FLV to MKV Converter
Convert FLV to MKV in your browser. Free, no signup. Conversion files are not uploaded to Format Convertly servers. Learn the formats, then convert when your workflow needs MKV.
Choose a file or drag and drop
Drop your FLV file here or
Choose file · Drag & drop · Public file link
- Processed on your device
- No conversion file stored on our servers
- Maximum file size: 100 MB
Conversion runs in your browser. Files are not uploaded to Format Convertly servers.
Processed on your device
No conversion file stored on our servers
Conversion Settings
Customize the output to match your needs.
Convert Quality
92%Output
Output options for this format are applied automatically during browser conversion. Drop your file above to begin.
Advanced settings
Additional Options
Quality or bitrate forces a re-encode. Width/FPS apply only when creating GIF or animated WebP.
How to Convert FLV to MKV
Add your FLV
Drop a FLV file into the browser panel. Nothing is sent to a remote queue.
Confirm settings
Review optional quality/size settings, then confirm MKV as the output.
Download MKV
Convert locally and download the MKV file when processing finishes.
Why Convert FLV to MKV?
Private by design
FLV → MKV runs in your browser. Files are not uploaded to a remote conversion queue.
Ready for the next step
Convert when a site, editor, or teammate expects MKV instead of FLV.
Practical quality
MKV: codec-dependent. Lossy targets trade size for speed — preview when it matters.
Wide compatibility
FLV is commonly used for Recovering old Flash-era recordings and Archival course videos from the 2000s–2010s.
FLV vs MKV
A quick side-by-side before you convert — deeper comparison lives on the full guide.
| Feature | FLV | MKV |
|---|---|---|
| Kind | video container | video container |
| Compression | lossy (legacy Flash codecs / H.264 in later FLV) | codec-dependent |
| Lossy / lossless | Typically lossy | Typically lossy |
| Transparency | Not supported / N/A | Not supported / N/A |
| Best for | Recovering old Flash-era recordings; Archival course videos from the 2000s–2010s | Multi-audio and multi-subtitle movies; Archival rips with chapters |
| Typical size | Varies; many old FLVs are low-resolution lecture captures | Matches the encoded streams; often large for high-bitrate rips |
| Browser / web support | Flash is gone — convert to MP4 for HTML5 | Poor compared with MP4 — convert for web |
| Compatibility | Legacy only — modern browsers will not play FLV without conversion; VLC can open many archives before you remux to MP4 | Excellent in VLC and enthusiast players; variable on iOS, some smart TVs, and web players that expect MP4 |
Choose FLV when…
- Recovering old Flash-era recordings
- Archival course videos from the 2000s–2010s
- Migrating legacy learning libraries
- One-time modernization to MP4
Choose MKV when…
- Multi-audio and multi-subtitle movies
- Archival rips with chapters
- Open-source container workflows
- Flexible track layouts
What happens to video quality?
MKV compatibility: Excellent in VLC and enthusiast players; variable on iOS, some smart TVs, and web players that expect MP4
Tip
Converting from FLV cannot restore detail already removed by lossy compression.
Does FLV to MKV reduce quality?
MKV is typically lossy (codec-dependent). Use a higher bitrate when fidelity matters, and keep the FLV master for archival.
MKV format guide →Should I keep the original FLV?
Yes when you may need to re-encode later. FLV: FLV powered early YouTube-style streaming inside Flash Player. Flash is gone — convert FLV to MP4 to keep old recordings playable on modern devices.
FLV format guide →FLV · MKV
Related converters FLV
Related converters MKV
Frequently Asked Questions
More on quality loss: conversion quality guides · problem-solution guides
Does converting FLV to MKV reduce quality?
It can — both sides are typically lossy. A careful encode may look similar; repeated re-encodes cause generational loss. Prefer converting once from the best master you have.
Can you recover quality after converting?
Not from a lossy output alone. Return to the original master (or a better source). Converting to a lossless format does not resurrect discarded detail.
What is generational loss?
Damage that stacks when you decode and lossy-encode the same file over and over (for example JPG→edit→JPG). Edit from masters and export delivery formats once.
Where can I learn more about conversion quality?
Browse Format Convertly’s Quality guides for topics like whether conversion reduces quality, JPG↔PNG myths, WebP/MP3/MP4 tradeoffs, recovery limits, and generational loss — each links to the right converter.
What is a FLV file?
FLV is Flash Video — a legacy streaming format from the Adobe Flash era. FLV powered early YouTube-style streaming inside Flash Player. Flash is gone — convert FLV to MP4 to keep old recordings playable on modern devices.
Is FLV lossy or lossless?
FLV is typically lossy (lossy (legacy Flash codecs / H.264 in later FLV)). That keeps files small but means discarded detail cannot be restored later.
What is a MKV file?
MKV is a Matroska multimedia container that can hold many video, audio, and subtitle tracks. MKV is a flexible open container beloved for rips and multi-track films (commentary, subtitles, multiple audio languages). Convert to MP4 when a device or web platform refuses Matroska.
Is FLV to MKV private?
Yes. The file is processed locally in your browser and is not uploaded to Format Convertly servers.
Ready to Convert Your Files?
FLV to MKV privately in your browser.