[Mp4-tech] Field VOPs in MPEG-4 part 2?

[Aaron Wells]

Hi Gary,
So, just to clarify,
Is it the case that, apart from the Studio profiles,
MPEG4 part 2 has no support for
"picture-adaptive-field/frame" coding such as one
can do in MPEG2 or H.264?
Thanks
Aaron
Barry et al, 
Regarding your remark:
+> Field VOPs seems to be allowed only in the Advanced Coding 
+> Efficiency 
+> profile.  See Tables V2-39  and V2-40 in Sec. 9 profiles and levels
That doesn't sound right.  The ACE profile was in the 2001 edition, but
I don't think field VOPs were defined yet in that edition.  As far as I
can tell, they arrived in the Studio Profile amendment -- they were
added later.
And those tables that you refer to don't actually say "field VOPs".
They just say "interlace".  As it existed at the time of the 2001
edition, I believe "interlace" did not include field VOPs.  As discussed
in the Alito hearings today, sometimes we must go back and do research
to try to figure out what the original framers intended.  :-)
Table 9-3 of the 2003 edition says that Simple Studio and Core Studio
include "Frame/Field Structure".  The phrase "frame/field structure" is
not defined in the standard.  However, I think it refers to frame and
field VOP support.  And I think those are the only profiles that contain
them.
Best Regards,
Gary Sullivan
+> -----Original Message-----
+> From: bhaskell [mailto:bhaskell apple.com
<http://lists.mpegif.org/mailman/listinfo/mp4-tech> ] 
+> Sent: Tuesday, January 10, 2024 11:48 AM
+> To: Gary Sullivan
+> Cc: mpeg-video lists.rwth-aachen.de
<http://lists.mpegif.org/mailman/listinfo/mp4-tech> ; mp4-tech
lists.mpegif.org <http://lists.mpegif.org/mailman/listinfo/mp4-tech> 
+> Subject: Re: [Mp4-tech] Field VOPs in MPEG-4 part 2?
+> 
+> Gary Sullivan wrote:
+> 
+> >Yes, I see it now.  I guess this was part of the Studio Profile
+> >amendment - I hadn't looked in there for it before.  It 
+> seems to only be
+> >supported in the Studio Profiles?  (e.g., not in the Advanced Simple
+> >Profile)
+> >  
+> >
+> 
+> Field VOPs seems to be allowed only in the Advanced Coding 
+> Efficiency 
+> profile.  See Tables V2-39  and V2-40 in Sec. 9 profiles and levels
+> 
+> 
+> >Best Regards,
+> >
+> >-Gary 
+> >
+> >+> -----Original Message-----
+> >+> From: bhaskell [mailto:bhaskell apple.com
<http://lists.mpegif.org/mailman/listinfo/mp4-tech> ] 
+> >+> Sent: Monday, January 09, 2024 11:55 AM
+> >+> To: Gary Sullivan
+> >+> Cc: mpeg-video lists.rwth-aachen.de
<http://lists.mpegif.org/mailman/listinfo/mp4-tech> ; mp4-tech
lists.mpegif.org <http://lists.mpegif.org/mailman/listinfo/mp4-tech> 
+> >+> Subject: Re: [Mp4-tech] Field VOPs in MPEG-4 part 2?
+> >+> 
+> >+> Gary Sullivan wrote:
+> >+> 
+> >+> >At first glance, it appears that MPEG-4 part 2 does not 
+> support VOPs
+> >+> >that represent a single field of an interlaced frame.
+> >+> >
+> >+> >Can anyone confirm or refute that assertion?
+> >+> >  
+> >+> >
+> >+> Well, there are field VOPs ( top field VOPs and bottom field 
+> >+> VOPs), but 
+> >+> they are constrained to occur in pairs.  See Sec. 6.1.3.4.1 
+> >+> Field VOPs
+> >+> 
+> >+> >Best Regards,
+> >+> >
+> >+> >Gary Sullivan
+> >+> >
+> >+> 
+> >
+> 
+> 
+> -- 
+> Barry G. Haskell                             tel +1 408 974 6333
+> Apple Computer Inc.                          fax  "  "  "   1756
+> 2 Infinite Loop      MS: 302-3KS
+> Cupertino, CA 95014
+> bhaskell apple.com
<http://lists.mpegif.org/mailman/listinfo/mp4-tech>      (also
B.Haskell ieee.org <http://lists.mpegif.org/mailman/listinfo/mp4-tech> )
+> 
+> 
+> 
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