FLV to MKV Converter

Switch FLV footage to widely supported MKV in your browser

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Settings

The codec to encode the video track. Codec "Without reencoding" copies the video stream from the input file into output without re-encoding if possible.
Set output AVC (H.264) encoding profile. The older the target device, the "lower" profile you should set. More info can be found on the wiki.
Set output AVC (H.264) profile level. Leaving this setting in "Auto" will calculate the correct level and is the best choice in most cases. More info can be found on the wiki.

flv

FLV (Flash Video) is a container format originally developed by Macromedia and later maintained by Adobe Systems after the 2005 acquisition. The format gained support for standalone playback with Flash Player 7 in 2003 and quickly became the dominant video format on the web, powering platforms like YouTube, Hulu, and Vimeo during the late 2000s. FLV files typically contain video encoded with the Sorenson Spark or VP6 codec alongside MP3 or ADPCM audio, wrapped in a lightweight proprietary container optimized for streaming delivery. The major strength of FLV was its ability to deliver consistent video playback across different operating systems and browsers through the ubiquitous Flash Player plugin, solving the fragmentation problem that plagued web video at the time. FLV files begin with a compact header followed by tagged data packets, a structure that enables fast seeking and efficient progressive download. The container supports embedded metadata with cue points, enabling interactive features like chapter navigation and timed events. FLV transformed online video from an unreliable niche experience into a mainstream medium, fundamentally reshaping entertainment, education, and communication on the internet. Although HTML5 video and modern codecs have replaced Flash-based delivery, FLV files remain in countless archives and legacy systems.
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mkv

MKV (Matroska Video) is an open-standard multimedia container format developed by the Matroska project, which announced the format in December 2002. Named after the Russian matryoshka nesting dolls, the format is built on the Extensible Binary Meta Language (EBML), a simplified binary variant of XML that provides a flexible and forward-compatible structure. MKV can hold virtually unlimited numbers of video, audio, and subtitle tracks within a single file, supporting codecs from H.264 and HEVC to VP9 and AV1 for video, and AAC, FLAC, Opus, and DTS for audio. A standout feature is comprehensive subtitle support, handling formats from simple SRT text to complex ASS styled subtitles and bitmap-based PGS tracks from Blu-ray discs. MKV also supports chapter markers, attachments (such as fonts needed for styled subtitles), and tagging metadata, making it one of the most feature-rich containers available. The open specification) ensures that any developer can implement MKV reading and writing without licensing fees, which has driven widespread adoption across media players, streaming tools, and encoding software. The ability to encapsulate virtually any codec combination in a single, well-organized file has made MKV the preferred container for high-quality video distribution, archival, and personal media libraries.
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No Installation

The converter runs entirely in your web browser. No plugins, no apps, no downloads — just open convertio.co and start converting immediately.

Quality Preserved

Moving from FLV to MKV keeps your video looking sharp. Choose the right bitrate and codec settings to maintain visual fidelity during conversion.

Batch Processing

Upload and convert multiple files simultaneously. Our cloud infrastructure processes them in parallel, saving you time on larger jobs.

How to convert FLV to MKV

1

Select or drag&drop FLV video to convert it to the MKV format from your computer, iPhone or Android. Moreover, it is possible to choose it from your Google Drive or Dropbox account.

2

Now your video is uploaded and you can start the FLV to MKV conversion. If it is needed, change the output format to one of the 37 video formats supported. After that, you can add more videos for batch conversion.

3

If you want, you can customize such settings as resolution, quality, aspect ratio and others by clicking the gear icon. Apply them to all the video files if necessary and click the button "Convert" to process.

4

Once your video is converted and edited, you can download it to your Mac, PC or another device. If necessary, save the file to your Dropbox or Google Drive account.

About formats

FLV (Flash Video) is a container format originally developed by Macromedia and later maintained by Adobe Systems after the 2005 acquisition. The format gained support for standalone playback with Flash Player 7 in 2003 and quickly became the dominant video format on the web, powering platforms like YouTube, Hulu, and Vimeo during the late 2000s. FLV files typically contain video encoded with the Sorenson Spark or VP6 codec alongside MP3 or ADPCM audio, wrapped in a lightweight proprietary container optimized for streaming delivery. The major strength of FLV was its ability to deliver consistent video playback across different operating systems and browsers through the ubiquitous Flash Player plugin, solving the fragmentation problem that plagued web video at the time. FLV files begin with a compact header followed by tagged data packets, a structure that enables fast seeking and efficient progressive download. The container supports embedded metadata with cue points, enabling interactive features like chapter navigation and timed events. FLV transformed online video from an unreliable niche experience into a mainstream medium, fundamentally reshaping entertainment, education, and communication on the internet. Although HTML5 video and modern codecs have replaced Flash-based delivery, FLV files remain in countless archives and legacy systems.
Developer: Adobe Systems
Initial release: 2003
MKV (Matroska Video) is an open-standard multimedia container format developed by the Matroska project, which announced the format in December 2002. Named after the Russian matryoshka nesting dolls, the format is built on the Extensible Binary Meta Language (EBML), a simplified binary variant of XML that provides a flexible and forward-compatible structure. MKV can hold virtually unlimited numbers of video, audio, and subtitle tracks within a single file, supporting codecs from H.264 and HEVC to VP9 and AV1 for video, and AAC, FLAC, Opus, and DTS for audio. A standout feature is comprehensive subtitle support, handling formats from simple SRT text to complex ASS styled subtitles and bitmap-based PGS tracks from Blu-ray discs. MKV also supports chapter markers, attachments (such as fonts needed for styled subtitles), and tagging metadata, making it one of the most feature-rich containers available. The open specification) ensures that any developer can implement MKV reading and writing without licensing fees, which has driven widespread adoption across media players, streaming tools, and encoding software. The ability to encapsulate virtually any codec combination in a single, well-organized file has made MKV the preferred container for high-quality video distribution, archival, and personal media libraries.
Developer: Matroska
Initial release: December 6, 2002

Frequently Asked Questions

Why should I convert FLV to MKV?

MKV is an open, versatile container that preserves quality and supports advanced features. Converting from FLV ensures your content stays accessible.

What software plays MKV?

MKV is supported by VLC, MPC-HC, PotPlayer, Kodi, and most advanced media players on desktop and mobile.

Are my videos kept private?

Privacy is a priority — FLV uploads are erased right after processing, and MKV output files are purged within 24 hours.

Does converting FLV to MKV affect video quality?

Using adequate bitrate and resolution settings, the MKV output retains excellent visual quality. Any slight loss is typically imperceptible.

Do I need special software?

Everything runs in the browser — no downloads required. Visit convertio.co, upload the FLV, select MKV, and get your converted video online.

How fast is the FLV to MKV conversion?

Speed varies with file size and resolution. Most FLV clips convert to MKV in a few minutes using our cloud processing infrastructure.

FLV to MKV Quality Rating

4.8 (168 votes)
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