Add your M4V file
Drop one or more .m4v files onto the converter above, or browse for them. They load into browser memory only — nothing is uploaded, so there is no size-based pricing and no server queue.
M4V to FLV
Pulling the soundtrack out of a .m4v video into .flv audio keeps what you can hear and drops the picture entirely. Free, private, and validated — the file never leaves your browser.
Private for supported formats — processed in your browser
Runs on your deviceConvert supported files
Drop M4V files here
Batch files can each use a different output. Nothing uploads for local conversions.
Working inputs include camera RAW, browser-local audio/video, PDF, CBZ/CBR comics, office documents, ebooks, markup, 3D models, structured text, images, and archives.About converting MPEG-4 video to Flash video
Pulling the soundtrack out of a .m4v video into .flv audio keeps what you can hear and drops the picture entirely. An .m4v file is Apple's flavor of the MPEG-4 container, used by iTunes for movies, TV episodes, and music videos. Structurally it is almost identical to .mp4, but the .m4v extension signaled iTunes-specific features such as chapter markers and, on purchased content, FairPlay copy protection.
An .flv file is a Flash Video container, the format that powered most web video during the 2000s. YouTube, news sites, and early streaming platforms delivered .flv streams into the Flash Player plugin before HTML5 video replaced the whole stack. For this route the practical draw is very small container overhead and h.264/AAC content re-wraps to MP4 without any re-encoding — balanced against no mainstream player ships FLV support anymore, which is worth knowing before you commit a large batch.
Why convert M4V to FLV?
The usual reason to take .flv audio out of a .m4v file is that only the sound matters — a talk, interview, song, or podcast segment. Keeping the video stream would waste storage, and a dedicated audio file is easier to trim, tag, and play. On the source side, fairPlay-protected files play only in Apple apps on authorized devices, and no converter can open them; on the target side, the payoff is very small container overhead, which is exactly what you want for recovering clips downloaded during the Flash era.
M4V vs FLV at a glance
| Aspect | MPEG-4 video (.m4v) | Flash video (.flv) |
|---|---|---|
| Format type | Container — quality depends on the codecs and settings inside | Container — quality depends on the codecs and settings inside |
| How it stores data | identical ISO base media layout to MP4, distinguished only by branding atoms and the extension | a simple sequence of tagged audio, video, and script packets designed for progressive download and RTMP streaming |
| Strongest at | playing back iTunes-era video libraries | recovering clips downloaded during the Flash era |
| Weak spot | fairPlay-protected files play only in Apple apps on authorized devices, and no converter can open them | no mainstream player ships FLV support anymore |
| Metadata | full iTunes atom metadata: title, show, season, episode, artwork, chapters, and content ratings | an onMetaData script tag embeds duration, dimensions, and encoder details; there is no standard field set for titles or authorship |
Pick FLV as the output
Select .flv in the output menu next to each file. The menu only offers targets this engine can genuinely produce, so if FLV is selectable, the route is real and validated.
Convert on your device
Press Convert. A WebAssembly FFmpeg build demuxes the audio track and re-encodes it locally; the video stream is simply discarded.
Verify and download
Each result is signature-checked before the download unlocks, so a failed encode can never masquerade as a valid FLV file. Outputs keep the original filename with the .flv extension.
M4V to FLV questions, answered
Will converting M4V to FLV lose quality?
Since m4v is container-oriented and flv is container-oriented, the conversion preserves the source content exactly as stored; no additional compression pass is applied beyond what .flv itself requires.
Is it private to convert M4V files here?
Yes — the .m4v file is processed inside your browser tab and never uploaded. A WebAssembly FFmpeg build demuxes the audio track and re-encodes it locally; the video stream is simply discarded. Close the tab and the file is gone from memory.
Where will the FLV file work?
No current browser can play .flv, since the plugin that decoded it was removed from Chrome, Firefox, and Edge at the end of 2020. VLC and ffmpeg-based tools still read the format reliably, which is how old files get rescued into MP4.
Will the FLV file be bigger or smaller than my M4V?
Much smaller — the video stream is usually 80–95% of a .m4v file's weight, and it is discarded entirely. The remaining audio is re-encoded at the bitrate implied by your quality setting.
What happens to the metadata in my M4V file?
This converter strips container metadata deliberately (the FFmpeg command runs with metadata mapping disabled) so exported files do not leak recording details. In the source, full iTunes atom metadata: title, show, season, episode, artwork, chapters, and content ratings; none of it is transmitted anywhere because the file never leaves your browser.
Can I convert FLV back to M4V?
Yes — the reverse route exists as a separate tool. Bear in mind that round-tripping .m4v → .flv → .m4v is not a perfect undo when any lossy step is involved; keep your original if fidelity matters.