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M4V to FLV converter

Convert M4V to FLV in your browser. No upload and no account: the file never leaves your device, so the only size limit is your device’s memory.

I want FLV
Quality

Applies only when the video has to be re-encoded. A straight copy keeps the original quality.

Advanced 2
Always re-encode Rebuilds the picture as H.264 (VP9 for WebM) even when it could be copied. Fixes files that won’t play on older TVs and PCs.

Bytes of your files sent anywhere: 0 B

Related conversions

Other ways to convert M4V

Convert other formats to FLV

Read more about the M4V format and the FLV format, or see every video tool and all video conversions.

Should you convert M4V to FLV?

Usually a quick, safe conversion. FLV can carry H.264, which is what M4V files normally contain, so the video can often be copied across without re-encoding: fast, and with no loss at all.

Check that FLV is really needed: it plays in VLC and some streaming software; no browser or phone plays it any more, while M4V is mainly an Apple format.

M4V is an MP4 video with Apple’s extension; FLV is the video format of the Flash-era web. You only need FLV for streaming software or an old system that asks for it.

M4V and FLV compared
Property M4V FLV
Usually contains H.264 video with AAC audio H.264 or Sorenson Spark video with AAC or MP3 audio
Support Mainly an Apple format A legacy format
Plays on Apple apps and VLC; some Windows apps and upload forms reject the extension VLC and some streaming software; no browser or phone plays it any more
Best for Apple TV and iTunes libraries RTMP live-streaming pipelines that still expect it
Introduced 2003 2002

How to convert M4V to FLV

  1. 01

    Add your M4V

    Drop your M4V video onto the box, or click to choose it. It is read from your disk and stays there.

  2. 02

    Check the settings

    The output is already set to FLV. Change the quality if you want to; the defaults suit most files.

  3. 03

    Save the FLV

    Press convert and save the FLV. Several files come back together as a ZIP.

What changes when M4V becomes FLV

Often a straight copy

When the M4V holds H.264 video, the stream is moved into the FLV container untouched, so the conversion takes seconds even for long files. If the codec inside is something FLV can’t hold, the picture is re-encoded instead and you’ll see a progress bar that takes longer.

FLV is an older format

You only need FLV for streaming software or an old system that asks for it. For sharing, uploading or playing on phones, MP4 is the better choice.

The size stays about the same

M4V and FLV are close in size for the same content, so do this for compatibility rather than to save space. M4V: The same as the equivalent MP4. FLV: Usually low resolution and modest size.

This page is put together from our notes on each format, choosing only what is true of M4V and FLV, so every pairing states the same facts the same way. How these pages are made.

Why it doesn’t upload

Video files are big, and uploading one just to change its container can take longer than the conversion itself. Your browser can read and write these formats, so the file never has to leave your device.

How to check for yourself

Worth knowing

  • About the M4V. Films bought from the iTunes Store are copy-protected and can’t be converted by any tool; your own M4V exports convert in seconds.
  • About the FLV. Old FLVs often use the Sorenson Spark codec, which nothing modern decodes, so they must be re-encoded rather than just renamed.
  • MP4, MOV, MKV and WebM are handled by your browser’s own video engine, often with hardware help. AVI, WMV, FLV, MPG and the other older formats use the FFmpeg engine, a one-time 31 MB download, and are slower.

Questions

Does converting M4V to FLV lose quality?

Not when the video can be copied, which is the case for most M4V files: the stream moves into FLV untouched. If it has to be re-encoded, the default quality keeps the difference invisible.

Will a FLV play on my phone?

FLV a legacy format: VLC and some streaming software; no browser or phone plays it any more. VLC and mpv play FLV files.

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