video suite

Convert MKV to FLV Online

Turn MKV files into FLV output online. The service is free, requires no account, supports batch queues, and limits server uploads to 100 MB per file. The conversion runs on the server in an isolated request. Keep the original file while you review the converted copy.

Convert .MKV to .FLV

Select a file to begin. Processing details and limits are listed below.

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How to convert MKV to FLV

  1. 1

    Choose MKV files

    Add one or more MKV files to the queue. The uploader keeps batch items separate.

  2. 2

    Configure the output

    Set the available quality or format options, or keep the defaults for a first pass.

  3. 3

    Run and save the result

    Run the queue and download the FLV files individually or together as a ZIP.

Matroska video vs Flash Video

SpecMatroska videoFlash Video
MIME typevideo/x-matroskavideo/x-flv
Format typevideovideo
StandardMatroska specificationPending review
First release2002Pending review
Browser supportLimited; most browsers do not play MKV nativelyPending review
ContentsExtensible container for video, audio, subtitles, chapters, and attachments. Common payloads include H.264, H.265, VP9, AV1, AAC, Opus, and FLAC.Flash video container.

About Matroska video

Open container, excellent subtitle and chapter support, and the ability to hold almost any codec. Hardware and browser support is less consistent than MP4; some mobile and smart-TV apps cannot open it.

Format reference

About Flash Video

Flash video container.

Why convert MKV to FLV?

  • The conversion can reduce playback friction when the original codec or container is not supported.
  • Keep the MKV master while using the FLV copy as the everyday delivery version.
  • The result can be tested on the target device before a larger batch is processed.
  • Sharing becomes simpler when the recipient does not need a specialist media player.

Will quality change?

Re-encoding can soften fine detail and change the file size. Keep the original master if editing or archival quality matters. Review the file in the application where it will be used.

Processing and limits

Processing
Server-side
Engine
FFmpeg
Maximum size
100 MB per file on the server.
Batch support
Yes, multiple files can be queued; completed results can be downloaded as a ZIP.
Quality controls
Options can adjust output dimensions, audio bitrate.

The file is processed on the server because the conversion requires a server-side engine or a utility operation.

  • Hardware and browser support is less consistent than MP4; some mobile and smart-TV apps cannot open it.
  • Conversion cannot restore detail that the source format already discarded.
  • Complex, encrypted, or unusually structured files may need manual review.

Platform compatibility

The output is a FLV file. Use an application or device that accepts that format, and test the result on the destination platform if compatibility is critical.

When not to convert

  • If FLV support is uncertain on the destination device, test a sample before processing a large batch.
  • Do not use a converted file as the legal or signed original when signatures or metadata must be preserved.
  • Do not overwrite the source; keep both versions until the output has been approved.

Frequently asked questions

Can I convert MKV to FLV without installing software?
Upload a MKV file, choose the available FLV options, run the conversion, and download the result. The tool is free, supports batches, and accepts server uploads up to 100 MB.
What does Convert MKV to FLV cost?
It is free, requires no account, and adds no watermark. Server uploads are limited to 100 MB per file, and browser-first paths are limited by device memory.
Does MKV to FLV conversion lose quality?
Re-encoding can soften fine detail and change the file size. Keep the original master if editing or archival quality matters. Review the file in the application where it will be used.
Where is the file processed?
Yes. This conversion uses a server-side engine, so the file is uploaded over HTTPS, processed in an isolated request, and removed after the result is produced.
Can I convert several files at once?
Queue multiple files, run them together, and download the finished results as a ZIP. Each server file is limited to 100 MB, and large batches may take longer.
What should I check before using the output?
Open the downloaded FLV file in the application or database you plan to use, check the structure against the source, and keep the original until the output is approved.

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