Browser FFmpeg recipe
Convert FLV to MP4 Online with FFmpeg
Create a compatible MP4 from an FLV video.
Command
Run this FFmpeg command
ffmpeg -i input.flv -c:v libx264 -crf 23 -preset fast -c:a aac -b:a 128k output.mp4When to use it
- legacy web video
- old exports
- modern playback
How it works
- Upload the FLV file.
- Run the H.264 and AAC conversion command.
- Download the MP4 output.
Option reference
| Option | What it does |
|---|---|
-c:v libx264 | Encodes video to H.264. |
-c:a aac | Encodes audio to AAC. |
-b:a 128k | Sets audio bitrate for compact output. |
Practical notes
- FLV is an older container and often benefits from conversion.
- If the source uses compatible streams, remuxing may be faster in desktop FFmpeg.
FAQ
Can browsers play FLV directly?
Most modern browsers do not support FLV as a normal video file.
Why does this use MP4?
MP4 is broadly supported and practical for downloads and sharing.