How to Convert FLV to MP4 Online
Follow these three simple steps to convert FLV to MP4. No software installation required. Free and secure.
Select an FLV Video
Choose an FLV file from a Flash-era website, media archive, or legacy export on your device.
Choose Video and Audio Settings
Keep the original resolution and frame rate or choose new values, then keep the automatic audio settings or select a sample rate and mono or stereo output.
Convert and Download
Start the conversion, review the original and output file sizes, and download the completed MP4 video.
How Does the FLV to MP4 Converter Work?
The CompressFly FLV to MP4 converter decodes the supported streams in the Flash Video file and re-encodes the video as H.264 and available audio as AAC inside an MP4 container. This creates a new playback file rather than merely renaming the FLV extension.
Conversion runs directly in your browser. Your FLV video is not uploaded to a server, and the completed MP4 file downloads from the browser to your device.
What "directly in your browser" means
- Your FLV video is not uploaded to a server.
- Video conversion runs locally on your device.
- The completed MP4 video downloads directly from your browser.
When to Convert FLV to MP4
Create an MP4 version when an older FLV asset needs to work outside a Flash-based or legacy playback environment.
Replace Flash-Era Video
Convert an archived FLV asset before publishing it in a modern website or browser-based workflow.
Open FLV in Current Players
Create an MP4 copy for devices and media players that no longer support Flash Video files.
Reuse Archived Footage
Prepare legacy FLV recordings for current editors, presentations, sharing tools, or upload forms.
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FLV to MP4 Converter FAQ
How do I convert FLV to MP4 online?
Use this online FLV to MP4 converter in three steps: 1. Select an FLV video from your device. 2. Keep or change the available video and audio settings. 3. Start the conversion and download the completed MP4 video.
What happens when I convert FLV to MP4?
The converter re-encodes supported FLV video as H.264 and available audio as AAC, then saves the new streams in an MP4 container.
Can I change the video resolution and frame rate?
Yes. Keep the source resolution and frame rate or select an available output resolution and frame rate before conversion.
Will converting FLV to MP4 make the file smaller?
Not necessarily. The output size depends on the source video, selected resolution, frame rate, audio settings, duration, and visual content. Use the Video Compressor when reducing file size is the main goal.
Is the FLV to MP4 converter free?
Yes. Convert FLV to MP4 for free with no registration or credit card required.
Is there a file size limit, and is my video uploaded?
Your video is processed locally in your browser and is not uploaded to a server, so there is no server upload limit. The practical limit depends on your device's available memory and processing power, as well as the video's duration and resolution.