[Mp4-tech] Sample MP4 file

[Dave Singer]

At 4:48 PM +0530 2/26/04, Shailendra Singh wrote:
>Hi ,
>    (1) Is there a site where I can find a sample MP4 file which 
>conforms to 14496-1 specification ?

no, but they are easily made with a lot of tools.  isma has a 
conformance suite.
>    (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 ) ?

generally yes
>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

we'll only play standard mp4 if it comes in with as an mp4 file, I think
>    - 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")

don't know what it doesn't like here
>    - rejected by Windows Media player (latest version, version 9), 
>warning about unrecognized file extension

I don't believe microsoft has committed to interoperable multimedia
>    -  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)

Real until recently was using an Envivio plug-in which was until 
recently in their automatic download program, but I believe no longer 
is.
>
>(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 ?

hit tracks are for servers but are designed so that local playback 
should not be affected by them.
>
>Regards,
>Shailendra
>
>
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-- 
David Singer
Apple Computer/QuickTime