Why does renaming file extensions work?

BluSky · 16 Jun 2012 at 15:36

Hi all

I have a large number of dvds which I ripped to MKV files using handbrake. My question is why do they still work when I change the file extension to m4v, mp4, avi etc? It doesn't make sense to me because, as I understand it, changing the file extension doesn't change the file itself, just the way the computer decodes it...

All of the mkv's were ripped with h.264 and ac3 passthru.

Thanks for any help

Linkex · 16 Jun 2012 at 15:54

The player is detecting the media type from the file itself rather than the extention. You could change the extention to anything you like and it will still work.

lurkio · 16 Jun 2012 at 16:02

Files can have header info at start of it , eg rar files have
Rar is the first 3 chars in any rar file , progs can read this

bledd · 16 Jun 2012 at 16:05

The extension just determines which program opens the file. The file header (start of the file) says what type of file it is.

If you renamed a video.mp4 to video.txt, you could drag it into your video player and it would play it no problem

BluSky · 16 Jun 2012 at 17:56

Hi, Thanks for the explanations. On a related note why is the audio much louder if I change the extension to anything other than MKV?

Thanks again