.264 stores most frames as small "differences" from a previous frame (P-frames and B-frames). A 1-minute 1080p30 MJPEG clip at typical settings is roughly 400–700 MB; the same clip in H.264 is usually 60–120 MB. The trade-off is that MJPEG decodes cheaply and edits cleanly, while H.264 streams more efficiently.

Can I cut MJPEG to an exact frame number, not just a time?

Yes, indirectly. Divide the target frame by the source frame rate to get the time. For a 30 fps clip, frame 450 is at 450 / 30 = 15.000 seconds — enter 00:00:15.000. Because every MJPEG frame is independent, the cut lands on that exact frame; there is no rounding to the nearest GOP boundary the way H.264 trimming usually requires.

Will VLC, QuickTime, and Windows Media Player play the cut file?

VLC plays MJPEG inside AVI, MOV, and MKV containers using the bundled FFmpeg decoder. QuickTime plays Apple-style MJPEG MOV natively. Windows Media Player has spotty MJPEG support and may need the K-Lite codec pack or a switch to H.264 output. If you need a clip that opens on any device with zero codec drama, set the output to MP4 (H.264) during the cut.

Can I cut multiple MJPEG clips at once?

Yes. Drop several files onto the dropzone or add them one at a time. Each file gets its own time range. The batch runs in a single browser session and you can download the results individually or as a single ZIP.

Does cutting strip the audio?

No. If the source MJPEG container carries an audio track (PCM, MP3, or AAC in AVI / MOV), the cut output keeps it synced to the trimmed video range. IP-camera and machine-vision MJPEG streams are usually video-only to begin with, so there is simply no audio to preserve.

Is there a file size limit and do my files leave my computer?

Uploads run through your XConvert session and are processed for your job only — they are not shared with third parties. There is no fixed cap published for the cut tool, but very large multi-GB MJPEG archives may be slower to upload over residential connections. If you need to share the result, see Compress MJPEG or MJPEG to MP4 to shrink the file dramatically before sending.

What if I just want to trim the ends rather than cut a clip out of the middle?

Use the Trim MJPEG tool, which is optimized for "remove the first 5 seconds and the last 10 seconds" workflows. Cut is better when you want to extract one or more arbitrary segments from the middle of a longer recording.