Convert FLV to MKV Online

How to convert FLV to MKV

1. 1

   Choose FLV files

   Add one or more FLV 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 MKV files individually or together as a ZIP.

Flash Video vs Matroska video

Why convert FLV to MKV?

• A converted copy keeps the original file intact for comparison and future edits.
• The output can be tested in the destination workflow before the original is archived.
• A separate copy makes it easier to compare the old and new behavior.
• Conversion is useful when the destination has a strict format requirement.

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

MKV is a broadly supported target, including limited; most browsers do not play mkv natively. The source is FLV, which may have narrower support.

When not to convert

• If MKV 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 FLV to MKV without installing software?

Upload a FLV file, choose the available MKV 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 FLV to MKV 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 FLV to MKV 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 MKV 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.