FormatDrop doesn't convert MP4 to FLV yet. The methods below use free tools that do. FormatDrop's own converters cover common image, audio, video and PDF formats, all in your browser.
Convert MP4 to FLV with FFmpeg
- 1
FFmpeg with H.264 (most players)
ffmpeg -i input.mp4 -c:v libx264 -c:a aac -ar 44100 output.flv. FLV can hold H.264 video and AAC sound, so this works with any player or server that reads modern FLV.
- 2
FFmpeg for very old Flash players
ffmpeg -i input.mp4 -c:v flv -c:a libmp3lame -ar 44100 output.flv uses Sorenson Spark (FLV1) video and MP3 sound, the codecs of early Flash. FFmpeg can't encode VP6.
- 3
Check the result in VLC
Browsers can't play FLV since Flash ended in 2020. Open the file in VLC or mpv, or load it into the tool that asked for FLV.
Why convert MP4 to FLV?
FLV is the format that built YouTube before HTML5. Its modern uses are niche, but converting to FLV remains occasionally necessary for legacy tools that haven't moved on.
Frequently asked questions
Is anyone still using FLV in 2026?
Rarely. RTMP live streaming still packs video in FLV form on the wire, and old e-learning and screen-recording systems produced FLV files that some setups still expect. Outside such niches, FLV is retired.
FFmpeg command for MP4 to FLV?
`ffmpeg -i input.mp4 -c:v libx264 -c:a aac -ar 44100 output.flv`. For the old Sorenson Spark codec (FFmpeg can't encode VP6): `ffmpeg -i input.mp4 -c:v flv -c:a libmp3lame -ar 44100 output.flv`.
Will FLV files play in modern browsers?
No — Flash Player is end-of-life since 2020. Modern browsers cannot play FLV via any plugin. To play in a browser, convert FLV to MP4 (HTML5 video) first.
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