[Mp4-tech] Can a single Macro Block data extend over multiple video packets?

[Herbert Thoma]

Arun Menon schrieb:
> Hi,
> I am a little confused with your reply. Gary had said that there is no
> maximum or minimum size for video packets in MPEG4 ( I am asking with
> respect to Simple Profile). And Herbert, you are saying that the Level 2 of
> simple profile has a maximum video packet size of 4096 bits.
> I checked with the momosys code and in that there is no maximum or minimum
> size for video packet size.
>  	I request you to please clarify my doubt. Thanks in advance.

The reference software does not care very much about profiles and levels ...
Gary is right, as there are no technical restrictions to video packet size,
i.e. there is no syntax element that restricts the length of a video
packet.
I am right, because e.g. table N-1 of ISO/IEC 14496-2 lists maximum
video packet lenght for the levels of main, core, simple scalable and
simple profiles.
This is like the size of the video. The technical restriction of MPEG-4
part 2 here is 8191x8191 pixels but e.g. Simple Profile level 1 restricts
this to a maximum of 99 macroblocks.
Hope this helps,
  Herbert.
> Regards,
> Arun
> 
> 
> -----Original Message-----
> From: Herbert Thoma [mailto:tma iis.fhg.de]
> Sent: Monday, February 07, 2024 4:18 PM
> To: Arun Menon
> Cc: mp4-tech lists.mpegif.org
> Subject: Re: [Mp4-tech] Can a single Macro Block data extend over
> multiple video packets?
> 
> 
> Arun Menon schrieb:
> 
>>Hi All,
>>
>>I would really appreciate if somebody would answer my questions.
>>
>>1) In MPEG4 is it possible for a single macro block data to extend over
>>multiple video packets?
> 
> 
> No.
> 
> 
>>2) Is there a maximum or minimum size for video packets in MPEG4?
> 
> 
> Maximum size of video packets is restricted by levels, e.g. Simple Profile
> Level 2 has a maximum video packet size of 4096 bits.
> 
> Kind regards,
>   Herbert.
> 
> 
>>Thanks & Regards,
>>Arun Menon
>>
>>
>>
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> --
> Herbert Thoma
> Group Manager Video
> Multimedia Realtime Systems Department
> Fraunhofer IIS
> Am Wolfsmantel 33, 91058 Erlangen, Germany
> Phone: +49-9131-776-323
> Fax:   +49-9131-776-399
> email: tma iis.fhg.de
> www: http://www.iis.fhg.de/
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-- 
Herbert Thoma
Group Manager Video
Multimedia Realtime Systems Department
Fraunhofer IIS
Am Wolfsmantel 33, 91058 Erlangen, Germany
Phone: +49-9131-776-323
Fax:   +49-9131-776-399
email: tma iis.fhg.de
www: http://www.iis.fhg.de/