Hi,
Can anyone please tell me how to play a video file bearing MPEG4 extension. I have downloaded FFDShow MPEG4 Video Decoder and Microsoft MPEG 4 software and nothing seems to work. The file won't open ! When I tried opening it with DIVX Player I was prompted with this message "Invalid MPEG4 File Format. Cannot find the ES ID in the initial object descriptor" (!!)

Try Videolan VLC, it'll play most things.

Also download GSpot & open the file in that , it'll tell you what codec is in use & if it's corrupt.

Do you mean "MP4"? If so, it's probably a QuickTime file.

Thank you so much for the tip. VLC did the trick !
GSpot, on the other hand described the codec status (mp4v) as undetermined. Is there anything I can do about it ?
Also, I use Nero for burning DVDs, do you happen to know if it recognizes mpeg4 extension ?
Thanks again.

Try downloading AviCodec, it'll help you find missing codecs.

You can't use mp4 in a normal dvd. DVD's use mpeg2, in a very specific format.

Since this one shows up in Gspot as mp4v, CDan is probably right about it being a Quicktime file. I don't know off hand if Nero Vision can convert quicktime files to dvd format or not. SUPER can probably do this.
http://www.erightsoft.com/SUPER.html

Nearly all Quicktime MP4v is protected content which cannot legally be saved, modified or even opened in most encoders. A common example is a TV episode downloaded from iTunes. It's also generally not DVD quality, by a long shot.

Thanks for the info CDan. I'm getting old and slow, not keeping up with formats and downloaded content, so I'm learning a lot around here lately.

Thanks all for the useful information.
Incidentally what is a "Quicktime" file ?

"Quicktime file" is a bit of a misnomer these days. .QT used to be a fairly commonly used format, but not anymore.

"Quicktime file" would now be what the ignorant call any file that is associated with QuickTime on their computer.