How to convert MP4 to FLV
To convert MP4 to FLV, upload your MP4 file, choose FLV as the output format and press Convert. The finished FLV file is ready to save to your phone or computer in seconds, free, with no watermark and no sign-up. Your file is deleted from our server about 30 minutes after the conversion.
This free online converter turns MP4 videos into FLV files in your browser, with no software to install and no watermark. When the video and audio inside your MP4 file can be placed in FLV as they are, the streams are copied without re-encoding, which is faster and keeps the original quality. Otherwise the video is re-encoded as H.264 video with AAC audio.
Reasons to switch from MP4 to FLV
- Supported by many legacy players and encoders
- Simple streaming-friendly structure
- H.264 video can be stored inside
- Plays on: VLC, MPC-HC, ffplay and legacy RTMP tools; not supported by modern browsers
What to expect from this conversion
- Expect a file of similar size to the MP4 original.
- Flash is discontinued, so FLV files play in desktop players and legacy streaming tools rather than in browsers.
- FLV is a legacy format. Convert to it only when an older player or device requires it, since MP4 is better for everyday use.
- The first audio track is kept. Subtitle tracks, extra audio tracks and chapters are not included in the converted file.
MP4 vs FLV
| Property | MP4 | FLV |
|---|---|---|
| Full name | MPEG-4 Part 14 | Flash Video |
| Released | 2001, ISO/IEC (MPEG) | 2002, Macromedia / Adobe |
| Generation | Modern | Legacy |
| Typical file size | Small | Small |
| Plays on | Windows, macOS, Android, iOS, smart TVs, game consoles and every major browser | VLC, MPC-HC, ffplay and legacy RTMP tools; not supported by modern browsers |
| Best for | uploading to YouTube, Instagram, TikTok and WhatsApp; sharing a video that has to play everywhere | older streaming servers and RTMP workflows; archival conversions |
Steps to convert MP4 to FLV
- Drop your MP4 video file onto the converter, or click to choose it.
- Check that FLV is selected as the target and adjust the options if you want.
- Press Convert, then download your new FLV file when it finishes.
Tips for the best result
- Leave Fast mode on to keep the original quality whenever the streams can be copied.
- Pick a lower resolution if the file is for a phone or messaging app.
- Use Mute if you only need the picture.
Frequently asked questions
How do I convert MP4 to FLV?
Upload your MP4 file, make sure FLV is the selected target and press Convert. When the progress bar finishes, download the FLV file. No account or software is needed.
Is the MP4 to FLV converter free?
Yes. It is free, with no watermark, no sign-up and no daily limit on how many files you convert. The site is supported by ads.
Will I lose quality when converting MP4 to FLV?
Not necessarily. If the video and audio streams already fit inside FLV, they are copied without re-encoding, so quality stays identical. If the file has to be re-encoded, the High setting keeps almost all visible detail, while Small trades some detail for a smaller file.
Will the FLV file be a similar size to my MP4?
Expect a file of similar size to the MP4 original. Choosing a lower quality or resolution reduces the size further.
Which devices can play FLV files?
FLV files play on VLC, MPC-HC, ffplay and legacy RTMP tools; not supported by modern browsers.
How large a file can I upload?
You can upload videos up to 500 MB. Files are deleted from the server about 30 minutes after conversion.