Do I need to upload my video file?

No. This tool only generates the FFmpeg command. All actual video processing happens on your own computer using FFmpeg, so your files never leave your device.

Where do I get FFmpeg?

Download FFmpeg free from ffmpeg.org. On Windows use the pre-built binaries or run "winget install ffmpeg"; on macOS run "brew install ffmpeg"; on Linux run "sudo apt install ffmpeg" or the equivalent for your distribution.

What is FLV and when should I use it?

FLV (Flash Video) is a container format developed by Adobe for the Flash Player. It uses H.264 or Sorenson Spark for video and MP3 or AAC for audio. FLV is largely obsolete for new projects — use MP4 (H.264) instead — but it is still needed for legacy Flash players, older streaming platforms, and certain archival workflows.

Will I lose quality when converting MKV to FLV?

Some quality loss is expected because re-encoding is required. Use a higher video bitrate (e.g. 2000k or above) to preserve visual quality. Lower bitrates reduce file size at the cost of more visible compression artifacts.

Which video codec should I choose for FLV?

H.264 (libx264) is the best choice for FLV — it produces the best quality at any given bitrate and is supported by all modern Flash players (Flash Player 9.0.115+). Sorenson Spark (flv) is the legacy option for older players that do not support H.264.

How do I convert multiple MKV files to FLV at once?

On Linux/macOS use a shell loop: for f in *.mkv; do ffmpeg -i "$f" -c:v libx264 -b:v 1500k -c:a libmp3lame -b:a 128k "${f%.mkv}.flv"; done. On Windows use a batch file iterating with a FOR loop.

MKV to FLV Converter

Name: MKV to FLV Converter
Availability: InStock
Author: Nham Vu

Configure your MKV-to-FLV conversion settings and get the exact FFmpeg command to run on your computer.

Conversion Settings

Input file name

Just the filename — or a full path like /home/user/videos/movie.mkv

Output file name

Video codec

H.264 is the best choice for modern Flash Player (9.0.115+).

Video bitrate: 1500 kbps

300 kbps (small) 6000 kbps (high quality)

Audio codec

Audio bitrate: 128 kbps

64 kbps 320 kbps

FFmpeg Command

ffmpeg -i "input.mkv" -c:v libx264 -b:v 1500k -c:a libmp3lame -b:a 128k "output.flv"

Command breakdown

MKV vs. FLV — Format Comparison

Feature	MKV	FLV
Developer	Matroska (open source)	Adobe Systems
Common codecs	H.264, H.265, AV1, VP9	H.264, Sorenson Spark, MP3
Use case	Modern storage, Blu-ray rips	Legacy Flash web video
Browser support	Via HTML5 video (limited)	Requires Flash Player (obsolete)
Subtitles / chapters	Full support	Not supported

Quick tips

Run the command in the same folder as your MKV file, or use full paths.
Add -y before the output filename to overwrite an existing file without a prompt.
Use -preset fast with libx264 to speed up encoding at a slight quality trade-off.
FLV does not support chapters, multiple audio tracks, or subtitles. For modern use, prefer MP4 instead.

Command copied!

Summary

Configure your MKV-to-FLV conversion settings and get the exact FFmpeg command to run on your computer.

How it works

Enter the name of your MKV input file (e.g. video.mkv).
Enter the desired output FLV filename.
Choose a video codec — H.264 (libx264) is the most compatible choice for FLV.
Set a video bitrate using the slider.
Choose an audio codec — MP3 is the standard for FLV containers.
Click "Generate Command" and copy the FFmpeg command shown.
Paste the command into your terminal and run it to convert the file.

Use cases

Convert MKV files for use with legacy Flash-based video players.
Prepare video content for older streaming servers that require FLV input.
Archive or re-encode footage in the FLV format for compatibility with older systems.
Generate FLV files for embedding in legacy SWF-based web applications.
Convert recorded MKV screencasts to FLV for older e-learning platforms.
Reduce file size during conversion by adjusting the bitrate.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu