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

[Ben Waggoner]

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)