By accident, I recently removed some videos from my phone. I tried to restoring them with Recuva and TuneUp Utilities and the results were "undf" files.

I tried to open with VLC, Media Player Classic and other video players to no avail. Where/how do I find out the codec for these files?

I would really love to be able to watch these videos again.

  • Thanks guys for your help but ether one of you answers didn't help me...:(
    – kvizii
    Jan 17, 2010 at 21:33

7 Answers 7


The 'undf' codec type for VLC just means that VLC did not recognize the format or, in other words, it is not one of the supported formats.

I would recommend using the GSpot Codec Information Appliance. This utility can identify just about any kind of media to help you find the right codec to play it.


undf is an undefined file mainly seen while opening partly downloaded files in VLC media player. The file is not yet build fully for any player to recognize the format. So wait for the file to dowload fully or till the stage where the player is able to recognize the format of the file. Be patient while downloading file.

Also if the file is corrupted we get an undf - undefined file.


It's an undefined file, either a file which is not complete or not designed for your operating system.

Usually downloaders from BitTorrent sites will download a movie and try to preview it and receive this error. Just wait till the download completes.


In my case this error message indicated that I hadn't downloaded the file, as JESUS mentioned. It's an easy mistake considering that BitTorrent clients, or at least µTorrent shows the file you're downloading on your harddrive before it's fully downloaded.


In the VideoLAN forums, they've found this:

Codec: undf
type: tone
channels: 1
Data rate: 22050 kHz
bits per sample: 16
bitrate: 24032 bps
Codec Name: Voxware MetaSound
Codec Description: AC24V1 24 Kbps, 22 kHz, Mono

You'll have to download the Voxware MetaSound codec and run the install yourself.


Well, they are undefined files. It's not a recognizable file format, they are some kind of corrupted files or incomplete files.

It's just a waste to keep on looking for the right codec to open such files. There aren't any. They are not audio nor video files. The solution? Delete the files and download them from a different site that you can play on your normal media players.


the gstreamer plugins, base, good, and bad worked for me. The fix was probably in only one of them, but I don't know which.

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