[M4IF Technotes] Profile@Level Visual Image size
B Jagadeesh
bj sasken.com
Thu Sep 19 15:52:53 EDT 2002
Hi,
The following mail gives very useful information regarding the features
supported in MPEG-4 Simple profile Level0.
Could you please clarify one more point regarding "vop_rounding_type" for
Level0? Can this variable take the values zero and 1 as in Simple
profile Level1 or Level 0 supports rounding type to be only 0.
thanks and regards,
bj.
On Fri, 17 Aug 2001, Peter Haighton wrote:
> Arcin,
>
> Level 0 came out as part of amendment 4. I do not know if ISO has
> published it yet though, I don't think so. MPEG-4 Simple Profile Level 0
> has the following restrictions:
>
> a) The maximum frame rate shall be 15 frames per second;
> b) The maximum f_code shall be 1;
> c) The intra_dc_vlc_threshold shall be 0;
> d) The maximum horizontal luminance pixel resolution shall be 176
> pels/line;
> e) The maximum vertical luminance pixel resolution shall be 144 pels/VOP;
> f) If AC prediction is used, the following restriction applies : QP value
> shall not be changed within a VOP (or within a video packet if video
> packets are used in a VOP). If AC prediction is not used, there are no
> restrictions to changing QP value.
>
> Other than Level 0, Simple Profile does not specify maximum frame size. It
> does specify buffer sizes which would for example not let you do CIF in
> Level 1.
>
> Peter
> --
> Peter Haighton
> VideoSpheres Inc.
> 84 Hines Road
> Kanata, Ontario
> Canada, K2K 3G3
> Tel: (613) 270-9646 x3022
> Fax: (613) 271-9442
> email: peterh VideoSpheres.com
>
> See http://www.m4if.org for the latest on MPEG-4
>
> -----Original Message-----
> From: technotes-admin lists.m4if.org
> [mailto:technotes-admin lists.m4if.org]On Behalf Of Arcin Bozkurt -
> Archie
> Sent: Friday, August 17, 2023 9:37 AM
> To: technotes lists.m4if.org
> Subject: Re: [M4IF Technotes] Profile Level Visual Image size
>
>
> I may be missing something here.
> I have the MPEG-4 standard, but I haven't seen any Level 0 description.
> Where can I get this information?
>
> I was trying to understand whether the size either in x or y dimension
> was restricted to any value (as in the example you gave for SP L0)
>
> Peter's example mentions an image of size 352x72 which is larger than a
> QCIF for SP L1, but the max MB of 99 restriction is met.
>
> Arcin
>
> >>>>>>>
>
> Dear Arcin,
>
> you were not mentioning Simple Profile @ Level 0 which explicitly
> restricts
> the image size to Width <= 176 pel and Height <= 144 pel. This P L
> combination is used e.g for 3GPP mobile terminals.
>
> Best regards,
> Andreas
>
> ----------------------------------------------------------------------
> Dr.-Ing. Andreas Hutter
> Siemens AG, Corporate Technology
> CT IC 2 phone: +49 89 636-50417
> Otto-Hahn-Ring 6 fax: +49 89 636-51115
> 81730 Munich, Germany email: Andreas.Hutter mchp.siemens.de
> ---------------------------------------------------------------------
>
>
>
> Peter Haighton wrote:
>
> >Hello Arcin,
> >
> >The typical value means that this is what most implementations would
> >probably use SP L1 for, but you can use other strange and wonderful video
> >shapes if desired. For example 352x72 but I don't of an application that
> >would.
> >
> >So basically in real world scenarios you are correct that SP L1 would be
> >used for sizes up to QCIF.
> >
> >Peter
> >
> >-----Original Message-----
> >From: technotes-admin lists.m4if.org
> >[mailto:technotes-admin lists.m4if.org]On Behalf Of Arcin Bozkurt -
> >Archie
> >Sent: Friday, August 17, 2023 8:00 AM
> >To: technotes lists.m4if.org
> >Subject: [M4IF Technotes] Profile Level Visual Image size
> >
> >
> >
> >MPEG-4 is able to handle any size image with the information taken from
> >video_object_layer_width and
> >video_object_layer_height.
> >
> >
> >Does Simple Profile @L1 or L2 or L3 bring any restrictions to this?
> >
> >Annex N.1 (definition of Visual Profiles Levels), specifies a "typical"
> >size which is for example QCIF for Simple Profile @ L1. Does this mean
> >that SP L1 support image sized UP TO QCIF?? This is in line with the
> >MAXimum 99 MB per VOP restriction of SP L1.
> >
> >Can you please clarify this issue?
> >
> >Arcin Bozkurt
> >Lumic Electronics Inc.
> >
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