Step 1: Supply your M4V files using the button above or by haul and lay.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Get your converted FLV files.
M4V to FLV Conversion FAQ
What does the M4V to FLV converter do?
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Converting modern M4V into FLV is useful for older editing software or legacy playback hardware. The converter remuxes or re-encodes as needed; expect a larger file because legacy codecs compress less efficiently.
Will resolution and frame rate be preserved in the FLV?
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Yes. M4V → FLV keeps resolution, frame rate, and aspect ratio unchanged by default. To change them, use the Resize or Speed tool on the result.
Is the M4V to FLV conversion reversible?
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You can convert the FLV back to M4V on this site. If either format involved is lossy, the round-trip is not bit-perfect even though it is visually or audibly close.
Will the converted FLV be a different size than the M4V?
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Modern codecs compress better, so FLV from a legacy M4V is typically 30-60% smaller at equivalent quality. Conversions in the opposite direction can grow the file.
What happens to the subtitle tracks in my M4V file?
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They cannot stay selectable, because FLV has no soft-subtitle stream to hold them. There are two ways out: burn them into the video during conversion, which makes them permanent and unstyleable, or export them as a separate .srt alongside the FLV for the player to load. The converter tells you which it did rather than dropping them silently. No current browser, phone or TV can play FLV — anything still in this container has to be moved out of it to remain watchable.
My M4V has several audio tracks — do they all survive into the FLV?
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Not dependably. M4V stores multiple audio streams as first-class tracks, but FLV playback support past the first track is inconsistent, so most players will only ever expose one. Choose the track you actually want before converting; the others are better extracted to their own files than left in a container that hides them. M4V keeps chapter markers, artwork and subtitle tracks in the shape the Apple TV app expects, which plain MP4 often loses.
Why does my M4V file fail to convert to FLV?
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Almost always DRM. Some M4V files are encrypted at the bitstream level by the store or software that issued them, and an encrypted stream cannot be decoded by us or by anything else without the licence key. Files you recorded, exported or downloaded unprotected convert normally; a licensed purchase will not, and no converter can honestly promise otherwise. DRM-protected M4V purchases cannot be converted by anything; only unprotected M4V files are convertible, and non-Apple players often need the extension renamed.
Will the FLV still play smoothly on a phone or a TV?
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It may not. M4V is decoded by dedicated silicon on phones, tablets and TVs, which is why it plays without flattening the battery. FLV typically falls back to software decoding on the same hardware — higher CPU load, a warmer device, and dropped frames on 4K material. For a device target, M4V is the safer container to stay in.
What happens to 5.1 surround audio when converting M4V to FLV?
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It is downmixed to stereo, because FLV has no dependable multichannel path. The fold-down uses the standard ITU coefficients so dialogue in the centre channel stays intelligible and the surrounds come in at reduced level rather than vanishing. Anything that relied on discrete channel placement is gone after that.
Why would I convert M4V to an older format like FLV?
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Because a lot of hardware never learned anything newer and never will. DVD players, in-car head units, camcorder playback modes, industrial displays and plenty of broadcast ingest equipment accept FLV and nothing else. The conversion is a deliberate step down in efficiency, bought in exchange for working on a device that has no other option. FLV’s low per-packet overhead made it excellent at streaming over the unreliable connections of its era, and huge archives of it still exist.
Is there a file-size limit when converting M4V to FLV?
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Anonymous uploads are capped at a generous default; signed-in free accounts get a higher cap, and Pro accounts have no per-file limit. Browser memory is usually the practical constraint long before our server-side limits kick in.
Can I batch-convert several M4V files to FLV at once?
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Yes. Drop or pick multiple M4V files in one upload — the converter processes them in parallel and returns a ZIP of the FLV results. There is no need to repeat the upload step per file.
