Browser edition: files stay on your device. Up to 100 MB total and 10 minutes. First use downloads a 32 MB engine. Some formats depend on codec support. Public-link downloading is not ready on this free deployment.
Convert FLV to MP4
Convert FLV to MP4 online for free. Smart remux when possible, high-quality encoding when not.
How to convert FLV to MP4
- Add your fileDrop it on the page, choose it from your device, or paste it with Ctrl+V.
- ConvertAdjust settings if you like, then press the button. You'll see live progress.
- Browser processing uses original files on your device. Public-link downloading is unavailable.
What happens to your file
FLV files are common for old Flash archives, RTMP streaming, but not every app or device opens them. MP4 is the better choice for sharing, uploading to social networks, playing on any device. All-in-One Saver converts FLV to MP4 with FFmpeg — real decoding and encoding, not a renamed file extension.
Convert and edit files on your device. The browser edition accepts up to 100 MB total, media up to 10 minutes and video up to 4K. Codec availability and device memory can limit individual jobs.
If your particular file uses a codec MP4 can't hold, or you pick "High", "Smaller file" or a lower resolution, we re-encode with H.264 and AAC instead.
Settings
- Quality — High, Balanced, Smaller file. Balanced keeps the original streams when possible (no quality loss, very fast).
- Resolution — Same as source, 4K (2160p), 1440p, 1080p, 720p, 480p, 360p, 240p
- Audio bitrate — Auto · keep original if possible, 320 kbps · best, 256 kbps, 192 kbps · standard, 128 kbps · small, 96 kbps, 64 kbps · voice
FLV vs MP4
| FLV | MP4 | |
|---|---|---|
| Full name | Flash Video | MPEG-4 Part 14 |
| Created by | Adobe (Macromedia), 2003 | ISO / MPEG, 2001 |
| Type | Video container | Video container |
| Typical contents | H.264 video with AAC audio | H.264 or H.265 video with AAC audio |
| Best for | old Flash archives, RTMP streaming | sharing, uploading to social networks, playing on any device |
| Strength | Still used by RTMP live-streaming workflows | Plays everywhere, including iPhone, Android, Windows and macOS |
| Weakness | No modern browser plays it directly | Lossy: every re-encode loses a little quality |
About FLV
- Type
- Flash Video
- Contains
- H.264 video with AAC audio
- Use
- old Flash archives, RTMP streaming
About MP4
- Type
- MPEG-4 Part 14
- Contains
- H.264 or H.265 video with AAC audio
- Use
- sharing, uploading to social networks, playing on any device
FAQ
Will converting FLV to MP4 reduce quality?
Not with the default settings in most cases: when the FLV contains codecs MP4 supports, All-in-One Saver copies the streams without re-encoding, so quality is identical. A re-encode happens only if needed or if you change quality or resolution.
How long does it take?
A remux takes a few seconds, even for large files — most of the time is spent uploading.
Can I convert several FLV files at once?
Yes. Drop up to 10 files at a time — each one is converted in parallel and you can download them individually or all at once.
Is there a file size limit?
Convert and edit files on your device. The browser edition accepts up to 100 MB total, media up to 10 minutes and video up to 4K. Codec availability and device memory can limit individual jobs.
Is this FLV to MP4 converter free and safe?
Yes. There are no pop-ups, redirects or fake download buttons, and no software to install. Files are transferred over HTTPS, processed in isolated job folders and deleted automatically.
Will the MP4 play on iPhone and Android?
Yes. MP4 with H.264 or HEVC video and AAC audio plays natively on iPhone, iPad and Android, as well as on Windows, macOS and smart TVs.