What is FLV and why would I still use it?

FLV (Flash Video) is Adobe's legacy video container, widely used between 2000 and 2015 for web streaming with Flash Player. While Flash is end-of-life, FLV remains useful for legacy archive playback systems, older media servers (Wowza, Red5), and CDN infrastructure that was built around FLV before H.264-in-MP4 became universal.

Which video codec should I choose for FLV?

H.264 (libx264) gives the best quality-to-file-size ratio and is supported by all modern FLV-aware players. VP6 (flv codec) is the original Flash codec and has the highest compatibility with very old Flash Player versions (6–8), but produces larger files at the same perceived quality.

Will converting MPEG to FLV reduce quality?

Yes. MPEG video must be re-encoded into a new codec when writing to FLV; re-encoding always introduces some quality loss. Using a high video bitrate (4000k or above) and H.264 minimizes visible degradation.

Do I need to upload my video?

No. This tool only generates the FFmpeg command. Your video file never leaves your computer — you run the command locally in your terminal or command prompt.

What audio codec should I use in FLV?

AAC (-c:a aac) is the default and works with all modern FLV players. MP3 (-c:a libmp3lame) offers broader compatibility with very old Flash Player builds. For maximum legacy reach, use MP3 at 128k.

How do I install FFmpeg?

On macOS, run "brew install ffmpeg". On Ubuntu/Debian, run "sudo apt install ffmpeg". On Windows, use "winget install --id=Gyan.FFmpeg -e" or download a pre-built binary from gyan.dev/ffmpeg/builds/.

What does -movflags +faststart do?

It moves the file metadata (moov atom) to the beginning of the file so that streaming players can start playback before the file has fully downloaded. This is most relevant for H.264-in-FLV delivered over HTTP progressive download.

MPEG to FLV Converter

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

Generate a ready-to-run FFmpeg command to convert MPEG-1 or MPEG-2 video files to FLV (Flash Video) format with your choice of codec, bitrate, and audio settings.

FFmpeg Command Builder

Target Video Codec

H.264 (libx264) Best quality, modern players

VP6 (flv) Legacy Flash compatibility

Video Bitrate

Audio Codec

AAC MP3

Audio Bitrate

Frame Rate (optional)

Generated Command

ffmpeg -i input.mpg -c:v libx264 -b:v 2000k -c:a aac -b:a 128k -movflags +faststart output.flv

Replace input.mpg with your actual file path. FFmpeg must be installed — download free from ffmpeg.org.

Common Presets

MPEG vs FLV — Format Comparison

Attribute	MPEG-2	FLV
Developed by	ISO / IEC	Adobe Systems
Typical use	DVD, broadcast TV	Flash web streaming (legacy)
Common codecs	mpeg2video, MP2 audio	H.264, VP6, MP3, AAC
Flash Player support	Not supported	Native
DVD authoring	Supported	Not supported
HTTP streaming	Limited	Progressive download
File extension	.mpg / .mpeg / .vob	.flv

Install FFmpeg

# Using winget (Windows 10/11)
winget install --id=Gyan.FFmpeg -e

# Or download from:
# https://www.gyan.dev/ffmpeg/builds/

# Using Homebrew
brew install ffmpeg

# Debian / Ubuntu
sudo apt update && sudo apt install ffmpeg

# Fedora / RHEL
sudo dnf install ffmpeg

# Arch Linux
sudo pacman -S ffmpeg

Copied!

Summary

Generate a ready-to-run FFmpeg command to convert MPEG-1 or MPEG-2 video files to FLV (Flash Video) format with your choice of codec, bitrate, and audio settings.

How it works

Choose a video codec: H.264 (libx264) for modern quality, or VP6 (flv) for maximum Flash player compatibility.
Set the video bitrate — higher values produce better quality and larger files.
Select an audio codec (AAC or MP3) and set the audio bitrate.
Optionally override the frame rate, or leave blank to keep the source frame rate.
Click "Build Command" to generate the exact FFmpeg command in the output panel.
Copy the command and run it in a terminal on a machine with FFmpeg installed.

Use cases

Prepare MPEG-2 video for legacy Flash-based web video players.
Convert MPG recordings for embedding in older HTML pages that use Flash.
Transcode MPEG-1 VCD content to FLV for archiving on Flash-era media servers.
Supply FLV files to CDN or video streaming infrastructure that requires the format.
Generate FLV from MPEG broadcast captures for use with JW Player or older Flowplayer.
Replace paid video conversion software with a free, scriptable FFmpeg workflow.
Batch-convert a folder of .mpg files to .flv for a uniform legacy archive.

Frequently Asked Questions

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