MKV to FLV Converter

Convert MKV to Flash Video FLV format online

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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 the video quality in a VBR mode. Choose "Custom" if you need to set a fixed bitrate (CBR).
Set an output video resolution by selecting one from the predefined set of the most popular resolutions or manually entering a custom resolution.

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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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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Legacy Streaming Format

FLV powers legacy Flash media servers and archived video platforms. Converting MKV to FLV keeps your content accessible in those systems.

Quality Configuration

Set resolution, bitrate, and audio quality before converting. Tailor the FLV output to match your bandwidth or storage constraints.

Privacy Protected

Your MKV is deleted after conversion, and the FLV output is automatically removed within 24 hours. No long-term data retention.

How to convert MKV to FLV

1

Select or drag&drop MKV video to convert it to the FLV 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 MKV to FLV 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

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
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

Frequently Asked Questions

Why convert MKV to FLV?

FLV was the dominant web video format for years. It is still needed for legacy streaming servers, archived web content, and Flash media systems.

What applications play FLV?

VLC, PotPlayer, MPC-HC, and the original Adobe Flash Player all handle FLV. Most modern media players include FLV codec support by default.

How does FLV compare to MP4?

FLV was designed for Flash Player streaming. MP4 has since replaced it for web use, but FLV remains necessary for legacy infrastructure.

Are FLV files compact?

FLV can produce reasonably small files at moderate quality — it was optimized for bandwidth-limited web streaming in the early 2000s era.

Can I convert multiple MKV files?

Yes — convertio.co lets you queue several MKV videos and convert them all to FLV in a single batch session.

MKV to FLV Quality Rating

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