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

[Gary Sullivan]

I think that is true (although the last quoted message on this thread
was from nearly a year ago, so the subject is not especially fresh in my
mind).
Best Regards,
Gary Sullivan
________________________________
	From: mp4-tech-bounces lists.mpegif.org
[mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Aaron Wells
	Sent: Wednesday, November 15, 2023 4:52 PM
	To: mp4-tech lists.mpegif.org
	Subject: [Mp4-tech] Field VOPs in MPEG-4 part 2?
	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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