[M4IF Technotes] Flexibility in resolution in Video levels

[Peter Haighton]

Hello Ben,
With the exception of Simple Pofile Level 0 there is quite a bit of
flexibility in the way an image can look. So your examples of 256 x 96 and
1584 x 16 are both valid, though you might get some complaints if you
tried to show Ben-Hur on the later. :-)
As for 4:3, you certainly can make an image in 4:3 ratio with some of the
larger levels such as level 2 which would support 192x144 or even 320x240.
You can also find ratios (a bit harder) such as 128x96.
Peter
--
Peter Haighton
VideoSpheres Inc.
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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 Ben Waggoner
Sent: Thursday, November 08, 2023 3:25 PM
To: MPEG4 technical notes (E-mail)
Subject: [M4IF Technotes] Flexibility in resolution in Video levels
Folks,
    I may be horribly confused about this, so bear with me.  Working with
a
bunch of white papers instead of product can get rather confusing!
    When a video level defines a resolution, like Simple   Level 1 with
QCIF,
how much flexibilty is there in distribution of the pixels?  176x144 has
99
16x16 blocks.  I gather you can redistribute those blocks to provide a
different aspect ratio, within some limits.  So, would a 256x96 would be
allowable if one wanted to stream Ben-Hur?  Is there any upper limit to
this?  Presumably 1584x16 wouldn't be a viable format for mobile devices.
    Also, was there any particular reason why non 4:3 resolutions were
chosen?  192x144 would be a lot more useful for normal content.  Is the
assumption that the 176x144 would be aspect ratio corrected to 4:3 on
playback?
Ben Waggoner
Interframe Media <http://www.interframemedia.com>
Digital Video Compression Consulting, Training, and Encoding
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