[M4IF Technotes] iods & 3GPP

[emre.aksu nokia.com]

Hi Olivier,
> I think there are some confusions there between an MPEG 
> sub-group (MPEG-4 Systems) and a specification (the ISO media 
> File format). File formats (the ISO File Format, MP4 File 
> Format, AVC, ...) have been developped by MPEG-4 Systems 
> (later jointly with JPEG for the ISO file format) so they 
> *are* MPEG-4 Systems. What you mean I think is that 3GPP 
> decided not use the OD framework (another specification 
> developped by MPEG-4 Systems). 
> 

What I mean is what is exactly stated in the 3GPP TS 26.234 spec. => "The receiving terminal is not required to implement any of the specific MPEG-4 system architectural elements". Hence, what is not defined in ISO Media file format is out of the scope of the 3GP file. 
Of course, this does not restrict you from putting those elements in the file. It simply means that the receiving terminal can ignore them and still be able to  playback the presentation. Only then that file is called a "3GPP compliant" file.
> All I am saying, is that people who care about having there 
> content used also on the internet (some company does ...) 
> should better do dual compatible files. What I am also saying 
> is that this extra burden is not ground on any technical 
> reasons. There is NO technical reason to derive yet another 
> format from the ISO File format in the 3GPP case (while in 
> some cases there are, e.g. we are currently making such 
> assessment for AVC coding that has some specifics). I am 
> saying this in the interest of interoperability and on the 
> minimization of the entropy in the multimedia standards. This 
> is also in the interest of future proofness.

I think the necessary reasoning for the usage of the ISO media file as the base format and introducing a new file format has been done quite well in the 3GPP SA4 Group discussions, which I am sure that you are very well aware of. 
Best Regards,
Emre
Emre Baris Aksu
Nokia Corp.
> -----Original Message-----
> From: ext AVARO Olivier FTRD/DIH/REN
> [mailto:olivier.avaro   rd.francetelecom.com]
> Sent: 04. September 2002 12:42
> To: Aksu Emre (NMP/Tampere); technotes   lists.m4if.org
> Subject: RE: [M4IF Technotes] iods & 3GPP
> 
> 
> 
> > Hence, iods atom is not mandated in a 3GP file, and it shall 
> > be ignored in a file that addresses 3GP file compliance 
> > according to TS.26.234 Rel.4 and beyond. 
> 
> > I also think that iods is not a part of ISO File format, but 
> > the MPEG-4 Specific file format which is inherited from ISO 
> > file format. 3GP file format is inherited from the ISO file 
> > format, which definitely makes the distinction between MPEG-4 
> > systems related elements, and the core file format template 
> > (i.e. ISO).
> 
> I think there are some confusions there between an MPEG 
> sub-group (MPEG-4 Systems) and a specification (the ISO media 
> File format). File formats (the ISO File Format, MP4 File 
> Format, AVC, ...) have been developped by MPEG-4 Systems 
> (later jointly with JPEG for the ISO file format) so they 
> *are* MPEG-4 Systems. What you mean I think is that 3GPP 
> decided not use the OD framework (another specification 
> developped by MPEG-4 Systems). 
> 
> All I am saying, is that people who care about having there 
> content used also on the internet (some company does ...) 
> should better do dual compatible files. What I am also saying 
> is that this extra burden is not ground on any technical 
> reasons. There is NO technical reason to derive yet another 
> format from the ISO File format in the 3GPP case (while in 
> some cases there are, e.g. we are currently making such 
> assessment for AVC coding that has some specifics). I am 
> saying this in the interest of interoperability and on the 
> minimization of the entropy in the multimedia standards. This 
> is also in the interest of future proofness.
> 
> Kind regards,
> 
> Olivier 
>