FLV → MP4 / online converter

FLV to MP4 Converter

Convert an old FLV (Flash Video) file to MP4, which plays everywhere now that Flash is gone.

01 / how to

How to convert FLV to MP4

01

ADD YOUR FLV

Drop the FLV file into the box above or choose it from your device.

02

CONVERT TO MP4

MP4 is already selected. Press Convert and wait a few seconds.

03

DOWNLOAD

Save the finished MP4 file. The original is deleted from our server.

02 / what you get

What happens to your data

Kept

  • Old Flash Video files, such as downloaded web clips and archived recordings, are read
  • H.264 video with AAC audio, the combination that plays on every phone, computer, TV and browser
  • The file is set up for streaming, so it starts playing before it has fully downloaded
  • The original resolution and frame rate are kept
  • A phone video recorded sideways or upside down is turned the right way up
  • Surround sound (5.1) is kept when the source has it
  • The result is usually smaller than the original, because H.264 compresses much better than older codecs

Good to know

  • The video is re-encoded, which is slightly lossy. Only one video track and one audio track are kept; extra audio tracks and subtitles are left out.
  • A width or height that is an odd number of pixels is trimmed by one pixel, because video encoders need even sizes.
  • HDR video (for example from a recent iPhone) is converted to normal SDR colors, and 10-bit video becomes 8-bit, so it plays everywhere.
  • Files up to 150 MB are accepted. Long or very high-resolution videos can take several minutes, and a conversion that runs past about 4 minutes is stopped with a message.

03 / formats

FLV vs MP4

FLV

An FLV file is the old Flash Video format that powered most web video in the 2000s and early 2010s. Flash itself is dead, but the container still shows up in some legacy systems.

Used in: Legacy web video · Old streaming systems

MP4

An MP4 file is the most universally supported video container — plays on every device, browser, and platform. The default choice when you're not sure what format to use.

Used in: Universal playback · Sharing · Web video