Step 1: Drop your FLV files using the button above or by deposit and leave.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Receive your converted MKV files.
FLV to MKV Conversion FAQ
How do I convert an FLV file to MKV?
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Upload your FLV file using the picker above and the converter detects the source type and runs the FLV → MKV pipeline. The result downloads automatically when conversion completes; no account needed for one-off conversions.
Can I add selectable subtitles once the file is MKV?
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Yes. FLV has no usable soft-subtitle track, so subtitles for FLV content had to be burned into the picture or shipped as a separate sidecar file. MKV carries subtitles as their own selectable stream, so after conversion you can attach an SRT track the viewer can switch on, switch off or restyle. MKV is codec-agnostic: H.264, HEVC, VP9 and AV1 video sit happily beside AAC, FLAC, Opus, DTS or Dolby audio in the same file.
Can the MKV hold more than one audio track?
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Yes, and it is a real upgrade over FLV. MKV treats every audio stream as a first-class track, so an original-language mix, a dub and a director commentary can live in one file with the player switching between them on demand. MKV is the archival container of choice because it stores unlimited audio tracks, soft subtitles, chapter markers and cover art in one file.
Does MKV support chapter markers that FLV did not?
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It does. MKV stores chapters as container metadata, so a long recording can be navigated by section instead of by scrubbing a progress bar. FLV has nowhere to put that information, so if the source shipped with a chapter list it was in a sidecar file — hand that to the converter and it gets written into the MKV.
Is it worth converting old FLV recordings to MKV at all?
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For anything you intend to keep, yes. FLV belongs to an earlier generation of video tooling and the software that reads it is steadily disappearing from phones, browsers and operating systems. Moving the footage to MKV now, while a clean decoder still exists, is the difference between an archive you can open in ten years and one you cannot. No current browser, phone or TV can play FLV — anything still in this container has to be moved out of it to remain watchable.
Is the FLV to MKV converter free?
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Yes — basic FLV → MKV conversion is free with no registration. Premium adds higher per-file size limits, more parallel batch workers, and removes ads.
How big an FLV file can I convert to MKV?
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Free accounts: up to 100 MB per FLV file. Premium: typically 1 GB per file, depending on the FLV source type. Very large files are split into chunks server-side when the MKV format allows.
Will conversion change the content of my FLV?
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Conversion preserves all information that both FLV and MKV can represent. Format-specific features that the MKV format doesn't support (e.g. vector data in raster output, formulas in plain-text output) are rasterized or stripped — see the format-specific notes on the result page.
Can I convert many FLV files to MKV at once?
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Yes — drop multiple FLV files into the upload zone and they are queued in parallel. Premium has more parallel workers; on a 50-file batch this is the difference between minutes and seconds.
Does the FLV to MKV converter work on phones and tablets?
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Yes — the UI is responsive and the conversion pipeline runs server-side, so mobile devices upload-then-download just like desktops. iOS and Android browser file pickers (camera roll, Files app) work end-to-end.
Which browsers does the FLV to MKV converter support?
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Chrome, Firefox, Safari (15+), Edge, and Opera. The converter uses standard `<input type="file">` upload — no WebAssembly or PWA dependencies — so even older browsers work.
Are my FLV files kept private?
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Yes — uploaded FLV files are processed in isolated workers and deleted within minutes. We never view, retain, or share content. See /privacy/ for the data-retention window.
