WMV / M4V / 3GP / FLV Tag Editor

WMV M4V 3GP FLV Tag Editor - Edit Video Metadata Tags Online Free — Read, edit and save the metadata tags (title, artist, album, album artist, genre, year, track, comment) of Windows Media Video (WMV), Apple M4V, 3GP / 3G2 and Adobe FLV files. Existing tags are read from the file automatically and shown in the form below; change any field and click Save. The video and audio streams are copied unchanged (-c copy) and never re-encoded, so quality is kept perfectly lossless. Everything runs locally in your browser, with files never uploaded to a server.
Lossless tag editing: this page only rewrites the metadata of the video container - the video and audio streams themselves are copied unchanged, so there is no quality loss at all. The original file is left untouched; a new "_tagged" file is produced. Note: 3GP / 3G2 containers do not store user tags (title / artist / album ...) in a way that can be rewritten, so tag edits on those files are not applied. Files protected by DRM (e.g. iTunes FairPlay M4V) cannot be processed.
First use loads an ~30MB video processing engine into the current browser. It is cached and reused afterwards, so please be patient.
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Click to select or drag and drop a WMV / M4V / 3GP / 3G2 / FLV file
WMV, ASF, M4V, 3GP, 3G2 or FLV video; under 500MB recommended
Video Tags
Select a WMV / M4V / 3GP / 3G2 / FLV file first. Its existing tags are read automatically and filled in below. Edit any field and click "Save Tags" - the video and audio streams are copied without re-encoding. Fields left empty keep the value already stored in the file.
The stream copy failed for this file, so the video and audio streams will be re-encoded to save the tags. Video quality may be reduced compared to the original.
What are WMV, M4V, 3GP and FLV?

These are four video containers from four eras of digital video. WMV is Microsoft's family (Windows Media Video codecs in the ASF container). M4V is Apple's video variant of MP4, the format iTunes video ships in. 3GP / 3G2 are the stripped-down MP4 cousins designed in 2001 for feature phones. FLV is Flash Video, the format that carried YouTube's first decade. What they share — and the reason one editor can handle all four — is the split between container and streams: the tags this page edits live in the container layer, and the video/audio streams themselves are copied through untouched.

Five facts to anchor the rest of the page:
• all four are containers; the codecs inside (WMV/VC-1, H.264, H.263, Sorenson Spark...) are separate decisions
• M4V is MP4 with Apple extras — it can carry FairPlay DRM, which no editor can bypass
• 3GP/3G2 were built for 2000s phones; their metadata standard has no slot for user tags, so edits cannot be saved into them
• FLV outlived Flash itself (browsers dropped plugin support in 2020) — millions of archived files remain
• saving tags runs a stream copy: streams are moved through byte-for-byte, never re-encoded
Four containers, one common idea

WMV arrived in 1999 as Microsoft's answer to RealVideo; its most advanced version was standardised as VC-1 (SMPTE 421M) and is legal inside Blu-ray discs. The WMV codec rides in the ASF container, whose tag objects this page rewrites exactly as in the WMA/ASF audio editor. M4V uses the same MPEG-4 atom structure as MP4 — the differences are conventional: iTunes treats .m4v as video, allows AC-3 audio tracks, and can wrap the file in FairPlay encryption. 3GP (3GPP) and 3G2 (3GPP2) are MPEG-4 files economised for phones: small boxes, H.263 or MPEG-4 Part 2 video, AMR or AAC audio, tuned for 3G bitrates of the day. FLV came from Macromedia for the Flash Player: a simple header plus timestamped packets, originally with Sorenson Spark video and MP3 audio.

Why 3GP files cannot store tags like the others

ASF, M4V and FLV each define a free-form metadata area the editor can rewrite. The 3GP standard does not: its predecessor formats were optimised for size, and the specification's metadata box covers technical descriptors, not user fields like title or artist. That is why the info box above states that tag edits are not applied to 3GP/3G2 files — not a limitation of this page but of the container itself. If you need searchable metadata on phone footage, remux it to MP4 (any of the video converters here can do that with a stream copy), then tag the MP4.

Stream copy, and the DRM boundary

For WMV, M4V and FLV the save button performs a remux: replace the metadata, copy every video and audio packet unchanged, write a new "_tagged" file. No decode, no re-encode, no quality cost — identical in principle to the audio tag editors. The one hard wall is DRM: a FairPlay-protected M4V or licence-bound WMV is encrypted, and no legitimate tool can rewrite a file it cannot read. Protected files are rejected rather than damaged; if you own the content, re-export it from the source app without protection first.

Common misconceptions
  • M4V and MP4 are the same thing. Almost: without DRM an M4V's content is standard MP4, and renaming works. But M4V signals Apple handling — FairPlay, AC-3 tracks, iTunes recognition — so treat the extensions as "same body, different paperwork".
  • Saving tags re-compresses the video. No. The streams are copied packet-for-packet; only the container's metadata area is rewritten. A yellow warning appears on this page only if a damaged file forces a fallback re-encode.
  • FLV is dead, so editing it is pointless. Flash Player died in 2020; the world's FLV archives did not. Libraries still hold millions of FLV recordings, and tagging them is exactly how those archives stay searchable — the files can be converted to MP4 later without losing the tags.

Related tools: WMA / ASF Tag Editor and M4A / AAC / ALAC Tag Editor for audio-only files, MP4 Tag Editor and MKV Tag Editor for modern video containers, and Video to MP4 to remux 3GP or FLV footage into a taggable format.