[Mp4-tech] Sample MP4 file

[Shailendra Singh]

Hi ,
    (1) Is there a site where I can find a sample MP4 file which 
conforms to 14496-1 specification ?
    (2) If a file has .mp4 extension, is it valid to assume that it is a 
MP4 file (and therefore by definition conforming to 14496-1 ) ? The 
context for this question is that I came across a couple of files with 
.mp4 extension containing audio and video data which were
     - played by QuickTime Player (Version 6.5), both audio and video
    - played by DivX Player 2.5.2 but video only (I see a warning which 
says "This file contains unknown audio data" and further complains about 
"Audio data :  Tag 5376")
    - rejected by Windows Media player (latest version, version 9), 
warning about unrecognized file extension
    -  attempted to play by Real Player but RealPlayer fails ( searches 
for a software update to enable playing this .mp4 file but fails to find 
one)
(3) I also recently heard that RealPlayer does not play MP4 file with 
hint tracks, MP4 files without hint tracks are decodable. Is this correct ?
Regards,
Shailendra