Why can't this tool convert the file directly in the browser?

FLV encoding requires H.264 or H.263 video codecs and AAC or MP3 audio, none of which are natively writable in an FLV container from a browser context. WebAssembly-based FFmpeg ports exist but are very slow for large files and add significant page weight. Generating the command and running FFmpeg locally is faster, more reliable, and handles files of any size.

Is FLV still a useful format?

FLV is a legacy format. Modern browsers dropped Flash in 2020, so FLV files no longer play natively in Chrome, Firefox, or Edge. However, FLV is still required by some legacy RTMP streaming servers (such as older Wowza or Nginx-RTMP setups), certain archival workflows, and some video platforms that have not yet migrated. For new projects, MP4 or WebM is strongly recommended.

What is the difference between MOV and FLV?

MOV is Apple's QuickTime container, commonly used on macOS and iOS. It supports a wide range of codecs including H.264, H.265, and Apple ProRes. FLV (Flash Video) is Adobe's legacy container designed for Flash Player delivery, supporting H.264 (or H.263) video with MP3 or AAC audio. FLV has a simpler structure and smaller overhead but far less ecosystem support today.

What FFmpeg codec flags produce the best FLV output?

Use -c:v libx264 for H.264 video inside the FLV container — it gives the best quality and broadest compatibility. Pair it with -c:a aac for audio. Avoid -c:v flv (H.263) unless the target player specifically requires it, as H.263 quality is noticeably lower at equivalent bitrates.

How do I install FFmpeg?

On macOS run "brew install ffmpeg" with Homebrew. On Windows, download a build from ffmpeg.org/download.html and add the bin folder to your PATH. On Ubuntu/Debian Linux, run "sudo apt install ffmpeg". Once installed, the commands this tool generates will work directly in your terminal or command prompt.

Will re-encoding reduce quality?

Yes — any transcode that changes the codec re-encodes the video, which is a lossy process. Using a higher CRF value (lower quality) increases compression artifacts. The High preset uses CRF 18 (near-lossless visually); Medium uses CRF 23 (good quality); Low uses CRF 28 (smaller file, visible compression). Always start with High unless file size is a concern.

MOV to FLV Converter

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

Generate a ready-to-run FFmpeg command to convert MOV (QuickTime) files to FLV (Flash Video) with your chosen quality preset — no upload required.

FFmpeg Command Generator

Input filename

File must be in the same directory where you run the command.

Output filename

Video quality preset

Target resolution

Audio codec

Audio bitrate

Your FFmpeg Command

Configure options on the left, then click Generate Command.

Install FFmpeg

macOS

brew install ffmpeg

Windows

Download a build from ffmpeg.org/download.html and add the bin folder to your system PATH.

Linux (Ubuntu / Debian)

sudo apt update && sudo apt install ffmpeg

MOV vs FLV — Format Comparison

Property	MOV (QuickTime)	FLV (Flash Video)
Developer	Apple	Adobe (Macromedia)
File extension	.mov	.flv
Video codecs	H.264, H.265, ProRes, AV1	H.264, H.263, VP6
Audio codecs	AAC, PCM, ALAC, MP3	AAC, MP3
Browser support	Good (via HTML5 video)	None (requires Flash, deprecated 2020)
Streaming	HLS, progressive download	RTMP (legacy streaming)
Max resolution	No practical limit (4K, 8K)	Up to 1080p (H.264 in FLV)
Primary use today	Video editing, macOS/iOS recording	Legacy RTMP servers, archival

FLV is a legacy format. For new projects, consider keeping your video as MP4 or WebM — both play natively in all modern browsers and streaming platforms without plugins or extra tooling.

Summary

Generate a ready-to-run FFmpeg command to convert MOV (QuickTime) files to FLV (Flash Video) with your chosen quality preset — no upload required.

How it works

Enter your MOV input filename (or leave the default placeholder).
Choose a video quality preset: High, Medium, or Low.
Select your target resolution and audio options.
Click "Generate Command" to build the FFmpeg command.
Copy the command with one click and run it in your terminal.
Optionally review the MOV vs FLV format comparison table to understand key differences.

Use cases

Prepare MOV recordings for legacy Flash-based video players.
Re-encode QuickTime footage for older RTMP streaming servers.
Convert Apple screen recordings or iPhone clips to FLV for archive compatibility.
Generate the correct FFmpeg flags without memorizing codec options.
Batch-script multiple MOV-to-FLV conversions using the generated command as a template.
Understand codec and container differences before committing to a conversion workflow.
Quickly produce FLV files for CDNs or video platforms that still require the format.
Learn FFmpeg options for H.264 video and AAC audio inside an FLV container.

Frequently Asked Questions

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