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About MP4 to FLV
Convert MP4 to FLV
MP4 to FLV converts MP4 files to FLV. MP4 is the most widely supported video container, normally holding H.264 video and AAC audio. FLV is the legacy Flash video format.
What to know about MP4 to FLV
The formats involved, when to use this conversion, and where it runs.
About MP4
MP4 is the most widely supported video container, normally holding H.264 video and AAC audio.
About FLV
FLV is the legacy Flash video format.
Best for
Legacy Flash-based players and old streaming setups that still require FLV.
Where it runs
Converted on our servers with FFmpeg. The file travels over HTTPS and is deleted automatically afterwards.
Works everywhere
Desktop, tablet, or mobile—use the same workflow on any device.
Free to use
Start converting for free with no account. Paid plans raise limits; see the Pricing page.
How MP4 to FLV works
What happens to your file from upload to download.
1
Upload your MP4 file
The file type and size are checked before anything is processed, so unsupported files are rejected straight away.
2
Convert on our servers
The file is uploaded over HTTPS and converted to FLV with FFmpeg.
3
Download the FLV file
Save the result to your device. Copies on our servers are deleted automatically by a cleanup job.
More MP4 and FLV conversions
Other conversions available for these formats; search above to open them.
From MP4
MP4
→
Convert to
MP3AVIMOVWMVWEBMMKV
How to use MP4 to FLV
Step-by-step instructions for this conversion.
01
Add your file
Add your MP4 file by dragging it into the upload area or choosing it from your device.
02
Choose the output
Confirm FLV as the output format.
03
Run the conversion
Start the conversion. The file is uploaded and converted on our servers while the progress bar updates.
04
Download and check
Download the FLV file and check it before deleting the original.
Good to know: MP4 to FLV
Differences between the two formats that affect the result.
01
The result is an FLV with Sorenson Spark (FLV1) video (about 1.5 Mbps) and 128 kbps MP3 audio, for legacy Flash-based players.
02
Video is always re-encoded rather than copied, so quality can drop slightly, especially on detailed or fast-moving footage. Keep the original if you may need to convert it again.
MP4 to FLV
MP4 to FLV in a sentence
MP4 to FLV converts MP4 files to FLV.
MP4 to FLV
Best for
Legacy Flash-based players and old streaming setups that still require FLV.
MP4 to FLV
What to expect
You download a new FLV file; your MP4 file is not changed.
Private by design
This conversion runs on ToolzStack servers: your file is uploaded over HTTPS, converted, and kept only so that you can download the result. An automated cleanup job then deletes it (see the Privacy Policy for the current retention period).
HTTPS in transit
Auto-Delete
Privacy Policy
Encrypted in transit (HTTPS)
No registration required
No watermarks added
Large files supported within plan limits
Ready to use MP4 to FLV?
Start a new conversion or jump to a related tool above.
FAQs for MP4 to FLV
Common answers so you can keep moving.
What is the difference between MP4 and FLV?
MP4 is the most widely supported video container, normally holding H.264 video and AAC audio. FLV is the legacy Flash video format.
Will converting MP4 to FLV change quality?
Video is always re-encoded rather than copied, so quality can drop slightly, especially on detailed or fast-moving footage. Keep the original if you may need to convert it again.
Is my MP4 file uploaded to a server?
This conversion runs on ToolzStack servers: your file is uploaded over HTTPS, converted, and kept only so that you can download the result. An automated cleanup job then deletes it (see the Privacy Policy for the current retention period).
My MP4 file will not convert
Make sure the file really is MP4 (renaming an extension does not change the format) and that it opens correctly on your device. Password-protected, DRM-protected or corrupted files are rejected. If the file is very large, try again with a smaller one.
The output does not look right
The result is an FLV with Sorenson Spark (FLV1) video (about 1.5 Mbps) and 128 kbps MP3 audio, for legacy Flash-based players.