[M4IF Technotes] B-frames in Simple? Which Levels?

[Rob Koenen]

This issue is common to compound file formats, that can have
a variety of coded bitstreams. The MPEG-4 player of a user's choice can
load the decoders that it finds indicated in the bitstream. 
But I do see the issue.
The Digital Item Declaration in MPEG-21 will help, but it is 
not ready yet (although it is getting quite close). 
This is an XML-based description of what a piece of content is 
composed of, including coding types, alternative representations
of the same content and the place where the actual resources is
to be found. 
Best,
Rob
> -----Original Message-----
> From: Ben Waggoner [mailto:ben   interframemedia.com]
> Sent: Thursday, January 24, 2024 17:26
> To: technotes   lists.m4if.org
> Subject: Re: [M4IF Technotes] B-frames in Simple? Which Levels?
> 
> 
> Rob,
> 
>     Right.  But by the time a player is looking at that, it's 
> already been
> handed the .mp4 file by the browser or the OS.  It doesn't provide any
> mechanism in advance to route the file to a compatible player.
> 
>     I'm foreseeing a circumstance where different players 
> support different
> profiles/levels.  Unless the user has one player that is a 
> full superset of
> all the other available players, they're going to get some 
> .mp4 files played
> in the wrong app.
> 
> 
> Ben Waggoner
> Interframe Media <http://www.interframemedia.com>
> Digital Video Compression Consulting, Training, and Encoding
> 
> 
> 
> on 1/24/02 5:03 PM, Rob Koenen at rkoenen   intertrust.com wrote:
> 
> >>     Anything happening with including a profile descriptor 
> in a MIME type
> > so
> >> that web-based content could be more accurately steered to 
> an appropriate
> >> player?
> > 
> > That's all in the Initial Object Descriptors, and MP4 files
> > support those. Also the Visual and AUdio streams themselves
> > can contain this information.
> > 
> > Furthermore, there is a profile_and_level_indication field in
> > the Visual bitstream (and also in the AUdio bitstream)
> 
> 
> 
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