Remove Video Metadata with a Verifiable MP4 Export

Video metadata can exist at several levels: global container tags, per-stream labels, chapters, embedded attachments, timed data, and codec or muxer fields. This page builds a new MP4 rather than editing the source in place. It maps the first video stream and available audio streams, optionally maps supported subtitles, disables automatic global and stream metadata mapping, removes chapters, and omits attachments and data streams. That is a strong practical cleanup for ordinary sharing, but it is not a forensic eraser. The new MP4 container and encoder can create fresh technical fields, so verification is part of the workflow.

1. 1

   Choose the source and define the privacy claim

   Select a video and decide what must not travel: location, title, comments, chapters, attachments, subtitle tracks, or internal labels. Also review the visible and audible content separately.

2. 2

   Choose compatible export or fast stream copy

   Compatible mode writes H.264 video and AAC audio with adjustable CRF and preset. Stream copy avoids another video or audio encode but only works reliably when the source codecs belong in MP4.

3. 3

   Export, inspect, and test the cleaned MP4

   Download the result, inspect it with an independent metadata tool, play every retained stream, and confirm the receiving system accepts it before deleting or archiving the original.

A video may carry a title, author, artist, album, description, copyright notice, comment, creation time, encoding application, camera or phone model, GPS-related location, rotation or display information, language labels, chapter names, thumbnail attachments, subtitle descriptions, and application-specific atoms. The exact fields depend on MP4, MOV, MKV, WebM, AVI, the recording device, and every editor that touched the file. Some platforms strip selected tags on upload; others retain, derive, or display them. Removing mapped source metadata before the upload gives the sender more control, but the only defensible statement is based on the downloaded derivative and an inspection tool, not on an assumption about a file extension.

Metadata is only one disclosure channel. A street sign, window reflection, badge, browser tab, notification, waveform, subtitle, spoken name, room sound, visible clock, unique device defect, or burned-in date can identify the same context without any hidden tag. File names and sharing accounts can add more information outside the media container. This tool therefore focuses on a precise technical job: stop selected source streams and mapped metadata structures from entering a new MP4. It does not blur faces, redact screens, mute names, remove logos burned into pixels, alter voice characteristics, erase platform logs, or certify that re-identification is impossible.

Compatible MP4 is the default. It decodes the selected range, writes the first video stream as H.264 with yuv420p pixel format, writes mapped audio streams as 192 kbps AAC, and applies fast-start layout. CRF controls the visual quality and size tradeoff: lower values retain more detail and create larger files; the preset trades encoding time for compression efficiency. Fast stream copy maps video and audio packets without re-encoding, which is much faster and introduces no new codec loss, but copied codecs may be invalid or poorly supported in MP4 and a trimmed start may align to a nearby keyframe. Both modes disable mapped global and stream metadata, remove chapters, and exclude attachments and data streams. Subtitles are off by default; when enabled, supported subtitle streams are converted to mov_text. Fresh muxer and encoder identification can remain as technical metadata.

Use at least one independent inspector such as ffprobe, MediaInfo, ExifTool, or the receiving asset system. Compare global tags, stream tags, chapters, attachments, data streams, subtitle tracks, duration, codecs, resolution, frame rate, audio layout, and file size. A field reported as encoder, compatible brands, codec name, duration, or resolution is often newly generated technical structure rather than copied personal description; decide whether your policy allows it. Search the visible frames and audible program for sensitive information as a separate review. Record the source hash and cleaned-file hash when chain of custody matters, and never overwrite evidence or the only master with the derivative.

• Inspect the downloaded MP4 with a separate metadata viewer or ffprobe and document which fields are absent and which technical fields were newly generated.
• Use compatible mode for uncertain codecs; use stream copy only for video and audio codecs that the receiving MP4 workflow accepts.
• Watch and listen through the entire retained range, check subtitle behavior, and keep the untouched source until the recipient accepts the cleaned derivative.

The normal workflow runs FFmpeg in this browser tab. The selected video is written into a browser-local virtual file system, the new MP4 is produced there, and the result is exposed as a local download. No account or server conversion queue is required. This can be useful for client captures, internal demonstrations, school recordings, support videos, personal phone clips, and pre-publication material that should not be uploaded merely to remove tags.

Browser-local processing does not create organizational controls by itself. The downloaded file still exists on the device, browser extensions or device management may affect the environment, and a user can share the wrong copy. The tool cannot verify consent, classify the content, enforce deletion, preserve evidence, or create an audit trail. For regulated records, investigations, legal discovery, medical media, protected student data, or high-risk source protection, use an approved workstation and a documented review procedure with qualified personnel.

Choose a format-aware forensic suite, ExifTool workflow, controlled transcoding farm, evidence system, or digital asset manager when you must enumerate every atom and private block, preserve or prove chain of custody, sanitize batches against policy, retain selected rights fields, sign a report, compare before-and-after structures, or process uncommon codecs and containers. Some technical metadata is necessary for playback and new encoding creates fresh values. Stream copy can also fail when the source codec cannot be muxed into MP4, while compatible mode changes the encoded picture and audio. Long 4K files can exceed browser memory. This page is intentionally a practical single-file exporter, not a guarantee that no identifying information remains anywhere in the media or surrounding workflow.

• Do not claim anonymity from metadata removal alone; faces, screens, voices, reflections, file names, burned-in overlays, and content can identify people or places.
• Use a forensic or compliance workflow when you need a signed sanitization report, evidence preservation, exhaustive format-specific atom review, or guaranteed policy enforcement.