Convert MP4 to FLV Online
Turn MP4 files into FLV output online. The service is free, requires no account, supports batch queues, and limits server uploads to 100 MB per file. The conversion runs on the server in an isolated request. Keep the original file while you review the converted copy.
Convert .MP4 to .FLV
Select a file to begin. Processing details and limits are listed below.
How to convert MP4 to FLV
- 1
Upload MP4 files
Add one or more MP4 files to the queue. The uploader keeps batch items separate.
- 2
Set the FLV options
Set the available quality or format options, or keep the defaults for a first pass.
- 3
Create the FLV file
Run the queue and download the FLV files individually or together as a ZIP.
MPEG-4 Part 14 video vs Flash Video
| Spec | MPEG-4 Part 14 video | Flash Video |
|---|---|---|
| MIME type | video/mp4 | video/x-flv |
| Format type | video | video |
| Standard | ISO/IEC 14496-14 | Pending review |
| First release | 2003 | Pending review |
| Browser support | All current major browsers for common codecs | Pending review |
| Contents | Container for video, audio, subtitles, and metadata. Common payloads include H.264, H.265, AV1, AAC, and MP3. | Flash video container. |
About MPEG-4 Part 14 video
Broad device support, efficient streaming, flexible codec choices, and good compatibility with social platforms. Compatibility depends on the codecs inside the container, not only the .mp4 extension; advanced subtitles and chapter support vary.
Format referenceAbout Flash Video
Flash video container.
Why convert MP4 to FLV?
- FLV is more widely accepted by browsers, phones, TVs, or sharing services than the source MP4 file.
- A standardized output makes it easier to archive, upload, or hand a file to someone with different software.
- Playback compatibility is usually the main reason to change a media container.
- A converted copy separates the delivery format from the original edit or camera file.
Will quality change?
FLV output uses a standard video codec and may drop subtitle, attachment, or metadata tracks. Test playback on the target device. Keep the source if you may need to adjust the conversion later.
Processing and limits
- Processing
- Server-side
- Engine
- FFmpeg
- Maximum size
- 100 MB per file on the server.
- Batch support
- Yes, multiple files can be queued; completed results can be downloaded as a ZIP.
- Quality controls
- Options can adjust output dimensions, audio bitrate.
The file is processed on the server because the conversion requires a server-side engine or a utility operation.
- Compatibility depends on the codecs inside the container, not only the .mp4 extension; advanced subtitles and chapter support vary.
- Review the converted file in the destination application before deleting the source.
- Batch results should be spot-checked before publication or delivery.
Platform compatibility
The output is a FLV file. Use an application or device that accepts that format, and test the result on the destination platform if compatibility is critical.
When not to convert
- Do not convert when the original MP4 must remain the only editable or archival copy.
- Skip the conversion when the destination already accepts MP4 and no compatibility problem exists.
- For a one-off preview, a local viewer may be faster than creating a new delivery file.
Frequently asked questions
- How do I convert MP4 to FLV online?
- Upload a MP4 file, choose the available FLV options, run the conversion, and download the result. The tool is free, supports batches, and accepts server uploads up to 100 MB.
- Does Convert MP4 to FLV require an account?
- It is free, requires no account, and adds no watermark. Server uploads are limited to 100 MB per file, and browser-first paths are limited by device memory.
- What happens to quality?
- FLV output uses a standard video codec and may drop subtitle, attachment, or metadata tracks. Test playback on the target device. Keep the source if you may need to adjust the conversion later.
- Is my MP4 file uploaded?
- Yes. This conversion uses a server-side engine, so the file is uploaded over HTTPS, processed in an isolated request, and removed after the result is produced.
- Is batch conversion supported?
- Queue multiple files, run them together, and download the finished results as a ZIP. Each server file is limited to 100 MB, and large batches may take longer.
- What can go wrong?
- Open the downloaded FLV file in the application or database you plan to use, check the structure against the source, and keep the original until the output is approved.