[M4IF Technotes] brightness change for sprites

[Klaus Diepold]

Friends and comrades,
actually we have checked the MoMuSys Reference Code and found that the
brightness_change_factor parameter is decoded from an input bit stream but
not used in the decoding process. I guess that was not the original
intention, n'est pas ?
Cheers
Klaus
  -----Original Message-----
  From: technotes-admin   lists.m4if.org
[mailto:technotes-admin   lists.m4if.org]On Behalf Of axel.binder   philips.com
  Sent: Monday, November 19, 2023 10:54 AM
  To: technotes   lists.m4if.org
  Subject: [M4IF Technotes] brightness change for sprites
  Hi together,
  I have a question about the brightness_change_factor in 14496-2 Amd.1 in
chapter 7.8.6.
  In the spec this factor is defined for the Y channel for static sprite and
GMC sprite decoding, right?
  However in the reference code (14496-5 from ISO) I couldn't find it's
usage during decoding neither in the
  Microsoft nor in the MoMuSys implementation. It is encoded to the stream
and decoded from the bitstream
  but during sample reconstruction it is ignored.
  Now my question: Do I need to take care of this factor for a compliant
sprite decoder implementation
  or can it be ignored?
  Another question, is there anybody out there who sets this factor (to non
trivial values == 1) during encoding?
  regards
  axel binder
  =======================================================
  Axel Binder                                              Philips Starnberg
(SP3D)
  Development Manager Software    Petersbrunner Str. 17
D-82319 Starnberg, Germany
  phone:  +49 8151 270 108
  fax:         +49 8151 270 200
  mobile: +49 172 92 18 623
  e-mail: axel.binder   philips.com
  =======================================================
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/mp4-tech/attachments/20011122/81e1692a/attachment.html