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

[Rob Koenen]

Ben,
There was some chaos but it is rapdily decreasing.
Over 20 companies have done (and are doing) interop testing
in M4IF, and we are doing these by the Profile, concentrating on 
Simple and Advanced Simple.
I cannot comment on individual companies (I will gladly leave that
to their representatives) but I do know that the behavior you
have observed is disappearing. I thought this was also the case
for the exampe that you mention.
Profiles and Levels define decoder requirements - the lower bounds,
that is. Implicitly, they also define upper bounds onwhat the 
encoder can spit out.
We are migrating from a situation in which people just stated "I am
doing MPEG-4" (and they didn't have a clue about Profiles and Levels)
to one in which people say "I am doing MPEG-4 X profile at Y Level."
(and sometimes they add "oh, by the way, my encoder doesn't do tool Z
yet, but it will be done next month"). 
ISMA helps, having picked concrete Advanced Simple Profile from the 
MPEG-4 spec for its own 1.0 spec.
M4IF will help further by designing a process of (self) certification.
The MPEG-4 syntax contains info on Profiles and Levels, but I am not
aware of any tools, except for the Video analysis tools of Interra,
http://www.interra.tv/products/Mpeg4_analysis.htm
(If listeners know of other such tools please let us know)
Rob
> -----Original Message-----
> From: Ben Waggoner [mailto:ben   interframemedia.com]
> Sent: Wednesday, January 23, 2024 15:21
> To: technotes   lists.m4if.org
> Subject: Re: [M4IF Technotes] B-frames in Simple? Which Levels?
> 
> 
> Rob,
> 
>     Thanks.
> 
>     I'm looking at a ton of encoders, and most of them aren't 
> at all clear
> as to what profile their output is compatible with.  And the 
> various players
> aren't any better about documenting what profiles they 
> actually support.
> Clearly, interoperability between players and encoders from different
> vendors isn't right now, but it's very hard right now to tell 
> if this is the
> fault of the encoders or the players (I'm guessing it's 
> mainly the players).
> 
>     For example, it looks like the Philips WebCine Encoder is 
> Simple or
> better, unless you have B-frames, in which case it requires 
> Advanced Simple
> or better.  But the Philips WebCine Player can't play other Simple or
> Advanced Simple content produced by other encoders.
> 
>     Are there any kind of validation apps I can run on an 
> .mp4 file that can
> tell me what it needs to run?
> 
> Ben Waggoner
> Interframe Media <http://www.interframemedia.com>
> Digital Video Compression Consulting, Training, and Encoding
> 
> 
> 
> on 1/23/02 3:03 PM, Rob Koenen at rkoenen   intertrust.com wrote:
> > Simple, Advanced Real-Time Simple (ARTS) don't hae it
> > ( and Simple Studio and Core Studio on the high end. )
> > 
> > Whether or not B frames are supported is exclusively determined by
> > the Profile.  Within the Profile, the level definition doesn't
> > change it.
> 
> 
> 
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